JPH0789714B2 - Reactive power compensator - Google Patents

Description

The present invention relates to a reactive power compensator, and relates to a reactive power compensator, which suppresses voltage fluctuations in an AC power supply system and suppresses voltage imbalance. The present invention relates to an effective var compensator for stabilizing.

(Prior art) In recent years, loads such as AC trains that take single-phase power have been connected to the power supply system, and the unbalanced current and the impedance of the power supply system cause an unbalanced voltage in the power supply system. It has become a problem, and the fluctuation of the voltage due to the change of the reactive power of the power system has become a problem. Therefore, a reactive power compensator is installed in the power supply system to compensate the reactive power of the power supply system and suppress voltage fluctuations, and to compensate the unbalanced current of the power supply system and remove the unbalanced component of the voltage. Attempts are being made.

As for the power supply system equipped with such a reactive power compensator, for example, a paper “A system using SVC using a digital controller” presented at the Institute of Electrical Engineers and Power Technology Study Group in July 1985. The simulator test for stabilization "is described in detail, and the basic configuration is as shown in FIG.

That is, in the figure, 10 and 11 are power supply buses of branch lines to loads such as AC trains, 100 is a reactive power compensator, and is composed of a reactor unit 300 and a phase advance capacitor 200. Reactor unit 300 is composed of reactors 302U to 302W, anti-parallel thyristors 301U to 301W connected in series thereto, voltage detection transistor 70, and its control circuit 350, detects the voltage of power supply bus bar 6 and responds to the detected value. Thyristor
The conduction angle of 301U to 301W is adjusted to control the reactor current. 3 is an impedance existing in the three-phase AC power supply system, and 1 is a main line three-phase AC power supply system. Here, the power capacity (lag capacity) of the reactor 300 of the reactive power compensator 100
Is usually the power capacity of the phase advancing capacitor 200 (phase advancing capacity)
Therefore, as shown in FIG. 6, by changing the reactor current I _R from zero to the maximum, the power Q generated as the reactive power compensator 100 is changed from the advanced phase to the delayed phase. It can change smoothly.

In the power supply system having the above configuration, when the reactive current (or reactive power) of the bus 6 changes, the voltage of the bus 6 changes due to the action of the impedance and the impedance 3, and the unbalanced current generated by a single-phase load such as an electric train. When the current flows through the bus bar 6, the impedance of the bus bar 6 causes an imbalance in the voltage of the bus bar 6. A reactive power compensator is used to suppress and compensate such voltage fluctuations and voltage imbalances, but the performance of the device depends on how to detect voltage fluctuations and how to detect voltage imbalances. . An example of this control circuit is shown in FIG.

That is, FIG. 7 shows the gist of the description in the above-mentioned document. First, the bus voltage is detected individually for each phase (e _RS ,
e _ST , e _TR ), rectify it through an absolute value circuit (ABS),
It is passed through a filter circuit FIL to obtain DC signals e _DR , e _DS , e _DT . e _{DR to} e _DT are proportional to the voltage value between each line of the bus voltage. On the other hand, ▲ V ^* _R ▼ is a signal indicating the voltage value to be maintained by the AC bus, and this signal and signals e _DR , e _DS , and e _DT are compared with comparators CR and C
S, CT are compared individually, and the deviation is amplified by an amplifier AMP to make reactor current commands ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲ I ^* _W ▼.
When the current of the reactor circuit 300 of FIG. 5 is controlled based on ▲ I ^* _U ▼, ▲ I ^* _V ▼, and ▲ I ^* _W ▼, when the reactive power of the AC bus changes and the bus voltage changes, it becomes invalid. The power compensator 100 compensates for it and keeps the voltage constant, and
When an unbalanced current flows in the AC bus and an imbalance occurs in the voltage, the reactive power compensator 100 compensates for the imbalance and operates in a direction to correct the imbalance in the voltage.

In addition, a reactive power compensator having various voltage detection methods has been proposed, but the gist thereof can be reduced to the method described in the above-mentioned document.

(Problems to be Solved by the Invention) The above is the description of the conventional reactive power compensating device, but this device has the following drawbacks. That is, the voltage fluctuation of the AC bus is caused by the change of the positive phase current (the positive phase voltage fluctuation).
, And an unbalanced component of voltage (negative phase voltage fluctuation) caused by negative phase current, but the conventional voltage detection method has no concept of clearly separating positive phase voltage fluctuation / negative phase voltage fluctuation. , Therefore, the voltage of the bus bar is regarded as a mere fluctuation component in which the positive and negative phase voltage fluctuations are mixed together.
The reactive power compensator is controlled based on it. Therefore, in the conventional reactive power compensator, what is to be compensated, that is, whether positive phase voltage fluctuation (particularly fluctuation due to positive phase reactive current) is controlled, or negative phase voltage fluctuation,
That is, it is impossible in principle to discriminate whether or not the unbalanced component of the voltage is controlled, and it has been impossible to develop a more advanced control.

