CN109066774B - Management and control system and method for area using distributed energy - Google Patents

Abstract

The invention discloses a distributed energy area management and control system. A distributed energy area management and control device is installed at the outlet end of a substation, and a grid connection interface device is installed at each distributed energy grid connection point. The communication connects the respective distributed energy grid connection points, and also communicates with the remote distributed energy area management and control equipment. Through the power control of the energy storage system, the system can effectively suppress the influence of the power fluctuation of the distributed energy and the irregular start and stop on the power supply voltage quality of the distribution network, and effectively improve the voltage level of the network.

Description

A regional management and control system using distributed energy and its control method

Technical field:

The invention belongs to the technical field of power transmission, and in particular relates to a distributed energy regional management and control system which solves the problem of voltage over-limit caused by the grid-connected distributed energy by utilizing the distributed energy regional management and control system, and also relates to a control method of the system.

Background technique:

The start and stop of distributed energy in the smart distribution network is easily affected by many factors such as natural conditions, user needs, policies and regulations, so distributed energy is prone to irregular start and stop, and intermittent distributed energy The inherent volatility and intermittent nature of power output can cause significant voltage fluctuations on the distribution grid. In addition, the uncoordinated operation of distributed energy resources and distribution network loads may also lead to further deterioration of the voltage quality of the distribution network. For example, photovoltaic power generation can emit a large amount of active power when the light intensity is high at noon, but has no power output at night, which may lead to a high voltage level at this point during the day, and a low voltage level during the night, especially This phenomenon is more obvious if the PV capacity is large and the access point is at the end of the feeder.

Invention content:

The purpose of the present invention is to provide a distributed energy area management and control system, so as to overcome the above-mentioned defects in the prior art.

In order to achieve the above purpose, the present invention provides a distributed energy area management and control system. A distributed energy area management and control device is installed at the outlet end of the substation, and a grid connection interface device is installed at each distributed energy grid connection point. The grid-connected interface devices are respectively connected to the respective distributed energy grid connection points, and are also connected to the remote distributed energy area management and control equipment.

The technical scheme further limited in the present invention is:

Preferably, in the above technical solution, the distributed energy source is a distributed photovoltaic power station.

A control method using a distributed energy area management and control system is carried out according to the following steps:

S1, communicate and connect the grid-connected interface equipment at the grid-connected place of distributed energy;

S2, the parameters of each distributed energy set on the distributed energy area management and control equipment include: rated capacity, voltage exceeding limit value and adjustment command;

S3, each interface device sends the voltage at its location and the operating status of the distributed energy to the distributed energy area management and control device;

S4, set a voltage standard value, compare the voltage value obtained by each grid-connected interface device with the voltage standard value, if the difference between the two is greater than the voltage exceeding the limit value, then enter S5, otherwise continue to repeat S4;

S5, when the distributed energy area management and control equipment determines that the voltage exceeds the limit, the distributed energy area management and control equipment executes the following two strategies: reducing the output of DG (Distributed Generation, DG), and charging the energy storage battery;

S6, send two strategies to the grid-connected interface device where the voltage crosses the line;

S7, the grid-connected interface device charges the energy storage battery there according to the received strategy and the amount of charging current;

S8, the distributed energy area management and control device compares the voltage value with the voltage standard value according to the voltage value received at this time. If the difference between the two is less than the voltage exceeding the limit value, it stops sending the adjustment command and repeats step S4. If the difference is greater than the voltage limit, continue to reduce the output of DG;

S9, repeat step S8 until the DG output is 0.

The technical scheme further limited in the present invention is:

Preferably, in the above technical solution, in step S4, the voltages of the grid connection points of the distributed energy resources are set to be U ₁ and U ₂ in the order of distance from the substation from near to far. . . U _n , the n is a positive integer. When the difference between U _n and the voltage standard value is greater than the voltage over-limit value, all the grid-connected points of distributed energy resources behind it all enter S5 .

