An energy-saving large power grid stability maintenance and control system

Abstract

An energy-saving large power grid stability control system proposed by the present invention includes: a main grid controller, a main grid AC bus, and N microgrids; among which, M microgrids are powered by photovoltaic modules and are denoted as photovoltaic microgrids; the remaining microgrids are denoted as maintenance microgrids, and the power supply of the maintenance microgrids is denoted as a maintenance power supply; M < N; each microgrid includes a microgrid controller; in the photovoltaic microgrid, the photovoltaic inverter is in the maximum operating power state, and the main grid controller adjusts the working state of each maintenance power supply according to the output power of all photovoltaic inverters and the main grid load power. The present invention balances the power supply fluctuations of the photovoltaic modules through the power adjustment of the maintenance power supply, that is, it realizes the full utilization of solar power generation and ensures the stable power supply of the main grid and the photovoltaic microgrid. The present invention is conducive to the popularization of photovoltaic microgrids.

Description

Technical Field

[0001] The present invention relates to the technical field of microgrids, and in particular to an energy-saving large power grid stabilization and control system. Background Art

[0002] Photovoltaic modules convert solar energy into electrical energy for power supply, which is a well-known pollution-free, energy-saving and environmentally friendly power supply method. However, photovoltaic power supply is limited by the intensity of sunlight, and it is difficult to ensure stable power supply. Therefore, it has not yet been widely popularized. Summary of the invention

[0003] Based on the technical problems existing in the background technology, the present invention proposes an energy-saving large power grid stabilization and control system.

[0004] The present invention proposes an energy-saving large power grid stabilization control system, comprising: a main grid controller, a main grid AC bus and N microgrids; wherein M microgrids are powered by photovoltaic modules, recorded as photovoltaic microgrids; the remaining microgrids are recorded as maintenance microgrids, and the power supply of the maintenance microgrids is recorded as maintenance power supply; M <N;

[0005] Each microgrid contains a microgrid controller;

[0006] In the photovoltaic microgrid, the photovoltaic inverter is in the maximum operating power state, and the main grid controller adjusts the working state of each maintenance power source according to the output power of all photovoltaic inverters and the main grid load power.

[0007] Preferably, a corresponding weight is set for each maintenance power source in the main grid controller, and the weight is proportional to the distance between the maintenance power source and the nearest photovoltaic component, and the smaller the distance, the smaller the weight;

[0008] The main grid controller is used to control the working state of each power supply according to the weight sequence when the main grid AC bus power is less than the main grid load power.

[0009] Preferably, the weight calculation model of each maintenance power source is:

[0010] Arrange each maintenance power source in ascending order according to the distance from the nearest photovoltaic module, and take the sequence number of each maintenance power source in the queue as the weight.

[0011] Preferably, the main grid controller has a preset self-sufficient power generation power corresponding to each maintenance power supply; when the main grid AC bus power is less than the main grid load power, the main grid controller detects each maintenance power supply one by one according to the order of weight from large to small, and adjusts the maintenance power supply whose current power generation power is less than the self-sufficient power generation power to the self-sufficient power generation power until the main grid AC bus power is greater than or equal to the main grid load power.

[0012] Preferably, the microgrid controller corresponding to the photovoltaic microgrid is recorded as a photovoltaic controller. Each photovoltaic controller calculates the output power of the photovoltaic inverter in real time and is used to control the photovoltaic component to be disconnected from the grid when the output power of the photovoltaic inverter is less than a preset power threshold.

[0013] Preferably, a power margin threshold corresponding to each photovoltaic component is preset in the main grid controller; when the photovoltaic component is off-grid, the main grid controller is used to control one or more maintenance power supplies closest to the off-grid photovoltaic component to increase the power generation power according to the preset power margin threshold.

[0014] Preferably, when the photovoltaic component is off-grid, the main grid controller allocates the power margin threshold corresponding to the off-grid photovoltaic component to one or more maintenance power sources in order from near to far from the off-grid photovoltaic component.

[0015] Preferably, a power margin threshold allocation model is provided in the main network controller:

[0016] Among them, S is the power margin threshold of the off-grid photovoltaic module; among the maintenance power sources from near to far away from the off-grid photovoltaic module, A i is the maximum power generation of the ith power supply, P i is the current power generation of the ith maintenance power source, η i is the power supply efficiency of the i-th maintaining power source to the microgrid where the off-grid PV module is located.

[0017] Preferably, the power margin threshold is equal to the load power of the microgrid where the photovoltaic assembly is located.

[0018] Preferably, the maintenance power source includes: a hydroelectric power generation device, a wind power generation device, a thermal power generation device and / or a battery.