In recent years, there has been a strong demand for improvement in the power quality of the AC power system, and the emergence of a power system capable of more advanced control, stabilization measures, and reactive power compensators has been sought. There is an urgent need to develop a reactive power compensator equipped with a highly accurate voltage detection method (positive-phase voltage fluctuation detection method, negative-phase voltage fluctuation detection method) based on various control concepts.

The present invention has been made in view of the above-mentioned problems of the prior art,
The purpose is to detect the voltage fluctuations of the power supply system separately in the positive phase component and the negative phase component in the device that compensates the voltage fluctuations of the AC power supply system and the unbalanced voltage, and clarify the compensation target. An object of the present invention is to provide a reactive power compensator capable of performing highly accurate voltage compensation control by performing control.

[Structure of the Invention] (Means for Solving Problems) The outline of the present invention will be described with reference to FIGS. 1 and 2. The system voltage is detected and led to elements 403 and 406 in FIG. At 406, a unit two-phase voltage signal synchronized with the system voltage is generated. On the other hand, 40
At 3, the three-phase voltage signal is converted into a two-phase signal. The signals of 403,406 are led to the elements 408,410, and the instantaneous power signals (P _1P , P _1N , Q _1N )
Is calculated. Elements 413, 414 and 415 extract the DC component from the signals P _1P , P _1N and Q _1N (P _1PD : positive phase fundamental wave voltage signal,
P _1ND , Q _1ND : 1st phase negative phase voltage signal). The contents of element 420A are shown in FIG. In the 412A and 424A of FIG. 2, the signals P _1ND and Q _1ND are used, and the negative phase voltage signals (P _2ND and Q) of the second phase and the third phase, respectively.
_2ND ), (P _3ND , Q _3ND ) are calculated. 437 sets the voltage value of the power supply system to be held. Signal P _1PD , P for 430A
_The voltage deviation signals ΔE _U , ΔE _V , and ΔE _W are calculated using _1ND , Q _1ND , P _2ND , Q _2ND , P _3ND , and Q _3ND . Amplifier 451U, 451V, 451W,
When the signals ΔE _U , ΔE _V , and ΔE _W are amplified, the reactor current commands ▲ I ^* _U ▼, ▲ I ^* _V ▼, and ▲ I ^* _W ▼ are obtained, and the reactive power compensator is controlled based on these.

(Operation) When the above control circuit is used, the information of the system voltage is the positive phase component (P _1PD ), the negative phase component (P _1ND , Q _1ND , P _2ND , Q _2ND , P _3ND , Q _3ND ).
Are clearly separated and detected. Therefore, by controlling the reactive power compensator by these signals, the object of compensation can be clarified and a highly accurate device can be realized.

[Embodiment of the Invention] A power supply system including a reactive power compensator of the present invention (a three-phase system will be described for convenience of the following description) is the same as that shown in FIG. The description of the elements referred to in 1 is omitted here.

In FIG. 5, a voltage detector 70 detects the line voltage (e _RS , e _ST , e _TR ) of the AC bus 6 to be compensated and guides it to the control circuit 350. 300 is a reactor part, which is usually delta-connected, and the magnitude of the current is adjusted by adjusting the firing angle of the thyristors 301U to 301W. The reactor current usually has a distorted waveform including harmonics in addition to the fundamental wave.

400 is an arithmetic circuit incorporating the present invention, the voltage signal e _RS, e
Input _ST and e _TR , perform various calculations, and set the direct current value command ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲ I ^* _W ▼ for instructing the fundamental current that the reactor unit 300 should flow. Output.

Reference numeral 500 denotes an ignition controller, which is a current command value ▲ I ^* _U ▼, ▲ I
Operates in response to ^* _V ▼, ▲ I ^* _W ▼, ▲ I ^* _U ▼, ▲ I ^* _V ▼,
The current (fundamental wave component) indicated by ▲ I ^* _W ▼
The thyristors 301U, 301V, 301W are controlled so that 302U, 302V, 302W will flow.

The control circuit is a combination of the arithmetic circuit 400 and the ignition controller 500.
Referred to as 350, the details of this circuit are shown in FIG.

Next, the main part of the present invention will be described with reference to FIGS.

In FIG. 1, the AC bus voltage signals of FIG. 5, e _RS , e _ST ,
The _eTR is input to the two-phase converter 403 and the two-phase signal generator 406. In the two-phase converter 403, the voltage signals e _RS , e _ST , e _TR are converted into two-phase voltage signals e _1ds , e _1qs by the calculation of the equation (1). The two-phase signal generator 406 is composed of a phase lock loop circuit, receives the voltage signals e _RS , e _ST , e _TR, and outputs the first phase of FIG. 5 as the R phase and the second phase. S phase,
If the third phase is the T phase, the line voltage e _{RS of} the first phase and the second phase
The unit sine wave signal ▲ e ^* _1d ▼ synchronized with and the unit sine wave signal ▲ e ^* _1q ▼ delayed by 90 ° are output.

