Energy-saving systems for solar power plants

Abstract

This energy-saving system avoids electrical energy loss due to no-load operation of box-type transformers at night, does not increase the workload of operation and maintenance workers, does not affect the safety and reliability of existing equipment, and prevents the effects of frequent switching operations of circuit breakers over long periods on the main insulation and inter-turn insulation of the box-type transformer windings and the arc extinguishing performance of the circuit breaker, thereby reducing energy consumption at substations and extending the service life of transformers. [Solution] The energy-saving system for the solar power plant includes a main transformer 1, to which the power grid 15 is connected to the high-voltage side of the main transformer, to which a bus 14 is connected to the low-voltage side of the main transformer, to which an energy-saving control module 6 is connected between the low-voltage side of the main transformer and the bus, to which a box-type transformer 16 is connected via a current collection line 17, the energy-saving control module is communicatively connected to a switchgear 5, and a light power prediction module 4 is connected to the switchgear.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy conservation in power plants and relates to an energy conservation system for a solar power plant.

Background Art

[0002] With the rapid development of the world economy, the demand for energy continues to increase. Conventional fossil fuels not only have limited reserves but also cause problems such as serious environmental pollution and climate change during their mining and use processes. In such a situation, solar power generation as a clean and renewable energy model has extremely important significance. During the day, the electrical energy generated by solar panels is sent to a booster station via a box-type transformer and a collector line, and then sent to the power grid through the main transformer in the booster station. At night, due to insufficient sunlight irradiation, the solar power generation system stops generating electricity. At this time, the power grid reversely transmits power to the box-type transformer via the main transformer of the booster station, and the box-type transformer enters a no-load operation state. As the construction scale of solar power plants gradually expands, the capacity of solar power plants is also rapidly increasing, and the number of installed box-type transformers is also increasing. The body loss caused by the no-load operation of box-type transformers at night cannot be ignored. Each collector line is equipped with an incoming line switch. When the incoming line switch is disconnected to disconnect the box-type transformer of the corresponding collector line, according to the specified requirements, it is necessary to disconnect the high-voltage side switch of each box-type transformer before disconnecting the incoming line switch. Therefore, in the morning, if the operator does not close the switches on the high-voltage side of the box-type transformers one by one, power generation cannot start. Such complicated power outage and power supply operations will surely increase the workload of the operation and maintenance personnel. In addition, it is inevitable that the frequent operations carried out daily will have an adverse impact on the reliability of the switch device. Avoiding the power loss caused by box-type transformers when solar power generation stops at night, achieving energy conservation and emission reduction, and eliminating the complicated operations of the operation and maintenance personnel are currently urgent issues to be solved.

[0003] Based on the above, conventional technology has the problem that the box-type transformer in a solar power generation system operates without load at night, causing excessive power loss and complicated switch management. [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The objective of the present invention is to provide an energy-saving system for solar power plants that solves the problems of conventional solar power generation systems, such as excessive loss of electrical energy due to the no-load operation of box-type transformers at night and the complexity of switch management. [Means for solving the problem]

[0005] The technical solution employed by the present invention is as follows: The energy-saving system for a solar power plant includes a main transformer, the high-voltage side of the main transformer is connected to a power grid, the low-voltage side of the main transformer is connected to a bus, an energy-saving control module is connected between the low-voltage side of the main transformer and the bus, a box-type transformer is connected to the bus via a power collection line, the energy-saving control module is communicatively connected to a switchgear controller, and an optical power prediction module is connected to the switchgear controller.

[0006] Furthermore, the features of the present invention are as follows.

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

[0008] One end of the resistance-capacitance absorption unit is connected between circuit breakers K3, K4, and K5 and the bus, and the other end of the resistance-capacitance absorption unit is grounded.

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

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

[0011] Between the bus and the box-type transformer, the bus-side current transformer and the circuit breaker K6 are connected in this order.

[0012] The bus has one end of its bus-side transformer connected, and the other end of the bus-side transformer is grounded.

[0013] The switchgear controller is electrically connected to the main transformer low-voltage side current transformer, the main transformer low-voltage side transformer, the bus side transformer, and the bus side current transformer, respectively.

