An electrical main wiring structure for combined thermal and energy storage frequency regulation using standby transformers.

Abstract

An electrical main wiring structure for combined thermal and energy storage frequency regulation using a start-up / standby transformer includes a start-up / standby transformer. The high-voltage side of the start-up / standby transformer is connected to the plant's 220kV power distribution equipment, and the low-voltage side of the start-up / standby transformer is connected to the plant's 10kV auxiliary power bus and the energy storage 10kV bus, respectively. The 10kV auxiliary power bus is connected to a plant circuit breaker and a 10kV current transformer. The 10kV energy storage bus is connected to an energy storage PCS via an energy storage vacuum circuit breaker and a 10kV current transformer. This invention utilizes the start-up / standby transformer for combined thermal and energy storage frequency regulation, achieving not only the utilization of the start-up / standby transformer but also the benefit of frequency regulation.

Description

Technical Field

[0001] This utility model relates to the electrical field, specifically an electrical main wiring structure for combined thermal and energy storage frequency regulation using a standby transformer. Background Technology

[0002] With the large-scale grid connection of new energy sources, grid-side frequency regulation issues are becoming increasingly complex, significantly increasing the demand for frequency regulation mileage. On the generation side, with the implementation of grid spot market policies, energy storage systems are encouraged to participate in grid auxiliary frequency regulation services, and energy storage systems assisting thermal power units in frequency regulation are gradually becoming commercialized. Utilizing the fast charging and discharging response of energy storage systems in conjunction with AGC frequency regulation of thermal power units can effectively alleviate equipment fatigue and wear caused by frequent AGC adjustments, stabilize unit output, improve coal combustion efficiency, and enhance unit availability and service life.

[0003] The principle for the implementation of thermal power-storage joint frequency regulation projects is to ensure that the energy storage access system does not affect the normal operation of the generating units and the power grid, the normal operation of the plant auxiliary equipment, or the flexibility of the plant power switching.

[0004] However, in current domestic integrated frequency regulation projects involving thermal power and energy storage, the energy storage is primarily connected to the medium-voltage section of the thermal power plant's auxiliary power system. This main wiring configuration requires minimal modification work, as it eliminates the need to modify the external generator busbar of the thermal power plant's A-row. However, this configuration also has inherent drawbacks: because the high-voltage transformer capacity of thermal power plants was not designed with the later integration of energy storage systems in mind, its capacity only considers its own auxiliary power load, leaving limited spare capacity. This essentially restricts the charging and discharging power of the energy storage system and limits the regulation speed performance during frequency regulation. Furthermore, most thermal power plants currently have two or more units, and connecting the energy storage section to the medium-voltage section of any unit carries the risk of downtime and idleness.

[0005] Because the standby transformer is in a hot standby and no-load state for a long time, the standby transformer also has to pay a high capacity fee to the power grid every year, which is a huge waste for the power plant. Utility Model Content

[0006] The technical problem to be solved by this utility model is: to provide a new electrical main wiring structure for joint frequency regulation of thermal power and energy storage by using a standby transformer to connect to the power grid, which addresses the problems of inconvenient access and high cost of the energy storage system in the existing technology.

[0007] To solve the above problems, this utility model is achieved through the following technical solution:

[0008] An electrical main wiring structure for joint frequency regulation of thermal power and energy storage using a start-up / standby transformer includes a start-up / standby transformer. The high-voltage side of the start-up / standby transformer is connected to the 220kV power distribution equipment in the plant, and the low-voltage side of the start-up / standby transformer is connected to the 10kV section busbar for plant power and the 10kV section busbar for energy storage, respectively.

[0009] The 10kV busbar for plant power is connected to a plant power circuit breaker and a 10kV current transformer for plant power; the 10kV busbar for energy storage is connected to an energy storage PCS through an energy storage vacuum circuit breaker and an energy storage 10kV current transformer.

[0010] The low-voltage side outgoing line of the start-up / standby transformer is connected to a common busbar, and a 10kV common busbar is connected to the 10kV section busbar of the energy storage.

[0011] The low-voltage side of the start-up / standby transformer is connected to at least two 10kV energy storage busbars.

[0012] Each 10kV energy storage section busbar is connected to at least two energy storage PCS, and each energy storage PCS is connected to an energy storage vacuum circuit breaker and an energy storage 10kV current transformer.

[0013] A harmonic suppression device is also connected to the 10kV section busbar of the energy storage.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention utilizes the start-up and standby transformers for combined thermal and energy storage frequency regulation, which not only realizes the utilization of the start-up and standby transformers but also generates frequency regulation benefits, achieving two goals at once. Attached Figure Description

[0015] Figure 1 This is the wiring diagram for this utility model. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0018] like Figure 1 As shown, an electrical main wiring structure for joint frequency regulation of thermal power and energy storage using a start-up / standby transformer includes a start-up / standby transformer 1. The high-voltage side of the start-up / standby transformer 1 is connected to the 220kV power distribution device 2 in the plant, and the low-voltage side of the start-up / standby transformer 1 is connected to the 10kV section busbar 3 of the plant power supply and the 10kV section busbar 4 of the energy storage, respectively.

