Energy-saving system of photovoltaic power station

Abstract

The invention discloses a photovoltaic power station energy-saving system which comprises a main transformer, the high-voltage side of the main transformer is connected with a power grid, the low-voltage side of the main transformer is connected with a bus, an energy-saving control module is connected between the low-voltage side of the main transformer and the bus, and the bus is connected with a box-type transformer through a current collection line. The energy-saving control module is in communication connection with the opening and closing controller, and the opening and closing controller is connected with an optical power prediction module. According to the photovoltaic power station energy-saving system, electric energy loss caused by no-load operation of a box-type transformer at night can be avoided, and the safety and reliability of existing equipment are not affected while the workload of operation and maintenance personnel is not additionally increased; the influence on the main insulation and turn-to-turn insulation of the box transformer winding and the arc extinguishing performance of the circuit breaker caused by the long-term frequent operation of the on-off of the circuit breaker is avoided, the energy consumption of a power distribution station is reduced, and the service life of the transformer is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of power station energy saving and relates to a photovoltaic power station energy saving system. Background Art

[0002] Photovoltaic power generation is a clean and renewable energy model with great significance. During the day, the electricity generated by solar panels is sent to the booster station through the box transformer via the collector line, and then transmitted to the power grid through the main transformer in the booster station. At night, due to the lack of sunlight, the photovoltaic power generation system stops generating electricity. At this time, the power grid reverses the power to the box transformer through the main transformer of the booster station, and the box transformer is in a no-load operation state. With the gradual expansion of the scale of photovoltaic power generation construction, the capacity of photovoltaic power stations is also growing rapidly, and the number of supporting box transformers is also increasing accordingly. The self-loss caused by the no-load operation of the box transformer at night cannot be ignored. Although each collector line is equipped with an incoming line switch, if the box transformer on the corresponding collector line is to be cut off by disconnecting the incoming line switch, according to the regulations, the high-voltage side switch of each box transformer must be disconnected before the incoming line switch can be cut off; in the morning, the operator must close the switch on the high-voltage side of the box transformer one by one before generating electricity. Such a complex power-off operation will undoubtedly increase the workload of the operation and maintenance personnel, and the frequent operation every day will inevitably affect the reliability of the switch equipment. Avoiding power loss caused by box-type transformers during the night when photovoltaic power generation is not taking place, achieving energy conservation and emission reduction while eliminating the need for operation and maintenance personnel to perform complex operations, is an urgent problem that needs to be solved.

[0003] In summary, the prior art has the problem that the box-type transformer of the photovoltaic power generation system operates at no-load at night, causing excessive power loss and inconvenient switch management. Summary of the invention

[0004] The purpose of the present invention is to provide a photovoltaic power station energy-saving system, which solves the problem in the prior art that the box-type transformer of the photovoltaic power generation system operates at no load at night, causing excessive power loss and inconvenient switch management.

[0005] The technical solution adopted by the present invention is a photovoltaic power station energy-saving system, including a photovoltaic power station energy-saving system, including a main transformer, the high-voltage side of the main transformer is connected to the power grid, the low-voltage side of the main transformer is connected to the bus, an energy-saving control module is connected between the low-voltage side of the main transformer and the bus, the bus is connected to a box-type transformer through a collector line, the energy-saving control module is communicatively connected to a switching controller, and the switching controller is connected to an optical power prediction module.

[0006] The present invention is also characterized in that:

[0007] The box-type transformer energy-saving control module includes a current transformer on the low-voltage side of the main transformer. One end of the current transformer on the low-voltage side of the main transformer is connected to the low-voltage side of the main transformer, and the other end is respectively connected to one end of the inrush current suppression resistor, circuit breaker K4, and circuit breaker K5. The other end of the inrush current suppression resistor is connected to the circuit breaker K3. The end of the circuit breaker K3 away from the inrush current suppression resistor is respectively connected to the end of the current transformer on the low-voltage side of the main transformer away from the circuit breaker K4 and the end of the current transformer on the low-voltage side of the main transformer away from the circuit breaker K5. The ends of the current transformer on the low-voltage side of the main transformer away from the circuit breaker K3, the circuit breaker K4, and the circuit breaker K5 are connected to the busbar.

[0008] One end of a RC absorption unit is connected between the circuit breakers K3, K4 and K5 and the busbar, and the other end of the RC absorption unit is grounded.

[0009] One end of a lightning arrester is connected between the circuit breakers K3, K4, and K5 and the busbar, and the other end of the lightning arrester is grounded.

