Station service power system based on photovoltaic power station

Abstract

The invention provides a plant power system based on a photovoltaic power station, which comprises a first photovoltaic power station, the first photovoltaic power station comprises a first photovoltaic side bus and a plurality of first photovoltaic power generation devices, and a power load comprises a first plant side bus, a high plant transformer and a boiler; the monitoring module is used for monitoring the power of the first power input end of the first photovoltaic side bus and the power of the power output end of the first photovoltaic side bus, and respectively controlling the start and stop of the plurality of first photovoltaic power generation devices; therefore, the power of the first power input end of the first photovoltaic side bus is always smaller than the power of the power output end of the first photovoltaic side bus. According to the station service power system based on the photovoltaic power station, quick response of load fluctuation is realized, so that the power utilization load and the photovoltaic power generation power are accurately matched, and photovoltaic residual power reverse transmission is avoided.

Description

Technical Field

[0001] This disclosure relates to the field of power supply technology for power plants, and in particular to a power supply system for power plants based on photovoltaic power plants. Background Technology

[0002] The power supply system for photovoltaic power plants needs to ensure that the maximum generating capacity of the photovoltaic power plant can be fully absorbed by the power load of the power supply system to avoid surplus power being fed into the grid. However, the current system control relies heavily on on-site operation and lacks real-time control methods, making it unable to respond quickly to load fluctuations. This leads to a mismatch between the power load and the generating capacity of the photovoltaic power plant, which can easily result in surplus photovoltaic power being fed back into the grid, violating the requirement of "self-consumption and no surplus power being fed into the grid". Summary of the Invention

[0003] This disclosure aims to at least partially address one of the technical problems in the related art.

[0004] Therefore, the purpose of this disclosure is to provide a power supply system for photovoltaic power plants.

[0005] To achieve the above objectives, this disclosure provides a power supply system for a photovoltaic power plant, comprising: a first photovoltaic power plant, the first photovoltaic power plant including: a first photovoltaic side bus and a plurality of first photovoltaic power generation devices, the first power input terminal of the first photovoltaic side bus being connected to the power output terminals of the plurality of first photovoltaic power generation devices respectively, and the second power input terminal of the first photovoltaic side bus being connected to the power output terminal of the power grid; a plurality of electrical loads, the electrical loads including: the first power supply side bus, a power transformer, and a boiler, the power input terminals of the plurality of first power supply side buses being connected to the power output terminals of the first photovoltaic side bus respectively, the power output terminals of the first power supply side bus being connected to the power input terminals of the power transformer, and the power output terminals of the power transformer being connected to the power input terminals of the boiler; and a monitoring module, the monitoring module being used to monitor the power of the first power input terminal and the power output terminal of the first photovoltaic side bus, and to control the start and stop of the plurality of first photovoltaic power generation devices respectively, so that the power of the first power input terminal of the first photovoltaic side bus is always less than the power output terminal of the first photovoltaic side bus.

[0006] Optionally, the electrical load further includes: a first switch, which is disposed between the power input terminal of the first plant service side bus and the power output terminal of the first photovoltaic side bus, and a first end of the first switch is connected to the power output terminal of the first photovoltaic side bus, and a second end of the first switch is connected to the power input terminal of the first plant service side bus; wherein, the signal output terminal of the monitoring module is connected to the signal input terminal of the first switch, and the monitoring module is used to monitor the power output terminal power of the first plant service side bus, and to disconnect the first switch when the power output terminal power of the first plant service side bus is lower than a first preset power, and to turn on the first switch when the power output terminal power of the first plant service side bus is higher than a second preset power; the first preset power is less than the second preset power.

[0007] Optionally, the first photovoltaic power station further includes: a second switch, which is disposed between the first power input terminal of the first photovoltaic side bus and the power output terminals of the plurality of the first photovoltaic power generation devices, and the first terminal of the second switch is connected to the power output terminals of the plurality of the first photovoltaic power generation devices respectively, and the second terminal of the second switch is connected to the first power input terminal of the first photovoltaic side bus; wherein, the signal output terminal of the monitoring module is connected to the signal input terminal of the second switch, and the monitoring module is used to monitor the fault status of the first photovoltaic power station and the electrical load, and to disconnect the second switch when the first photovoltaic power station and / or the electrical load malfunctions.