[0019] The 10kV busbar 3 for plant power supply is connected to a plant power circuit breaker 8 and a 10kV current transformer 9; the 10kV busbar 4 for energy storage is connected to an energy storage PCS 7 through an energy storage vacuum circuit breaker 5 and an energy storage 10kV current transformer 6.

[0020] In practice, the low-voltage side outgoing line of the start / standby transformer 1 is connected to the common busbar, and a 10kV common busbar 11 is connected from the common busbar T to the 10kV section busbar 4 of the energy storage.

[0021] Furthermore, the low-voltage side of the start-up / standby transformer 1 is connected to at least two 10kV energy storage busbars 4, and the electrical devices connected to each 10kV energy storage busbar 4 are identical.

[0022] Furthermore, each 10kV energy storage busbar 4 is connected to at least two energy storage PCS 7, and each energy storage PCS 7 is connected to an energy storage vacuum circuit breaker 5 and an energy storage 10kV current transformer 6. Better yet, it can also be connected to devices such as surge arresters and live indicators.

[0023] Furthermore, even better, a primary harmonic suppression device 10 is also connected to the 10kV section busbar 4 of the energy storage.

[0024] The working principle of this utility model is as follows:

[0025] During normal operation of the thermal power unit, the station service power circuit breaker 8 connected to the starting / standby transformer 1 is in the open position, the energy storage vacuum circuit breaker 5 in the 10kV energy storage bus 4 is closed, and the energy storage PCS 7 is put into operation. When the thermal power plant's station service power is switched to the standby incoming line of the starting / standby transformer 1, the energy storage PCS 7 is taken out of operation, and its energy storage vacuum circuit breaker 5 is opened to ensure the normal operation of the station service power.

[0026] While thermal power units possess advanced overall performance, compared to hydropower units, they still exhibit limitations such as longer response times to frequency regulation commands, lower ramp-up rates, and inaccurate tracking of grid frequency regulation commands. Therefore, it is necessary to enhance the unit's regulation capabilities through flexibility upgrades. Configuring energy storage facilities can significantly improve the unit's AGC (Automatic Generation Control) frequency regulation performance, leading to increased frequency regulation revenue. This enhances the unit's flexibility and generates frequency regulation compensation income.

[0027] The technology of this utility model patent can be promoted and adopted in future combined frequency regulation projects of thermal power and energy storage, effectively solving the problem of idle capacity of start-up and standby transformers, participating in frequency regulation and obtaining frequency regulation benefits.

[0028] The above description is only a preferred embodiment of the present utility model. It should be noted that those skilled in the art can make several changes and improvements without departing from the overall concept of the present utility model, and these should also be considered within the protection scope of the present utility model.

Claims

1. An electrical main wiring structure for combined frequency modulation of a thermal power plant using a standby generator, characterized by: It includes a start-up / standby transformer (1), the high-voltage side of the start-up / standby transformer (1) is connected to the 220kV power distribution device (2) in the plant, and the low-voltage side of the start-up / standby transformer (1) is connected to the 10kV section busbar (3) of the plant power supply and the 10kV section busbar (4) of the energy storage. The 10kV busbar (3) for plant power is connected to a plant power circuit breaker (8) and a 10kV current transformer (9); the 10kV busbar (4) for energy storage is connected to an energy storage PCS (7) through an energy storage vacuum circuit breaker (5) and an energy storage 10kV current transformer (6).

2. The electrical main wiring structure for combined frequency modulation of thermal and storage according to claim 1, characterized in that: The starting / standby transformer (1) has a low-voltage side outgoing common box busbar, and the common box busbar T is connected to a 10kV common box busbar (11) to the energy storage 10kV section busbar (4).

3. The electrical main wiring structure for combined frequency modulation of thermal and storage according to claim 1, characterized in that: The start-up / standby transformer (1) has at least two 10kV energy storage busbars (4) connected to its low-voltage side.

4. The electrical main wiring structure for combined thermal and energy storage frequency regulation using a standby transformer according to claim 1, characterized in that: Each 10kV energy storage busbar (4) is connected to at least two energy storage PCS (7), and each energy storage PCS (7) is connected to an energy storage vacuum circuit breaker (5) and an energy storage 10kV current transformer (6).

5. The electrical main wiring structure for combined frequency modulation of thermal and storage according to claim 1, characterized in that: A primary harmonic suppression device (10) is also connected to the 10kV section busbar (4) of the energy storage.

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