It can be expressed as ▲ e ^* _1d ▼, ▲ e ^* _1q ▼.

_{Reference numeral} 408 denotes an arithmetic unit, which outputs signals e _1ds , e _1qs and ▲ e ^* _1d ▼, ▲
Input e ^* _1q and calculate the signal P _1P by the equation (3).

P _1P = ▲ e ^* _1d ▼ ・ e _1ds ＋ ▲ e ^* _1q ▼ ・ e _1qs …… (3) When the system voltage e _RS , e _ST , e _TR includes positive / negative phase component, P _1P
Is a pulsating flow containing a DC component and an AC component that oscillates at twice the fundamental wave. _{Reference numeral} 413 is a DC detection filter, which outputs the DC component of the signal P _1P as a signal P _1PD . That is, P _1PD is the system voltage e
_It represents the positive-phase fundamental wave voltage included in _RS , e _ST , and e _TR .

410 is a computing unit, which is used for signals e _1ds , e _1qs and ▲ e ^* _1d ▼, ▲ e ^*
Input _1q and calculate the signals Q _1N and P _1N by the equation (4).

When the system voltage e _RS , e _ST , e _TR includes positive / negative phase component,
P _1N and Q _1N become pulsation signals, and these signals P _1N and Q _1N are passed through DC detection filters 414 and 415, respectively, and DC component signals P _1ND and Q ₁
Detect _1ND . The P _1ND and Q _1ND obtained in this way are the reverse-phase voltage included in the line voltage e _RS of the first and second phases of the system as the positive-phase fundamental wave component of the line voltage of the first and second phases. In-phase component (P
_1ND ) and the voltage of each component when it is decomposed into 90 ° phase difference component (Q _1ND ), where P _1ND is the first phase in-phase negative phase voltage signal and Q _1ND is the first phase It is called a 90 ° anti-phase voltage signal.

Reference numeral 420A denotes a distributor, which receives signals P _1PD , P _1ND , Q _1ND to perform calculation, and current command values ▲ I ^* _U ▼, ▲ I ^* _V for instructing the current flowing through the reactor unit 300 shown in FIG. Output ▼ and ▲ I ^* _W ▼. The details of the distributor 420A are shown in FIG.

500 is an ignition controller, which is a current command value ▲ I ^* _U ▼, ▲ I ^* _V
Operates in response to ▼, ▲ I ^* _W ▼, ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲
The current (fundamental wave component) indicated by I ^* _W ▼
Ignition control of thyristors 301U, 301V, 301W so that 300 flows.

Next, the distributor 420A will be described with reference to FIG. Figure 1 and 2
Signals with the same symbols in the figure are connected according to the signals. Second
In the figure, 421A and 424A are arithmetic units, which input the first-phase 90 ° anti-phase voltage signal Q _1ND and the first-phase in-phase anti-phase voltage signal P _1ND , respectively, in equations (5) and (6). 2nd phase 90 ° negative phase voltage signal Q _2ND , 2nd phase common phase negative phase voltage signal P through calculation
_2ND , third-phase 90 ° negative-phase voltage signal Q _3ND , and third-phase in-phase negative-phase voltage signal P _3ND are output.

Here, P _2ND and Q _2ND are the in-phase components of the line voltage e _ST of the second and third phases and the in-phase component of the positive phase fundamental wave component of the line voltage of the second and third phases. It shows the in-phase component voltage (P _2ND ), when decomposed into 90 ° phase different components, and the 90 ° different phase voltage components (Q _2ND ).

Similarly, P _3ND and Q _3ND are the in-phase _components of the third-phase and first-phase line voltage e _{TR and} the in-phase component of the positive-phase fundamental wave component of the third-phase and first-phase line voltage, respectively. It _shows the in-phase component voltage (P _3ND ) when decomposed into 90 ° phase different components, and the 90 ° different phase voltage components (Q _3ND ).

Reference numeral 437 denotes a setter which outputs a voltage setting signal ▲ E ^* _REF ▼ for instructing a voltage to be maintained on the AC bus 6 in FIG.

430A is a distributor, in which the positive phase fundamental wave voltage signal P _1PD detected from the AC bus voltage, the first phase, the second phase, the third phase
_Input the 90 ° reverse phase voltage signal Q _1ND , Q _2ND , Q _3ND of the phase and the reverse phase voltage signal P _1ND , P _2ND , P _{3ND of the} same phase and the voltage setting signal ▲ E ^* _REF ▼, and formula based on these signals. The calculation of (7) is performed and the voltage deviation signals ΔE _U , ΔE _V , and ΔE _W are output.