[0008] Optionally, the monitoring module is used to disconnect the second switch when it receives a bus differential protection signal from the first photovoltaic power station, an islanding protection signal from the first photovoltaic power station, a trip signal from the generator, or a tripping signal from the working power switch.

[0009] Optionally, the monitoring module is used to monitor the current, voltage and power of the first photovoltaic side bus, and to disconnect the second switch when the first photovoltaic side bus experiences an overcurrent fault, overvoltage fault or harmonic exceedance fault.

[0010] Optionally, the first photovoltaic power generation device includes: an inverter and multiple photovoltaic modules, wherein the power input terminal of the inverter is connected to the power output terminals of the multiple photovoltaic modules, and the power output terminal of the inverter is connected to the first power input terminal of the first photovoltaic side bus; wherein, the signal output terminal of the monitoring module is connected to the signal input terminal of the inverter, and the monitoring module is used to control the start and stop of the multiple inverters respectively, so that the power at the first power input terminal of the first photovoltaic side bus is always less than the power at the power output terminal of the first photovoltaic side bus.

[0011] Optionally, the first photovoltaic power station further includes: a photovoltaic step-up transformer, which is disposed between the first power input terminal of the first photovoltaic side bus and the power output terminals of the plurality of inverters, and the power input terminal of the photovoltaic step-up transformer is connected to the power output terminals of the plurality of inverters respectively, and the power output terminal of the photovoltaic step-up transformer is connected to the first power input terminal of the first photovoltaic side bus.

[0012] Optionally, the plant power system further includes: a second photovoltaic power station, the second photovoltaic power station including: a second photovoltaic side bus and multiple second photovoltaic power generation devices, the first power input terminal of the second photovoltaic side bus being connected to the power output terminals of the multiple second photovoltaic power generation devices respectively, and the second power input terminal of the second photovoltaic side bus being connected to the power output terminal of the power grid; the power load further includes: a second plant side bus, the power input terminals of the multiple second plant side buses being connected to the power output terminals of the second photovoltaic side bus respectively, and the power output terminal of the second plant side bus being connected to the power input terminal of the power substation; wherein, the monitoring module is also used to connect the path between the power output terminal of the first plant side bus and the power input terminal of the power substation, or the path between the power output terminal of the second plant side bus and the power input terminal of the power substation.

[0013] Optionally, the monitoring module is further configured to monitor the power of the first power input terminal of the second photovoltaic side bus and the power output terminal of the second photovoltaic side bus when the path between the power output terminal of the second plant service side bus and the power input terminal of the high-voltage transformer is connected, and to control the start and stop of multiple second photovoltaic power generation devices respectively, so that the power of the first power input terminal of the second photovoltaic side bus is always less than the power output terminal of the second photovoltaic side bus.

[0014] The technical solution provided in this disclosure may include the following beneficial effects: The monitoring module controls the start and stop of multiple first photovoltaic power generation devices to ensure that the power input terminal of the first photovoltaic side bus is always less than the power output terminal of the first photovoltaic side bus. Thus, by regulating each first photovoltaic power generation device, a rapid response to load fluctuations is achieved, thereby accurately matching the power load with the photovoltaic power generation capacity, avoiding the backfeeding of surplus photovoltaic power, and meeting the requirement of "self-generation and self-consumption, with surplus power not fed into the grid".

[0015] Additional aspects and advantages of this disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this disclosure. Attached Figure Description

[0016] The above and / or additional aspects and advantages of this disclosure will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, in which: Figure 1 This is a schematic diagram of the structure of a power supply system based on a photovoltaic power station (first photovoltaic power station) according to an embodiment of this disclosure. Figure 2 This is a schematic diagram of the structure of a plant power system based on a photovoltaic power station (second photovoltaic power station) according to an embodiment of this disclosure. As shown in the figure: 1. First photovoltaic power station, 11. First photovoltaic side busbar, 12. First photovoltaic power generation device, 13. Second switch, 14. Photovoltaic step-up transformer; 2. Electrical loads, 21. First plant auxiliary busbar, 22. High-voltage transformer, 23. First switch, 24. Second plant auxiliary busbar; 3. Second photovoltaic power station; 31. Second photovoltaic side busbar; 32. Second photovoltaic power generation device. Detailed Implementation

[0017] Embodiments of this disclosure are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are used only to explain this disclosure, and should not be construed as limiting this disclosure. Rather, embodiments of this disclosure include all variations, modifications, and equivalents falling within the spirit and scope of the appended claims.