[0019] The present invention proposes an energy-saving large power grid stabilization control system, which realizes environmentally friendly power generation through solar power generation by maintaining the cooperation of power supply and photovoltaic components, and is conducive to reducing the working efficiency of the power supply, thereby achieving energy conservation and emission reduction; when the photoelectric conversion efficiency of the photovoltaic components is reduced and the power supply is insufficient, the main grid controller generates a power generation control instruction for the maintenance power supply according to the difference between the power supply power in the main grid and the load power of the main grid, and the microgrid controller in the maintenance microgrid adjusts the corresponding working state of the maintenance power supply according to the received power generation control instruction, thereby balancing the power supply fluctuation of the photovoltaic components through the power regulation of the maintenance power supply, thereby achieving full utilization of solar power generation and ensuring stable power supply of the main grid and the photovoltaic microgrid.

[0020] The present invention is beneficial to the popularization of photovoltaic microgrids. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1Schematic diagram of an energy-saving large power grid stability control system proposed by the present invention. Detailed implementation manners

[0022] Referring to Figure 1 An energy-saving large power grid stability control system proposed by the present invention includes: a main grid controller, a main grid AC bus, and N microgrids. Among them, M microgrids are powered by photovoltaic modules, denoted as photovoltaic microgrids; the remaining microgrids are denoted as maintenance microgrids, and the power supply of the maintenance microgrids is denoted as the maintenance power supply. M < N. Specifically, during implementation, in order to ensure sufficient power supply of the main grid when sunlight is insufficient, it can be further set that M ≤ N / 2; for example, M = N / 3.

[0023] Each microgrid includes a microgrid controller.

[0024] In the photovoltaic microgrid, the photovoltaic inverters are in the maximum operating power state, and the main grid controller adjusts the working states of each maintenance power supply according to the output powers of all photovoltaic inverters and the main grid load power.

[0025] Specifically, in this implementation manner, the main grid controller communicates with the microgrid controller to obtain the working states of each photovoltaic module and the maintenance power supply in real time. When the photoelectric conversion efficiency of the photovoltaic module decreases and the power supply is insufficient, the main grid controller generates a power generation control command for the maintenance power supply according to the difference between the power supply power and the main grid load power in the main grid. The microgrid controller in the maintenance microgrid adjusts the working state of the corresponding maintenance power supply according to the received power generation control command, so as to balance the power supply fluctuation of the photovoltaic module through the power adjustment of the maintenance power supply, that is, it realizes the full utilization of solar power generation and ensures the stable power supply of the main grid and the photovoltaic microgrid.

[0026] In this implementation manner, the maintenance power supply can adopt a hydroelectric power generation device, a wind power generation device, a thermal power generation device, a storage battery, etc.

[0027] In this implementation manner, the main grid controller sets corresponding weights for each maintenance power supply. The weight is proportional to the distance of the maintenance power supply from the nearest photovoltaic module. The smaller the distance, the smaller the weight.

[0028] The main grid controller is used to control the working states of each maintenance power supply according to the weight order when the power of the main grid AC bus is less than the main grid load power.

[0029] Specifically, in the main grid controller, the self-generated power corresponding to each maintenance power supply is preset. When the power of the main grid AC bus is less than the main grid load power, the main grid controller detects each maintenance power supply one by one according to the order of decreasing weight, and adjusts the maintenance power supply with the current power generation less than the self-generated power to the self-generated power until the power of the main grid AC bus is greater than or equal to the main grid load power.

[0030] The AC bus power of the main grid is the power supply power of the main grid, that is, the sum of the power generation of all networked power sources (including photovoltaic modules and maintenance power sources) in the main grid. When the AC bus power of the main grid is less than the load power of the main grid, it means that the solar energy in the environment where some or all photovoltaic modules are located is insufficient, and the photovoltaic power supply efficiency is reduced. At this time, the power generation of the maintenance power source far away from the photovoltaic module is increased first, which is conducive to reducing the power dispatch distance in the main grid, thereby reducing network losses and improving power supply utilization.

[0031] Specifically, in this implementation, the weight calculation model of each maintenance power source is:

[0032] Arrange each maintenance power source in ascending order according to the distance from the nearest photovoltaic module, and take the sequence number of each maintenance power source in the queue as the weight. In this way, it can be ensured that each weight value is a positive integer, which is convenient for storage and call.

[0033] In this implementation, the microgrid controller corresponding to the photovoltaic power grid is recorded as a photovoltaic controller. Each photovoltaic controller calculates the output power of the photovoltaic inverter in real time and is used to control the photovoltaic module to be disconnected from the grid when the output power of the photovoltaic inverter is less than the preset power threshold. In this way, by disconnecting the photovoltaic module in time, the reverse charging of the photovoltaic module can be avoided, thereby increasing the load power of the main grid.

