A black start system and method for a gas turbine power station with single busbar segmentation and bypass busbar connection

Abstract

The invention discloses a black start system and method for a gas turbine power station with a single busbar segmentation and a side busbar connection, comprising a first gas turbine generator, a first main transformer, a first 110kV line, a plant transformer, a 400V plant power supply switch, a 400V plant busbar, a first 400V common busbar, a second 400V common busbar and a diesel generator. When the voltage of the first 110kV line is completely lost, the first gas turbine generator does not rely on any external power supply, but only relies on a self-provided diesel generator set to drive 400V plant busbar auxiliary equipment to run, completes the start and speed setting of the first gas turbine generator set, excites the generator, and builds up the stator voltage to the rated value, establishes a stable frequency and a correct indication voltage for the 110kV busbar on this side, and the first gas turbine generator resumes the island operation of the self-provided 400V plant busbar auxiliary equipment, and at the same time sends it to the opposite side of the 110kV line of the power grid, and restores the normal power supply of the first 110kV line. A reasonable isolation method is adopted to reduce the black start power outage range, and provide a safety line of defense for the safe and stable operation of the coastal power grid.

Description

Technical Field

[0001] The invention belongs to the technical field of black start of a gas turbine power station, and in particular relates to a black start system and method for a gas turbine power station with a single busbar segment and a bypass busbar connection. Background Art

[0002] Every year, my country's coastal power grid faces different levels of typhoons. Given that a coastal power grid is a typical isolated island power grid, the risk of a collapse of the entire island power grid has always existed. The large-scale power outage in a certain power grid is the first large-scale power outage in a provincial power grid caused by natural disasters in China in recent years. Summarizing the lessons learned from this accident, while carrying out risk assessment and prevention work for the power system, it is also necessary to pay attention to the black start of the system after a large-scale power outage in the power system, that is, when the power system is out of power due to a fault, it does not rely on the help of other networks, and uses the self-starting generator sets in the network to self-start, and supply power to the power transmission equipment, important users and other generator sets in a certain order. At the same time, maintain qualified voltage and frequency, and gradually drive other generator sets to generate electricity and expand the power supply range, and finally restore the normal operation of the entire network. Therefore, it is of great practical significance to carry out black start of gas turbine power stations in coastal areas lacking hydropower. The existing black start technology of gas turbine power plants has the following problems: (1) After the gas turbine generator reaches rated voltage, it directly charges the main transformer and the transmission line. The transformer excitation surge current generated by closing the switch has a certain impact and influence on the generator; (2) During the black start, other normally operating lines and busbars are shut down, which expands the scope of the power outage and brings inconvenience to the normal production and operation of the power grid; (3) At present, there is no relevant literature on the black start system and method of 110kV single busbar segmented gas turbine power plants with bypass bus connection. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention provides a black start system and method for a gas turbine power station with a single busbar segmentation and a bypass busbar connection, which can avoid the impact of the black start on the generator, transformer and line, adopt a reasonable isolation method, reduce the scope of the black start power outage, and provide a safety line of defense for the safe and stable operation of the coastal power grid.

[0004] The present invention is achieved through the following technical solutions:

[0005] A black start system of a gas turbine power station with a single busbar segmentation and a side busbar connection, comprising a first gas turbine generator, a first 110kV busbar, a third 110kV knife switch, a first 110kV line, a 400V plant power supply switch, a 400V plant busbar, a first 400V public busbar, a first 400V feeder switch, a diesel generator, a 400V public contact switch and a second 400V public busbar;

[0006] The first gas turbine generator is connected to the first 110kV busbar via the first outlet switch, the first main transformer, the first 110kV knife switch, the first 110kV circuit breaker, and the second 110kV knife switch in sequence;

[0007] One end of the third 110kV knife switch is connected to the first 110kV busbar, and the other end is connected to the first 110kV line via the second 110kV circuit breaker and the fourth 110kV knife switch in sequence;

[0008] The common end of the 400V plant power switch is connected to the 400V plant busbar, one end of the non-common end of the 400V plant power switch is connected to the common point of the first outlet switch and the first main transformer via the plant 400V incoming line switch, the plant transformer, and the first 10kV switch in sequence, and the other end of the non-common end of the 400V plant power switch is connected to the second 400V common busbar via the second 400V feeder switch;

[0009] The diesel generator is connected to the first 400V common bus via a first 400V feeder switch. One end of the 400V common contact switch is connected to the first 400V common bus, and the other end is connected to the second 400V common bus.

