JPH1118297A - Power system monitoring controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To calculate the time until the system becomes unstable as the evaluation index referring to stable time margin by computing the difference between the future time, when it is decided that the system will turn unstable based on the calculation result of computed voltage stability and the present time as the stability time margin. SOLUTION: A stability time margin computation means 7 outputs the difference between the further time, when the system will turn unstable and the present time as the stability time margin. In the case that the check result of a stability judging means 6 is 'stable', a future time deciding means 1 seeks the new future time and outputs it as the future time data 8. So long as the result of the stability judgment by the stability judging means 6 is 'stable', the operation processing by a power facility operation state deciding means 2, a future power system condition making means 3, a voltage stability calculating means 4, and a stability judging means 6 is repeated to the updated future time. The stability time margin at the present time is obtained by this series of processing, but the stability can be monitored by executing this in with a constant period fixed cycles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power system monitoring and control device, and more particularly to a power system monitoring and control device having stability time margin detecting means and instability avoiding means.

[0002]

2. Description of the Related Art Conventionally, a power system monitoring and control device evaluates the voltage stability of a power system, and evaluates the margin for the voltage stability of the power system up to the limit total demand at normal time or for each assumed accident. The demand margin is used as a margin, and this margin is used as an index.

FIG. 22 is a functional block diagram of a conventional power system monitoring and control apparatus for calculating a stability margin, and FIG.
FIG. 3 shows a flowchart thereof.

First, an outline of a conventional power system monitoring and control device will be described with reference to FIG.

[0005] The power system monitoring and control device of FIG. 22 includes a current system creating unit 31, a voltage stability calculating unit 4, and a stability margin calculating unit 36. Current system creation means 31
Calculates the power flow using the current power system data 38,
The current power system state data 39 is created. The voltage stability calculation means 4 calculates the voltage stability using the direct solution method (dP / dV method) of the voltage stability limit for the normal or assumed accident with respect to the current power system state data 39, and obtains the voltage stability calculation result data. 14 is output. The stability margin calculating means 36 converts the marginal total demand into the stability margin data 3e.
Output as

Next, a flow of each function of the apparatus shown in FIG. 22 will be described with reference to FIG. First, the current state of the power system, that is, the current power system is created by the current system creating means 31 (step S31), and the voltage stability calculation means 4 limits the voltage stability to the system state created here. The calculation is directly solved (so-called “dP / dV
Law. " The dP / dV method is described in, for example, Suzuki and Tanagi, “Direct Solution of Voltage Stability Limit of Power System”, IEICE B, 10
0, 895, (see 2-11)) to calculate the marginal total demand (step S3).
3). Next, the stability margin calculating means 36 calculates the stability margin (step S36). In the stability margin calculation step S36, the voltage stability calculation step S3
The margin up to the marginal total demand calculated in 3 is calculated as the stability margin, and the process ends.

Conventionally, the margin for the voltage stability has been evaluated using the stability margin thus obtained as an index. In that case, the future gross demand and future system status are predicted not only for the current system but also for the future system, the future marginal gross demand is calculated in the same manner as above, and the margin to the marginal gross demand is calculated as the stability margin. It was calculated as an amount and evaluated using it as an index.

The above prior art is described in detail in, for example, JP-A-2-55526, JP-A-2-55529, and JP-A-3-215125.

[0009]

As described above, the conventional voltage stability margin in the power system monitoring and control apparatus is based on the marginal total demand in the target power system state during normal or assumed accidents as an evaluation index. Was to be used. That is, the conventional calculation of the stability margin has been performed from the viewpoint of "how much more increase in total demand becomes unstable". In other words, the conventional method does not include the concept of time, and therefore, there is a problem that it is difficult to know how long after which time it becomes unstable.

Conventionally, the total demand is monitored so that the system does not become unstable, and if the total demand exceeds the limit total demand, measures such as performing reactive power control have been taken.

The present invention captures a time-series change in the state of the system from the present to the future, and can calculate the time until the system becomes unstable as an evaluation index of stability time margin. It is an object to provide a control device.

Further, according to the present invention, before the system becomes unstable, the reactive power control is performed in advance in consideration of the stability time margin and the required control time of the control target device, so that the power that can stabilize the system can be obtained. It is an object to provide a system monitoring and control device.

[0013]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, a future time is determined by accumulating and adding a time at a predetermined interval starting from the current time. Future time determining means, power equipment operating state determining means for determining the operating state of the power system at the determined time, future power system state creating means for creating a power system state based on the determined operating state, creation Voltage stability calculation means for performing voltage stability calculation on the determined future power system state, stability determination means for performing stability determination based on the calculated voltage stability calculation result, and when the stability determination means becomes unstable. The gist of the present invention is a power system monitoring and control device including a stability time margin calculating unit that calculates a difference between the determined future time and the current time as a stability time margin.

According to a second aspect of the present invention, in the power system monitoring and controlling apparatus according to the first aspect, when the stability determination result by the stability determining means is unstable, the power system becomes unstable. The present invention is characterized in that a reactive power control amount for avoidance is obtained, and an avoidance measure creating means for presenting an avoidance measure in consideration of the stability time margin and the control required time of the control target device is provided.

According to a third aspect of the present invention, there is provided a voltage stability calculating means for calculating a voltage stability based on a current power system state, and a voltage stability limit as a result of the voltage stability calculation by the voltage stability calculating means. Stability margin calculation means for calculating the marginal total demand power as a stability margin, and future time determination means for determining the future time by cumulatively adding the time at a predetermined interval starting from the current time. Power equipment operating state determining means for determining the operating state of the power system at the time, a future power system state creating means for creating a power system state including the total demand power based on the determined operating state,
The total demand power is compared with the stability margin, and the stability determining means for performing the total demand stability determination depending on whether the former is greater than the latter, and the total demand power is less than the stability margin by the stability determining means. And a stability time margin calculation unit that calculates a time from the current time to a future time point at which an unstable state is reached as a stability time margin.

According to a fourth aspect of the present invention, there is provided the apparatus according to the first aspect and the apparatus according to the third aspect.
A stability discrimination switching means for obtaining a stability time margin at a fixed cycle by the device, and switching from the device of claim 3 to the device of claim 1 when the stability time margin becomes a predetermined value or less. Is further provided.

According to a fifth aspect of the present invention, there is provided the power system monitoring and control apparatus according to the first aspect, wherein the voltage stability calculation result at the current time calculated by the voltage stability calculation means corresponds to the same time calculated in the past. A stabilization tendency judging means for judging whether or not the system stability is increasing by comparing the result of the voltage stability calculation of the system, and judging that the system stability is increasing by the stabilization tendency judging means. A time step width determining means for advancing the time step width for the future time determining means to a previously calculated stability time margin time.