451U, 451V, 451W are amplifiers composed of a proportional / integrator, etc., which amplify the deviations ΔE _U , ΔE _V , ΔE _W , and output the result as a signal ▲ I
Output as ^* _U ▼, ▲ I ^* _V ▼, ▲ I ^* _W ▼. The signals ▲ I ^* _U ▼, ▲ I ^* _V ▼, and ▲ I ^* _W ▼ obtained here are the fifth signals respectively.
First-phase current command ▲ I for instructing the current to be generated by the first-phase reactor 302U of the reactor unit 300 in the figure
^* _U ▼, and similarly a second-phase current command ▲ I ^* _V ▼ for the reactor 302V, and a third-phase current command ▲ I ^* _W ▼ for the reactor 302W. Here, the following elements are included in the distributor 430A. That is, 431A, 432A, 433A are coefficient multipliers And output. 434A, 435A, 436A are adders and coefficient units 43
Add the outputs of 1A, 432A, and 433A with the polarities shown. Adder 43
The outputs of 4A, 435A, and 436A correspond to the calculation of the third term of the equation (7). 438A is an adder, which is a setting signal ▲ E ^* _REF ▼ and signal P _1PD
Is calculated with the polarity shown. That is, the output of the adder 438A corresponds to the calculation of the first term of Expression (7). Reference numerals 439A, 440A and 441A denote adders which add the signals P _1ND , P _2ND and P _3ND , the output signal of the adder 438A and the output signals of the coefficient units 434A, 435A and 436A with the polarities shown.

Signals obtained by the above calculation ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲ I ^* _W
The black triangle represents a DC amount signal, and this signal includes all the information about the positive phase voltage and the information about the negative phase voltage. Therefore, by controlling the reactor unit 300 of FIG. 5 based on these ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲ I ^* _W ▼,
The voltage fluctuation of the bus bar 6 caused by the positive-phase reactive current and the bus line impedance 3 generated by the branch line power supply systems 10 and 11 and the anti-phase current and the bus line impedance 3 generated by the power supply systems 10 and 11 in FIG. It is possible to freely stabilize and balance the imbalance of the voltage of the bus bar 6 caused by the.

The above is a typical configuration of the present invention.

In FIG. 5, the voltage of the AC bus is detected as signals e _RS , e _ST , e _TR , but this voltage is usually an unbalanced voltage including a positive phase component and a negative phase component.

This voltage is first introduced into the two-phase generator 406 and is given by equation (2).
Two-phase signals ▲ e ^* _1d ▼, ▲ e ^* _1q ▼ based on the above are output.
Here, the two-phase generator 406 is adjusted so as to respond only to the positive-phase fundamental wave component of the voltage signals e _RS , e _ST , and e _TR .
The two-phase signals ▲ e ^* _1d ▼, ▲ e ^* _1q ▼ contain only information about the positive-phase fundamental wave of the voltage.

On the other hand, the voltage signals e _RS , e _ST , e _TR are introduced into the two-phase converter 403, converted by the equation (1), and the two-phase signals e _1ds , e _1qs
Is obtained. Next, the arithmetic operation of the equation (3) is performed in the arithmetic unit 408 to obtain the signal P _1P , which is passed through the DC detection filter 413 to take out the DC component signal P _1PD . The signal thus extracted
P _1PD represents the positive-phase fundamental wave voltage included in the system voltages e _RS , e _ST , and e _TR . On the other hand, the arithmetic operation of the equation (4) is performed in the arithmetic unit 410 to obtain the signals P _1N and Q _1N , which are passed through the DC detection filters 417 and 418 to extract the DC component signals P _1ND and Q _1ND .
The signals P _1ND and Q _1ND obtained in this manner are the positive-phase fundamental wave components of the line voltages of the first phase and the second phase, which are the reverse-phase voltage components included in the line voltages e _RS of the first and second phases. The voltage of each component when it is decomposed into the in-phase component and the 90 ° phase difference component, that is, the in-phase voltage component (P _1ND ), and the 90 ° phase difference voltage component (Q
_1ND ). (P _1ND : In-phase and out-of-phase voltage of the first phase,
Q _1ND : It is called the 90 ° negative phase voltage of the first phase).

Next, in the distributor 420A of FIG. 2, the arithmetic operations of the equations (5) and (6) are performed in the arithmetic units 421A and 424A, and the in-phase negative phase voltage P _{2ND of} the second phase and the 90 ° phase voltage Q _2ND , in-phase and out-of-phase voltage of the third phase
P _3ND , 90 ° reverse phase voltage Q _3ND is obtained.

The signal P _1PD obtained as described above is the system voltage e _RS , e _ST ,
It is a signal related only to the positive-phase fundamental wave voltage contained in _eTR , and more specifically, a signal related to only the component in phase with the positive-phase fundamental wave voltage. In the calculation of various quantities related to the positive phase of the voltage, for example, the conversion of the equation (3), the same quantity is calculated regardless of which phase the calculation is performed. Therefore, the calculation for the positive phase component may be performed for one phase.

