A power distribution network-based virtual power station control system and a control method thereof

Abstract

The application discloses a kind of virtual power station control systems and control method based on distribution network, the system includes multiple virtual power station controllers and multiple distributed power sources, the multiple virtual power station controllers are established on distribution network line, and grid-connected controller is arranged on the line where each distributed power source is connected, the multiple virtual power station controllers and all grid-connected controllers on distributed power source establish ring connection, the multiple virtual power station controllers coordinate control all distributed power sources on the line;The application has the advantages that: by the virtual power station controller on distribution network, directly control distributed power source, there is no super-long delay, dispatching control responds timely, guarantees power grid operation safety, in the case where single virtual power station controller exists fault, can be taken over by other virtual power station controller, avoid dispatching control interruption due to fault, further guarantee power grid operation safety.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power systems, more particularly to a virtual power station control system based on a distribution network and a control method thereof. BACKGROUND

[0002] To build a new type of power system, a large number of distributed energy sources are connected to the distribution network, making the active characteristics of the distribution network more obvious. However, the distributed energy sources have characteristics such as randomness and volatility, and the power flow changes greatly. The scheduling means is lacking, and the active and reactive power imbalance is prominent. At the present stage, the group control and group regulation control response is slow, the control granularity is large, and there is a lack of primary frequency modulation, dynamic reactive power response and other transient controls, which are difficult to meet the functions that the distributed power supply should have as a power supply point.

[0003] Chinese Patent Publication No. CN110416998A discloses a regional complex distribution network scheduling control management system based on a virtual power plant, which includes different types of virtual power plants and a big data cloud computing platform constructed at the regional distribution network scheduling center. By developing the scheduling control management system of the regional power grid, the complex distribution network can be connected in the form of a virtual power plant and uniformly coordinated and optimized. It is a new type of complex distribution network management mode. The regional complex distribution network scheduling control management system can be widely applied in distributed new energy rich areas, and has practical significance for the development of virtual power plants, the development of renewable green energy and the realization of energy transformation. However, in the patent application, the distribution network is connected in the form of a virtual power plant and is uniformly coordinated and optimized. However, the scheduling control mainly depends on the power trading center and the superior dispatching center, and the distributed power supply is connected to the distribution network. The control of the superior dispatching center will have a delay, resulting in a slow response and affecting the safe operation of the power grid. SUMMARY

[0004] The technical problem to be solved by the present application is that the scheduling control in the existing technology distribution network mainly depends on the power trading center and the superior dispatching center, and the distributed power supply is connected to the distribution network. The control of the superior dispatching center will have a delay, resulting in a slow response and affecting the safe operation of the power grid.

[0005] The present application solves the above technical problems by the following technical means: a virtual power station control system based on a distribution network, comprising a plurality of virtual power station controllers and a plurality of distributed power sources. The plurality of virtual power station controllers are established on the distribution network lines, and a grid-connected controller is provided on the line where each distributed power source is connected. The plurality of virtual power station controllers and the grid-connected controllers on all distributed power sources are connected in a ring shape. The plurality of virtual power station controllers coordinate and control all distributed power sources on the entire line.

[0006] Beneficial effects: multiple virtual power station controllers of the application are established on distribution network lines, and the distributed power is directly controlled through the virtual power station controllers on the distribution network, without long delay, the scheduling control response is timely, the power grid operation safety is guaranteed, and the multiple virtual power station controllers and all grid-connected controllers on the distributed power are connected in a ring, in the case of failure of a single virtual power station controller, other virtual power station controllers can take over, avoiding interruption of scheduling control due to failure, further guaranteeing the safety of power grid operation.

[0007] Further, each grid-connected controller is connected with a switching station, and the switching stations corresponding to all grid-connected controllers are sequentially connected in series.

[0008] Further, one end of the line is configured with a virtual power station controller, and the other end of the line is configured with another virtual power station controller, the two virtual power station controllers work in coordination, one of all switching stations is set as a tie point, the tie point and the distributed power corresponding to one side of the tie point are controlled by the same virtual power station controller, and the distributed power on the other side of the tie point is controlled by the other virtual power station controller.

[0009] Further, the multiple virtual power station controllers and all grid-connected controllers on the distributed power are connected in a ring through optical fibers or establish a network communication architecture through 5G communication.