According to a sixth aspect of the present invention, in the power system monitoring and controlling apparatus according to the first aspect, the generator for calculating the initial phase angle of the generator based on the future power system state created by the future power system state creating means. The initial phase angle calculation means and the generator initial phase angle calculated this time are compared with the generator initial phase angle calculated in the past, and when there is no significant change, the stability time margin calculation means is calculated by the stability time margin calculation means. And an initial phase angle comparing means for omitting the above processing.

According to a seventh aspect of the present invention, in the power system monitoring and control apparatus according to the first aspect, a demand maximum point calculating means for calculating a demand maximum time closest to the current time as a demand maximum point based on the predicted demand data; Second power equipment operating state determining means for creating maximum point system data at the calculated maximum demand point, and second future power system state creating means for creating a maximum point power system state based on the maximum point system data. A second voltage stability calculating means for calculating the voltage stability at the maximum demand point based on the state of the local maximum power system;
The stability is determined based on the voltage stability calculation result calculated by the voltage stability calculation means, and when it is determined that the voltage becomes unstable, the difference between the future time determined by the future time determination means and the current time is calculated as the stability. And a second stability determining means for allowing time.

According to an eighth aspect of the present invention, in the power system monitoring and control apparatus according to the seventh aspect, when the system at the maximum demand point is determined to be stable by the second voltage stability calculation means, the second future power A demand maximum point total demand calculation means for calculating a marginal total demand at the time when the time is returned at predetermined time intervals from the demand maximum point based on the output of the system state creation means, and the marginal total demand has a predetermined margin And a designated margin holding time calculating means for calculating the time from the current time to the time when the margin is held as the stability time margin.

The invention according to claim 9 is the invention according to claims 3 to 7
In the power system monitoring and control apparatus according to any one of the above, when the stability determination result by the stability determination means is unstable, the reactive power control amount for avoiding the power system from becoming unstable is determined. The present invention is characterized in that it comprises an avoidance measure creating means for presenting an avoidance measure in consideration of the stability time margin and the control required time of the controlled device.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) (Configuration of Embodiment 1) Embodiment 1 is an embodiment of the invention according to claim 1, and the configuration will be described with reference to FIG.

The illustrated power system monitoring and control apparatus 100 calculates a future time using the current time data 9 and the time interval data 10 and outputs it as future time data 8; A power facility operating state determining means for determining an operating state of the power equipment at a time determined by the future time determining means using the power system state data and outputting the operating state as future power system data; A future power system state creating means 3 for creating the generated power system state and outputting it as future power system state data 13, and calculating the voltage stability for the created future power system state at normal, assumed, or normal and assumed accidents And outputs the voltage stability calculation result data 14 as voltage stability calculation result data 14; A stability determination means 6 for performing stability determination based on the stability calculation result, and a stability which calculates a time until the system voltage becomes unstable as a stability time margin from the current time and outputs the time as stability time margin data 16. Degree time margin calculating means 7.

(Operation of the First Embodiment) The operation of the first embodiment will be described with reference to FIGS. 1, 2, and 3. FIG. Consider the power system at the current time Tp. The future time determination means 1 determines the current time Tp given as the current time data 9
Time step width Δ given as time step width data 10
ΔT is added for each T to advance the time, and a future time Tf = Tp + n · ΔT to be calculated is calculated and determined as a result of the cumulative addition (FIG. 2: Step 101). Where n · Δ
When T = ΔH, n = 0, 1, 2,..., M
Is 0. m · ΔT is a preset upper limit of the stability time margin. Power equipment operating state determination means 2
Using the current power system state data 15 received as on-line transmission data from the local power equipment and the schedule data 11 set as fixed data in advance or set as variable data by input from the screen,
The future power system state, which is the operating state of the power equipment at the current time Tp and the future time Tf, is determined, and the future power system data 1 is determined.
2 is output (step 102). The current power system state data 15 is data of the connection state of the system, and is output as it is as future power system state data.

As shown in FIG. 3, the schedule data 11 taken into the power equipment operation state determining means 2 includes:
In addition to the total load demand forecast data 11b, the generator data 11
c, transformer tap setting data 11d, phase setting data 1
1e, etc., and how the power equipment operating state determining means 2 determines the future power system data 12 using these data will be described.

First, from the total load demand forecast data 11b,
The time Tf determined by the future time determining means 1 = (Tp + n ·
Active power and reactive power at ΔT) are determined. First, from the total load demand forecast data 11b for one day, the time Tf
At the time Tf at the time Tf, taking out the total demand data at the time Tf, and setting the data as fixed data in advance, or as variable data by input from the screen, as variable data for each load set for each load. Determine the active power. Then, according to the reactive power to active power ratio, that is, the Q / P ratio, which is set in advance as fixed data or set as variable data by input from a screen,
Determine the reactive power of the load.

Next, the active power and voltage of the generator at the time Tf determined by the future time determining means 1 are determined from the active power of the load determined above and the generator data 11c. Using the active power of the load at time Tf, the generator output of each generator is calculated by economic load distribution calculation by the equal incremental fuel cost method. The calculation of the economic load distribution by the equal incremental fuel cost method is a known technique, and a detailed description thereof will be omitted. Further, the generator voltage at the time Tf is extracted from the reference voltage of the automatic voltage regulator (AVR) for each generator which is set in advance as fixed data or set as variable data by input from a screen.

Next, whether it is set as fixed data in advance,
Alternatively, the data at the time Tf is extracted from the transformer tap setting data 11d which is the operating data of the transformer tap of the day set as variable data by input from the screen, and the tap position of each tap at the time Tf is determined. . Finally, the data at the time Tf is extracted from the phase setting data 11e which is the operation data of the phase of the day, which is set in advance as fixed data or set as variable data by input from the screen, and The input amount of each phase of Tf is determined.

The future power system state creating means 3 outputs the time Tf
, The power flow is calculated based on the future power system data 12 in step (a), the voltage and phase angle of each node after the time interval ΔT are obtained, and the future power system state data 13 is created (step 103). The voltage stability calculation means 4 calculates the total demand that is the voltage stability limit for the created future power system state data 13 and the normal power, the assumed accident, or the normal and assumed accident for the future power system state data 13. The stability demand is calculated by a direct solution method (dP / dV method), and the total demand is set as a limit total demand value, which is output as voltage stability calculation result data 14 (step 104). dP / dV
The method is a known technique, and a detailed description thereof will be omitted. Voltage stability calculation can be performed multiple times with multiple assumed accidents, but for simplicity of explanation here,
Description will be given assuming one assumed accident.