[0034] In this embodiment, the main grid controller is preset with a power margin threshold corresponding to each photovoltaic module. When the photovoltaic module is off-grid, the main grid controller is used to control one or more maintenance power supplies closest to the off-grid photovoltaic module to increase the power generation according to the preset power margin threshold. In this way, the power supply gap caused by the off-grid photovoltaic module can be supplemented by the maintenance power supply, thereby ensuring the power supply and working stability of the main grid and the microgrid where the off-grid photovoltaic module is located.

[0035] Specifically, in this embodiment, when the photovoltaic module is off-grid, the main network controller allocates the power margin threshold corresponding to the off-grid photovoltaic module to one or more maintenance power sources in order from near to far from the off-grid photovoltaic module. Specifically, the main network controller is provided with a power margin threshold allocation model:

[0036] Among them, S is the power margin threshold of the off-grid PV module. Among the maintenance power sources from near to far away from the off-grid PV module, A i is the maximum power generation of the ith power supply, P i is the current power generation of the ith maintenance power source, η i is the power supply efficiency of the i-th maintaining power source to the microgrid where the off-grid PV module is located.

[0037] In this way, the power supply loss of off-grid photovoltaic components can be supplemented by increasing the power generation power of the maintenance power source in sequence from near to far, which is beneficial to shorten the power supply scheduling distance of the maintenance power source, thereby reducing network losses and improving power supply utilization.

[0038] Specifically, in this implementation, the power margin threshold is equal to the load power of the microgrid where the photovoltaic component is located, and the preset power threshold is less than the power margin threshold.

[0039] The above description is only a preferred specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solution and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An energy-saving large power grid stabilization control system, characterized in that: include: Main grid controller, main grid AC bus and N microgrids; Among them, M microgrids are powered by photovoltaic modules, which are recorded as photovoltaic microgrids; the remaining microgrids are recorded as maintenance microgrids, and the power supply of the maintenance microgrids is recorded as maintenance power supply; M <N; Each microgrid contains a microgrid controller; In the photovoltaic microgrid, the photovoltaic inverter is in the maximum operating power state, and the main grid controller adjusts the working state of each maintenance power source according to the output power of all photovoltaic inverters and the main grid load power; The microgrid controller corresponding to the photovoltaic microgrid is recorded as a photovoltaic controller. Each photovoltaic controller calculates the output power of the photovoltaic inverter in real time and is used to control the photovoltaic component to be disconnected from the grid when the output power of the photovoltaic inverter is less than a preset power threshold. The main grid controller is preset with a power margin threshold corresponding to each photovoltaic module; when the photovoltaic module is off-grid, the main grid controller is used to control one or more maintenance power sources closest to the off-grid photovoltaic module to increase the power generation according to the preset power margin threshold; The main grid controller has a corresponding weight for each maintenance power source. The weight is proportional to the distance between the maintenance power source and the nearest photovoltaic module. The smaller the distance, the smaller the weight. The main grid controller is used to control the working state of each power supply according to the weight sequence when the main grid AC bus power is less than the main grid load power; The weight calculation model of each maintenance power source is: Arrange each maintenance power source in ascending order according to the distance from the nearest photovoltaic module, and take the sequence number of each maintenance power source in the queue as the weight; The main grid controller is preset with the self-sufficient power generation corresponding to each maintenance power source; when the main grid AC bus power is less than the main grid load power, the main grid controller detects each maintenance power source one by one according to the order of weight from large to small, and adjusts the maintenance power source whose current power generation is less than the self-sufficient power generation to the self-sufficient power generation until the main grid AC bus power is greater than or equal to the main grid load power; When the PV module is off-grid, the main grid controller allocates the power margin threshold corresponding to the off-grid PV module to one or more maintenance power sources in order from near to far from the off-grid PV module; The main network controller is equipped with a power margin threshold allocation model: Among them, S is the power margin threshold of the off-grid photovoltaic module; among the maintenance power sources from near to far away from the off-grid photovoltaic module, A i is the maximum power generation of the ith power supply, P i is the current power generation of the ith maintenance power source, η i The power supply efficiency of the i-th power supply to the microgrid where the off-grid photovoltaic module is located; The power margin threshold is equal to the load power of the microgrid where the PV module is located.

2. The energy-saving large power grid stabilization control system according to claim 1, characterized in that: The maintenance power source includes: a hydroelectric power generation device, a wind power generation device, a thermal power generation device and / or a battery.

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