[0010] One end of the voltage mutual inductance on the low voltage side of the main transformer is connected between the current mutual inductance on the low voltage side of the main transformer and the circuit breaker K4, and the other end of the voltage mutual inductance on the low voltage side of the main transformer is grounded.

[0011] The busbar side current transformer and circuit breaker K6 are connected in sequence between the busbar and the box-type transformer.

[0012] The busbar is connected to one end of a busbar-side voltage transformer, and the other end of the busbar-side voltage transformer is grounded.

[0013] The opening and closing controller is electrically connected to the current transformer on the low voltage side of the main transformer, the voltage transformer on the low voltage side of the main transformer, the voltage transformer on the bus side, and the current transformer on the bus side respectively.

[0014] The low-voltage side of the main transformer is connected to the substation transformer, and a circuit breaker K1 is provided between the low-voltage side of the main transformer and the substation transformer.

[0015] The low-voltage side of the main transformer is connected to a static VAR generator, and a circuit breaker K2 is provided between the low-voltage side of the main transformer and the static VAR generator.

[0016] The beneficial effects of the present invention are as follows: the present invention can avoid the power loss caused by the no-load operation of the box-type transformer at night, does not increase the workload of the operation and maintenance personnel, and does not affect the safety and reliability of the existing equipment. It avoids the influence of long-term frequent operation of the circuit breaker on the main insulation and inter-turn insulation of the box-type transformer winding and the arc extinguishing performance of the circuit breaker, reduces the energy consumption of the distribution station and prolongs the service life of the transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the photovoltaic power station energy-saving system of the present invention.

[0018] In the figure, 1. main transformer; 2. transformer for distribution station; 3. static VAR generator; 4. optical power prediction module; 5. opening and closing controller; 6. energy-saving control module; 7. inrush suppression resistor; 8. RC absorption unit; 9. current transformer on low voltage side of main transformer; 10. voltage transformer on low voltage side of main transformer; 11. lightning arrester; 12. voltage transformer on bus side; 13. current transformer on bus side; 14. bus; 15. power grid; 16. box transformer; 17. collector line. DETAILED DESCRIPTION

[0019] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] Photovoltaic power station energy-saving system, such as Figure 1 As shown, it includes an energy-saving system for a photovoltaic power station, including a main transformer 1, the high-voltage side of the main transformer 1 is connected to a power grid 15, the low-voltage side of the main transformer 1 is connected to a bus 14, an energy-saving control module 6 is connected between the low-voltage side of the main transformer 1 and the bus 14, the bus 14 is connected to a box-type transformer 16 through a collector line 17, the energy-saving control module 6 is communicatively connected to a switch-on and switch-off controller 5, and the switch-on and switch-off controller 5 is connected to an optical power prediction module 4.

[0021] The box-type transformer energy-saving control module 6 includes a current transformer 9 on the low-voltage side of the main transformer. One end of the current transformer 9 on the low-voltage side of the main transformer is connected to the low-voltage side of the main transformer 1, and the other end is respectively connected to one end of the surge suppression resistor 7, the circuit breaker K4, and the circuit breaker K5. The other end of the surge suppression resistor 7 is connected to the circuit breaker K3. The end of the circuit breaker K3 away from the surge suppression resistor 7 is respectively connected to the end of the circuit breaker K4 away from the low-voltage side of the main transformer and the end of the circuit breaker K5 away from the low-voltage side of the main transformer. The ends of the circuit breakers K3, K4, and K5 away from the low-voltage side of the main transformer are connected to the bus 14.

[0022] One end of the RC absorption unit 8 is connected between the circuit breaker K3, the circuit breaker K4, the circuit breaker K5 and the bus 14, and the other end of the RC absorption unit 8 is grounded. One end of the lightning arrester 11 is connected between the circuit breaker K3, the circuit breaker K4, the circuit breaker K5 and the bus 14, and the other end of the lightning arrester 11 is grounded. One end of the main transformer low-voltage side voltage transformer 10 is connected between the main transformer low-voltage side current transformer 9 and the circuit breaker K4, and the other end of the main transformer low-voltage side voltage transformer 10 is grounded. The bus 14 and the box-type transformer 16 are connected in sequence with the bus-side current transformer 13 and the circuit breaker K6. The bus 14 is connected to one end of the bus-side voltage transformer 12, and the other end of the bus-side voltage transformer 12 is grounded. The opening and closing controller 5 is electrically connected to the main transformer low-voltage side current transformer 9, the main transformer low-voltage side voltage transformer 10, the bus-side voltage transformer 12, and the bus-side current transformer 13 respectively.

