Photovoltaic power station stability control device capable of monitoring photovoltaic array

Abstract

The utility model relates to a photovoltaic power station stability control device capable of monitoring a photovoltaic array, and belongs to the field of stability control. Comprising a processor, a power supply module, a monitoring module, a control instruction module, a network state module, a data storage module, an indicating lamp / alarm output module, a main switch and a distributed monitoring module. The monitoring module comprises voltage and current signals of a grid-connected point of the photovoltaic power station, and voltage and current signals of each current collection line; the control instruction module is used for controlling an outgoing circuit breaker of the photovoltaic power station and a circuit breaker of each current collection circuit; the distributed monitoring module comprises a plurality of sub-switches, and the sub-switches communicate with a relay protection device of the box-type transformer through optical fiber communication. The stability control device provided by the utility model not only can control circuit breakers of outgoing lines and current collection lines of the photovoltaic power station, but also can directly control circuit breakers of photovoltaic arrays in the photovoltaic power station; the active power of the photovoltaic power station is accurately controlled, and the economic loss of the photovoltaic power station is reduced; operation is simple, and use is convenient.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaic, in particular to a stable control device for a photovoltaic power station capable of monitoring a photovoltaic array. Background Art

[0002] Standards such as GB 38755-2018 "Guidelines for Power System Security and Stability", GB / T 40594-2021 "Technical Guidelines for Grid-Connected Source Coordination in Power Systems", and GB / T 19964-2024 "Technical Requirements for Photovoltaic Power Stations Connected to the Power System" have clearly required that photovoltaic power stations must be equipped with stable control devices. However, there are no clear requirements on whether to directly cut off the entire photovoltaic power station, cut off the collector line, or even directly cut off the photovoltaic inverter by the stable control device. Existing stable control devices all directly cut off the entire photovoltaic power station or cut off the collector line. For photovoltaic power stations, the economic losses are relatively large.

[0003] With the construction of a new power system and the large-scale grid connection of photovoltaic power stations, the capacity of a single photovoltaic power station is gradually increasing. And most of the existing photovoltaic power stations adopt string inverters. A photovoltaic array consists of dozens of inverters, that is, dozens of string inverters are connected under one box-type transformer. Although the active power control rate of the inverter is relatively fast, the existing communication between the string inverter and the photovoltaic power station is at the second level, and the communication is slow. It is impossible to directly control the power of the inverter by using the existing communication. If optical fibers are re-laid for communication with the string inverter, the cost is relatively high. Summary of the Invention

[0004] The technical problem to be solved by the utility model is to provide a stable control device for a photovoltaic power station capable of monitoring a photovoltaic array to make up for the deficiencies of existing stable control equipment for photovoltaic power stations.

[0005] To solve the above technical problem, the technical solution adopted by the utility model is:

[0006] A stable control device for a photovoltaic power station capable of monitoring a photovoltaic array, the stable control device is composed of a processor, a monitoring module, a control instruction module, a main switch, and a distributed monitoring module. The monitoring module is connected to the input end of the processor, the control instruction module is connected to the output end of the processor. The monitoring module monitors the voltage and current at the grid connection point of the photovoltaic power station, the voltage of the bus, and the current signals of each collector line. The control instruction module controls the outgoing circuit breaker of the photovoltaic power station and the incoming circuit breaker of each collector line. The processor is communicatively connected to the main switch, and the main switch is communicatively connected to the distributed monitoring module.

[0007] The above-mentioned distributed monitoring module includes multiple sub-switches. Each sub-switch communicates with the relay protection device of the box-type transformer in a collector line through optical fiber communication, and the main switch communicates with each sub-switch through optical fiber communication.

[0008] The above-mentioned control instruction module is connected to the control signals of the outgoing line circuit breaker of the photovoltaic power station and the incoming line circuit breakers of each collector line.

[0009] The above-mentioned processor is communicatively connected to the network status module, and the network status module is used to monitor the communication status between the stability control device and the remote monitoring system.

[0010] The above-mentioned processor is communicatively connected to the data storage module.

[0011] An indicator light / alarm output is connected to the output end of the above-mentioned processor.

[0012] The above-mentioned processor, monitoring module, control instruction module, network status module, data storage module, indicator light / alarm output, main switch, and distributed monitoring module are powered by a power supply module.

