Wiring structure suitable for start-stop and standby power supply of thermal power plant

Abstract

The utility model belongs to the technical field of power transmission and distribution, and particularly discloses a wiring structure suitable for a start-stop and standby power supply of a thermal power plant. Through selective connection of the working bus and the standby bus, the maximum utilization rate of energy supply of the generator set is ensured, the reliability and the service life of a power plant standby power supply are improved, the flexibility and the economical efficiency of plant power operation are enhanced, the operation and maintenance benefits of a power plant are remarkably improved, and the system has important significance for long-term stable operation and maintenance of the power plant. The method is worthy of popularization in high-power power plants.

Description

Technical Field

[0001] The utility model belongs to the technical field of power transmission and distribution, and specifically discloses a wiring structure suitable for start-stop and standby power supply of a thermal power plant. Background Art

[0002] The development and construction of my country's power industry has entered a phase characterized by large power grids, large generating units, and (ultra-) ultra-high voltage transmission. Generators of 300MW and above have become the mainstay of the power system, and the safe and full power generation of these units plays a vital role in the system. Properly connecting starting / backup power sources helps ensure successful unit startup, safe and continuous full power generation, facilitates operation and maintenance, saves construction investment, reduces operating costs, and enhances the competitiveness of power plant on-grid electricity prices.

[0003] Generally, thermal power plants use generator sets to provide the power required for auxiliary power generation and factory energy consumption. The backup power supply is connected in parallel to the plant's 10KV working bus. When the generator set is under maintenance or a line fault occurs, the backup power supply becomes an alternative power source. However, the backup power supply is generally taken from the power grid, and thermal power plants are generally equipped with multiple units. When one unit has a maintenance problem, the other units can still provide power. At this time, if the backup power supply is started to feed power back through the power grid, there will be unnecessary losses both in terms of economic benefits and environmental protection and energy saving. Moreover, the frequent activation of the backup power supply also reduces its own reliability. How to build a new model of backup power supply architecture to reduce the above losses and improve the transmission efficiency and economy while ensuring the normal operation of maintenance work such as shutdown and maintenance is a problem that technical personnel in this field urgently need to solve. Utility Model Content

[0004] To solve the technical problems listed in the background technology, the present invention provides a wiring structure suitable for starting and stopping thermal power plants and for backup power supply. The specific technical solution is as follows:

[0005] A wiring structure suitable for start-up and shutdown and backup power supply of a thermal power plant, comprising a power generation line and a plant power branch; the power generation line comprises a generator set and a main transformer connected via a circuit breaker; the plant power branch is tapped from the low-voltage side of the main transformer and comprises a high-voltage plant transformer, a 10kV working bus section, a 10kV standby bus section, and a high-voltage standby transformer, which are sequentially connected via a circuit breaker; wherein the high-voltage plant transformer and the high-voltage standby transformer both have a split structure on the low-voltage side, and the high-voltage standby transformer provides backup power for the power plant; the 10kV working bus section and the 10kV standby bus section both have a twin double-circuit configuration.

[0006] Preferably, one set of high-voltage backup transformers can provide backup power for up to four power generation lines.

[0007] Preferably, the capacity of the high-voltage standby transformer is not less than the capacity of a single high-voltage plant transformer.

[0008] Preferably, the circuit breakers connected between the high-voltage plant transformer, 10kV working bus section, 10kV standby bus section, and high-voltage standby transformer are used for switching the starting power supply, shutdown power supply, and standby power supply of the generator in the thermal power plant.

[0009] Compared with the prior art, the present invention has the following advantages:

[0010] The utility model provides a wiring structure suitable for starting and stopping and standby power supply of a thermal power plant, which can meet the starting and stopping and standby power supply requirements of four generator sets under normal working conditions.

[0011] This wiring structure allows the unit's high-voltage auxiliary transformer to provide power for maintenance, lighting, and commissioning after shutdown to other shut-down units, without using a backup transformer, provided the unit's high-voltage auxiliary transformer meets the required capacity. This improves the reliability of the plant's backup power supply, enhances the flexibility and economy of auxiliary power, and significantly improves the plant's operation and maintenance efficiency, which is of great significance to the long-term stable operation and maintenance of the power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a wiring diagram of a wiring structure suitable for starting and stopping a thermal power plant and a standby power supply in an embodiment of the present utility model. DETAILED DESCRIPTION

[0013] To make the purpose, technical solutions, and advantages of the present invention more clearly apparent, the present invention is described below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments described are merely a portion of the embodiments of the present invention, and not all of them. All other embodiments derived by persons of ordinary skill in the art based on these embodiments without inventive effort are also within the scope of protection of the present invention.