[0014] A distribution station transformer is connected to the low-voltage side of the main transformer, and a circuit breaker K1 is installed between the low-voltage side of the main transformer and the distribution station transformer.

[0015] A static reactive power generator is connected to the low-voltage side of the main transformer, and a circuit breaker K2 is installed between the low-voltage side of the main transformer and the static reactive power generator. [Effects of the Invention]

[0016] The beneficial effects of the present invention are as follows: The present invention avoids electrical energy loss due to no-load operation of box-type transformers at night, does not increase the workload of operation and maintenance workers, and does not affect the safety and reliability of existing equipment. Furthermore, it avoids the effects of frequent switching operations of circuit breakers over long periods on the winding main insulation and inter-turn insulation of box-type transformers and the arc extinguishing performance of the circuit breakers, thereby reducing the energy consumption of substations and extending the service life of transformers. [Brief explanation of the drawing]

[0017] [Figure 1] This is a schematic diagram of the energy-saving system for a solar power plant according to the present invention. [Modes for carrying out the invention]

[0018] The present invention will be described in detail below with reference to the drawings and specific embodiments.

[0019] As shown in Figure 1, the energy-saving system of the solar power plant includes a main transformer 1, with the power grid 15 connected to the high-voltage side of the main transformer 1, and a bus 14 connected to the low-voltage side of the main transformer 1. An energy-saving control module 6 is connected between the low-voltage side of the main transformer 1 and the bus 14, and a box-type transformer 16 is connected to the bus 14 via a current collection line 17. The energy-saving control module 6 is communicatively connected to a switchgear 5, and an optical power prediction module 4 is connected to the switchgear 5.

[0020] The energy-saving control module 6 of the box-type transformer includes 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 connected to one end of an inrush current suppression resistor 7, circuit breaker K4, and circuit breaker K5, respectively. Circuit breaker K3 is connected to the other end of the inrush current suppression resistor 7. The end of circuit breaker K3 that is not connected to the inrush current suppression resistor 7 is connected to the end of circuit breaker K4 that is not connected to the main transformer low-voltage side current transformer 9, and the end of circuit breaker K5 that is not connected to the main transformer low-voltage side current transformer 9 is connected to bus 14.

[0021] One end of the resistance absorption unit 8 is connected between circuit breakers K3, K4, and K5 and bus 14, and the other end of the resistance absorption unit 8 is grounded. One end of the surge arrester 11 is connected between circuit breakers K3, K4, and K5 and bus 14, and the other end of the surge arrester 11 is grounded. One end of the main transformer low-voltage side transformer 10 is connected between the main transformer low-voltage side current transformer 9 and circuit breaker K4, and the other end of the main transformer low-voltage side transformer 10 is grounded. A bus-side current transformer 13 and circuit breaker K6 are connected in this order between bus 14 and box-type transformer 16. One end of the bus-side transformer 12 is connected to bus 14, and the other end of the bus-side transformer 12 is grounded. The switchgear controller 5 is electrically connected to the main transformer low-voltage side current transformer 9, the main transformer low-voltage side transformer 10, the bus side transformer 12, and the bus side current transformer 13, respectively.

[0022] A distribution station transformer 2 is connected to the low-voltage side of the main transformer 1, and a circuit breaker K1 is provided between the low-voltage side of the main transformer 1 and the distribution station transformer 2. A static reactive power generator 3 is connected to the low-voltage side of the main transformer 1, and a circuit breaker K2 is provided between the low-voltage side of the main transformer 1 and the static reactive power generator 3.

[0023] The distribution station transformer 2 supplies power to the low-voltage electrical equipment throughout the distribution station, ensuring the normal operation of protection, control, metering, and monitoring equipment within the distribution station. Even during daytime power generation and nighttime reverse power transmission by the power grid 15, the energy saving of the box-type transformer does not affect the normal operation of the factory system. The static reactive power generator 3 provides reactive power compensation to the power grid 15 and plays a role in maintaining the stability of the power grid 15 and the quality of electrical energy. The static reactive power generator 3 is equipment for adjusting and managing the power grid 15 and needs to be operated continuously day and night. Since the static reactive power generator 3 and the low-voltage side of the main transformer 1 are directly connected via the circuit breaker K2, the normal operation of the static reactive power generator 3 is not affected even if the box-type transformer is not energized at night. If the static reactive power generator 3 malfunctions and requires maintenance, its operation can be stopped by disconnecting the circuit breaker K2.