[0010] Preferably, it also includes a second 10kV switch, a third 10kV switch, a first 10kV bus, a fifth 10kV switch, a second gas turbine generator, a fourth 110kV circuit breaker, a 110kV voltage transformer, a tenth 110kV knife switch, a fifth 110kV circuit breaker, an eleventh 110kV knife switch, a 110kV side bus, a twelfth 110kV knife switch, a thirteenth 110kV knife switch, a second 110kV bus, a second 110kV line, a sixteenth 110kV knife switch, a seventeenth 110kV knife switch, a third outlet switch, a third gas turbine generator and a second 10kV bus;

[0011] The second gas turbine generator is connected to the second 110kV line via the second outlet switch, the second main transformer, the fifth 110kV knife switch, the third 110kV circuit breaker, the sixth 110kV knife switch, the fourteenth 110kV knife switch, the sixth 110kV circuit breaker, and the fifteenth 110kV knife switch in sequence;

[0012] The third gas turbine generator is connected to the second 110kV busbar via the third main transformer, the nineteenth 110kV switch, the seventh 110kV circuit breaker, and the eighteenth 110kV switch in sequence;

[0013] The second 10kV busbar is connected to the common point between the third main transformer and the third outlet switch via the seventh 10kV switch and the sixth 10kV switch in sequence;

[0014] One end of the seventeenth 110kV knife switch is connected to the 110kV bypass bus, and the other end is connected to the common point between the nineteenth 110kV knife switch and the third main transformer;

[0015] One end of the sixteenth 110kV knife switch is connected to the second 110kV line, and the other end is connected to the 110kV bypass bus; one end of the fourth 110kV circuit breaker is connected to the second 110kV bus via the seventh 110kV knife switch, and the other end is connected to the first 110kV bus via the eighth 110kV knife switch;

[0016] The 110kV voltage transformer is connected to the first 110kV busbar via the ninth 110kV switch;

[0017] The tenth 110kV knife switch, the fifth 110kV circuit breaker and the eleventh 110kV knife switch are connected in series and then both ends are connected in parallel between the first 110kV busbar and the 110kV side busbar;

[0018] One end of the thirteenth 110kV knife switch is connected to the 110kV bypass bus, and the other end is connected to the common point between the first main transformer and the first 110kV knife switch;

[0019] One end of the twelfth 110kV knife switch is connected to the first 110kV line, and the other end is connected to the 110kV bypass bus;

[0020] One end of the fifth 10kV switch is connected to the common point between the second outlet switch and the second main transformer, and the other end is connected to the second 400V common busbar via the second common transformer and the second common 400V incoming line switch in sequence;

[0021] One end of the second 10kV switch is connected to the common point between the first outlet switch and the first main transformer, and the other end is connected to the first 400V common busbar via the first common transformer and the first common 400V incoming line switch in sequence;

[0022] One end of the third 10kV switch is connected to the common point between the first outlet switch and the first main transformer, and the other end is connected to the first 10kV busbar via the fourth 10kV switch.