[0010] Further, the distributed power includes distributed photovoltaic, distributed wind power, distributed energy storage power station and super capacitor.

[0011] The application also provides a control method of a virtual power station control system based on a distribution network, the method comprising:

[0012] The grid-connected controller receives the control of the virtual power station controller, collects the electrical data of the distributed power, and simultaneously uploads the current electrical data of the distributed power in real time, in addition, the grid-connected controller realizes fast power control of the distributed power through the internal communication network of the distributed power.

[0013] The virtual power station controller collects the active and reactive power information of the incoming line and the electrical information of the grid-connected controller, and realizes real-time related control of the grid-connected controller, the related control including AGC / AVC, primary frequency modulation, dynamic reactive power response and line inertia response control.

[0014] Further, the fast power control of the distributed power realized by the grid-connected controller includes:

[0015] The grid-connected controller controls the active and reactive power output response time of the distributed power to be 200ms or less.

[0016] Further, the electrical data of the distributed power collected by the grid-connected controller includes:

[0017] And off-grid state and current active, reactive, active reserve, reactive reserve information.

[0018] Further, the virtual power station controller performs automatic tie detection regularly, and dynamically adjusts the distributed power in the control domain of the virtual power station controller.

[0019] Further, the automatic tie detection comprises:

[0020] After the virtual power station controller issues the Qs size of the capacitive reactive power remote control to a distributed power, all virtual power station controllers monitor whether the reactive power changes and the size of the change at the beginning and end of the line. If the virtual power station controller monitors that the reactive power changes by Qs size within the starting monitoring time, the distributed power is put into the control domain of the virtual power station controller, and if there is no change, the distributed power is removed from the control domain of the virtual power station controller.

[0021] The application has the advantages that:

[0022] (1) The multiple virtual power station controllers of the application are established on the distribution network line, the distributed power is directly controlled by the virtual power station controller on the distribution network, there is no long delay, the dispatching control responds in time, the power grid operation safety is guaranteed, and the multiple virtual power station controllers and all grid-connected controllers on the distributed power establish a ring connection, so that in the case of failure of a single virtual power station controller, the other virtual power station controllers can take over, avoiding interruption of dispatching control due to failure, and further guaranteeing the safety of power grid operation.

[0023] (2) The application sets a tie point, the tie point and the corresponding distributed power on one side thereof are controlled by the same virtual power station controller, the distributed power on the other side of the tie point is controlled by another virtual power station controller, the distribution line is divided into two sections for control, the control ability of the distributed power in the entire line is guaranteed, the line topology change or tie point change is avoided, and the distributed power in the entire line is controlled; the problem of slow instruction and data transmission due to control of too many distributed powers by a single virtual power station controller is avoided.

[0024] (3) The grid-connected controller of the application realizes fast power control of the distributed power station through the internal communication network of the distributed power, greatly improves the response time of the distributed power, and improves the system response speed.

[0025] (4) The virtual power station controller of the application has perfect power characteristic control requirements, supports AGC / AVC, primary frequency modulation, dynamic reactive power response, line inertia response and other functions.

[0026] (5) The virtual power station controller performs automatic tie detection regularly, dynamically adjusts the distributed power in the control domain of the virtual power station controller, realizes dynamic autonomy of the line, and simplifies manual operation and maintenance work. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 An architecture diagram of a virtual power station control system based on a power distribution network according to an embodiment of the present application;

[0028] Figure 2 A schematic diagram of a virtual power station control system based on a power distribution network according to an embodiment of the present application in a fault condition;

[0029] Figure 3 A schematic diagram of a virtual power station control system based on a power distribution network according to an embodiment of the present application in a fault condition;

[0030] Figure 4 A flowchart of a control method of a virtual power station control system based on a power distribution network according to an embodiment of the present application;

[0031] Figure 5 An automatic tie detection flowchart in a control method of a virtual power station control system based on a power distribution network according to an embodiment of the present application. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in a clear and complete manner in conjunction with the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0033] As shown in Figure 1 A virtual power station control system based on a power distribution network, comprising two virtual power station controllers (XNZC1 and XNZC2) and four distributed power sources (FG1 to FG4), the two virtual power station controllers are established on a power distribution line, as shown in Figure 1 The first end and the end of the power distribution line, respectively, a grid controller BWC is arranged on the line where each distributed power source is arranged, the two virtual power station controllers and the grid controller BWC on all distributed power sources are connected through an optical fiber to form a ring, or a hand-in-hand network communication architecture is established through 5G communication, that is, a ring wireless communication architecture, the multiple virtual power station controllers coordinate and control all distributed power sources on the line.