[0024] The resistance capacity absorption unit 8 and the lightning arrester 11 suppress the overvoltage generated by the switch of the circuit breaker K4, and make the voltage level lower than the turn-to-turn insulation level between the line cable and the box-type transformer, thereby playing a role in preventing the occurrence of insulation failure between the cable and the box-type transformer. The circuit breaker K4 functions as the main switch for controlling the connection and disconnection of the box-type transformer. When the solar power generation panel does not generate electricity at night, the circuit breaker K4 disconnects the electrical connection with the box-type transformer. As a result, the box-type transformer does not consume electrical energy at night. When power generation starts during the day, by closing the circuit breaker K4, the electrical energy generated by sunlight is sent to the power grid 15 through the circuit breaker K4 by the box-type transformer. The circuit breaker K5 functions as a backup device for the circuit breaker K4. Even when the circuit breaker K4 fails and cannot be opened and closed normally, the entire solar power system can be operated normally by closing the circuit breaker K5. The opening and closing action of the circuit breaker K3 is interlocked with the circuit breaker K4. When receiving a closing command, the circuit breaker K3 closes earlier than the circuit breaker K4. Since the circuit breaker K3 is connected to the inrush current suppression resistor 7, the circuit of the circuit breaker K3 conducts first, and the inrush current suppression resistor 7 limits the magnetizing inrush current caused by the closing of the no-load operation of the box-type transformer. The magnetizing inrush current of the box-type transformer is limited within a reasonable range, and the magnetizing inrush current disappears several milliseconds after the circuit breaker K3 is closed. Furthermore, when the circuit breaker K4 is closed, the circuit breaker K3 is disconnected.

[0025] The main transformer's low-voltage side transformer 10, the main transformer's low-voltage side transformer 9, and the bus-side transformers 12 and 13 collect voltage and current signals from both sides and transmit them to the switchgear 5. The role of the switchgear 5 is as follows: During the day, when sunlight meets the conditions for power generation, it acquires voltage and current information from the main transformer's low-voltage side transformer 10, the main transformer's low-voltage side current transformer 9, and the bus-side transformers 12 and 13, calculates the optimal closing phase angle, and transmits a closing command to the energy-saving control module 6. In the afternoon, if the light power prediction module 4 detects insufficient light irradiation, sunlight stops generating power and transmits a signal to the switchgear 5. Upon receiving the signal, the switchgear 5 transmits a trip command to the energy-saving control module 6, the circuit breaker K4 is disconnected, and the box-type transformer 16 disconnects from the power grid 15. This enables energy saving at night.

[0026] The operating principle of the energy-saving system of the solar power plant of the present invention is as follows. When the optical power prediction module 4 detects insufficient light irradiation, it sends a signal to the opening / closing controller 5. When the opening / closing controller 5 receives the insufficient light irradiation signal, it sends a disconnection command to the energy-saving control module 6, and the circuit breaker K4 performs a disconnection operation. At this time, if the generated disconnection overvoltage exceeds the set value, the resistance-capacitance absorption unit 8 and the lightning arrester 11 operate to protect the insulation state of the cable connector and the box-type transformer. When the circuit breaker K4 is disconnected, the bus 14 becomes in a non-charged state, and all the box-type transformers 16 connected to the bus 14 are disconnected from the power grid 15. At this time, the box-type transformer 16 stops consuming electrical energy, and the power required for the low-voltage electrical equipment in the solar power plant is supplied from the distribution transformer 2. When the optical power prediction module 4 detects that the light irradiation intensity has reached the set value, it sends a closing signal to the opening / closing controller 5. The opening / closing controller 5 collects the voltage and current values of the main transformer low-voltage side transformer 10, the main transformer low-voltage side current converter 9, the bus side transformer 12, and the bus side current converter 13, selects the optimal closing phase angle, and sends a closing command to the energy-saving control module 6. When receiving the closing command, the circuit breaker K3 first starts a closing operation. Since the circuit breaker K3 is connected to the inrush current suppression resistor 7, the inrush magnetizing current caused by the closing of the box-type transformer can be more effectively suppressed. After a few milliseconds, when the inrush current disappears, the circuit breaker K4 is closed and the circuit breaker K3 is disconnected to end the operation, and the entire system enters a normal power generation state.