Next, the stability determination means 6 determines whether or not the marginal total demand value has been calculated based on the voltage stability calculation result data 14. If not, it is determined to be "unstable" (step 10).
5). In the case of "stable", step 101 for determining the future time
Proceed to. In the case of "unstable", stability time margin calculating means 7
To the stability time margin calculation. The stability time margin calculation means 7 outputs the difference ΔH (= Tf−Tp) between the future time Tf, which is the time at which the time becomes unstable, and the current time Tp as the stability time margin (step 106). If the check result of the stability determination means 6 is "stable", the future time determination means 1
Updates n as n = n + 1, finds a new future time Tf = Tp + n · ΔT based on the updated n,
Output as future time data 8.

As long as the result of the stability determination by the stability determination means 67 is "stable", the power equipment operation state determination means 2, the future power system state creation means 3, the voltage stability calculation for the updated future time Tf. Means 4 and stability determination means 6
Is repeated (steps 101 to 104).

The stability time margin at the current time Tp is obtained by the above series of processing.
(Every 5 minutes), it is possible to monitor the stability of the power system that changes every moment. For example, it is assumed that the stability time margin obtained at the current time Tp = 0: 0 is as shown in Table 1.

[0033]

[Table 1] The stability time margin in this case is a time until the system voltage becomes unstable, and is 1 hour and 15 minutes.
When the result at the time 0:15, which is the next cycle, is shown in Table 2, the stability margin is one hour.

[0034]

[Table 2] In this embodiment, the generator output calculated by the economic load distribution calculation by the equal incremental fuel cost method is used, but the generator output calculated by another distribution method, for example, the optimal power flow calculation by the secondary programming method. Can also be used. Also, AVR reference values and tap schedule data,
For the phase adjustment schedule data, a reference value determined based on the reactive power / voltage control method can be used.

(Effects of the First Embodiment) According to the first embodiment, the time until the system becomes unstable is captured by capturing the time-series change of the margin regarding the stability from the present to the future. Since it is calculated as an evaluation index of stability time margin, it is possible to easily evaluate the stability in consideration of a change in daily demand.

(Embodiment 2) (Structure of Embodiment 2) Embodiment 2 is an embodiment of the invention according to claim 2, and its structure will be described with reference to FIG.

The power system monitoring and control device 110 shown in FIG.
In addition to the power system monitoring and control device 100 described with reference to FIG. 1, when the stability determination result is unstable, an avoidance measure is determined in consideration of the control required time of the control target device, and the avoidance measure data 2
2 is provided. In the power system monitoring and control device 100 of FIG. 1, when the result of the stability determination by the stability determination unit 6 is “unstable”, the stability time margin data 16 at the current time is output. In addition, the avoidance measure creating means 21 creates avoidance measure data 22 and presents the operator with an unstable avoidance measure as a stabilization measure. Here, as an avoidance measure, an example of a measure for avoiding the instability of the power system by controlling the input amount of the reactive power adjustment equipment (SC) will be described.

The detailed functional configuration of the avoidance measure creating means 21 will be described with reference to FIG.

In the avoidance measure creating means 21 shown in FIG.
First, the SC input target substation extraction means 21a outputs the output of the SC input substation at a future time when the stability determination means 6 (FIG. 1) determines that the substation is unstable.
Extract as 1h. At the time of extraction, an SC whose required control time of the SC to be controlled is within the stability time margin calculated by the stability time margin calculation means 7 is selected.

Next, the post-control output calculating means 21b calculates the post-control output 21j from the control amount 21i by the following equation.

Qai = Qbi + Qsi Here, Qai: Control input of substation i subject to SC input Qbi: Control input of substation i subject to SC input Qsi: Control quantity of substation i subject to SC input System state after control The creating unit 21c performs a power flow calculation using the calculated post-control output 21j, obtains the voltage and phase angle of each node of the system, and creates the post-control system state 211.
The voltage stability calculation means 4 detects the system state 2 after the output suppression control.
The voltage stability calculation is performed for the normal time, the assumed accident, or the normal time and the assumed accident with respect to 1 l, and is output as the voltage stability calculation result data 14. The voltage stability calculation can be performed a plurality of times with a plurality of assumed accidents. However, in order to simplify the description, the description will be made assuming one assumed accident.

The stability judging means 21e uses the voltage stability calculation result data 14 to control the controlled PV (power-voltage).
Check if the total demand, which is the voltage stability limit of the curve, exceeds the operating point. If it exceeds, it is determined as “stable”, and if not, it is determined as “unstable”. In the case of "unstable", the process proceeds to the control amount changing means 21f. "Stable"
In the case of, the process proceeds to the control amount calculating means 21g.

If the stability determination result is "unstable", the control amount changing means 21f changes the control amount 21i, and the post-control output calculating means 21b, the post-control system state creating means 21c, and Voltage stability calculation means 21
Each calculation processing by d is repeated.

The control amount 21i is changed by setting an initial value and a change step width in advance. For example, when the initial value is 0 and the change step size is 1.0 (Mvar), the values are sequentially changed to 0, 10, 20, and 30.

When the stability determination result is "stable", the control amount calculating means 21g calculates the control amount 21n by the following equation.

ΔQai = Qbi−Qai Here, ΔQai: control amount of substation i for SC input Qbi: input amount before control of substation i for SC input Qai: input amount after control of substation i for SC input

(Operation of Embodiment 2) Future time determination means 1, power equipment operation state determination means 2, future power system state creation means 3, voltage stability calculation means 4, stability determination means 6, shown in FIG. The flow up to the stability time margin calculation means 7 is the same as that described in the first embodiment, and the description of steps 101 to 106 for executing that part is shown in FIG.
Are duplicated with the description of steps 101 to 106 in FIG. After the stability time margin is calculated by the stability time margin calculation means 7 (FIG. 1), an avoidance measure is created by the avoidance measure creation means 21 shown in FIGS. An SC input control amount for an unstable system state at a future time is calculated (step 111).

(Effect of Second Embodiment) According to the second embodiment, not only the effect of the first embodiment by calculating the stability time margin but also the case where the stability judgment result by the stability judgment means 21e is unstable is obtained. Since the instability avoidance measure is created, a stabilization measure can be taken in consideration of the required control time of the controlled device.

(Third Embodiment) (Structure of Third Embodiment) The structure of the third embodiment will be described with reference to FIGS.

The power system monitoring and control apparatus 120 according to the third embodiment is a
In addition to the power equipment operating state determination means 2, the future power system state creation means 3, and the stability time margin calculation means 7, a current power system state creation means 31 for creating a current power system state,
Voltage stability calculation means 33 for performing voltage stability calculation for the system state created here at normal time, at the time of an assumed accident, or at the time of normal and assumed accidents, a stability margin for calculating the marginal total demand as a stability margin Amount calculating means 36,
And a stability determining means 37 for performing stability determination by comparing the stability margin, which is the marginal total demand, with the monitoring point total demand in the future power system state.

(Operation of Third Embodiment) The operation of the third embodiment will be described with reference to FIGS.