[0034] Continuing to refer to Figure 1Each grid-connected controller BWC is connected with a switch station, and all the grid-connected controllers BWC are sequentially connected with corresponding switch stations in series. One of all the switch stations is set as a tie point, and the distributed power supply corresponding to the tie point and on one side thereof is controlled by a same virtual power station controller, and the distributed power supply on the other side of the tie point is controlled by another virtual power station controller. Figure 1 In the middle, the switch station C is taken as the tie point, and the distributed power supplies FG1, FG2 and FG3 in the switch station A, the switch station B and the switch station C are controlled by a same virtual power station controller, that is, by Figure 1 In the left, the virtual power station controller located at the first end of the distribution network line controls, and the distributed power supply of the switch station E is controlled by another virtual power station controller, that is, by Figure 1 In the right, the virtual power station controller located at the end of the distribution network line controls. In the case of change of the tie point, the virtual power station controller automatically adjusts the controlled distributed power supply according to the change of the tie point.

[0035] In the embodiment, the distributed power supply includes a distributed photovoltaic power supply, a distributed wind power supply, a distributed energy storage power station and a super capacitor.

[0036] As shown in Figure 4 The application further provides a control method of the virtual power station control system based on the distribution network, and the method comprises the following steps:

[0037] The grid-connected controller BWC realizes the fast power control of the distributed power station through the internal communication network of the distributed power supply, and the active and reactive power output response time needs to reach 200 ms or below. The grid-connected controller BWC directly samples the electrical data of the grid-connected point, including the information such as the grid-connected and off-grid state, the current active power, the reactive power, the active power reserve and the reactive power reserve.

[0038] The virtual power station controller has a real-time analog channel, and the real-time sampling information includes the current, the voltage, the active power and the reactive power information. The virtual power station controller subscribes to the electrical information of the grid-connected controller BWC through the optical fiber or the 5G mode. The virtual power station controller supports the AGC / AVC, the primary frequency modulation, the dynamic reactive power response, the line inertia response and other functions, and has perfect power supply characteristic control requirements. The virtual power station controller issues control instructions through the optical fiber or the 5G mode to control the distributed power supply in the control domain of the virtual power station controller.

[0039] The virtual power station controller has a communication interaction function with dispatching and supports receiving dispatching instructions, dispatching with the virtual power station controller as a dispatching control interface, and controlling power supply parameters of the whole line, including primary frequency modulation, AGC / AVC, inertia support, etc. The virtual power station controller has voltage management and reactive power regulation functions, and can automatically control the reactive power output of the distributed power source in the line during normal operation to balance the line voltage and dynamic reactive power, control the automatic operation AGC function, and control the active power output in real time to achieve dynamic autonomy of the active and reactive power of the line.

[0040] The virtual power station controller detects the tie point at regular intervals, and when the tie point changes, it performs automatic tie detection and dynamically adjusts the distributed power sources in the control domain of the virtual power station controller. Figure 5 As shown in the following example of automatic tie detection:

[0041] S6-1, the initial operating state is as shown in Figure 1 Two virtual power station controllers are named as the first virtual power station controller XNZC1 and the second virtual power station controller XNZC2, the tie point is 302, the distributed power sources FG1, FG2, and FG3 belong to the control domain of the first virtual power station controller and are controlled by the first virtual power station controller XNZC1, and FG4 belongs to the control domain of the second virtual power station controller and is controlled by the second virtual power station controller XNZC2.

[0042] S6-2, when F1 fault occurs, as shown in Figure 2 The line will trip the switches 202 and 301, and the line operating structure is converted to Figure 3 At this time, the tie point is at 202.