Also, focusing on the signals P _1ND , Q _1ND and P _2ND , Q _2ND and P _3ND , Q _3ND , these signals are related only to the negative phase component voltage contained in the system voltages e _RS , e _ST , e _TR. In addition, P _1ND , Q _1ND is a signal for P _2ND , Q _2ND only in the opposite phase of voltage e _RS.
Is a signal related only to the anti-phase _component of e _ST , and P _3ND , Q _3ND is a signal related only to the anti-phase _component of voltage e _TR , and more specifically, P _1ND , Q
_{Taking 1ND} as an example, P _1ND is the voltage component in phase with the positive-phase fundamental wave component of the line voltage in the negative-phase component of the voltage e _RS , and Q _1ND is 90 ° out of phase with the positive-phase fundamental wave voltage. It is a signal related only to the voltage component.

As mentioned above, all the information of the system voltages e _RS , e _ST , e _TR are separately detected in the form of DC signals P _1PD , P _1ND , P _2ND , P _3ND , Q _1ND , Q _2ND , Q _3ND . It will be clear.

The signal thus obtained is calculated along the equation (7) in the distributor 430A shown in FIG. 2 to generate voltage deviation signals ΔE _U , ΔE _V , ΔE _W , which are amplified to obtain ▲ I ^* _U ▼, ▲ I ^* _V ▼ and ▲ I ^* _W ▼ are obtained.

If the reactor current of FIG. 5 is controlled based on the current commands ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲ I ^* _W ▼, the reactive power compensator
The 100 works as follows.

For example, when a reverse-phase current flows in the system and voltage imbalance occurs, it is detected by the control circuit (P _1ND , Q _1ND ,
P _2ND , Q _2ND , P _3ND , Q _3ND ), based on which the reactor part 3
00 generates a compensating anti-phase current (which is generated so that the phase is exactly opposite to the anti-phase current injected from the load to the system) so as to cancel this, and therefore the impedance 3 of FIG. The reverse-phase current apparently does not flow there, and the voltage imbalance due to the reverse-phase current is eliminated. Note that this compensation function is achieved by the amplifiers 451U, 451V, whose control circuit in FIG.
Since it includes 451W, it is executed until the reverse phase voltage of the grid becomes completely zero.

Next, when the reactive current flows through the system and the voltage of the system changes, it is detected by the control circuit (signal of FIG. 2).
P _1PD ), and the current of the reactor unit 300 is adjusted based on the result of comparison between it and the voltage setting value ▲ E ^* _REF ▼. For example, when the voltage of the system drops, the reactor current becomes small. Therefore, as can be seen from the explanation of FIG. 6, the current generated by the reactive current compensating device 100 becomes a phase advance and the voltage of the system 6 is raised ( The voltage rises when a phase-advancing current is passed through the inductance). When the voltage is about to rise, the reactive power compensator 100 acts to generate a delay current and lower the system voltage, so that the system voltage is maintained at the set value.

As is apparent from the above description, in the power supply system including the reactive power compensating device of the present invention, even if the voltage fluctuation caused by the fluctuation of the reactive power of the load is about to occur, it is also caused by the negative phase current. Even if voltage imbalances are about to occur, they are compensated by the reactive power compensator, so that it is possible to supply high-quality power with a small voltage fluctuation and a balanced voltage.

The above is a typical embodiment of the present invention.

Next, another embodiment of the present invention will be described with reference to FIG. That is, FIG. 3 is a modification of the distributor 420A of FIG. 2 of the above-described invention, and FIG. 3 is inserted and used in the distributor 420A of FIG. Therefore, this modified example has many parts that overlap with the invention described above, and a description of the parts that overlap will be omitted. The same symbols in FIGS. 3 and 1 are connected according to the symbols.

In FIG. 3, 421B and 424B are arithmetic units, which input the above-mentioned first-phase 90 ° negative-phase voltage signal Q _1ND and the first-phase in-phase negative-phase current signal P _1ND , respectively, and use equations (8), Through the calculation of (9), the second-phase in-phase and anti-phase voltage signal P _2ND and the third-phase in-phase and anti-phase voltage signal P _3ND are output. The P _2ND and P _3ND are the same as the signals P _2ND and P _3ND obtained by the equations (5) and (6) described above.

Reference numeral 437 denotes a setting device that outputs a voltage setting signal ▲ E ^* _REF ▼. 430B is a distributor, which is a positive-phase fundamental wave voltage signal P _1PD , first-phase, second-phase, and third-phase in-phase negative-phase voltages P _1ND , P _2ND , P _3ND, and a voltage setting signal ▲ E ^* _REF ▼ Input, and calculate the equation (10) based on these signals. Voltage deviation signals ΔE _U , ΔE _V , Δ
Outputs E _W.