The arithmetic processing stage of the third embodiment includes a first stage for obtaining a marginal total demand at the current time and a second stage for obtaining a stability time margin. First, the first stage will be described. The same reference numerals as those in FIG. 1 indicate the same elements.

The current power system state creating means 31 performs a power flow calculation based on the current power system state data 15 at the current time, obtains the voltage and phase angle of each node, and creates the current power system state data 39 ( Figure 8: Step 12
1). Next, the voltage stability calculation means 33 performs the voltage stability calculation on the created current power system state data 39 at the normal time, at the time of the assumed accident, or at the time of the normal and the assumed accident, and calculates the voltage stability calculation result data 14. Output (step 122). The voltage stability calculation may be performed a plurality of times with a plurality of assumed accidents. However, in order to simplify the description, the explanation will be given on the assumption that the number of assumed accidents is one. Proceeding to the stability margin calculating means 36, assuming that the marginal total demand is 1300 MW,
A stability margin having W as a content is calculated, and stability margin data 3e is output (step 123). This is the first
It is a stage.

Next, the stability margin data 3 obtained above
Finally, a second step of performing stability determination by the stability determination means 37 using e and obtaining a stability time margin will be described.

The second stage processing for obtaining the stability time margin is different from that of the first embodiment in that the voltage stability calculating means 4 is not used here and the stability determining means different from the stability determining means 6 is used instead. 37 is used. Determination of future time by future time determination means 1 (step 10
1), power equipment operation state determination by the power equipment operation state determination means 2 (step 102), and future power system state creation by the future power system state creation means 3 (step 10)
3) is the same as that of FIG. 1 and the description of their individual actions is omitted.

The stability judging means 37 outputs the stability margin 3e,
And the future power system state data 13, and compares the stability margin 3 e with the total power demand at the future time Tf starting from the current time Tp.
Is determined to be "unstable" when it exceeds the threshold value, and is determined to be "stable" otherwise (step 124). If the result of the determination is "stable" in the stability determining means 37, the future time determining means 1 performs a future time determining process (step 101). The future time determination means 1 adds the time step size ΔT to the future time Tf to advance the time by ΔT,
The result of the addition is updated and output as a new future time Tf,
A series of processes of steps 101, 102, and 103 are repeated.

If the result of the determination made by the stability determining means 37 at step 124 is "unstable", the stability time margin calculating means 7 outputs the stability time margin data 16 representing the time difference ΔH = Tf-Tp. Is output (step 125).

(Effect of Third Embodiment) According to the third embodiment, the total demand forecast is used instead of the voltage stability calculation, and the number of times of the voltage stability calculation is reduced, so that the effect of the first embodiment is maintained. However, it is possible to reduce the calculation processing time in comparison with the above.

(Embodiment 4) (Configuration of Embodiment 4) The configuration of Embodiment 4 will be described with reference to FIG.

The power system monitoring and control apparatus 130 shown in FIG. 9 includes, in addition to the apparatus 100 shown in FIG. 1 and the apparatus 120 shown in FIG. 7, a stability time margin storage means 44 for storing the calculated stability time margin.
And stability determining means switching means 41 for switching from the device 120 to the device 100 when the stability time margin falls below a certain value.

(Operation of Embodiment 4) FIGS. 9 and 10
The overall operation of the fourth embodiment will be described with reference to (flow chart). Here, the stability determination means switching means 4
1 determines whether to use the device 100 of FIG. 1 or the device 120 of FIG. 7 using the current time Tp, the switching set value data 42, and the previously calculated stability time margin data 43, The processing by the device 120 in FIG. 7 is executed. More specifically, the stability determining means switching means 41 checks whether or not the previously calculated stability time margin is smaller than the switching set value (step 131).
0 is executed (step 132), and if not small (large), the processing of the device 120 is executed (step 133) and the stability time margin obtained in each step is stored in the stability time margin storage means. 44 (step 134). The stability time margin storage means 44 is the same as that shown in FIG.
The stability time margin calculated by the device 100 of FIG. 7 or the device 120 of FIG. 7 is output as the previously calculated stability time margin storage data 43.

The above series of processing is performed at a constant cycle (for example, 15
(Every minute), it is possible to monitor the stability of the power system that changes every moment.

FIG. 11 is a flowchart showing the operation of the stability determining means switching means 41. First, it is determined whether or not the previously calculated stability time margin 43 obtained as a result of the calculation at the time of the previous execution in the execution of the process in the fixed cycle has been calculated (step 141). If the previously calculated stability time margin 43 has not been calculated, the apparatus 1 of FIG.
20 is set (step 142), and the process ends. If the stability time margin storage data 43 has been calculated, it is determined using the stability time margin storage data 43 and the switching setting value data 42 whether or not stability time margin> switching setting value (step 143). If the above is satisfied, the apparatus 120 of FIG. 7 is set as the discriminating means (step 144). Otherwise, the device 100 of FIG.
Is set (step 145). Here, the switching set value is set in advance, and it is assumed that the setting is made from several minutes to several tens of minutes in accordance with the execution cycle of a fixed cycle and the system characteristics of the calculation target system.

In this way, the stability determining means switching means 41
Switches the stability determination means. That is, if there is a time until the device becomes unstable, the stability time margin is obtained by the device 300 of FIG. 7, and if the time of the instability approaches, the stability time margin is obtained by the device 100 of FIG.

(Effects of the Fourth Embodiment) According to the fourth embodiment, since the stability determining means is switched by the stability determining means switching means 41, the calculation time is always shortened by the device 120 to obtain the stability time margin. When the time becomes unstable, the stability time margin can be obtained with high accuracy by the apparatus 100.

(Fifth Embodiment) (Structure of Fifth Embodiment) The structure of the fifth embodiment is shown in FIG.
This will be described with reference to FIG. This power system monitoring and control device 150
Is a voltage stability calculation result storage means 51 for storing the minimum value of the marginal total demand as a voltage stability calculation result, in addition to the apparatus 100 of FIG. 1, a voltage stability calculation result at the current time and a prediction calculation in the past. Stabilization tendency determining means 52 for determining whether or not the stability is increasing from the voltage stability calculation result at the same time using the minimum value of the marginal total demand as a stability evaluation index.
And a stability time margin storing means 44 for storing the calculated stability time margin, and a time step width determining means 54 for increasing the time step width ΔT when the stability of the system is increasing.

(Operation of Fifth Embodiment) The operation of the fifth embodiment will be described with reference to FIGS. 12 and 13 (flowchart). FIG. 1 shows an apparatus 100 including a future time determining means 1, a power equipment operating state determining means 2, a future power system state creating means 3, a voltage stability calculating means 4, a stability determining means 6, and a stability time margin calculating means 7. These are the same as those shown, and the description of their individual operations is omitted. These processing blocks are shown as steps 101-105.