[0023] The low voltage side of the main transformer 1 is connected to the transformer 2 for distribution station, and a circuit breaker K1 is provided between the low voltage side of the main transformer 1 and the transformer 2 for distribution station. The low voltage side of the main transformer 1 is connected to the static VAR generator 3, and a circuit breaker K2 is provided between the low voltage side of the main transformer 1 and the static VAR generator 3.

[0024] The transformer 2 of the distribution station supplies power to the low-voltage electrical equipment of the whole station to ensure the normal operation of the protection, control, metering, monitoring and other equipment in the distribution station. No matter it generates electricity during the day or the power grid reverses power at night, the normal operation of the plant system will not be affected by the energy saving of the box transformer; the function of the static VAR generator 3 is to provide reactive power compensation for the power grid 15 to maintain the stability and power quality of the power grid 15. The static VAR generator 3 is the regulating device of the power grid 15 and needs to be put into operation continuously regardless of day or night. Since the static VAR generator 3 is directly connected to the low-voltage side of the main transformer 1 through the circuit breaker K2, even if the box transformer is not energized at night, it will not affect the normal operation of the static VAR generator 3; when the static VAR generator 3 fails and needs maintenance, the circuit breaker K2 can be disconnected to make the static VAR generator 3 stop running;

[0025] The function of the RC absorption unit 8 and the lightning arrester 11 is to suppress the overvoltage generated by the opening and closing of the circuit breaker K4, so that the overvoltage level is lower than the insulation level between the line cable and the box transformer, so as to prevent the insulation failure of the cable and the box transformer; the function of the circuit breaker K4 is to serve as the main switch to control whether the box transformer is put into use. When the photovoltaic panel does not generate electricity at night, the electrical connection between the photovoltaic panel and the box transformer is disconnected through the circuit breaker K4, so that the box transformer no longer consumes electricity at night; when power generation starts during the day, by closing the circuit breaker K4, the photovoltaic power generated is sent to the power grid through the box transformer via the circuit breaker K4; the circuit breaker K5 is used as a backup for the circuit breaker K4. Device, when the circuit breaker K4 fails and cannot be normally opened or closed, the circuit breaker K5 is closed to make the whole photovoltaic system operate normally; the switch function of the circuit breaker K3 is to form a linkage with the circuit breaker K4. After receiving the closing command, the circuit breaker K3 is closed before the circuit breaker K4. Since the circuit breaker K3 is connected to the surge suppression resistor 7, the circuit breaker K3 circuit is first turned on, and the excitation surge current generated by the no-load closing of the box transformer is limited by the surge suppression resistor 7, and the excitation surge current of the box transformer is limited to a reasonable range. A few milliseconds after the circuit breaker K3 is closed, the excitation surge current disappears, and the circuit breaker K4 is closed, and the circuit breaker K3 is disconnected at the same time;

[0026] The function of the voltage transformer 10, current transformer 9 on the low voltage side of the main transformer, and the voltage transformer 12 and current transformer 13 on the bus side is to collect the voltage and current signals on both sides and send them to the opening and closing controller 5; the function of the opening and closing controller 5 is to calculate the optimal closing phase angle by obtaining the voltage and current information of the voltage transformer 10, current transformer 9, bus side voltage transformer 12 and bus side current transformer 13 on the low voltage side of the main transformer when the photovoltaic power generation conditions are met during the day, and send a closing instruction to the energy-saving control module 6; in the afternoon, when the light power prediction module 4 detects insufficient light, the photovoltaic power generation stops, and sends a signal to the opening and closing controller 5. After receiving the signal, the opening and closing controller 5 sends a tripping command to the energy-saving control module 6, the circuit breaker K4 is disconnected, and the box-type transformer 16 is disconnected from the power grid 15, thereby achieving the purpose of energy saving at night.

[0027] The working principle of the photovoltaic power station energy-saving system of the present invention is as follows: when the optical power prediction module 4 detects insufficient light, it sends a signal to the opening and closing controller 5. After receiving the insufficient light signal, the opening and closing controller 5 sends an opening command to the energy-saving control module 6, and the circuit breaker K4 performs an opening operation. At this time, if the opening overvoltage generated is higher than the set value, the resistor-capacitor absorption unit 8 and the lightning arrester 11 will be activated to protect the cable joint and the box transformer insulation. After the circuit breaker K4 is disconnected, the bus 14 is not energized, and all the box transformers 16 connected to the bus 14 are disconnected from the power grid 15. At this time, the box transformer 16 no longer consumes electrical energy, and the low-voltage electrical equipment required for electricity in the photovoltaic station is provided by the distribution station transformer 2; when the optical power When the prediction module 4 detects that the light intensity reaches the set value, it sends a closing signal to the opening and closing controller 5. The opening and closing controller 5 collects the voltage and current values ​​of the voltage transformer 10 on the low-voltage side of the main transformer and the current transformer 9 on the low-voltage side of the main transformer, the voltage transformer 12 on the bus side and the current transformer 13 on the bus side, selects the best closing phase angle, and sends a closing command to the energy-saving control module 6. After receiving the closing command, the circuit breaker K3 first starts the closing operation. Since the circuit breaker K3 is connected to the surge suppression resistor 7, it can better suppress the excitation surge current generated by the closing of the box transformer. After about a few milliseconds, the surge current disappears, the circuit breaker K4 is closed, and the circuit breaker K3 is disconnected and exits operation. The entire system is in a normal power generation state.