451U, 451V, 451W are amplifiers composed of a proportional / integrator, etc., which amplify the deviations ΔE _U , ΔE _V , ΔE _W, and current commands ▲ I ^* _U ▼ for the first phase, the second phase, and the third phase. , ▲ I ^* _V ▼, ▲ I ^* _W ▼ are output. Here, 446B, 447B and 448B are coefficient multipliers that double the input signal and output it. Reference numerals 438A, 439B, 440B, and 441B are adders that add the illustrated signals with the illustrated polarities.

The current commands ▲ I ^* _U ▼, ▲ I ^* _V ▼, and ▲ I ^* _W ▼ are shown in FIG.
It is exactly the same as the current command value obtained in step 1. Therefore, if the current of the reactor part 300 in FIG. 5 is controlled based on these ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲ I ^* _W ▼, Done first
The same compensation effect as the invention according to FIGS. 2 and 3 can be obtained.

As described above, in this embodiment, the arithmetic operations of the arithmetic units 421B and 424B in FIG. 3 can be simplified as compared with the arithmetic units 421A and 424A in FIG.

Next, another embodiment of the present invention will be described with reference to FIG. This embodiment also relates to the modification of the above-mentioned invention shown in FIG. 2, and FIG. 4 is used by being inserted into the distributor 420A shown in FIG. Therefore, the description of the same parts as those of the above-mentioned invention will be omitted.

In FIG. 4, reference numerals 421C and 424C are arithmetic units, which input the above-mentioned first-phase 90 ° negative-phase voltage signal Q _1ND and the first-phase in-phase negative-phase voltage signal P _1ND , respectively, and use equations (11), Through the calculation of (12), the 90 ° negative phase voltage signal Q _{2ND of} the second phase and the 90 ° negative phase voltage signal Q _3ND of the third phase are output. These Q _2ND and Q _3ND are the same as the signals Q _2ND and Q _3ND obtained by the equations (5) and (6) described above.

Reference numeral 437 denotes a setting device that outputs a voltage setting signal ▲ E ^* _REF ▼. 430C is a distributor, which is a positive-phase fundamental wave voltage signal P _1PD , first-phase, second-phase, and third-phase 90 ° negative-phase voltage signals Q _1ND , Q _2ND , Q
_{Input 3ND} and voltage setting signal ▲ E ^* _REF ▼, calculate equation (13) based on these signals, and input voltage deviation signal Δ
Outputs E _U , ΔE _V , and ΔE _W.

451U, 451V, 451W are amplifiers composed of a proportional / integrator, etc., which amplify the deviations ΔE _U , ΔE _V , ΔE _W, and current commands ▲ I ^* _U ▼ for the first phase, the second phase, and the third phase. , ▲ I ^* _V ▼, ▲ I ^* _W ▼ are output. Here, 431A, 432A, 433A are coefficient multipliers, And output. The 446B, 447B, and 448B are also coefficient units, which double the input signal and output it.

Further, 438A, 439B, 440B441B, 434A, 435A, 436A are adders, which add the illustrated signals with the illustrated polarities.

The current commands ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲ I ^* _W ▼ are exactly the same as the current command values obtained in FIG.
If the current of the reactor part 300 of FIG. 5 is controlled based on I ^* _U ▼, ▲ I ^* _V ▼, and ▲ I ^* _W ▼, the above-mentioned FIG. 1 and FIG.
The same compensation effect as the invention according to the figure can be obtained.

As described above, in the present embodiment, the arithmetic operations of the arithmetic units 421C and 424C in FIG. 4 can be simplified as compared with the arithmetic units 421A and 424A in FIG.

[Effects of the Invention] As is clear from the above description, the reactive power compensator of the present invention has the following effects.

That is, (1) When a fluctuating load or an unbalanced load is connected to the AC power supply system, voltage fluctuations and voltage imbalances on the AC bus become a problem. In the present invention, these fluctuations are due to the positive phase component. Since it is possible to clearly detect whether it is due to the negative phase component, it becomes clear what the reactive power compensator is to compensate for. Therefore, control focusing only on the voltage fluctuation of the system (voltage fluctuation control), unbalance of the system The control focusing only on the voltage (voltage balancing control), the control focusing on both of them, and the like can be freely configured, and more sophisticated voltage compensation control can be easily realized as compared with the conventional control.

(2) The positive-phase component and the negative-phase component of the system voltage can be continuously detected in the form of a DC signal, and therefore discontinuity does not enter the control, so that stable control can be realized.

(3) Further, in the control circuit, when detecting a positive phase component / a negative phase component of the voltage, a coefficient unit, an adder, a signal processing unit,
Accurate and high-precision signals (regarding positive-phase components and negative-phase components) without any ambiguity in the detection signals, because simple signals such as multipliers are used for simple calculation to obtain the desired signal. Can be obtained. Moreover, the cost is low because the circuit is simple.