[0014] like Figure 1 As shown, the present invention provides an embodiment of a wiring structure suitable for start-up and shutdown and backup power supply of a thermal power plant, comprising: generators G10-G40 of the first through fourth units, transformer units T1-T4, and output circuit breakers GCB10-GCB40 of the first through fourth units. The first generator G10 is provided with two sections of 10kV working busbars 10A and 10B; the second generator G20 is provided with two sections of 10kV working busbars 20A and 20B; the third generator G30 is provided with two sections of 10kV working busbars 30A and 30B; and the fourth generator G40 is provided with two sections of 10kV working busbars 40A and 40B.

[0015] The first unit G10 is connected to the 10kV working busbars 10A and 10B through a high-voltage auxiliary transformer T10 with a split structure at the main transformer T1 and the generator outlet circuit breaker GCB10 respectively.

[0016] The second unit G20 is connected to the 10kV working busbars 20A and 20B through a high-voltage auxiliary transformer T20 with a split structure at the main transformer T2 and the generator output circuit breaker GCB20.

[0017] The third unit G30 is connected to the 10kV working busbars 30A and 30B through a high-voltage auxiliary transformer T30 with a split structure at the main transformer T3 and the generator output circuit breaker GCB30 respectively.

[0018] The fourth unit G40 is connected to the 10kV working busbars 40A and 40B through a high-voltage plant transformer T40 with a split structure at the main transformer T4 and the generator output circuit breaker GCB40 respectively.

[0019] Incoming circuit breakers DL10A, DL10B, DL20A, DL20B are installed between high-voltage plant transformers T10 and T20 and the 10kV busbars 10A, 10B, and 10kV busbars 20A, 20B, respectively. Incoming circuit breakers DL30A, DL30B, DL40A, DL40B are installed between high-voltage plant transformers T30 and T40 and the 10kV busbars 30A, 30B, and 10kV busbars 40A, 40B, respectively.

[0020] The four units are equipped with a split-structure high-voltage standby transformer T01. Two sections of 10kV standby busbars, 01A and 01B, are installed for the four units. The 110kV standby power supply line near the power plant is connected to the 10kV standby busbars 01A and 01B respectively through the high-voltage standby transformer T01.

[0021] The 10kV standby bus 01A is connected to the 10kV working bus 10A of the first unit G10, the 10kV working bus 20A of the second unit G20, the 10kV working bus 30A of the third unit G30, and the 10kV working bus 40A of the fourth unit G40 through the connecting circuit breakers DL011A, DL012A, DL013A, and DL014A respectively. The 10kV standby bus 01B is connected to the 10kV working bus 10B of the first unit G10, the 10kV working bus 20B of the second unit G20, the 10kV working bus 30B of the third unit G30, and the 10kV working bus 40B of the fourth unit G40 through the connecting circuit breakers DL011B, DL012B, DL013B, and DL014B respectively.

[0022] The four units' high-voltage plant transformers T10~T40 use large-capacity split-structure high-voltage transformers, and the standby transformer T01 uses a split-structure high-voltage transformer with a capacity not less than that of a single high-voltage plant transformer.

[0023] The operation control modes that can be achieved by each circuit breaker combination include but are not limited to the following:

[0024] When units G10-G40 start, GCB10-GCB40 are disconnected, DL10A, DL10B, DL20A, DL20B, DL30A, DL30B, DL40A, and DL40B are closed, DL01A and DL01B are disconnected, and DL011A-DL014A and DL011B-DL014B are disconnected. Unit startup power is supplied from the system via main transformers T1-T4 and high-voltage auxiliary transformers T10-T04 to 10kV sections 10A-40A and 10kV sections 10B-40B, respectively. Standby transformer T01 is in hot standby mode. 10kV standby sections 01A and 01B are de-energized.

[0025] During normal operation of units G10-G40, generating electricity through main transformers T1-T4 and connected to the grid, GCB10-GCB40 are closed, DL10A, DL10B, DL20A, DL20B, DL30A, DL30B, DL40A, and DL40B are closed, DL01A and DL01B are disconnected, and DL011A-DL014A and DL011B-DL014B are disconnected. Auxiliary power is supplied from units G10-G40 via high-voltage auxiliary working transformers T10-T40 to 10kV working bus sections 10A-40A and 10kV working bus sections 10B-40B, respectively. High-voltage standby transformer T01 is in hot standby mode. 10kV standby sections 01A and 01B are de-energized.