[0023] Preferably, before the first gas turbine generator and the first main transformer are black-started with the first 110kV line, the first 110kV knife switch, the first 110kV circuit breaker, the second 110kV knife switch, the third 110kV knife switch, the second 110kV circuit breaker, the fourth 110kV knife switch, the second 10kV switch, the first public 400V incoming line switch, the 400V public contact switch, the third 10kV switch, the fourth 10kV switch, the ninth 110kV knife switch, the fourteenth 110kV knife switch, the sixth 110kV circuit breaker, the fifteenth 110kV knife switch, the eighteenth 110kV knife switch, the seventh 110kV circuit breaker, the nineteenth 110kV knife switch, the sixth 10kV switch, the seventh 10kV switch, the nineteenth 110kV knife switch, the sixth 10kV switch, the seventh 10kV All switches are in closed state; the first outlet switch, the first 10kV switch, the plant 400V incoming line switch, the first 400V feeder switch, the second 400V feeder switch, the second public 400V incoming line switch, the fifth 10kV switch, the second outlet switch, the fifth 110kV knife switch, the third 110kV circuit breaker, the sixth 110kV knife switch, the seventh 110kV knife switch, the fourth 110kV circuit breaker, the eighth 110kV knife switch, the tenth 110kV knife switch, the fifth 110kV circuit breaker, the eleventh 110kV knife switch, the twelfth 110kV knife switch, the thirteenth 110kV knife switch, the sixteenth 110kV knife switch, the seventeenth 110kV knife switch and the third outlet switch are all in open state.

[0024] Preferably, after the first gas turbine generator and the first main transformer carry out the black start isolation switching operation of the first 110kV line, the first 110kV knife switch, the first 110kV circuit breaker, the second 110kV knife switch, the third 110kV knife switch, the second 110kV circuit breaker, the fourth 110kV knife switch, the 400V public contact switch, the second public 400V incoming line switch, the fifth 10kV switch, the fifth 110kV knife switch, the third 110kV circuit breaker, the sixth 110kV knife switch, the ninth 110kV knife switch, the fourteenth 110kV knife switch, the sixth 110kV circuit breaker, the fifteenth 110kV knife switch, the eighteenth 110kV knife switch, the seventh 110kV circuit breaker, the nineteenth 110kV knife switch , the sixth 10kV switch, and the seventh 10kV switch are all in the closed state; the first outlet switch, the first 10kV switch, the plant 400V incoming line switch, the second 10kV switch, the first public 400V incoming line switch, the first 400V feeder switch, the second 400V feeder switch, the third 10kV switch, the fourth 10kV switch, the second outlet switch, the seventh 110kV knife switch, the fourth 110kV circuit breaker, the eighth 110kV knife switch, the tenth 110kV knife switch, the fifth 110kV circuit breaker, the eleventh 110kV knife switch, the twelfth 110kV knife switch, the thirteenth 110kV knife switch, the sixteenth 110kV knife switch, the seventeenth 110kV knife switch, and the third outlet switch are all in the open state.

[0025] Furthermore, when the first gas turbine generator and the first main transformer charge the first 110kV line during black start, the first export switch, the first 400V feeder switch, and the second 400V feeder switch are all in a closed state, the second public 400V incoming line switch is in a disconnected state, and the non-common end of the 400V plant power supply switching switch is connected to the second 400V feeder switch.

[0026] Furthermore, when the first gas turbine generator is black-started and islanded with the first main transformer, the first 110kV line, and the plant transformer, the first 10kV switch and the plant 400V incoming line switch are in a closed state, and the non-common end of the 400V plant power supply switching switch is connected to the plant 400V incoming line switch.

[0027] Furthermore, after the black start of the first gas turbine generator and the first main transformer with the first 110kV line is completed, the first export switch, the first 400V feeder switch, and the second 400V feeder switch are in the disconnected state, the non-common end of the 400V plant power supply switch is connected to the second 400V feeder switch, and the second public 400V incoming line switch is in the closed state.

[0028] A black start method for a gas turbine power station with a single busbar segmentation and a side busbar connection comprises the following steps:

[0029] 1) Check and confirm the status of the first gas turbine generator and the first main transformer with the first 110kV line before black start, and proceed to step 2);

[0030] 2) performing isolation and switching operations on the first combustion engine generator and the first main transformer with the first 110 kV line before black start, and proceeding to step 3);

[0031] 3) Start the diesel generator, measure the outlet voltages Uab, Uac, Ubc, and frequency f, confirm that the phase sequence is correct, and proceed to step 4);

[0032] 4) Closing the first 400V feeder switch to supply power to the first 400V common bus and the second 400V common bus, and proceeding to step 5);

[0033] 5) Switch the 400V plant power switch to connect to the second 400V feeder switch to supply power to the 400V plant bus, and proceed to step 6);