[0028] Example 1

[0029] This embodiment proposes a photovoltaic power station energy-saving system, such as Figure 1As shown, it includes an energy-saving system for a photovoltaic power station, including a main transformer 1, the high-voltage side of the main transformer 1 is connected to a power grid 15, the low-voltage side of the main transformer 1 is connected to a bus 14, an energy-saving control module 6 is connected between the low-voltage side of the main transformer 1 and the bus 14, the bus 14 is connected to a box-type transformer 16 through a collector line 17, the energy-saving control module 6 is communicatively connected to a switch-on and switch-off controller 5, and the switch-on and switch-off controller 5 is connected to an optical power prediction module 4.

[0030] Example 2

[0031] This embodiment proposes a photovoltaic power station energy-saving system, such as Figure 1 As shown, it includes an energy-saving system for a photovoltaic power station, including a main transformer 1, the high-voltage side of the main transformer 1 is connected to a power grid 15, the low-voltage side of the main transformer 1 is connected to a bus 14, an energy-saving control module 6 is connected between the low-voltage side of the main transformer 1 and the bus 14, the bus 14 is connected to a box-type transformer 16 through a collector line 17, the energy-saving control module 6 is communicatively connected to a switch-on and switch-off controller 5, and the switch-on and switch-off controller 5 is connected to an optical power prediction module 4. The box-type transformer energy-saving control module 6 includes a current transformer 9 on the low-voltage side of the main transformer. One end of the current transformer 9 on the low-voltage side of the main transformer is connected to the low-voltage side of the main transformer 1, and the other end is respectively connected to one end of the surge suppression resistor 7, the circuit breaker K4, and the circuit breaker K5. The other end of the surge suppression resistor 7 is connected to the circuit breaker K3. The end of the circuit breaker K3 away from the surge suppression resistor 7 is respectively connected to the end of the circuit breaker K4 away from the low-voltage side of the main transformer and the end of the circuit breaker K5 away from the low-voltage side of the main transformer. The ends of the circuit breakers K3, K4, and K5 away from the low-voltage side of the main transformer are connected to the bus 14.

[0032] Example 3

[0033] This embodiment proposes a photovoltaic power station energy-saving system, such as Figure 1As shown, it includes an energy-saving system for a photovoltaic power station, including a main transformer 1, the high-voltage side of the main transformer 1 is connected to a power grid 15, the low-voltage side of the main transformer 1 is connected to a bus 14, an energy-saving control module 6 is connected between the low-voltage side of the main transformer 1 and the bus 14, the bus 14 is connected to a box-type transformer 16 through a collector line 17, the energy-saving control module 6 is communicatively connected to a switch-on and switch-off controller 5, and the switch-on and switch-off controller 5 is connected to an optical power prediction module 4. The box-type transformer energy-saving control module 6 includes a current transformer 9 on the low-voltage side of the main transformer. One end of the current transformer 9 on the low-voltage side of the main transformer is connected to the low-voltage side of the main transformer 1, and the other end is respectively connected to one end of the surge suppression resistor 7, the circuit breaker K4, and the circuit breaker K5. The other end of the surge suppression resistor 7 is connected to the circuit breaker K3. The end of the circuit breaker K3 away from the surge suppression resistor 7 is respectively connected to the end of the circuit breaker K4 away from the low-voltage side of the main transformer and the end of the circuit breaker K5 away from the low-voltage side of the main transformer. The ends of the circuit breakers K3, K4, and K5 away from the low-voltage side of the main transformer are connected to the bus 14.