[0026] When units G10~G40 are shut down normally, GCB10~GCB40 are closed, DL10A, DL10B, DL20A, DL20B, DL30A, DL30B, DL40A, DL40B are closed, DL01A and DL01B are disconnected, and DL011A~DL014A, DL011B~DL014B are disconnected. Auxiliary power is supplied from generators G10-G40 via high-voltage auxiliary transformers T10-T40 to 10kV busbar sections 10A-40A and 10kV busbar sections 10B-40B. When reverse power occurs in the generator-transformer system, GCB10-GCB40 disconnects, and the unit's shutdown power is supplied from the system via main transformers T1-T4 and high-voltage auxiliary transformers T10-T04 to 10kV busbar sections 10A-40A and 10kV busbar sections 10B-40B. Standby transformer T01 is in hot standby mode. 10kV standby sections 01A and 01B are de-energized.

[0027] When a line fault or high-voltage auxiliary transformer fault occurs in one of the G10 to G40 units, taking the G10 unit as an example, GCB10 is disconnected, DL10A and DL10B are disconnected, DL01A and DL01B are closed, DL011A and DL011B are closed, DL012A to DL014A and DL012B to DL014B are disconnected, and the unit's standby or emergency shutdown power is sent through the high-voltage standby transformer T01 to the 10kV standby sections 01A and 01B. Then, it is sent to the G10 unit's 10kV working bus sections 10A and 10B via the 10kV standby bus sections 01A and 01B.

[0028] When one of the G10 to G40 units is shut down, if the outgoing line or high-voltage transformer of the shut down unit fails and the unit needs to be debugged or the power supply needs to be repaired, taking G10 as an example, there are two specific operation methods as follows:

[0029] (1) When the other three units are also shut down: The operation is as follows: GCB10 is disconnected, DL10A and DL10B are disconnected, DL01A and DL01B are closed, DL011A and DL011B are closed, DL012A to DL014A and DL012B to DL014B are disconnected, and the commissioning or maintenance power supply for G10 unit is sent to 10kV standby bus sections 01A and 01B through high-voltage standby transformer T01. Then, it is sent to 10kV working bus sections 10A and 10B of G10 unit through 10kV standby bus sections 01A and 01B.

[0030] (2) When at least one other unit is operating normally (taking G20 operation as an example), the operation is as follows: after confirming that the capacity of T20 high-voltage plant transformer meets the conditions for G20 operation and G10 commissioning or maintenance, GCB10 is disconnected, DL10A and DL10B are disconnected, DL01A and DL01B are disconnected, DL011A, DL011B, DL012A and DL012B are closed, DL013A to DL014A are disconnected, DL013B to DL014B are disconnected, and the power supply for G10 unit commissioning or maintenance is sent to G10 unit 10kV working bus sections 10A and 10B through G20 10kV working bus sections 20A and 20B and 10kV standby bus sections 01A and 01B.

[0031] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A wiring structure suitable for start-up and shutdown of thermal power plants and for standby power supply, characterized in that: It includes power generation lines and plant power branches; the power generation lines include generator sets and main transformers connected by circuit breakers, and the plant power branches are tapped off from the low-voltage side of the main transformer, including high-voltage plant transformers, 10kV working bus sections, 10kV standby bus sections, and high-voltage standby transformers connected in sequence by circuit breakers; among them, the high-voltage plant transformers and high-voltage standby transformers are both transformers with split structures on the low-voltage side, and the high-voltage standby transformers provide backup power for the power plant; the 10kV working bus sections and 10kV standby bus sections are both twin double-circuit configurations.

2. A wiring structure suitable for start-up and shutdown of thermal power plants and for backup power supply according to claim 1, characterized in that: One set of high-voltage backup transformer can provide backup power for up to four power generation lines.

3. A wiring structure suitable for start-up and shutdown and backup power supply of a thermal power plant according to claim 2, characterized in that: The capacity of the high-voltage standby transformer shall not be less than the capacity of a single high-voltage plant transformer.

4. A wiring structure suitable for start-up and shutdown of thermal power plants and for standby power supply according to claim 3, characterized in that: The circuit breakers connected between the high-voltage plant transformer, 10kV working bus section, 10kV standby bus section, and high-voltage standby transformer are used to switch the starting power supply, shutdown power supply, and standby power supply of the generators in the thermal power plant.

Images