Preferably, in the above technical solution, in step 1, if there is already a similar device at the grid-connected place of the distributed energy, a communication switching device is deployed to complete the functions of local data collection and communication with the distributed energy area management and control equipment .

Compared with the prior art, the present invention has the following beneficial effects: through the power control of the energy storage system, the power fluctuation of the distributed energy source and the influence of irregular start and stop on the power supply voltage quality of the distribution network can be effectively suppressed, and the voltage of the network can be effectively improved. Level.

Description of drawings:

Figure 1 is a schematic diagram of an existing power distribution network;

2 is a schematic diagram of the distributed energy area management and control system of the present invention installed in a distribution network;

FIG. 3 is a schematic diagram of adjustment after the voltage exceeds the lower limit;

FIG. 4 is a schematic diagram of adjustment after the voltage exceeds the upper limit.

Detailed ways:

The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

Unless expressly stated otherwise, throughout the specification and claims, the term "comprising" or its conjugations such as "comprising" or "comprising" and the like will be understood to include the stated elements or components, and Other elements or other components are not excluded.

A distributed energy area management and control system is characterized in that: a distributed energy area management and control device is installed at the outlet of a substation, and a grid connection interface device is installed at each distributed energy grid connection point at the lower end. The grid-connected interface device transmits the current, voltage, switch position, and distributed energy-related parameters of the corresponding node to the regional management and control device in real time. The regional management and control equipment controls the distributed energy resources at the lower end according to these data.

A schematic diagram of the system is shown in Figure 2.

In many cases, grid integration of DERs reduces voltage quality. However, through the distributed energy regional management and control system shown in Figure 2, the voltage quality of some nodes can be significantly improved, and the problem of voltage over-limits can be avoided.

A control method of a distributed energy area management and control system is carried out according to the following steps:

1) Deploy distributed energy area management and control equipment at the outlet of the substation.

2) Deploy interface equipment at the grid-connected place of distributed energy (if similar equipment already exists at the grid-connected place of distributed energy, deploy a communication switching device to complete local data collection and communication with distributed energy regional management and control equipment. Function);

3) Set the parameters of each distributed energy source on the distributed energy area management and control equipment: rated capacity, voltage over-limit value, adjustment command, etc.;

4) Each grid-connected interface device sends the voltage and distributed energy operating status at its location to the distributed energy regional management and control equipment;

5) When the distributed energy area management and control equipment determines that the voltage of U3 exceeds the limit, a strategy is given according to the operation state of the distributed energy at this time; (taking the voltage of U3 exceeding the upper limit as an example)

6) The distributed energy area management and control equipment implements the following two strategies: 1) Reduce the output of DG; 2) Charge the energy storage battery;

7) Send strategy 2 to the grid-connected interface device at the energy storage battery.

8) The grid-connected interface device at the energy storage battery charges the battery according to the received strategy and charging current;

9) According to the voltages of U2 and U3 received at this time, the distributed energy area management and control equipment stops sending adjustment commands if they are within the qualified range. If not within the qualified range, continue with the following steps.

10) Send strategy 1 to the grid-connected interface device at the DG.

11) The grid-connected interface device at the DG adjusts the DG according to the received strategy and output adjustment amount;

12) According to the voltages of U2 and U3 received at this time, the distributed energy area management and control equipment stops sending adjustment commands if they are within the qualified range. If not within the qualified range, continue with steps 10) and 11). Until the adjustment amount reaches the maximum value (that is, the distributed DG output is 0).

The process of improving the voltage quality through the distributed energy regional management and control system and solving the problem of voltage exceeding the limit is as follows:

Curve II in Figure 3 shows that DG has no output (or quits work) and the energy storage is not involved in regulation. It can be seen that the node voltage level of U ₂ is low at this time. Because U ₃ is at the end of the feeder, the node voltage level exceeds the low voltage. limits.