Assume that the processing is first executed at time 0:00, assuming execution processing every 15 minutes in a fixed cycle. Table 3 shows the calculation results of the device 100 at this time. Here, the mark ○ indicates that the calculation by the voltage stability calculating means 4 is executed for the time. Time step width ΔT for determining future time
Is 15 minutes.

[0069]

[Table 3] The stability time margin storage unit 44 stores the stability time margin data 16 representing the stability time margin calculated by the stability time margin calculation unit 7 (step 106) as the stability time margin storage data 43 (step 153). ). Further, the voltage stability calculation result storage unit 51 stores the data 14 relating to the voltage stability calculation result calculated by the voltage stability calculation unit 4 as the minimum value of the marginal total demand as the voltage stability calculation result storage data 55. In the example of Table 3, the stability time margin of 1 hour and 15 minutes is stored, and the minimum value of the total limit demand at each time is stored together with the time.

The stabilization tendency determining means 52 calculates the voltage stability calculation result 14 at the current time and the marginal total demand minimum value obtained from the voltage stability calculation result storage data 55 and calculated in the past at the same time. The time interval determining means 54 determines the time interval ΔT according to the result (step 155), and sends it to the future time determination determining means 1.

A series of operations will be described with reference to the above specific example.

When the current time (data 10) becomes 0:15 and the stability time margin (data 16) is obtained again by execution at a constant cycle, the voltage stability calculation result (data 14) at the current time is used. At this time, the minimum value of the marginal total demand is 920 MW, which is compared with the calculation result at the same time predicted by the stabilization tendency determining means 52 from the voltage stability calculation result storage data 55 at 0 o'clock, ie, 900 MW. Here, the result at the current time is large, and it can be said that the stability tends to decrease.
, And returns to the future time determination means 1 to proceed to the next execution time of 0:30.

The future time determining means 1, the power equipment operating state determining means 2, the future power system state creating means 3, the voltage stability calculating means 4, the stability determining means 6, and the stability time margin calculating means 7 included in the apparatus 100. Processing (step 101)
To 106), and the prediction calculation at 0:30 is performed. As a result, the minimum limit total demand is 980 MW, and the stability tendency determining means 52 compares the saved minimum demand with the stored result at the same time. Is determined to be increasing. Therefore, if the result calculated in the past is stable, it is considered to be stable even now. The time step size determining means 54 executes step 1
At 55, the time interval (data 10) is increased so that the process proceeds to an unstable time calculated and stored in the past. In this example, the process is advanced until 1:15. Similarly, when the calculation is performed at 1:15, the minimum value of the total demand becomes unstable at 1330 MW. Therefore, the stability time margin calculation means 7 sets the stability time margin (data 16) to ΔH = 1.
A time (difference between the current time 0:15 and the future time 1:15) is set, and the stability time margin storage means 44 outputs the data as stability time margin storage data 43. 0 described above
Table 4 shows the calculation results at 15 minutes.

[0074]

[Table 4] As a criterion for determining the tendency to be unstable, the fifth embodiment
Then, the minimum total demand minimum value Sold calculated at the same time in the past is compared with the minimum total demand minimum value Snew currently calculated at the same time. If Snew> Sold, it is determined that the stability is more unstable. This may be determined by the following equation, and the determination constant ε may be set according to the characteristics of the target system. Snew-Sold> ε

(Effect of Fifth Embodiment) According to the fifth embodiment, the tendency of the increase / decrease of the system stability is determined using the previously calculated voltage stability calculation result, and the stability increases. If there is a tendency, the time interval is increased, so that the voltage stability calculation is efficiently performed in the calculation of the stability time margin, and as a result, the calculation processing time can be reduced.

(Sixth Embodiment) (Structure of Sixth Embodiment) The structure of the sixth embodiment is shown in FIG.
This will be described with reference to FIG. Power system monitoring and control device 1 of FIG.
Reference numeral 60 denotes an initial phase angle storage unit 61 for storing the initial phase angle of the generator terminal voltage as a voltage stability calculation result in addition to the apparatus 100 of FIG. Generator initial phase angle calculating means 62 for calculating the phase angle of the generator, and initial phase angle comparing means 63 for comparing the calculated generator initial phase angle with the generator initial phase angle at the same time stored in the past. I have.

(Operation of the Sixth Embodiment) The operation of the sixth embodiment will be described with reference to FIGS. 14 and 15 (flowchart).

The future time determining means 1, the power equipment operating state determining means 2, the future power system state creating means 3, the voltage stability calculating means 4, the stability determining means 6, and the stability time margin calculating means 7 included in the apparatus 100. Are the same as those described with reference to FIG. 1, and the description of the operation will be omitted.

Here, the initial phase angle storage means 61 uses the phase angle of each generator terminal voltage, which is the voltage stability calculation result (data 14) created by the voltage stability calculation means 4, as the initial phase angle storage data 65. save. The generator initial phase angle calculating means 62 calculates the future power system state (data 1
Based on 3), the voltage stability calculation is performed only at the initial time, and the initial phase angle of the generator terminal voltage is calculated (step 161). The phase angle of the terminal voltage is determined depending on the initial state of the system for which the stability calculation is to be performed. It can be said that the degree has not changed. Therefore, the initial phase angle comparing means 63 compares the generator terminal voltage phase angle with respect to a certain time and the generator initial phase angle at the same time calculated in the past extracted from the phase angle storage data 65 created above ( Step 162) If the following equation is satisfied, that is, it is determined whether or not the current time has not reached the time of the stability time margin calculated in the past (step 163). The result is adopted, and the processing returns to the processing of the future time determining means 1 without performing the arithmetic processing of the voltage stability calculating means 4 at that time.
Calculate the next execution time.

Where δ1: generator terminal voltage phase angle at the same time extracted from voltage stability calculation result data 14 δ2: generator terminal voltage initial phase angle calculation means 61 Generator terminal voltage initial phase angle ε: Judgment constant Σ: Total for all generators.

Here, it is assumed that the determination constant is set according to the characteristics of the system object.

If it is determined in step 163 that the current time has a margin of stability time calculated in the past, the process ends.

If there is a change in the generator initial phase angle in step 162, the voltage stability calculating means 5
(Step 10)
4) In the initial phase angle storage means 62, a new initial phase angle is stored from the result (step 164). Next, the stability calculation unit 6 determines the stability calculation result (step 105). If stable here, future time determination means 1
(Step 101), and if unstable, a stability time margin calculation process (Step 106) is performed, and stability time margin data is output.

The above series of processing is performed at a constant cycle, and a stability time margin is obtained using the stability time margin and the initial phase angle calculated in the past.