[0018] like Figure 1 As shown in the figure, this disclosure proposes a plant power system based on a photovoltaic power station, including: a first photovoltaic power station 1, multiple electrical loads 2, and a monitoring module (not shown in the figure). The first photovoltaic power station 1 includes: a first photovoltaic side bus 11 and multiple first photovoltaic power generation devices 12. The first power input terminal of the first photovoltaic side bus 11 is connected to the power output terminal of the multiple first photovoltaic power generation devices 12, and the second power input terminal of the first photovoltaic side bus 11 is connected to the power output terminal of the power grid. The electrical loads 2 include: a first plant power supply side bus 21, a high-voltage transformer 22, and a boiler (not shown in the figure). The multiple first photovoltaic power stations 1 and 2 are connected to the power output terminal of the power grid. The power input terminal of the plant service side bus 21 is connected to the power output terminal of the first photovoltaic side bus 11. The power output terminal of the first plant service side bus 21 is connected to the power input terminal of the high-voltage transformer 22. The power output terminal of the high-voltage transformer 22 is connected to the power input terminal of the boiler. The monitoring module is used to monitor the power of the first power input terminal and the power output terminal of the first photovoltaic side bus 11, and to control the start and stop of multiple first photovoltaic power generation devices 12, so that the power of the first power input terminal of the first photovoltaic side bus 11 is always less than the power output terminal of the first photovoltaic side bus 11.

[0019] It is understandable that, since the first power input terminal of the first photovoltaic side bus 11 is connected to the power output terminals of multiple first photovoltaic power generation devices 12, and the power input terminals of multiple first plant service side bus 21 are connected to the power output terminals of the first photovoltaic side bus 11, the power output terminal of the first plant service side bus 21 is connected to the power input terminal of the power plant transformer 22, and the power output terminal of the power plant transformer 22 is connected to the power input terminal of the boiler, the electrical energy generated by the multiple first photovoltaic power generation devices 12 can be transmitted to the boiler in sequence through the first photovoltaic side bus 11, the first plant service side bus 21, and the power plant transformer 22. Furthermore, since the second power input terminal of the first photovoltaic side bus 11 is connected to the power output terminal of the power grid, the electrical energy of the power grid can also be transmitted to the boiler in sequence through the first photovoltaic side bus 11, the first plant service side bus 21, and the power plant transformer 22. Thus, based on the cooperation between the first photovoltaic power station 1 and the power grid, the power demand of the boiler can be met.

[0020] Moreover, the monitoring module controls the start and stop of multiple first photovoltaic power generation devices 12 respectively, so that the power at the first power input end of the first photovoltaic side bus 11 is always less than the power at the first power output end of the first photovoltaic side bus 11. Thus, by regulating each first photovoltaic power generation device 12, a rapid response to load fluctuations is achieved, thereby accurately matching the power load and photovoltaic power generation, avoiding the backfeeding of surplus photovoltaic power, and meeting the requirements of "self-generation and self-consumption, with surplus power not fed into the grid".

[0021] It should be noted that in the first photovoltaic power station 1, the first photovoltaic power generation device 12 is used for photovoltaic power generation, and after power generation, it performs electrical energy conversion and outputs AC power. The first photovoltaic side bus 11 is used to collect the electrical energy output by multiple first photovoltaic power generation devices 12, and to transfer the collected electrical energy to each electrical load 2. The specific types of the first photovoltaic side bus 11 and the first photovoltaic power generation device 12 can be set according to actual needs, and there are no restrictions on them.

[0022] Among them, the first photovoltaic power station 1 is also equipped with mature supporting equipment for circuit protection, power conversion and on / off control, which will not be described in detail here.

[0023] In electrical load 2, the first plant service side bus 21 is used to transmit the electrical energy collected by the first photovoltaic side bus 11 to the high-voltage transformer 22. The high-voltage transformer 22 (which can be 20000kVA) transforms and converts the electrical energy transmitted from the first plant service side bus 21 and then transmits it to the power supply bus of the boiler to meet the boiler's power demand, thereby achieving efficient thermal power generation. The specific types of the first plant service side bus 21, the high-voltage transformer 22, and the boiler can be set according to actual needs and are not limited thereto.