[0013] A photovoltaic power station stability control device capable of monitoring a photovoltaic array provided by the present utility model has the following beneficial effects:

[0014] 1. It can not only control the circuit breakers of the outgoing line and collector lines of the photovoltaic power station, but also directly control the circuit breakers of the photovoltaic array inside the photovoltaic power station;

[0015] 2. It can accurately control the active power of the photovoltaic power station and reduce the economic losses of the photovoltaic power station;

[0016] 3. It is simple to operate and convenient to use;

[0017] 4. It can be widely applied to occasions such as wind farms, energy storage power stations, "wind-solar-storage" combined power stations, and distributed new energy. Brief Description of the Drawings

[0018] The following further describes the present utility model in conjunction with the drawings and embodiments:

[0019] Figure 1 It is a structural schematic diagram of the present utility model.

[0020] In the figure: processor 1, power supply module 2, monitoring module 3, control instruction module 4, network status module 5, data storage module 6, indicator light / alarm output 7, main switch 8, distributed monitoring module 9. Detailed Embodiments

[0021] As Figure 1As shown in the figure, a stable control device for a photovoltaic power station capable of monitoring a photovoltaic array. The stable control device is composed of a processor 1, a monitoring module 3, a control instruction module 4, a main switch 8, and a distributed monitoring module 9. The monitoring module 3 is connected to the input end of the processor 1, and the control instruction module 4 is connected to the output end of the processor 1. The monitoring module 3 monitors the voltage and current at the grid connection point of the photovoltaic power station, the voltage of the bus, and the current signals of each collector line. The control instruction module 4 controls the outgoing circuit breaker of the photovoltaic power station and the incoming circuit breakers of each collector line. The processor 1 is communicatively connected to the main switch 8, and the main switch 8 is communicatively connected to the distributed monitoring module 9.

[0022] The above-mentioned distributed monitoring module 9 includes multiple sub-switches. Each sub-switch communicates with the relay protection device of the box-type transformer in a collector line through optical fiber communication, and the main switch 8 communicates with each sub-switch through optical fiber communication.

[0023] The above-mentioned control instruction module 4 is connected to the control signals of the outgoing circuit breaker of the photovoltaic power station and the incoming circuit breakers of each collector line.

[0024] The above-mentioned processor 1 is communicatively connected to a network status module 5, and the network status module 5 is used to monitor the communication status between the stable control device and the remote monitoring system.

[0025] The above-mentioned processor 1 is communicatively connected to a data storage module 6, and the data storage module 6 is used to store abnormal data.

[0026] An indicator light / alarm output 7 is connected to the output end of the above-mentioned processor 1. The indicator light / alarm output 7 is used to display the abnormalities of the device and the action information of the photovoltaic power station.

[0027] The above-mentioned processor 1, monitoring module 3, control instruction module 4, network status module 5, data storage module 6, indicator light / alarm output 7, main switch 8, and distributed monitoring module 9 are powered by a power supply module 2.

[0028] Embodiment:

[0029] A stable control device for a photovoltaic power station capable of monitoring a photovoltaic array, comprising a processor, a power supply module, a monitoring module, a control instruction module, a network status module, a data storage module, an indicator light / alarm output module, a main switch, a distributed monitoring module, etc. The monitoring module includes signals such as the voltage and current at the grid connection point of the photovoltaic power station, the voltage of the 35kV bus, and the current of each collector line; the control instruction module controls the outgoing line circuit breaker of the photovoltaic power station and the incoming line circuit breakers of each collector line; the distributed monitoring module includes sub-switch 1, sub-switch 2, sub-switch n. The main switch communicates with sub-switch 1, sub-switch 2, sub-switch n through optical fiber communication, and the sub-switch communicates with the relay protection device of the box-type transformer through optical fiber communication.

[0030] The number of sub-switches in the distributed monitoring module is determined according to the specific situation of the photovoltaic power station. The number of sub-switches for monitoring the box-type transformer is half of the number of box-type transformers in the corresponding collector line; the selection of the relay protection device for monitoring between the sub-switch and the box-type transformer can be arbitrarily selected without limitation;

[0031] The processor is connected to the main switch through optical fiber communication;

[0032] The main switch is respectively connected to sub-switch 1, sub-switch 2, sub-switch n through optical fiber communication. Sub-switch 1 is connected to the relay protection devices of box-type transformer 1-1 and box-type transformer 1-2 of collector line 1 through optical fiber communication; Sub-switch 2 is connected to the relay protection devices of box-type transformer 2-1 and box-type transformer 2-n of collector line 2 through optical fiber communication; Sub-switch n is connected to the relay protection devices of box-type transformer n-2 and box-type transformer n-n of collector line n through optical fiber communication.

[0033] Based on the existing relay protection device of the box-type transformer, the processor reads the active power of the photovoltaic array through the main switch, sub-switch 1, 2, n, and issues a control instruction to separate the circuit breaker of the box-type transformer; that is, the purpose of controlling the active power of the photovoltaic array is achieved.