[0034] 6) Close the first outlet switch, check that the closing indication state of the first outlet switch is normal, and proceed to step 7);

[0035] 7) Operate the first gas turbine generator at a constant speed of 2950 r / min, check that the first gas turbine generator is operating normally at a constant speed, and proceed to step 8);

[0036] 8) Manually operate the first gas turbine generator to build up the voltage to 50% of the rated voltage, check that the voltage indications of the first 110 kV bus and the first 110 kV line are correct, and proceed to step 9);

[0037] 9) Operate the first gas turbine generator to build up voltage to 10.04 kV and frequency to 49.0 Hz, the first 110 kV bus voltage is 114.5 kV, observe at the line protection of the first 110 kV line, the line secondary voltage and current parameters are correct, the secondary phase voltage is about 58 V and the three phases are balanced, the secondary phase current is 35 mA, and proceed to step 10);

[0038] 10) Check and confirm that the voltage indication on the opposite side of the first 110 kV line is correct, and proceed to step 11);

[0039] 11) The 400V plant power switch is switched to the plant 400V incoming line switch, the first gas turbine generator is operated with its own plant transformer, the output voltage and frequency of the first gas turbine generator are displayed correctly, and the process goes to step 12);

[0040] 12) Switch the 400V factory power switch to the second 400V feeder switch, stop the first gas turbine generator, disconnect the first outlet switch, confirm that the first gas turbine generator is shut down, and proceed to step 13);

[0041] 13) The second 400V feeder switch is opened, and the second public 400V incoming line switch is closed. The first 400V public bus and the second 400V public bus are powered by the second main transformer, and the black start of the first gas turbine generator and the first main transformer with the first 110kV line is completed.

[0042] Further, the status check and confirmation work before black start in step 1) includes: confirming that the first gas turbine generator, the second gas turbine generator, and the third gas turbine generator are all in a shutdown standby state; confirming that the first 110kV line and the second 110kV line are all in an operating state; confirming that the first 110kV bus, the second 110kV bus, the first main transformer, and the third main transformer are all in an operating state; confirming that the first 10kV bus, the second 10kV bus, the first 400V common bus, and the second 400V common bus are in an operating state; confirming that the diesel generator is in a shutdown state; the isolation switching operation in step 2) includes: operating the second main transformer to switch to operation, switching the first main transformer from operation to hot standby, switching the first 10kV bus from operation to cold standby, switching the first 4 100KV common bus and the second 400V common bus are powered by the second common transformer; the first 110kV line and the first 110kV bus are converted to hot standby state; check and confirm that the fourth 110kV circuit breaker and the fifth 110kV circuit breaker are in cold standby state, the second 110kV circuit breaker and the first 110kV circuit breaker are in hot standby state, check that the ninth 110kV knife switch is in the closed position, and the secondary circuit breaker of the 110kV voltage transformer is in the closed state; close the second 110kV circuit breaker, check and confirm that the first 110kV line and the first 110kV bus have no voltage, and close the first 110kV circuit breaker; disconnect the second public 400V incoming line switch, and confirm that the first 400V common bus and the second 400V common bus have no voltage.

[0043] Compared with the prior art, the present invention has the following beneficial technical effects:

[0044] In the case that the voltage of the first 110kV line is completely lost, the first gas turbine generator does not rely on any external power supply, but only relies on the self-provided diesel generator set to drive the 400V plant bus auxiliary equipment to operate, completes the start-up and speed control of the first gas turbine generator set, the excitation of the generator, and the stator voltage is built up to the rated value, and a stable frequency and a correct indication voltage are established for the 110KV bus on this side. The first gas turbine generator resumes the island operation of its own 400V plant bus auxiliary equipment, and at the same time sends it to the opposite side of the 110kV line of the power grid, restoring the normal power supply of the first 110kV line.

[0045] Furthermore, before the first gas turbine generator is built up with voltage, the present invention closes the first outlet switch, the first 110kV circuit breaker, and the second 110kV circuit breaker, and adopts a generator-transformer-line zero-start voltage-raising method, thereby avoiding the impact of the first gas turbine generator, the first main transformer, and the first 110kV line caused by closing the first outlet switch when the first gas turbine generator is built up to the rated voltage, thereby ensuring the safety of the black start equipment body.