[0024] Among them, for electrical load 2, there are also mature supporting equipment for circuit protection, power conversion, on / off control, etc., which will not be described in detail here.

[0025] The first photovoltaic side busbar 11 and the first plant service side busbar 21 can both be 6kV busbars.

[0026] The monitoring module is used for monitoring system operating parameters and controlling the system. The specific type of monitoring module can be set according to actual needs and is not limited thereto. The monitoring module can directly monitor target parameters using various sensors, or it can connect to the system's monitoring center to indirectly obtain various parameters.

[0027] like Figure 1 As shown, in some embodiments, the electrical load 2 further includes a first switch 23, which is disposed between the power input terminal of the first plant service side bus 21 and the power output terminal of the first photovoltaic side bus 11. The first end of the first switch 23 is connected to the power output terminal of the first photovoltaic side bus 11, and the second end of the first switch 23 is connected to the power input terminal of the first plant service side bus 21. The signal output terminal of the monitoring module is connected to the signal input terminal of the first switch 23, and the monitoring module is used to monitor the power output terminal power of the first plant service side bus 21. When the power output terminal power of the first plant service side bus 21 is lower than a first preset power, the first switch 23 is disconnected; when the power output terminal power of the first plant service side bus 21 is higher than a second preset power, the first preset power is less than the second preset power.

[0028] Understandably, since the first switch 23 is located between the power input terminal of the first plant service side bus 21 and the power output terminal of the first photovoltaic side bus 11, and the signal output terminal of the monitoring module is connected to the signal input terminal of the first switch 23, the monitoring module can use the first switch 23 to control the opening and closing of the path between the power input terminal of the first plant service side bus 21 and the power output terminal of the first photovoltaic side bus 11. Specifically, when the power output terminal of the first plant service side bus 21 is lower than the first preset power, the first switch 23 is disconnected, and when the power output terminal of the first plant service side bus 21 is higher than the second preset power, the first switch 23 is turned on. Thus, through dynamic adjustment linked with boiler operation, the problem that the existing fixed access point cannot adapt to load changes can be effectively solved, and the backfeeding of surplus power can be prevented from the source.

[0029] It should be noted that the first switch 23 is used to connect or disconnect the power input terminal of the first plant service side bus 21 and the power output terminal of the first photovoltaic side bus 11 under the control of the monitoring module. The specific type of the first switch 23 can be set according to actual needs and is not limited thereto. For example, the first switch 23 can be a circuit breaker, etc.

[0030] When the power output of the first plant service side bus 21 is lower than the first preset power, it indicates that the boiler is shut down; when the power output of the first plant service side bus 21 is higher than the second preset power, it indicates that the boiler is running.

[0031] For example, when switching from boiler 1 to boiler 2, the load of boiler 1 gradually decreases while the load of boiler 2 gradually increases. Therefore, when the power output of the first plant service side bus 21 corresponding to boiler 1 is lower than the first preset power, the first switch 23 corresponding to boiler 1 is disconnected, so that the first photovoltaic power station 1 is put into cold standby for boiler 1, and boiler 1 is maintained by the power supply of the generator. When the power output of the first plant service side bus 21 corresponding to boiler 2 is higher than the second preset power, the first switch 23 corresponding to boiler 2 is turned on. Thus, effective adaptation to load fluctuations is achieved, and the backfeed of surplus power is prevented.

[0032] The second preset power can be 2.5MW.

[0033] like Figure 1 As shown, in some embodiments, the first photovoltaic power station 1 further includes a second switch 13. The second switch 13 is disposed between the first power input terminal of the first photovoltaic side bus 11 and the power output terminals of the plurality of first photovoltaic power generation devices 12. The first terminal of the second switch 13 is connected to the power output terminals of the plurality of first photovoltaic power generation devices 12, and the second terminal of the second switch 13 is connected to the first power input terminal of the first photovoltaic side bus 11. The signal output terminal of the monitoring module is connected to the signal input terminal of the second switch 13. The monitoring module is used to monitor the fault status of the first photovoltaic power station 1 and the electrical load 2, and to disconnect the second switch 13 when a fault occurs in the first photovoltaic power station 1 and / or the electrical load 2.