(Effects of the Sixth Embodiment) According to the sixth embodiment, the stability time margin is normally obtained by the apparatus 100 of FIG. 1, but the phase angle of the generator terminal voltage was calculated in the past at the current time. If the phase angle has not changed significantly compared to the phase angle, it is assumed that there is no large change in the system state and the voltage stability does not change, and the calculation of the stability time margin again is omitted. Therefore, it is possible to reduce the calculation time when obtaining the stability time margin.

(Seventh Embodiment) (Structure of Seventh Embodiment) The structure of the seventh embodiment is shown in FIG.
This will be described with reference to FIG. Power system monitoring and control device 1 of FIG.
A substantial feature 70 is that, in addition to the apparatus 100 of FIG. 1, a demand maximum point calculating means 71 for taking in forecast demand data and calculating a maximum point of the forecast demand is provided. Power equipment operation state determination means 72, future power system state creation means 7
3. Voltage stability calculation means 74 and stability determination means 76
Has the same configuration and function as each of the means 2, 3, 4, and 6 having the same name, but the former differs from the latter in that it handles data at the maximum demand point.

(Operation of the Seventh Embodiment) The operation of the seventh embodiment will be described with reference to the flowchart of FIG.

The demand maximum point calculating means 71 calculates the demand maximum point closest to the current time by using the predicted demand data 70, and uses the time as the maximum point time to obtain the maximum point time data 75.
Is output (step 171). With respect to the maximum point time data 75, the power equipment operating state determining means 72 determines the power equipment operating state of the maximum point based on the schedule data 11, and creates the maximum point system data 77 (step 17).
2), the future power system state creation means 73 creates the maximum point power system state data 78 (step 173), and the voltage stability calculation means 74 outputs the voltage stability calculation result data 79 of the maximum demand point (step 174). ). The operation of each of these means is that only the future time data 8 in FIG. 1 is changed to the maximum point time data 75, and the substantial operation of both is not changed at all.

The stability judging means 76 judges the stability at the maximum demand point based on the voltage stability calculation result (data 78) calculated as described above (step 175). If it is stable, the process ends. If it is unstable, the following process is performed.

When the stability of the system at the maximum demand point is unstable, the time is returned to the point where the system becomes stable, and the stability time margin is calculated from the time and the current time. In the apparatus 100 of FIG. 1, the maximum point time (data 75) is set as the initial value of the future time determination means 1, and the time interval (data 1) is set.
0) is a negative value. Thereby, the future time setting means 1 returns the time from the maximum point time to the current time (data 9) (step 176). Hereinafter, the steps 103 and subsequent steps in FIG. 2 are executed, and the stability time margin calculating means 7 obtains a time at which the stability becomes stable retroactively from the time of the maximum demand point at which the stability is unstable, as the stability time margin. Then, the difference between the time when the current time becomes and the current time is output as stability time margin (data 16) (step 106).

The operation of the other means is the same as that described with reference to FIGS. 1 and 2, and the description thereof will not be repeated.

(Effects of the Seventh Embodiment) According to the seventh embodiment, the stability time margin is obtained based on the maximum demand point, thereby focusing on the point of the maximum demand point in the change of daily demand. Stability evaluation can be performed.

(Eighth Embodiment) (Structure of Eighth Embodiment) The structure of the eighth embodiment is shown in FIG.
This will be described with reference to FIG. The power system monitoring and control apparatus 180 according to the eighth embodiment is different from the power system monitoring and control apparatus 170 in FIG. 16 in the power system state at the maximum demand point in the normal state, at the time of the assumed accident, or the limit between the normal time and the assumed accident. A demand maximum point limit total demand calculation means 81 for obtaining the total demand; and a designated margin amount for returning the time from the time of the demand maximum point and calculating a difference between a time satisfying a preset margin amount and the current time as a stability time margin. The holding time calculation means 82 is added.

(Operation of the Eighth Embodiment) The operation of the eighth embodiment will be described with reference to the flowchart of FIG. In FIG. 19, blocks corresponding to the processing in FIG. 17 are denoted by the corresponding reference numerals, and the individual description is omitted. Here, when the stability is determined by the stability determining means 76 of the device 170 in FIG. 16 at the maximum demand point, the demand maximum point limit total demand calculating means 81 and the designated margin holding time calculating means 82 operate. I do.

Before the description of the apparatus 180, first, the local maximum demand point limit total demand calculating means 81 will be described. FIG.
0 represents the function of the maximum demand point limit total demand calculation means 81 in the form of a flowchart.

In the third embodiment (FIGS. 7 and 8), the processing for obtaining the marginal total demand at the time of the normal system, at the time of the assumed accident, or at the time of the normal and the assumed accident with respect to the current system state has been described. Then, the limit total demand is determined for the state of the maximum demand point (FIG. 19: Step 181).
Voltage stability calculation means 74 and stability margin calculation means 36
The operation is as described in the third embodiment, except that the state of the maximum demand point is targeted. The designated margin total demand calculating means 81a calculates a difference between the stability margin (data 3e) calculated by the stability margin calculating means 36 and a preset designated margin (data 81b), and calculates the designated margin. Output as total demand (data 83) (Step 1)
82). For example, the stability margin (data 3e) is 100
0 MW, and the designated margin (data 81b) is 200M
If W, the designated margin total demand (data 83) is 8
00 MW.

Next, the function of the designated margin holding time calculating means 82 will be described with reference to FIG. In the third embodiment, future time (data 8) based on the current system state
The process of calculating the total demand for the system status of
Here, the time is returned from the time of the maximum demand point, and the total demand at that time is obtained. The future time determination means 1, the power equipment operation state determination means 2, the future power system state creation means 3, and the stability time margin calculation means 7 set a negative value as the time step width starting from the time of the maximum demand point. The operation is as described in the third embodiment, except that the time is returned by

The stability discriminating means 82a calculates the total demand of the future power system state (data 13) by the designated margin total demand (data 8).
Compared with 3), if the former is smaller than the latter, the process proceeds to the stability time margin calculating means 7 as stable. If the former is larger than the latter, the process returns to the future time determining means 1 as unstable. The stability time margin calculation means 7 outputs a difference between the time at which the stability becomes stable and the current time as a stability time margin (data 16).

In the above example, since the designated margin total demand (data 83) is 800 MW, the total demand value is 800 M
If it is larger than W, it is unstable, and if it is smaller than W, it is stable.
If the difference between the stable time and the current time is one hour, the stability time margin (data 16) is one hour.
It means that you can keep the margin of W. (Effect of Embodiment 8) According to Embodiment 8, in addition to the effect of the method of Embodiment 7 performed when the system is unstable at the point of maximum demand, in the case of stability, Calculate the marginal total demand at the normal time, at the time of the assumed accident, or at the time of the normal and the assumed accident, return the time until the preset margin is satisfied, create the forecast state, and retain the preset margin Since the stability time margin from the current time is calculated, the stability evaluation can be performed by focusing on the point of the maximum demand point in the change of daily demand.

