An electrical main wiring system of a hydropower plant with new energy line access

Abstract

The utility model provides a kind of new energy line access hydropower plant's electrical main wiring system, including autotransformer, autotransformer is connected with 500kV branch bus, 220kV branch bus, 35kV branch bus respectively, 500kV branch bus is connected with 500kV main bus, 220kV branch bus is connected with 220kV main bus, and at least one 220kV new energy line is equipped on 220kV main bus;35kV branch bus is connected with 35kV main bus, and at least one 35kV new energy line is equipped on 35kV main bus, autotransformer 220kV side, 35kV side line voltage boosting is gathered and then is accessed 500kV main bus, and it is accessed power grid by hydropower station 500kV sending-out line.Wind power photovoltaic access hydropower station can realize water wind light complementary operation, utilize dry period water storage, more wind light;Rainy season abundant water, more hydropower, both realize the continuous stable output of power generation, and increase the utilization hours of line;Reduce land cost, reduce construction difficulty, reduce sending-out circuit construction, greatly reduce cost.

Description

Technical Field

[0001] This utility model relates to the field of power generation, specifically to an electrical main wiring system for connecting new energy lines to hydropower plants. Background Technology

[0002] The typical grid connection scheme for new energy power plants such as wind power and photovoltaic power is to set up a step-up substation in the wind power and photovoltaic field. The power generation arrays in each area of ​​the field are collected by the collection line to the step-up substation and stepped up to the voltage level of the grid to be connected to the local power grid. Alternatively, several wind power and photovoltaic fields can be stepped up to a certain voltage level (such as 110kV or 220kV) and then bundled and collected to a new energy collection station for unified external transmission.

[0003] Southwest my country's mountainous regions possess abundant wind and solar energy resources, but local electricity demand is limited. The main way to utilize renewable energy is through long-distance transmission (e.g., wind and solar power from Yunnan being transmitted to Guangdong). These wind and solar power projects are often located in mountainous valleys, far from the local grid. If bundled transmission is achieved through a newly built collection station, a new collection station needs to be built in the mountainous area to collect data from nearby renewable energy plants before a new high-voltage transmission line is constructed for long-distance transmission. This approach presents the following problems for renewable energy plants in mountainous areas: 1) The surrounding mountains and valleys are numerous and geologically complex, making site selection for new collection stations difficult due to the need for a large flat area. 2) Constructing new high-voltage transmission lines in mountainous areas is challenging due to steep terrain, limiting available transmission routes, increasing construction difficulty and investment, and resulting in low economic viability. 3) The power generation of wind and solar power plants is highly volatile, typically requiring nearby energy storage stations to regulate and balance power generation, further increasing the construction cost and difficulty of renewable energy power plants in valley areas. Utility Model Content

[0004] The main objective of this invention is to provide an electrical main wiring system for connecting new energy lines to hydropower plants, addressing the aforementioned problems.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An electrical main wiring system for connecting a new energy line to a hydropower plant includes an autotransformer, which is connected to a 500kV branch bus, a 220kV branch bus, and a 35kV branch bus. The 500kV branch bus is connected to a 500kV main bus, and the 220kV branch bus is connected to a 220kV main bus. At least one 220kV new energy line is installed on the 220kV main bus.

[0007] The 35kV branch bus is connected to the 35kV main bus. At least one 35kV new energy line is provided on the 35kV main bus. The lines on the 220kV side and 35kV side of the autotransformer are stepped up and connected to the 500kV main bus after being combined. The lines are then connected to the power grid through the 500kV transmission line of the hydropower station.

[0008] While adopting the above technical solutions, this utility model may also adopt or combine the following technical solutions:

[0009] As a preferred technical solution of this utility model: a detachable break is reserved on the 220kV branch bus, and a 220kV circuit breaker reserved interval is provided between the detachable break and the 220kV main bus.

[0010] As a preferred technical solution of this utility model: the 500kV GIS branch bus is equipped with a 500kV surge arrester and a 500kV circuit breaker.

[0011] As a preferred technical solution of this utility model: the 35kV branch bus is equipped with a 35kV surge arrester and a 35kV circuit breaker.

[0012] As a preferred technical solution of this utility model: the 220kV main bus is equipped with a combination of 220kV bus voltage transformer and surge arrester.

[0013] As a preferred technical solution of this utility model: the 35kV main bus is equipped with a combination of 35kV bus voltage transformer and surge arrester.

[0014] As a preferred technical solution of this utility model: the 35kV main bus is equipped with an SVG reactive power compensation device and a capacitor bank.

[0015] As a preferred technical solution of this utility model: a 35kV feeder circuit breaker is provided between the 35kV main bus and the SVG reactive power compensation device.