[0034] The processor uses an existing conventional processor; the full-wave Fourier method is used to calculate the fundamental positive-sequence active power at the grid connection point of the photovoltaic power station according to the grid connection point voltage and current, and calculate the fundamental positive-sequence active power of each corresponding collector line according to the 35kV bus voltage and the current of each collector line.

[0035] The power supply module supports 220V AC power supply and ±110V DC power supply.

[0036] The monitoring module can monitor the voltage and current at the grid connection point of the photovoltaic power station, the voltage of the 35kV bus, the current of collector line 1, the current of collector line 2, the current of collector line n, etc.; if there are multiple sections of the 35kV bus in the photovoltaic power station, the voltage of each section of the 35kV bus needs to be collected.

[0037] The control instruction module can control the outgoing circuit breaker of the PV power station to open, and the incoming circuit breakers of collector line 1, collector line 2, and collector line n to open;

[0038] The network status module monitors the communication status between this device and the remote monitoring system.

[0039] The data storage module stores abnormal data.

[0040] The indicator light / alarm output module displays the abnormalities of the device and the action information of the PV power station.

[0041] The usage steps of this control device are as follows:

[0042] Step 1: The processor (1) receives the instruction P for remotely cutting the active power of the PV power station M , or the instruction P for cutting the active power of the PV power station determined by calculation M ;

[0043] Step 2: Calculate that the fundamental positive-sequence active power at the grid connection point of the PV power station is P 总 , and the fundamental positive-sequence active powers of each collector line are P1, P2, P n ;

[0044] Step 3: When the instruction P for cutting the active power M is greater than P 总 , then the entire PV power station is cut off, that is, the processor (1) issues an instruction to disconnect the outgoing circuit breaker of the PV power station through the control instruction module (4);

[0045] Step 4: When the instruction P for cutting the active power M is less than P 总 , and the instruction P for cutting the active power M is greater than the fundamental positive-sequence active power P1, P2, P of a certain collector line n , then a certain collector line or several collector lines are cut off, and for the remaining insufficient active power, the box-type transformer is cut off. Multiple box-type transformers can be cut off;

[0046] When the instruction P for cutting the active power M is less than P 总 , and the instruction P for cutting the active power M is less than the fundamental positive-sequence active powers P1, P2, P of all collector lines n , then the box-type transformer is cut off. Multiple box-type transformers can be cut off, and the box-type transformers of the collector lines can be selected arbitrarily;

[0047] Step 5: The stability control device finishes the judgment.

Claims

1. A stable control device for a photovoltaic power station capable of monitoring a photovoltaic array, characterized in that, The stability control device consists of a processor (1), a monitoring module (3), a control instruction module (4), a main switch (8), and a distributed monitoring module (9). The monitoring module (3) is connected to the input end of the processor (1), and the control instruction module (4) is connected to the output end of the processor (1). The monitoring module (3) monitors the voltage and current at the grid connection point of the photovoltaic power station, the voltage of the bus, and the current signals of each collector line. The control instruction module (4) controls the outgoing circuit breaker of the photovoltaic power station and the incoming circuit breakers of each collector line. The processor (1) is communicatively connected to the main switch (8), and the main switch (8) is communicatively connected to the distributed monitoring module (9).

2. The photovoltaic power station stable control device capable of monitoring a photovoltaic array according to claim 1, characterized in that The distributed monitoring module (9) includes multiple sub-switches. Each sub-switch communicates with the relay protection device of the box-type transformer in a collector line through optical fiber communication, and the main switch (8) communicates with each sub-switch through optical fiber communication.

3. The photovoltaic power station stable control device capable of monitoring a photovoltaic array according to claim 2, wherein, The control instruction module (4) is connected to the control signals of the outgoing circuit breaker of the photovoltaic power station and the incoming circuit breakers of each collector line.

4. The photovoltaic power station stable control device capable of monitoring a photovoltaic array according to claim 3, characterized in that, The processor (1) is communicatively connected to a network status module (5), and the network status module (5) is used to monitor the communication status between the stability control device and the remote monitoring system.

5. The photovoltaic power station stable control device capable of monitoring a photovoltaic array according to claim 4, characterized in that, The processor (1) is communicatively connected to a data storage module (6).

6. The photovoltaic power station stable control device capable of monitoring a photovoltaic array according to claim 5, wherein An indicator light / alarm output (7) is connected to the output end of the processor (1).

7. The photovoltaic power station stability control device capable of monitoring a photovoltaic array according to claim 6, wherein, The processor (1), the monitoring module (3), the control instruction module (4), the network status module (5), the data storage module (6), the indicator light / alarm output (7), the main switch (8), and the distributed monitoring module (9) are powered by a power supply module (2).

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