[0027] Example 1 In this embodiment, an energy-saving system for a solar power plant is proposed. As shown in FIG. 1, the energy-saving system of the solar power plant includes a main transformer 1. The power grid 15 is connected to the high-voltage side of the main transformer 1, the bus 14 is connected to the low-voltage side of the main transformer 1, and an energy-saving control module 6 is connected between the low-voltage side of the main transformer 1 and the bus 14. A box-type transformer 16 is connected to the bus 14 via a collector line 17. The energy-saving control module 6 is communicably connected to an opening / closing controller 5, and an optical power prediction module 4 is connected to the opening / closing controller 5.

[0028] Example 2 In this embodiment, an energy-saving system for a solar power plant is proposed. As shown in Figure 1, the energy-saving system for the solar power plant includes a main transformer 1, with a power grid 15 connected to the high-voltage side of the main transformer 1, a bus 14 connected to the low-voltage side of the main transformer 1, an energy-saving control module 6 connected between the low-voltage side of the main transformer 1 and the bus 14, a box-type transformer 16 connected to the bus 14 via a current collection line 17, the energy-saving control module 6 being communicatively connected to a switchgear 5, and an optical power prediction module 4 connected to the switchgear 5. The energy-saving control module 6 of the box-type transformer includes a main transformer low-voltage side current transformer 9, one end of which is connected to the low-voltage side of the main transformer 1, and the other end of which is connected to one end of an inrush current suppression resistor 7, circuit breaker K4, and circuit breaker K5, respectively. Circuit breaker K3 is connected to the other end of the inrush current suppression resistor 7, and the end of circuit breaker K3 away from the inrush current suppression resistor 7 is connected to the end of circuit breaker K4 away from the main transformer low-voltage side current transformer 9, and the end of circuit breaker K5 away from the main transformer low-voltage side current transformer 9 is connected to bus 14.

[0029] Example 3 In this embodiment, an energy-saving system for a solar power plant is proposed. As shown in Figure 1, the energy-saving system for the solar power plant includes a main transformer 1, a power grid 15 connected to the high-voltage side of the main transformer 1, a bus 14 connected to the low-voltage side of the main transformer 1, an energy-saving control module 6 connected between the low-voltage side of the main transformer 1 and the bus 14, a box-type transformer 16 connected to the bus 14 via a current collection line 17, the energy-saving control module 6 being communicatively connected to a switchgear 5, and an optical power prediction module 4 connected to the switchgear 5. The energy-saving control module 6 of the box-type transformer includes a main transformer low-voltage side current transformer 9, one end of which is connected to the low-voltage side of the main transformer 1, and the other end of which is connected to one end of an inrush current suppression resistor 7, circuit breaker K4, and circuit breaker K5, respectively. Circuit breaker K3 is connected to the other end of the inrush current suppression resistor 7, and the end of circuit breaker K3 away from the inrush current suppression resistor 7 is connected to the end of circuit breaker K4 away from the main transformer low-voltage side current transformer 9, and the end of circuit breaker K5 away from the main transformer low-voltage side current transformer 9 is connected to bus 14.