[0043] S6-3, after the automatic tie identification function is running, the first virtual power station controller XNZC1 will sequentially issue a reactive power instruction to the distributed power sources FG1-FG4, and the first virtual power station controller XNZC1 and the second virtual power station controller XNZC2 will sequentially monitor the reactive current change to determine the current distributed power source control domain.

[0044] S6-4, taking FG3 as an example. After the first virtual power station controller XNZC1 issues a 200 kvar capacitive reactive power remote control to the distributed power source FG3, the first virtual power station controller XNZC1 and the second virtual power station controller XNZC2 monitor whether the reactive power changes and the size of the change at the beginning and end of the line within the starting monitoring time, such as 500 ms. If the first virtual power station controller XNZC1 monitors that the reactive power changes by about 200 kvar, the distributed power source FG3 is put into the control domain of the first virtual power station controller XNZC1, and if there is no change, the distributed power source FG3 is removed from the control domain of the first virtual power station controller XNZC1.

[0045] Similarly, if the second virtual power station controller XNZC2 monitors a change in reactive power of about 200 kvar, then the distributed power source FG3 is placed in its control domain. If there is no change, then it is removed from its control domain.

[0046] The above embodiments are only used to illustrate the technical solutions of the present application, but not limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, those ordinarily skilled in the art should understand: the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A power distribution grid based virtual power plant control system, characterized by, The multiple virtual power station controllers are established on a distribution network line, and a grid-connected controller is arranged on a line where each distributed power source is located, the multiple virtual power station controllers and the grid-connected controllers on all distributed power sources establish a ring connection, and the multiple virtual power station controllers coordinate to control all distributed power sources on the entire line. After a virtual power station controller issues a Qs size of capacitive reactive power remote adjustment to a distributed power source, all virtual power station controllers monitor whether the reactive power changes and the size of the change at both ends of the line, and if the virtual power station controller monitors that the reactive power changes by Qs size within the starting monitoring time, the distributed power source is put into the control domain of the virtual power station controller, and if there is no change, the distributed power source is removed from the control domain of the virtual power station controller.

2. The power distribution grid based virtual power plant control system as claimed in claim 1, wherein, Each grid-connected controller is connected with a switching station, and the switching stations corresponding to all grid-connected controllers are sequentially connected in series.

3. The power distribution grid based virtual power plant control system as claimed in claim 1, wherein, One virtual power station controller is arranged at each end of the line, and the two virtual power station controllers work in coordination, one of all switching stations is set as a tie point, the tie point and the distributed power sources on its side are controlled by the same virtual power station controller, and the distributed power sources on the other side of the tie point are controlled by another virtual power station controller.

4. The power distribution grid based virtual power plant control system of claim 1, wherein, The multiple virtual power station controllers and the grid-connected controllers on all distributed power sources establish a ring connection through optical fibers or a network communication architecture through 5G communication.

5. The power distribution grid based virtual power plant control system as claimed in claim 1, wherein, The distributed power sources include distributed photovoltaic power sources, distributed wind power sources and distributed energy storage power stations.

6. The control method of a power distribution grid based virtual power plant control system according to any one of claims 1-5, characterized in that, The method comprises: The grid-connected controller receives control of the virtual power station controller, collects electrical data of the distributed power source, and simultaneously uploads the current electrical data of the distributed power source in real time, and additionally, realizes fast power control of the distributed power source through an internal communication network of the distributed power source. The virtual power station controller collects in-line active and reactive power information in combination with electrical information of the grid-connected controller, and performs relevant control on the grid-connected controller in real time, and the relevant control includes AGC, AVC, primary frequency modulation, dynamic reactive power response and line inertia response control.

7. The control method of a virtual power plant control system based on a power distribution network according to claim 6, characterized by, The grid-connected controller realizes fast power control of the distributed power source, which comprises: The grid-connected controller controls the active and reactive power output response time of the distributed power source to reach 200 ms or less.

8. The control method of a virtual power plant control system based on a power distribution network according to claim 6, wherein The electrical data of the distributed power source collected by the grid-connected controller comprises: On-off grid state and current active power, reactive power, active power reserve and reactive power reserve information.

9. The control method of a virtual power plant control system based on a power distribution network according to claim 6, characterized by, The virtual power station controller performs automatic tie detection at regular intervals, and dynamically adjusts the distributed power sources in the control domain of the virtual power station controller.

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