[0034] It is understandable that, since the second switch 13 is located between the first power input terminal of the first photovoltaic bus 11 and the power output terminals of the multiple first photovoltaic power generation devices 12, and the signal output terminal of the monitoring module is connected to the signal input terminal of the second switch 13, the monitoring module can use the second switch 13 to control the opening and closing of the path between the first power input terminal of the first photovoltaic bus 11 and the power output terminals of the multiple first photovoltaic power generation devices 12. Specifically, when the first photovoltaic power station 1 and / or the electrical load 2 malfunctions, the second switch 13 is disconnected, thereby quickly isolating the first photovoltaic power station 1 and the electrical load 2 and achieving effective protection.

[0035] It should be noted that the second switch 13 is used to open or close the power input terminal of the first photovoltaic side bus 11 and the power output terminal of the multiple first photovoltaic power generation devices 12 under the control of the monitoring module. The specific type of the second switch 13 can be set according to actual needs and there is no restriction. For example, the second switch 13 can be a circuit breaker, etc.

[0036] In some embodiments, the monitoring module is used to disconnect the second switch 13 when it receives a bus differential protection signal of the first photovoltaic power station 1, an islanding protection signal of the first photovoltaic power station 1, a trip signal of the generator, or a tripping signal of the working power switch (at the first plant service side bus 21).

[0037] It should be noted that the monitoring module can obtain the bus differential protection signal of the first photovoltaic power station 1, the islanding protection signal of the first photovoltaic power station 1, the trip signal of the generator, and the opening signal of the working power switch from the system's monitoring center.

[0038] Differential protection compares the current vector difference between the two ends (or convergence point) of the same circuit. When the difference exceeds a set threshold, it is determined to be an internal short circuit or ground fault. It then trips instantly to disconnect the faulty branch, preventing the fault energy from continuing to be injected, thus protecting equipment safety and reducing the risk of fire.

[0039] Islanding protection is a mechanism that, when the main grid loses voltage or power, if the photovoltaic inverter still forms a self-supplied electronic grid ("island") with the local load, the inverter output must be cut off within 2 seconds to avoid harm to maintenance personnel, electrical equipment, and grid reclosing.

[0040] In some embodiments, the monitoring module is used to monitor the current, voltage and power of the first photovoltaic bus 11, and to disconnect the second switch 13 when the first photovoltaic bus 11 experiences an overcurrent fault, an overvoltage fault or a harmonic over-limit fault.

[0041] Understandably, when an overcurrent fault, overvoltage fault, or harmonic exceedance fault occurs on the first photovoltaic bus 11, the monitoring module disconnects the second switch 13, thereby quickly isolating the first photovoltaic power station 1 and the electrical load 2, achieving effective protection.

[0042] It should be noted that the monitoring module can use the line protection and control device to monitor the current, voltage and power of the first photovoltaic side bus 11. The line protection and control device integrates protection, control, measurement and remote transmission functions.

[0043] In some embodiments, the first photovoltaic power generation device 12 includes an inverter and a plurality of photovoltaic modules. The power input terminal of the inverter is connected to the power output terminals of the plurality of photovoltaic modules, and the power output terminal of the inverter is connected to the first power input terminal of the first photovoltaic side bus 11. The signal output terminal of a monitoring module is connected to the signal input terminal of the inverter, and the monitoring module is used to control the start and stop of the plurality of inverters respectively, so that the power at the first power input terminal of the first photovoltaic side bus 11 is always less than the power at the power output terminal of the first photovoltaic side bus 11.

[0044] Understandably, since the power input terminal of the inverter is connected to the power output terminals of multiple photovoltaic modules, and the power output terminal of the inverter is connected to the first power input terminal of the first photovoltaic side bus 11, the DC power output by multiple photovoltaic modules can be converted into AC power by the inverter and collected to the first photovoltaic side bus 11. Furthermore, the monitoring module controls the start and stop of multiple inverters respectively, so that the power at the first power input terminal of the first photovoltaic side bus 11 is always less than the power at the first power output terminal of the first photovoltaic side bus 11. Thus, by regulating each inverter, a rapid response to load fluctuations is achieved, thereby accurately matching the power load with the photovoltaic power generation, avoiding the backfeeding of surplus photovoltaic power, and meeting the requirement of "self-generation and self-consumption, with surplus power not fed into the grid".