(Ninth Embodiment) (Configuration of Ninth Embodiment) A ninth embodiment will be described with reference to FIGS.
In addition to the configuration of the third embodiment shown in FIG.
If the result of the stability determination is unstable, there is provided an avoidance measure creating means 21 for creating the avoidance measure data 22 in consideration of the required control time of the device to be controlled.

(Operation of the Ninth Embodiment) As shown in FIGS. 7 and 8, in the third embodiment, the stability time margin calculating means 7 is used.
When the stability time margin is obtained by the above, if the stability determination result is “unstable”, the stability time margin data 16 at the current time is output. In the ninth embodiment described here, in addition to this, The avoidance measure creating means 21 creates the avoidance measure data 22 in consideration of the control required time of the control target device, and presents a stabilization measure to the operator. The operation of the avoidance measure creating means 21 is as described in the second embodiment (FIGS. 4 to 6). (Effects of the Ninth Embodiment) According to the ninth embodiment, not only the effect of the third embodiment by calculating the stability time margin is exerted, but also an avoidance measure is created when the stability determination result is unstable. In addition, stabilization measures can be taken in consideration of the required control time of the control target device.

(Tenth Embodiment) (Structure of Tenth Embodiment) A tenth embodiment will be described with reference to FIGS.
In addition to the fourth embodiment shown in FIG. 1, when the stability time margin is obtained by the stability time margin calculating means 7 and the stability determination result is “unstable”, the control required time of the control target device is reduced. It is provided with an avoidance measure creating means 21 for creating the avoidance measure data 22 considered.

(Operation of the Tenth Embodiment) As shown in FIGS. 9 to 11, in the fourth embodiment, when the stability determination result is “unstable”, the stability time margin at the current time (data 16) is output, but the tenth embodiment described here is used.
Then, in addition to this, the avoidance measure creating means 21 creates the avoidance measure data 22 in consideration of the required control time of the control target device, and presents a stabilization measure to the operator. The operation of the avoidance measure creating means 21 is described in the second embodiment shown in FIGS.
As described in the above.

(Effect of Embodiment 10) Embodiment 10
According to the above, not only the effect of the fourth embodiment by calculating the stability time margin is exerted, but also a countermeasure is created when the stability determination result is unstable. Stabilization measures taking time into account can be taken.

(Eleventh Embodiment) (Configuration of Eleventh Embodiment) In the eleventh embodiment, in addition to the fifth embodiment shown in FIG. 12 and FIG. When the stability determination result when the allowance is obtained is “unstable”, there is provided an avoidance measure creating unit 21 that creates avoidance measure data 22 in consideration of the control required time of the control target device.

(Operation of Embodiment 11) FIGS. 12 and 1
As shown in FIG. 3, in the fifth embodiment, the stability time margin data 16 at the current time is output when the stability determination result by the stability time margin calculation means 7 is “unstable”. In the eleventh embodiment, in addition to this, the avoidance measure creating means 21 creates the avoidance measure data 22 in consideration of the control required time of the control target device, and presents the stabilization measure to the operator. The operation of the avoidance measure creating means 21 is described in FIGS.
This is as described in the second embodiment shown in FIG.

(Effect of Embodiment 10) Embodiment 11
According to the above, not only the effect of the fifth embodiment by calculating the stability time margin is exerted, but also, if the stability determination result is unstable, an avoidance measure is created. Stabilization measures taking time into account can be taken.

(Twelfth Embodiment) (Structure of the Twelfth Embodiment) In the twelfth embodiment, in addition to the sixth embodiment shown in FIG. 14 and FIG. When the stability determination result when the allowance is obtained is “unstable”, there is provided an avoidance measure creating unit 21 that creates avoidance measure data 22 in consideration of the control required time of the control target device.

(Operation of Embodiment 12) FIGS. 14 and 1
As shown in FIG. 5, in the sixth embodiment, when the stability determination result by the stability time margin calculation means 7 is “unstable”, the stability time margin data 16 at the current time is output. In the twelfth embodiment, in addition to the above, the avoidance measure creating means 21 creates the avoidance measure data 22 in consideration of the required control time of the control target device, and presents a stabilization measure to the operator. The operation of the avoidance measure creating means 21 is described in FIGS.
This is as described in the second embodiment shown in FIG.

(Effect of Embodiment 12) Embodiment 12
According to the above, not only the effect of the sixth embodiment by calculating the stability time margin is exerted, but also a countermeasure is created when the stability determination result is unstable. And stabilization measures can be taken.

(Thirteenth Embodiment) (Structure of the thirteenth embodiment) In the thirteenth embodiment, in addition to the seventh embodiment shown in FIGS. 16 and 17, the stability judgment result by the stability judgment means 6 is unstable. In the case of, the avoidance measure creating means 21 for creating the avoidance measure data 22 in consideration of the required control time of the control target device is provided.

(Operation of Embodiment 13) FIGS. 16 and 1
As shown in FIG. 7, in the sixth embodiment, when the stability determination result by the stability time margin calculating means 7 is “unstable”, the stability time margin data 16 at the current time is output. In the thirteenth embodiment, in addition to the above, the avoidance measure creating means 21 creates the avoidance measure data 22 in consideration of the required control time of the control target device, and presents a stabilization measure to the operator. The operation of the avoidance measure creating means 21 is described in FIGS.
This is as described in the second embodiment shown in FIG.

(Effect of Embodiment 13) Embodiment 13
According to the above, not only the effect of the seventh embodiment by calculating the stability time margin is exerted, but also a countermeasure is created when the stability determination result is unstable. And stabilization measures can be taken.

[0114]

According to the present invention, the power system monitoring and control apparatus captures a time-series change in a margin from the present time to the future to reach an unstable state. The time margin can be calculated as an evaluation index, and the stability can be evaluated in consideration of a change in daily demand.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a power system monitoring and control device according to a first embodiment.

FIG. 2 is a flowchart illustrating an operation of the power system monitoring and control device according to the first embodiment;

FIG. 3 is a configuration diagram of schedule data according to the first embodiment.

FIG. 4 is a functional block diagram of a power system monitoring and control device according to a second embodiment.

FIG. 5 is a functional block diagram of an avoidance measure creating unit according to the second embodiment.

FIG. 6 is a flowchart illustrating an operation of the power system monitoring and control device according to the second embodiment.

FIG. 7 is a functional block diagram of a power system monitoring and control device according to a third embodiment.

FIG. 8 is a flowchart illustrating the operation of the power system monitoring and control device according to the third embodiment.

FIG. 9 is a functional block diagram of a power system monitoring and control device according to a fourth embodiment.

FIG. 10 is a flowchart illustrating the operation of the power system monitoring and control device according to the fourth embodiment.

FIG. 11 is a flowchart illustrating an operation of a stability determining unit switching unit according to the fourth embodiment.