[0034] One end of the RC absorption unit 8 is connected between the circuit breaker K3, the circuit breaker K4, the circuit breaker K5 and the bus 14, and the other end of the RC absorption unit 8 is grounded. One end of the lightning arrester 11 is connected between the circuit breaker K3, the circuit breaker K4, the circuit breaker K5 and the bus 14, and the other end of the lightning arrester 11 is grounded. One end of the main transformer low-voltage side voltage transformer 10 is connected between the main transformer low-voltage side current transformer 9 and the circuit breaker K4, and the other end of the main transformer low-voltage side voltage transformer 10 is grounded. The bus 14 and the box-type transformer 16 are connected in sequence with the bus-side current transformer 13 and the circuit breaker K6. The bus 14 is connected to one end of the bus-side voltage transformer 12, and the other end of the bus-side voltage transformer 12 is grounded. The opening and closing controller 5 is electrically connected to the main transformer low-voltage side current transformer 9, the main transformer low-voltage side voltage transformer 10, the bus-side voltage transformer 12, and the bus-side current transformer 13. The main transformer 1 is connected to the low-voltage side with the distribution station transformer 2, and a circuit breaker K1 is provided between the low-voltage side of the main transformer 1 and the distribution station transformer 2. The main transformer 1 is connected to the low-voltage side with the static VAR generator 3, and a circuit breaker K2 is provided between the low-voltage side of the main transformer 1 and the static VAR generator 3.

Claims

1. Photovoltaic power station energy-saving system, It is characterized in that The invention comprises a photovoltaic power station energy-saving system, comprising a main transformer (1), wherein the high-voltage side of the main transformer (1) is connected to a power grid (15), the low-voltage side of the main transformer (1) is connected to a busbar (14), an energy-saving control module (6) is connected between the low-voltage side of the main transformer (1) and the busbar (14), the busbar (14) is connected to a box-type transformer (16) via a collector line (17), the energy-saving control module (6) is communicatively connected to a switch-on and switch-off controller (5), and the switch-on and switch-off controller (5) is connected to an optical power prediction module (4).

2. The photovoltaic power station energy-saving system according to claim 1, It is characterized in that The box-type transformer energy-saving control module (6) comprises a main transformer low-voltage side current transformer (9), one end of the main transformer low-voltage side current transformer (9) is connected to the low-voltage side of the main transformer (1), and the other end is respectively connected to one end of an inrush current suppression resistor (7), a circuit breaker K4, and a circuit breaker K5; the other end of the inrush current suppression resistor (7) is connected to a circuit breaker K3; the end of the circuit breaker K3 away from the inrush current suppression resistor (7) is respectively connected to one end of the circuit breaker K4 away from the main transformer low-voltage side current transformer (9) and one end of the circuit breaker K5 away from the main transformer low-voltage side current transformer (9); the ends of the circuit breakers K3, K4, and K5 away from the main transformer low-voltage side current transformer (9) are connected to a busbar (14).

3. The photovoltaic power station energy-saving system according to claim 2, It is characterized in that One end of a resistor-capacitor absorption unit (8) is connected between the circuit breakers K3, K4, K5 and the busbar (14), and the other end of the resistor-capacitor absorption unit (8) is grounded.

4. The photovoltaic power station energy-saving system according to claim 3, It is characterized in that One end of a lightning arrester (11) is connected between the circuit breakers K3, K4, K5 and the busbar (14), and the other end of the lightning arrester (11) is grounded.

5. The photovoltaic power station energy-saving system according to claim 4, It is characterized in that One end of the main transformer low-voltage side voltage mutual inductance (10) is connected between the main transformer low-voltage side current mutual inductance (9) and the circuit breaker K4, and the other end of the main transformer low-voltage side voltage mutual inductance (10) is grounded.

6. The photovoltaic power station energy-saving system according to claim 5, It is characterized in that A busbar-side current transformer (13) and a circuit breaker K6 are connected in sequence between the busbar (14) and the box-type transformer (16).

7. The photovoltaic power station energy-saving system according to claim 6, It is characterized in that The busbar (14) is connected to one end of a busbar-side voltage transformer (12), and the other end of the busbar-side voltage transformer (12) is grounded.

8. The photovoltaic power station energy-saving system according to claim 7, It is characterized in that The switch-on and switch-off controller (5) is electrically connected to a main transformer low-voltage side current transformer (9), a main transformer low-voltage side voltage transformer (10), a busbar side voltage transformer (12), and a busbar side current transformer (13), respectively.

9. The photovoltaic power station energy-saving system according to claim 1, It is characterized in that The low-voltage side of the main transformer (1) is connected to a transformer (2) for a power distribution station, and a circuit breaker K1 is provided between the low-voltage side of the main transformer (1) and the transformer (2) for a power distribution station.

10. The photovoltaic power station energy-saving system according to claim 1, It is characterized in that The low-voltage side of the main transformer (1) is connected to a static VAR generator (3), and a circuit breaker K2 is provided between the low-voltage side of the main transformer (1) and the static VAR generator (3).

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