[0045] It should be noted that the photovoltaic modules are used for photovoltaic power generation, producing direct current (DC), and the inverter is used to convert the DC output from multiple series-connected and / or parallel-connected photovoltaic modules into alternating current (AC) and transmit it to the first photovoltaic side bus 11. The specific types of photovoltaic modules and inverters can be set according to actual needs and there are no restrictions on them.

[0046] For example, the first photovoltaic power station 1 uses 12 196kW inverters.

[0047] like Figure 1 As shown, in some embodiments, the first photovoltaic power station 1 further includes a photovoltaic step-up transformer 14, which is disposed between the first power input terminal of the first photovoltaic side bus 11 and the power output terminals of multiple inverters. The power input terminal of the photovoltaic step-up transformer 14 is connected to the power output terminals of the multiple inverters respectively, and the power output terminal of the photovoltaic step-up transformer 14 is connected to the first power input terminal of the first photovoltaic side bus 11.

[0048] It is understandable that, since the photovoltaic step-up transformer 14 is located between the first power input terminal of the first photovoltaic side bus 11 and the power output terminals of multiple inverters, the DC power output by the inverters can be stepped up and converted using the photovoltaic step-up transformer 14, thereby meeting the power demand of the electrical load 2.

[0049] It should be noted that the specific type of photovoltaic step-up transformer 14 can be set according to actual needs, and there are no restrictions on it. For example, photovoltaic step-up transformer 14 can be a box-type transformer with a capacity of 3150kVA.

[0050] like Figure 2As shown, in some embodiments, the plant power system further includes: a second photovoltaic power station 3, which includes: a second photovoltaic side bus 31 and multiple second photovoltaic power generation devices 32. The first power input terminal of the second photovoltaic side bus 31 is connected to the power output terminals of the multiple second photovoltaic power generation devices 32, and the second power input terminal of the second photovoltaic side bus 31 is connected to the power output terminal of the power grid. The power load 2 further includes: a second plant power side bus 24, the power input terminals of the multiple second plant power side buses 24 are connected to the power output terminals of the second photovoltaic side bus 31, and the power output terminal of the second plant power side bus 24 is connected to the power input terminal of the power transformer 22. The monitoring module is also used to establish a connection between the power output terminal of the first plant power side bus 21 and the power input terminal of the power transformer 22, or between the power output terminal of the second plant power side bus 24 and the power input terminal of the power transformer 22.

[0051] Understandably, since the first power input terminal of the second photovoltaic side bus 31 is connected to the power output terminals of multiple second photovoltaic power generation devices 32, and the power input terminals of multiple second plant service side bus 24 are connected to the power output terminals of the second photovoltaic side bus 31, and the power output terminal of the second plant service side bus 24 is connected to the power input terminal of the power plant transformer 22, the electrical energy generated by the multiple second photovoltaic power generation devices 32 can be transmitted to the boiler in sequence through the second photovoltaic side bus 31, the second plant service side bus 24, and the power plant transformer 22. Furthermore, since the second power input terminal of the second photovoltaic side bus 31 is connected to the power output terminal of the power grid, the electrical energy of the power grid can also be transmitted to the boiler in sequence through the second photovoltaic side bus 31, the second plant service side bus 24, and the power plant transformer 22. Thus, based on the cooperation between the second photovoltaic power station 3 and the power grid, the power demand of the boiler can be met.

[0052] Furthermore, the monitoring module connects the power output terminal of the first plant service side bus 21 and the power input terminal of the high-voltage transformer 22, or the power output terminal of the second plant service side bus 24 and the power input terminal of the high-voltage transformer 22, thereby achieving redundant design by utilizing the independent operation between the first photovoltaic power station 1 and the second photovoltaic power station 3, and improving the reliability of system operation.

[0053] It should be noted that the second photovoltaic power station 3 and the first photovoltaic power station 1 have the same structure and are independent of each other. The second photovoltaic power generation device 32 is used for photovoltaic power generation, and after power generation, it performs electrical energy conversion and outputs AC power. The second photovoltaic side bus 31 is used to collect the electrical energy output by multiple second photovoltaic power generation devices 32, and to transfer the collected electrical energy to each electrical load 2. The specific types of the second photovoltaic side bus 31 and the second photovoltaic power generation device 32 can be set according to actual needs, and there are no restrictions on this.