FIG. 12 is a functional block diagram of a power system monitoring and control device according to a fifth embodiment.

FIG. 13 is a flowchart illustrating the operation of the power system monitoring and control device according to the fifth embodiment.

FIG. 14 is a functional block diagram of a power system monitoring and control device according to a sixth embodiment.

FIG. 15 is a flowchart illustrating an operation of the power system monitoring and control device according to the sixth embodiment.

FIG. 16 is a functional block diagram of a power system monitoring and control device according to a seventh embodiment.

FIG. 17 is a flowchart illustrating an operation of the power system monitoring and control device according to the seventh embodiment.

FIG. 18 is a functional block diagram of a power system monitoring and control device according to an eighth embodiment.

FIG. 19 is a flowchart illustrating the operation of the power system monitoring and control device according to the eighth embodiment.

FIG. 20 is a flowchart illustrating functions of a demand maximum point limit total demand calculation unit according to the eighth embodiment.

FIG. 21 is a flowchart illustrating functions of a designated margin holding time calculating unit according to the eighth embodiment.

FIG. 22 is a functional block diagram of a conventional power system monitoring and control device.

FIG. 23 is a flowchart illustrating the operation of a conventional power system monitoring and control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Future time determination means 2 Power equipment operation state determination means 3 Future power system state creation means 4 Voltage stability calculation means 6 Stability determination means 7 Stability time margin calculation means 21 Avoidance measure creation means 21a SC input target substation extraction means 21b Post-control output calculating means 21c Post-control system state creating means 21e Stability determining means 21f Control amount changing means 21g Control amount calculating means 31 Current power system state creating means 33 Voltage stability calculating means 36 Stability margin calculating means 37 Stability determining means 41 stability determination means switching means 44 stability time margin storage means 51 voltage stability calculation result storage means 52 stabilization tendency determination means 54 time step width determination means 61 initial phase angle storage means 62 generator initial phase angle calculation means 63 initial phase Angle comparison means 71 Maximum demand point calculation means 72 Power equipment operation state determination means 73 Future power system state creating means 74 Voltage stability calculating means 76 Stability determining means 81 Demand maximum point limit total demand calculating means 82 Designated margin holding time calculating means 81a Designated margin total demand calculating means 82a Stability determining means 100 Power system monitoring control Device 110 Power system monitoring and control device 120 Power system monitoring and control device 130 Power system monitoring and control device 150 Power system monitoring and control device 160 Power system monitoring and control device 170 Power system monitoring and control device 180 Power system monitoring and control device

Claims (9)

[Claims] 1. A future time determining means for determining a future time by cumulatively adding a time at a predetermined interval starting from the current time,
Power equipment operating state determining means for determining the operating state of the power system at the determined time, future power system state creating means for creating a power system state based on the determined operating state, and the created future power system state Voltage stability calculation means for performing voltage stability calculation, stability determination means for performing stability determination based on the calculated voltage stability calculation result, and a future time determined to be unstable by the stability determination means. A power system monitoring and control device comprising: a stability time margin calculating unit that calculates a difference from a current time as a stability time margin. 2. The power system monitoring and control device according to claim 1, wherein when the stability determination result by said stability determination means is unstable, invalidity for preventing the power system from becoming unstable. An electric power system monitoring and control device, comprising: an electric power control amount, and an avoidance measure creating means for presenting an avoidance measure in consideration of the stability time margin and the control required time of the control target device. 3. A voltage stability calculating means for calculating a voltage stability based on a current power system state, and a limit total demand power which becomes a voltage stability limit as a result of the voltage stability calculation by the voltage stability calculating means. A stability margin calculating means for calculating the stability margin, a future time determining means for cumulatively adding the time at a predetermined interval starting from the current time to determine a future time, and a power system at the determined time. Power equipment operating state determining means for determining the operating state, future power system state creating means for creating a power system state including the total demand power based on the determined operating state, and the stability margin amount and the total demand power In comparison, a stability determining means for performing a total demand stability determination based on whether or not the former is greater than the latter, and the stability determining means determines that the total demand power is less than the stability margin. It has been a power system monitoring control system and a stability time margin calculation for calculating a stability time margin time to the future time become unstable from the current time. 4. An apparatus according to claim 1, comprising a device according to claim 1, wherein the stability time margin is always determined at a constant cycle by the device according to claim 3, and the stability time margin is a predetermined value. 4. A power system monitoring and control device, further comprising a stability determination switching means for switching from the device of claim 3 to the device of claim 1 when the following conditions are satisfied, and obtaining a stability time margin. 5. The power system monitoring and control device according to claim 1, wherein the voltage stability calculation result at the current time calculated by said voltage stability calculation means and the voltage stability calculation corresponding to the same time calculated in the past in the past. A stabilization tendency determining means for determining whether or not the system stability is increasing by comparing the result with the result; and A power system monitoring and control device comprising: a time step width determining means for advancing a time step width for a time determining means to a time of a stability time margin calculated in the past. 6. A generator initial phase angle calculating means for calculating a generator initial phase angle based on a future power system state created by said future power system state creating means. And the generator initial phase angle calculated this time is compared with the generator initial phase angle calculated in the past, and when there is no significant change, the processing of the stability time margin calculation by the stability time margin calculation means is omitted. And an initial phase angle comparing means. 7. The power system monitoring and control device according to claim 1, wherein a demand maximum point calculating means for calculating a demand maximum time closest to the current time as a demand maximum point based on the predicted demand data, and a calculated demand maximum. Second power equipment operating state determining means for creating maximum point system data at a point, second future power system state creating means for creating a maximum point power system state based on the maximum point system data, and the maximum point power A second voltage stability calculating means for calculating the voltage stability at the maximum demand point based on the system state; and a stability determination based on the voltage stability calculation result calculated by the second voltage stability calculating means. And a second stability determination unit that sets a difference between the future time determined by the future time determination unit and the current time when it is determined to be unstable as a stability time margin. Power system monitoring control system. 8. The power system monitoring and control device according to claim 7, wherein the second voltage stability calculating means determines that the system at the maximum demand point is stable, and creates the second future power system state. A demand maximum point total demand calculation means for calculating a marginal total demand at the time when the time is returned at predetermined time intervals from the demand maximum point based on the output of the means, and until the time when the marginal total demand has a predetermined margin. A power system monitoring and control device comprising: a designated margin holding time calculating means for calculating a time from a current time back to a time when the margin is held as a stability time margin. 9. The power system monitoring and control apparatus according to claim 3, wherein the power system is in an unstable state when the stability determination result by said stability determining means is unstable. Power system monitoring control, comprising: a reactive power control amount for avoiding the problem, and an avoidance measure creating means for presenting an avoidance measure in consideration of the stability time margin and the control required time of the controlled device. apparatus.