As described above, the reactive power compensator of the present invention incorporates a completely new control concept that "the positive phase component and the negative phase component are separately detected and the compensation control is performed based on them" which is not in the conventional control. Therefore, the demand for reactive power compensation control, which will become more complex and sophisticated in the future, can be sufficiently satisfied.

[Brief description of drawings]

1 is a block diagram showing an embodiment of the present invention, FIGS. 2 to 4 are block diagrams showing other embodiments of the present invention, and FIG. 5 is an invalidity to which the present invention is applied. FIG. 6 is a main circuit diagram of the power compensator, FIG. 6 is an operation explanatory diagram of the reactive power compensator, and FIG. 7 is a block diagram of a voltage control circuit adopted in a conventional reactive power compensator. 1 ... Main line AC power supply system, 3 ... System impedance, 10, 11 ... Branch AC power supply system, 100 ... Reactive power compensator, 200 ... Advancing capacitor, 300 ... Reactor section, 350 ... Control circuit, 400 ... Operation circuit, 500 ... Firing control circuit, 403 ... Two-phase converter, 408, 410 ... Operation unit, 40
6 …… 2-phase generator, 413 ～ 415 …… DC detection filter, 420
A …… Distributor, 500 …… Ignition controller, 421A, 424A, 421B, 424
B, 421C, 424C …… Calculator, 430A, 430B, 430C …… Distributor, 4
37: Setting device, 431A to 433A, 446B to 448B: Coefficient device, 434
A ~ 436A, 438A ~ 441A, 439B ~ 441B ... Adder, 451U, 451V,
451W …… Amplifier.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 6260012 (JP, A) JP 6260013 (JP, A) JP 6260014 (JP, A) JP 62- 60015 (JP, A)

Claims (4)