After the distributed energy area management and control system is installed, the grid-connected interface equipment in the system transmits the voltage values of U ₁ , U ₂ and U ₃ , the output state of DG, and the running state of the energy storage battery to the distributed energy storage system through the ring network. Energy area management and control equipment. After the equipment collects data, it determines that the voltage at U ₃ exceeds the lower limit, and implements the following two strategies: 1) Increase the output of DG; 2) Discharge the energy storage battery. The execution of these two strategies is also transmitted to the grid-connected interface device through the ring network to implement specific operations.

Curve II in Figure 4 shows that the output power of DG is large and the energy storage is not involved in the regulation. It can be seen that the voltage level of the node U ₂ is high at this time, and the voltage level of the node U ₃ exceeds the low voltage limit.

After the distributed energy area management and control system is installed, the grid-connected interface equipment in the system transmits the voltage values of U ₁ , U ₂ and U ₃ , the output state of DG, and the running state of the energy storage battery to the distributed energy storage system through the ring network. Energy area management and control equipment. After the equipment collects data, it determines that the voltage exceeds the upper limit at U ₃ , and implements the following two strategies: 1) Reduce the output of DG; 2) Charge the energy storage battery. The execution of these two strategies is also transmitted to the grid-connected interface device through the ring network to implement specific operations.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and illustration. These descriptions are not intended to limit the invention to the precise form disclosed, and obviously many changes and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described for the purpose of explaining certain principles of the invention and their practical applications, to thereby enable others skilled in the art to make and utilize various exemplary embodiments and various different aspects of the invention. Choose and change. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims (5)

1. a control method utilizing a distributed energy area management and control system, is characterized in that: carry out according to the following steps: S1, communicate and connect the grid-connected interface equipment at the grid-connected place of distributed energy; S2, the parameters of each distributed energy set on the distributed energy area management and control equipment include: rated capacity, voltage exceeding limit value and adjustment command; S3, each interface device sends the voltage at its location and the operating status of the distributed energy to the distributed energy area management and control device; S4, set a voltage standard value, compare the voltage value obtained by each grid-connected interface device with the voltage standard value, if the difference between the two is greater than the voltage exceeding the limit value, then enter S5, otherwise continue to repeat S4; S5, when the distributed energy area management and control equipment determines that the voltage exceeds the limit, the distributed energy area management and control equipment executes the following two strategies: reducing the output of the DG and charging the energy storage battery; S6, send two strategies to the grid-connected interface device at the voltage crossing line; S7, the grid-connected interface device charges the energy storage battery there according to the received strategy and the amount of charging current; S8, the distributed energy area management and control device compares the voltage value with the voltage standard value according to the voltage value received at this time. If the difference between the two is less than the voltage exceeding the limit value, it stops sending the adjustment command and repeats step S4. If the difference is greater than the voltage limit, continue to reduce the output of DG; S9, repeat step S8 until the DG output is 0. 2. The control method using the distributed energy area management and control system according to claim 1, wherein in step S4, the voltage of the grid connection point of the distributed energy is set to be U1, U2...Un according to the distance from the substation from near to far. , the n is a positive integer. When the difference between Un and the voltage standard value is greater than the voltage over-limit value, all the grid-connected points of distributed energy resources behind it enter S5. 3. The control method of utilizing a distributed energy area management and control system according to claim 1, wherein in step 1, if there is a device similar to a grid-connected interface device at the grid-connected place of the distributed energy, then deploy communication The transfer device completes the functions of local data collection and communication with distributed energy area management and control equipment. 4. The control method using a distributed energy area management and control system according to claim 1, wherein the distributed energy area management and control system is specifically: installing a distributed energy area management and control device at the outlet end of the substation, and A grid-connected interface device is installed at each distributed energy grid-connected point, and each grid-connected interface device communicates with its own distributed energy grid-connected point, and also communicates with remote distributed energy area management and control equipment. 5 . The control method using a distributed energy area management and control system according to claim 1 , wherein the distributed energy is a distributed photovoltaic power station. 6 .

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