[0030] One end of the resistance absorption unit 8 is connected between circuit breakers K3, K4, and K5 and bus 14, and the other end of the resistance absorption unit 8 is grounded. One end of the surge arrester 11 is connected between circuit breakers K3, K4, and K5 and bus 14, and the other end of the surge arrester 11 is grounded. One end of the main transformer low-voltage side transformer 10 is connected between the main transformer low-voltage side current transformer 9 and circuit breaker K4, and the other end of the main transformer low-voltage side transformer 10 is grounded. A bus-side current transformer 13 and circuit breaker K6 are connected in this order between bus 14 and box-type transformer 16. One end of the bus-side transformer 12 is connected to bus 14, and the other end of the bus-side transformer 12 is grounded. The switchgear controller 5 is electrically connected to the main transformer low-voltage side current transformer 9, the main transformer low-voltage side transformer 10, the bus side transformer 12, and the bus side current transformer 13, respectively. The distribution station transformer 2 is connected to the low-voltage side of the main transformer 1, and a circuit breaker K1 is provided between the low-voltage side of the main transformer 1 and the distribution station transformer 2. A static reactive power generator 3 is provided on the low-voltage side of the main transformer 1, and a circuit breaker K2 is provided between the low-voltage side of the main transformer 1 and the static reactive power generator 3. [Explanation of Symbols]

[0031] 1. Main transformer 2. Transformers for power distribution stations 3. Static reactive power generator 4. Optical power prediction module 5. Open / Close Controller 6. Energy-saving control module 7 Inrush current suppression resistor 8 Resistance Capacitance Absorption Unit 9. Main transformer low-voltage side current transformer 10. Main transformer, low-voltage side transformer 11 Lightning arrester 12 Bus-side transformer 13 Bus-side current transformer 14 bus 15 Power grid 16 Box-type transformer 17 Current collection line

Claims

1. An energy-saving system for a solar power plant, comprising a main transformer (1), the high-voltage side of the main transformer (1) connected to a power grid (15), the low-voltage side of the main transformer (1) connected to a bus (14), an energy-saving control module (6) connected between the low-voltage side of the main transformer (1) and the bus (14), a box-type transformer (16) connected to the bus (14) via a current collection line (17), the energy-saving control module (6) being communicatively connected to a switchgear (5), and the switchgear (5) being connected to an optical power prediction module (4).

2. The energy-saving control module (6) includes a main transformer low-voltage side current transformer (9), one end of which is connected to the low-voltage side current transformer (1), and the other end of which is connected to one end of an inrush current suppression resistor (7), a circuit breaker K4, and a circuit breaker K5, respectively, and the other end of which is connected to a circuit breaker K3, the other end of which is connected to an inrush current suppression resistor (7), the end of which is connected to the inrush current suppression resistor (7), the end of which is connected to the end of which is connected to the end of which is connected to the main transformer low-voltage side current transformer (9) of the circuit breaker K4, and the end of which is connected to the end of which is connected to the main transformer low-voltage side current transformer (9) of the circuit breaker K5, respectively, and the ends of which are connected to the main transformer low-voltage side current transformer (9) of the circuit breaker K3, the circuit breaker K4, and the circuit breaker K5, the ends of which are connected to the main transformer low-voltage side current transformer (9) of the circuit breaker K3, the circuit breaker K4, and the circuit breaker K5, the ends of which are connected to the main transformer low-voltage side current transformer (9) are connected to the bus (14), characterized in that the energy-saving system for a solar power plant according to claim 1.

3. The energy-saving system for a solar power plant according to claim 2, characterized in that one end of a resistance-capacitance absorption unit (8) is connected between the circuit breakers K3, K4, and K5 and the bus (14), and the other end of the resistance-capacitance absorption unit (8) is grounded.

4. The energy-saving system for a solar power plant according to claim 3, characterized in that one end of a surge arrester (11) is connected between the circuit breakers K3, K4, and K5 and the bus (14), and the other end of the surge arrester (11) is grounded.

5. The energy-saving system for a solar power plant according to claim 4, characterized in that one end of the main transformer low-voltage side 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 transformer (10) is grounded.

6. The energy-saving system for a solar power plant according to claim 5, characterized in that a bus-side current transformer (13) and a circuit breaker K6 are connected in this order between the bus (14) and the box-type transformer (16).

7. The energy-saving system for a solar power plant according to claim 6, characterized in that one end of the bus (14) is connected to the bus-side transformer (12), and the other end of the bus-side transformer (12) is grounded.

8. The energy-saving system for a solar power plant according to claim 7, characterized in that the switch controller (5) is electrically connected to the main transformer low-voltage side current transformer (9), the main transformer low-voltage side transformer (10), the bus side transformer (12), and the bus side current transformer (13), respectively.

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

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

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