[Claims] 1. A unit sine wave signal synchronized with a first phase voltage of an N-phase AC power supply in a reactive power compensator for compensating an unbalanced voltage and a voltage fluctuation of an N-phase multi-phase AC power supply.
e _1d ^* and unit sine wave signal e _1q ^{* with} a 90 degree phase delay
And a line voltage of the N-phase AC power supply, e _1S , e _2S ... e _NS are detected, the d axis is taken in accordance with the first phase voltage e _1S, and the phase is delayed by 90 degrees. Taking the q-axis, each of the line voltages e _1S ,
Signals e _1ds are obtained by projecting and combining e _2S ... e _NS on the d-axis, and projecting and combining the respective line voltages e _1S , e _2S ... e _NS on the q-axis to obtain a signal e _1qs . In the case of the means, that is, the case where the N-phase AC power supply has three phases, the line voltages e _1S , e _2S , e _3S are detected and the detected signals are used. P _1P = e _1d ^*・ e _1ds + e _1q ^*・ e _1qs P _1N = e using the means for obtaining the calculated values e _1ds , e _1qs of E _1d ^* , e _1q ^* and e _1ds , e _{1qs 1d} ^*・ e _1ds −e _1q ^*・ e _1qs Q _1N = e _1d ^*・ e _1qs + e _1q ^*・ e _1ds means for obtaining the calculated values P _1P , P _1N , Q _1N and the DC component of the signal P _1P , that is, the N-phase AC power supply line voltages e _1S of the signal representative of the positive-phase fundamental voltages included in the e _2S ... e _NS P
Means for obtaining _1PD , and a direct-current component of the signals P _1N , Q _1N , that is, a reverse-phase voltage including the first-phase line voltage e _1S of the N-phase AC power supply, of the first-phase line voltage e _1S Signal P _1ND decomposed into the in-phase component and the in-phase fundamental wave component, and the signal decomposed into components with a 90 degree phase difference from it
Means for obtaining Q _1ND , means for setting a voltage setting signal E _REF ^* for indicating the voltage value of the power supply system to be maintained, and E _REF ^* , P _1PD ,
P _1ND , Q _1ND are used as input signals to perform a calculation to create a voltage deviation signal, and means for amplifying the signal to create an N-phase current command, based on the current command obtained by the means. Controlling the reactive power compensator. 2. A means for generating the current command, means for setting a system voltage setting signal E _REF ^* for indicating a voltage value of a power supply system to be maintained by the action of the reactive power compensator, and the signal P. Based on _1ND , Q _1ND And the line voltage e of the second phase of the N-phase AC power supply is calculated.
And a signal Q _2ND reverse phase voltage decomposed into different components of the positive phase fundamental wave component and the signal decomposed into components in-phase P _2ND and therewith 90 degree phase of the second phase line voltage e _2S, including the _2S, said A signal P _{3ND obtained} by decomposing the negative phase voltage included in the third-phase line voltage e _3S of the N-phase AC power supply into a component in phase with the positive-phase fundamental wave component of the third-phase line voltage e _3S , and 90 ° with it _Means for obtaining a signal Q _3ND decomposed into components having different phases, and the signals E _REF ^* , P _1PD , Q _1ND , Q _2ND , Q _3ND , P _1ND , P _2ND , P _3ND
On the basis of And the signal ΔE _U which is the deviation between the voltage setting signal E _REF ^* and the first-phase line voltage e _1S of the N-phase AC power supply, the voltage setting signal E _REF ^* and the N-phase AC a signal Delta] E _V is the difference between the line voltage e _2S of the second phase of the power supply, the voltage setting signal E _REF ^* and the deviation in a signal of the line voltage e _3S of the third phase of the N-phase AC power supply Means for creating ΔE _W, and a current that amplifies the signals ΔE _U , ΔE _V , and ΔE _W and indicates a current to be generated by the power unit of the reactive power compensator corresponding to the first phase of the N-phase AC power supply. The command signal I _U ^* , the current command signal I _V ^* for instructing the current to be generated by the power section of the reactive power compensator corresponding to the second phase of the N-phase AC power supply, and the third phase of the N-phase AC power supply A means for producing a current command signal I _W ^* for instructing a current to be generated by the power section of the corresponding reactive power compensator. 2. A reactive power compensator according to claim 1. 3. A means for generating the current command, means for setting a system voltage setting signal E _REF ^* for indicating the voltage value of the power system to be maintained by the action of the reactive power compensator, and the signal P Based on _1ND , Q _1ND And the line voltage e of the second phase of the N-phase AC power supply is calculated.
A signal P _2ND of the reverse-phase voltage is decomposed into positive phase fundamental wave component and a phase component of the line voltage e _2S of the second phase containing the _2S, line voltage of the third phase of the N-phase AC power source e _{3S Means} for obtaining a signal P _3ND by decomposing the negative-phase voltage included in the signal into a component in phase with the positive-phase fundamental wave component of the line voltage e _3S of the third phase, and the signal E _REF ^* , P _1PD , P _1ND , P Based on _2ND and P _3ND , ΔE _U = -E _REF ^* + P _1PD + 2P _1ND ΔE _V = -E _REF ^* + P _1PD + 2P _2ND ΔE _W = -E _REF ^* + P _1PD + 2P _3ND and calculate the voltage setting signal E _REF ^* and the signal Delta] E _U is a deviation between the line voltage e _1S N-phase alternating current first phase of the power supply, the voltage setting signal E _REF ^* and the line voltage of the N-phase AC second phase of the power source e Means for generating a signal ΔE _V which is a deviation from _2S, and a signal ΔE _W which is a deviation between the voltage setting signal E _REF ^* and the line voltage e _3S of the third phase of the N-phase AC power supply; Amplifies the signals ΔE _U , ΔE _V , ΔE _W , A current command signal I _U ^* instructing a current to be generated by the power section of the reactive power compensator corresponding to the first phase of the N-phase AC power supply, and a reactive power compensator corresponding to the second phase of the N-phase AC power supply Current command signal I _V ^* for instructing the current to be generated by the power section of the power supply and the current command signal I _W for instructing the current to be generated by the power section of the reactive power compensator corresponding to the third phase of the N-phase AC power supply The reactive power compensator according to claim 1, further comprising means for creating ^* . 4. A means for generating the current command, a means for setting a system voltage setting signal E _REF ^* for instructing a voltage value of a power system to be maintained by the action of the reactive power compensator, and the signal P. Based on _1ND , Q _1ND And the line voltage e of the second phase of the N-phase AC power supply is calculated.
Signal Q obtained by decomposing the inverse phase voltages including the _2S to different components of the positive phase fundamental wave component and a 90-degree phase of the line voltage e _2S of the second phase
_2ND, and a negative phase voltage included in the third-phase line voltage e _3S of the N-phase AC power supply is decomposed into a positive phase fundamental wave component of the third phase line voltage e _{3S and} a component having a phase difference of 90 degrees. _Means for obtaining a signal Q _3ND , based on said signals E _REF ^* , P _1PD , Q _1ND , Q _2ND , Q _3ND And the signal ΔE _U which is the deviation between the voltage setting signal E _REF ^* and the first-phase line voltage e _1S of the N-phase AC power supply, the voltage setting signal E _REF ^* and the N-phase AC a signal Delta] E _V is the difference between the line voltage e _2S of the second phase of the power supply, the voltage setting signal E _REF ^* and the deviation in a signal of the line voltage e _3S of the third phase of the N-phase AC power supply Means for creating ΔE _W, and a current that amplifies the signals ΔE _U , ΔE _V , and ΔE _W and indicates a current to be generated by the power unit of the reactive power compensator corresponding to the first phase of the N-phase AC power supply. The command signal I _U ^* , the current command signal I _V ^* for instructing the current to be generated by the power section of the reactive power compensator corresponding to the second phase of the N-phase AC power supply, and the third phase of the N-phase AC power supply A means for producing a current command signal I _W ^* for instructing a current to be generated by the power section of the corresponding reactive power compensator. 2. A reactive power compensator according to claim 1.