[0016] As a preferred technical solution of this utility model: the capacity of the third winding (35kV side winding) of the autotransformer is controlled to be no less than 35% of the autotransformer's electromagnetic capacity to compensate for the third harmonic current. The autotransformer's electromagnetic capacity is calculated according to the following formula:

[0017]

[0018] In the formula, S T For autotransformer total capacity; S C U1 is the electromagnetic capacitance of the autotransformer; U2 is the medium-voltage side voltage of the autotransformer; U1 is the high-voltage side voltage of the autotransformer.

[0019] As a preferred technical solution of this utility model: both the 220kV new energy line and the 35kV new energy line are equipped with circuit breakers.

[0020] This utility model provides an electrical main wiring system for connecting new energy lines to hydropower plants, which has the following beneficial effects: connecting wind and solar power to hydropower stations can achieve complementary operation of water, wind and solar power, utilizing water storage during the dry season to generate more wind and solar power; during the rainy season, when water is plentiful, more hydropower is generated, achieving both continuous and stable power output and increasing the utilization hours of the lines; compared with using a three-winding transformer to connect three voltage levels, using an autotransformer and utilizing a common winding for high and medium voltage can reduce the electromagnetic capacity of the transformer, reduce the weight and manufacturing cost of the transformer, and has better economic efficiency; it reduces land costs, lowers the difficulty of constructing the collection station, and reduces the construction of the transmission circuit, greatly reducing the cost of the wind and solar power station access system. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the electrical main wiring system for connecting a new energy line to a hydropower plant, as provided by this utility model.

[0022] In the diagram: 1-Autotransformer; 2-500kV branch busbar; 3-500kV surge arrester; 4-500kV circuit breaker; 5-500kV main busbar; 6-220kV branch busbar; 7-220kV circuit breaker; 8-220kV main busbar; 9-220kV busbar voltage transformer and surge arrester assembly; 10-220kV renewable energy line; 11-Reserved 220kV renewable energy line; 12-35kV V-branch busbar; 13-35kV surge arrester; 14-35kV main busbar; 15-35kV circuit breaker; 16-35kV busbar voltage transformer and surge arrester combination; 17-35kV feeder circuit breaker; 18-SVG reactive power compensation device; 19-capacitor bank; 20-35kV new energy line; 21-reserved 35kV new energy line; 22-500kV transmission line from hydropower station; 23-detachable break. Detailed Implementation

[0023] The present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

[0024] like Figure 1As shown, an electrical main wiring system for connecting a new energy line to a hydropower plant includes an autotransformer 1, which is connected to a medium-high voltage (hydropower) 500kV branch bus 2, a medium voltage (wind power) 220kV branch bus 6, and a low voltage (photovoltaic) 35kV branch bus 12. The 500kV branch bus 2 is connected to the 500kV main bus 5, and the 220kV branch bus 6 is connected to the 220kV main bus 8. At least one 220kV new energy line 10 is provided on the 220kV main bus 8, and a reserved 220kV new energy line 11 can be added later as needed.

[0025] The 35kV branch bus 12 is connected to the 35kV main bus 14. The 35kV main bus 14 is equipped with at least one 35kV new energy line 20. A 35kV new energy line 21 can be added as needed. The 220kV and 35kV lines of the autotransformer 1 are stepped up and connected to the 500kV main bus 5, and then connected to the power grid through the 500kV transmission line 22 of the hydropower station.

[0026] In the early stages, when there are few 220kV renewable energy lines 10 connected, a detachable break 23 is reserved on the 220kV branch bus 6, and a 220kV circuit breaker 7 is reserved between the detachable break 23 and the 220kV main bus 8. That is, when only one 220kV renewable energy line 10 is connected in the early stages of system commissioning, the 220kV side of the autotransformer 1 is directly connected to the 220kV main bus 8 through the 220kV branch bus 6. In the later stages of commissioning, when it is necessary to add a new 220kV renewable energy line 11, the 220kV branch bus 6 between the detachable break 23 and the 220kV main bus 8 will be disconnected, and the 220kV circuit breaker 7 will be connected between the detachable break 23 and the 220kV main bus 8.

[0027] The 500kV GIS branch busbar 2 is equipped with a 500kV surge arrester 3 and a 500kV circuit breaker 4. The 500kV surge arrester 3 is used to suppress lightning and switching overvoltage.

[0028] The 35kV branch busbar 12 is a copper or aluminum tube busbar. The 35kV branch busbar 12 is equipped with a 35kV surge arrester 13 and a 35kV circuit breaker 15. The 35kV surge arrester is used to suppress lightning and switching overvoltage.

[0029] The 220kV main busbar 8 is equipped with a 220kV busbar voltage transformer and surge arrester combination 9, which is used to suppress lightning and switching overvoltage.

[0030] The 35kV main busbar 14 is equipped with a 35kV busbar voltage transformer and surge arrester combination 16.

[0031] The 35kV main bus 14 is equipped with an SVG reactive power compensation device 18 to compensate for short-term fluctuating reactive power, and the capacitor bank 19 is used to compensate for long-term relatively stable inductive reactive power. Switching is performed according to the reactive power situation of the system.