[0054] Among them, the second photovoltaic power station 3 is also equipped with mature supporting equipment for circuit protection, power conversion, and on / off control, which will not be described in detail here.

[0055] In electrical load 2, the second plant service side bus 24 is used to transmit the electrical energy collected by the second photovoltaic side bus 31 to the high-voltage transformer 22. The specific type of the second plant service side bus 24 can be set according to actual needs and is not limited thereto.

[0056] The second photovoltaic side busbar 31 and the second plant service side busbar 24 can both be 6kV busbars.

[0057] In some embodiments, the monitoring module is further configured to monitor the power of the first power input terminal and the power output terminal of the second photovoltaic side bus 31 when the power output terminal of the second plant service side bus 24 and the power input terminal of the high-voltage transformer 22 are connected, and to control the start and stop of multiple second photovoltaic power generation devices 32 respectively, so that the power of the first power input terminal of the second photovoltaic side bus 31 is always less than the power output terminal of the second photovoltaic side bus 31.

[0058] Understandably, the monitoring module controls the start and stop of multiple second photovoltaic power generation devices 32 respectively, so that the power at the first power input end of the second photovoltaic side bus 31 is always less than the power at the power output end of the second photovoltaic side bus 31. Thus, by regulating each second photovoltaic power generation device 32, a rapid response to load fluctuations is achieved, thereby accurately matching the power load with the photovoltaic power generation capacity, avoiding the backfeeding of surplus photovoltaic power, and meeting the requirement of "self-generation and self-consumption, with surplus power not fed into the grid".

[0059] In the plant power system of this embodiment, before boiler start-up / shutdown or 6kV busbar switching operations, the corresponding photovoltaic grid-connected transformer is forcibly switched from operation to cold standby. This avoids fast switching operations while the photovoltaic system is running and prevents the photovoltaic system from being directly connected to the 110kV power grid system via the start-up / standby transformer, thus eliminating the risk of failure from the operational process. This multi-level protection system solves the problem that existing protection systems are not adapted to photovoltaic access scenarios.

[0060] The plant power system of this embodiment has at least the following beneficial effects: Economic efficiency: After applying this solution, the power generation efficiency of the photovoltaic power station is increased by 7-10 percentage points compared with the traditional solution. The power loss in the station meets the design requirements, saving a lot of plant power consumption and reducing the company's electricity costs. Reasonable grid connection point setting and equipment selection reduce project budget and further improve economic efficiency.

[0061] Safety: Through dynamic access point adjustment, remote inverter control and multi-level protection interlocks, residual power backfeed and fault range expansion are avoided, ensuring the safe and stable operation of the plant power system and generating units and reducing the risk of safety accidents.

[0062] Environmental friendliness: The power generated by photovoltaic power plants is efficiently utilized, reducing reliance on traditional thermal power, lowering pollutant emissions, and meeting environmental policy requirements.

[0063] Stability: It solves problems such as photovoltaic output fluctuations and harmonic interference, ensures the power quality of the plant power system, ensures stable equipment operation, and reduces equipment failures and downtime caused by power quality issues.

[0064] It should be noted that in the description of this disclosure, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0065] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of preferred embodiments of this disclosure includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the function involved, as will be understood by those skilled in the art to which embodiments of this disclosure pertain.

[0066] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0067] Although embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present disclosure.

Claims

1. A plant power supply system based on a photovoltaic power station, characterized by, The utility model relates to a photovoltaic power station and a method for controlling the photovoltaic power station, and belongs to the field of photovoltaic power station control. The photovoltaic power station comprises a first photovoltaic bus and a plurality of first photovoltaic power generation devices, the first power input end of the first photovoltaic bus is connected to the power output end of the plurality of first photovoltaic power generation devices, and the second power input end of the first photovoltaic bus is connected to the power output end of a power grid. The utility load comprises a first auxiliary bus, a high auxiliary transformer, and a boiler, the power input end of the plurality of first auxiliary buses is connected to the power output end of the first photovoltaic bus, the power output end of the first auxiliary bus is connected to the power input end of the high auxiliary transformer, and the power output end of the high auxiliary transformer is connected to the power input end of the boiler. The monitoring module is used to monitor the first power input end power of the first photovoltaic bus and the power output end power of the first photovoltaic bus, and to control the start and stop of the plurality of first photovoltaic power generation devices, so that the first power input end power of the first photovoltaic bus is always less than the power output end power of the first photovoltaic bus.