[0046] Furthermore, the present invention isolates the units and lines within the black start range through switching operations, thereby ensuring the normal operation of the units outside the black start range and avoiding the impact of the black start on the normal operating system.

[0047] Furthermore, the present invention adopts a reasonable black start structure to reduce the operation time, which can speed up the black start recovery time and ensure that the combustion engine power station can quickly, safely and stably send out power after the power grid fails. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a schematic diagram of the black start system of the present invention.

[0049] Figure 2 This is a schematic diagram of the state before black start of the present invention.

[0050] Figure 3 This is a schematic diagram of the black start isolation switching operation principle of the present invention.

[0051] Figure 4 This is a schematic diagram of the black start circuit charging principle of the present invention.

[0052] Figure 5 This is a schematic diagram of the black start island operation principle of the present invention.

[0053] Figure 6 This is the black start shutdown principle diagram of the present invention.

[0054] In the figure: the first gas turbine generator 1; the first outlet switch 2; the first main transformer 3; the first 110kV switch 4; the first 110kV circuit breaker 5; the second 110kV switch 6; the third 110kV switch 7; the second 110kV circuit breaker 8; the fourth 110kV switch 9; the first 110kV line 10; the first 10kV switch 11; the plant transformer 12; the plant 400V incoming line switch 13; the 400V plant power supply transfer switch 14; the 400V plant bus 15; the second 10kV switch 16; the first public transformer 17 ; first public 400V incoming line switch 18; first 400V public bus 19; first 400V feeder switch 20; diesel generator 21; 400V public tie switch 22; second 400V public bus 23; second 400V feeder switch 24; second public 400V incoming line switch 25; third 10kV switch 26; fourth 10kV switch 27; first 10kV bus 28; second public transformer 29; fifth 10kV switch 30; second combustion engine generator 31; second outlet switch 32; second main transformer 33; first The fifth 110kV switch 34; the third 110kV circuit breaker 35; the sixth 110kV switch 36; the seventh 110kV switch 37; the fourth 110kV circuit breaker 38; the eighth 110kV switch 39; the ninth 110kV switch 40; the 110kV voltage transformer 41; the tenth 110kV switch 42; the fifth 110kV circuit breaker 43; the eleventh 110kV switch 44; the first 110kV bus 45; the 110kV side bus 46; the twelfth 110kV switch 47; the thirteenth 110kV switch 48; the second 110kV bus 49; fourteenth 110kV knife switch 50; sixth 110kV circuit breaker 51; fifteenth 110kV knife switch 52; second 110kV line 53; sixteenth 110kV knife switch 54; seventeenth 110kV knife switch 55; eighteenth 110kV knife switch 56; seventh 110kV circuit breaker 57; nineteenth 110kV knife switch 58; third main transformer 59; third outlet switch 60; third gas turbine generator 61; sixth 10kV switch 62; seventh 10kV switch 63; second 10kV bus 64. DETAILED DESCRIPTION

[0055] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0056] The present invention can solve the impact problem of the black start of a gas turbine power station on the main equipment, reduce the operation of the normally operating power grid, narrow the scope of power outage, and enable the gas turbine power station to become a reliable, stable and controllable black start power supply.

[0057] The present invention discloses a black start system and method for a gas turbine power station with a single busbar segmentation and a side busbar connection, comprising a first gas turbine generator, a first main transformer, a first 110kV line, a plant transformer, a 400V plant power supply switch, a 400V plant busbar, a first 400V common busbar, a second 400V common busbar and a diesel generator. When the voltage of the first 110kV line is completely lost, the first gas turbine generator does not rely on any external power supply, but only relies on a self-provided diesel generator set to drive the 400V plant busbar auxiliary equipment to operate. The first gas turbine generator set was started and kept at a constant speed. The generator was excited and the stator voltage was built up to the rated value. A stable frequency and correct voltage indication were established for the 110KV bus on this side. The first gas turbine generator resumed island operation with its own 400V plant bus auxiliary machine, and at the same time, it was sent to the opposite side of the 110kV line of the power grid to restore normal power supply to the first 110kV line. The impact of black start on generators, transformers and lines can be avoided, and reasonable isolation methods can be adopted to reduce the scope of black start power outages, providing a safety line for the safe and stable operation of the coastal power grid.