[0032] A 35kV feeder circuit breaker 17 is installed between the 35kV main bus 14 and the SVG reactive power compensation device 18.

[0033] The total capacity of autotransformer 1 is determined based on the sum of the capacity of new energy lines connected to the medium-voltage and low-voltage sides and the reactive power compensation capacity. The voltage levels of the high, medium, and low-voltage sides of autotransformer 1 are determined based on the corresponding voltages of the systems on each side. In areas with limited transportation conditions, such as hydropower stations in canyons, a single-phase transformer type is selected; in areas with unrestricted transportation conditions, a three-phase transformer type can be used. The first and second windings correspond to the 500kV and 220kV windings of the autotransformer, respectively. The capacity of the third winding (i.e., the 35kV side winding) is controlled to be no less than 35% of the autotransformer's electromagnetic capacity to compensate for the third harmonic current. The autotransformer's electromagnetic capacity is calculated using the following formula:

[0034]

[0035] In the formula, S T For autotransformer total capacity; S C U1 is the electromagnetic capacitance of the autotransformer; U2 is the medium-voltage side voltage of the autotransformer; U1 is the high-voltage side voltage of the autotransformer.

[0036] Circuit breakers are installed on both the 220kV new energy line 10 and the 35kV new energy line 20.

[0037] All equipment on the 500kV side of the autotransformer 1 is in GIS form and is connected via a reserved or newly added bay on the 500kV main bus 5.

[0038] All equipment on the 220kV side of autotransformer 1 is in GIS form.

[0039] The switchgear on the 35kV side can be a combination of prefabricated 35kV box-type switchgear or 35kV open-type switchgear.

[0040] The above specific embodiments are used to explain and illustrate the present utility model, and are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc. made to the present utility model within the spirit and protection scope of the claims shall fall within the protection scope of the present utility model.

Claims

1. An electrical main wiring system for connecting a new energy line to a hydropower plant, characterized in that: The system includes an autotransformer (1), which is connected to a 500 kV branch bus (2), a 220 kV branch bus (6), and a 35 kV branch bus (12). The 500 kV branch bus (2) is connected to a 500 kV main bus (5), and the 220 kV branch bus (6) is connected to a 220 kV main bus (8). At least one 220 kV new energy line (10) is provided on the 220 kV main bus (8). The 35 kV branch bus (12) is connected to the 35 kV main bus (14). At least one 35 kV new energy line (20) is provided on the 35 kV main bus (14). The 220 kV side and 35 kV side lines of the autotransformer (1) are stepped up and connected to the 500 kV main bus (5) after being combined. The power grid is connected through the 500 kV transmission line (22) of the hydropower station.

2. The electrical main wiring system for connecting new energy lines to hydropower plants according to claim 1, characterized in that: A detachable break (23) is reserved on the 220 kV branch bus (6), and a 220 kV circuit breaker (7) is reserved between the detachable break (23) and the 220 kV main bus (8).

3. The electrical main wiring system for connecting new energy lines to hydropower plants according to claim 1, characterized in that: The 500 kV branch bus (2) is equipped with a 500 kV surge arrester (3) and a 500 kV circuit breaker (4).

4. The electrical main wiring system for connecting new energy lines to hydropower plants according to claim 1, characterized in that: The 35 kV branch bus (12) is equipped with a 35 kV surge arrester (13) and a 35 kV circuit breaker (15).

5. The electrical main wiring system for connecting new energy lines to hydropower plants according to claim 1, characterized in that: The 220 kV main bus (8) is equipped with a 220 kV bus voltage transformer and surge arrester combination (9).

6. The electrical main wiring system for connecting new energy lines to hydropower plants according to claim 1, characterized in that: The 35 kV main bus (14) is equipped with a 35 kV bus voltage transformer and surge arrester combination (16).

7. The electrical main wiring system for connecting new energy lines to hydropower plants according to claim 1, characterized in that: The 35 kV main bus (14) is equipped with an SVG reactive power compensation device (18) and a capacitor bank (19).

8. The electrical main wiring system for connecting new energy lines to hydropower plants according to claim 1 or 7, characterized in that: A 35kV feeder circuit breaker (17) is provided between the 35 kV main bus (14) and the SVG reactive power compensation device (18).

9. The electrical main wiring system for connecting new energy lines to hydropower plants according to claim 1, characterized in that: The third winding of the autotransformer (1) is controlled to be no less than 35% of the autotransformer's electromagnetic capacity to compensate for the third harmonic current. The autotransformer's electromagnetic capacity is calculated according to the following formula: In the formula, S T For autotransformer total capacity; S C U1 is the electromagnetic capacitance of the autotransformer; U2 is the medium-voltage side voltage of the autotransformer; U1 is the high-voltage side voltage of the autotransformer.

10. The electrical main wiring system for connecting new energy lines to hydropower plants according to claim 1, characterized in that: Circuit breakers are installed on both the 220 kV new energy line (10) and the 35 kV new energy line (20).

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