2. The system according to claim 1, wherein, The utility load further comprises: A first switch is arranged between the power input end of the first auxiliary bus and the power output end of the first photovoltaic bus, the first end of the first switch is connected to the power output end of the first photovoltaic bus, and the second end of the first switch is connected to the power input end of the first auxiliary bus. The signal output end of the monitoring module is connected to the signal input end of the first switch, the monitoring module is used to monitor the power output end power of the first auxiliary bus, and the first switch is turned off when the power output end power of the first auxiliary bus is lower than a first preset power, and the first switch is turned on when the power output end power of the first auxiliary bus is higher than a second preset power. The first preset power is less than the second preset power.

3. The system according to claim 1, wherein the system is characterized by, The first photovoltaic power station further comprises: A second switch is arranged between the first power input end of the first photovoltaic bus and the power output end of the plurality of first photovoltaic power generation devices, the first end of the second switch is connected to the power output end of the plurality of first photovoltaic power generation devices, and the second end of the second switch is connected to the first power input end of the first photovoltaic bus. The signal output end of the monitoring module is connected to the signal input end of the second switch, and the monitoring module is used to monitor the fault state of the first photovoltaic power station and the utility load, and the second switch is turned off when the first photovoltaic power station and / or the utility load fails.

4. The system according to claim 1, wherein the system is characterized by, The monitoring module is used to turn off the second switch when receiving the bus differential protection signal of the first photovoltaic power station, the island protection signal of the first photovoltaic power station, the tripping signal of a generator, or the opening signal of a working power supply switch.

5. The system for house service power supply based on the photovoltaic power station according to claim 1, characterized in that, The monitoring module is used to monitor the current, voltage, and power of the first photovoltaic bus, and to turn off the second switch when the first photovoltaic bus fails due to overcurrent, overvoltage, or excessive harmonics.

6. The system according to claim 1, wherein the system is characterized by, The first photovoltaic power generation device comprises: an inverter and a plurality of photovoltaic components, a power input end of the inverter and a power output end of the plurality of photovoltaic components are connected, and a power output end of the inverter and a first power input end of the first photovoltaic side bus are connected; wherein a signal output end of the monitoring module and a signal input end of the inverter are connected, and the monitoring module is used to control the start and stop of the plurality of inverters respectively, so that the first power input end power of the first photovoltaic side bus is always less than the power output end power of the first photovoltaic side bus.

7. The system for house service power supply based on the photovoltaic power station according to claim 1, characterized in that, The first photovoltaic power station further comprises: a photovoltaic booster transformer, which is arranged between the first power input end of the first photovoltaic side bus and the power output end of the plurality of inverters, and the power input end of the photovoltaic booster transformer is connected with the power output end of the plurality of inverters respectively, and the power output end of the photovoltaic booster transformer is connected with the first power input end of the first photovoltaic side bus.

8. The plant power system based on the photovoltaic power station according to claim 1, wherein The plant power system further comprises: a second photovoltaic power station, which comprises: a second photovoltaic side bus and a plurality of second photovoltaic power generation devices, a first power input end of the second photovoltaic side bus is connected with a power output end of the plurality of second photovoltaic power generation devices respectively, and a second power input end of the second photovoltaic side bus and a power output end of a power grid are connected; The power consumption load further comprises: a second plant side bus, a power input end of the plurality of second plant side buses is connected with a power output end of the second photovoltaic side bus respectively, and a power output end of the second plant side bus and a power input end of the high plant transformer are connected; wherein the monitoring module is further used to turn on a path between the first plant side bus power output end and the high plant transformer power input end, or a path between the second plant side bus power output end and the high plant transformer power input end.

9. The system for house service power supply based on the photovoltaic power station according to claim 1, characterized in that, The monitoring module is further used to monitor the first power input end power of the second photovoltaic side bus and the power output end power of the second photovoltaic side bus when the path between the second plant side bus power output end and the high plant transformer power input end is turned on, and control the start and stop of the plurality of second photovoltaic power generation devices respectively, so that the first power input end power of the second photovoltaic side bus is always less than the power output end power of the second photovoltaic side bus.

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