[0058] The present invention provides a black start system for a gas turbine power station with a single busbar segment and a side busbar connection. Figure 1As shown, it includes a first gas turbine generator 1, a first export switch 2, a first main transformer 3, a first 110kV switch 4, a first 110kV circuit breaker 5, a second 110kV switch 6, a first 110kV bus 45, a third 110kV switch 7, a second 110kV circuit breaker 8, a fourth 110kV switch 9, a first 110kV line 10, a first 10kV switch 11, a plant transformer 12, a plant 400V incoming line switch 13, a 400V plant power supply transfer switch 14, 400V plant bus 15, first 400V common bus 19, first 400V feeder switch 20, diesel generator 21, 400V common tie switch 22, second 400V common bus 23 and second 400V feeder switch 24; wherein, the first gas turbine generator 1 is connected to the first 110kV bus 45 via the first outlet switch 2, the first main transformer 3, the first 110kV knife switch 4, the first 110kV circuit breaker 5, the second 110kV knife switch 6 in sequence, and the first 110kV bus 45 is connected to the first 110kV bus 45 via the first outlet switch 2, the first main transformer 3, the first 110kV knife switch 4, the first 110kV circuit breaker 5, the second 110kV knife switch 6 in sequence. One end of the third 110kV knife switch 7 is connected to the first 110kV bus 45, and the other end is connected to the first 110kV line 10 via the second 110kV circuit breaker 8 and the fourth 110kV knife switch 9 in sequence; the common end of the 400V plant power supply switch 14 is connected to the 400V plant bus 15, and one end of the non-common end of the 400V plant power supply switch 14 is connected to the first 110kV line 10 via the plant 400V incoming line switch 13, the plant transformer 12, the first 10kV switch 11 and the first 110kV line 10 in sequence. An export switch 2 is connected to a common point of the first main transformer 3, the other non-common end of the 400V plant power supply transfer switch 14 is connected to the second 400V common bus 23 via a second 400V feeder switch 24, the diesel generator 21 is connected to the first 400V common bus 19 via a first 400V feeder switch 20, one end of the 400V public connecting switch 22 is connected to the first 400V common bus 19, and the other end is connected to the second 400V common bus 23.

[0059] In this embodiment, the parameters of the first combustion engine generator 1 are as follows:

[0060]

[0061] In this embodiment, the parameters of the first main transformer 3 are as follows:

[0062]

[0063] In this embodiment, the parameters of the first 110kV line 10 are as follows:

[0064]

[0065] In this embodiment, the parameters of the diesel generator 21 are as follows:

[0066]

[0067] In this embodiment, the second 10kV switch 16, the first public transformer 17, the first public 400V incoming line switch 18, the second public 400V incoming line switch 25, the third 10kV switch 26, the fourth 10kV switch 27, the first 10kV bus 28, the second public transformer 29, the fifth 10kV switch 30, the second gas turbine generator 31, the second outlet switch 32, the second main transformer 33, the fifth 110kV knife switch 34, the third 110kV circuit breaker 35, the sixth 110kV knife switch 36, the seventh 110kV knife switch 37, the fourth 110kV circuit breaker 38, the eighth 110kV knife switch 39, the ninth 110kV knife switch 40, the 110kV voltage Transformer 41, tenth 110kV switch 42, fifth 110kV circuit breaker 43, eleventh 110kV switch 44, 110kV busbar 46, twelfth 110kV switch 47, thirteenth 110kV switch 48, second 110kV busbar 49, fourteenth 110kV switch 50, sixth 110kV circuit breaker 51, fifteenth 110kV switch 52, second 110kV line 53, sixteenth 110kV switch 54, seventeenth 110kV switch 55, eighteenth 110kV switch 56, seventh 110kV circuit breaker 57, nineteenth 110kV switch 58, third main transformer 59, third outlet switch 60, third gas turbine generator 61 , the sixth 10kV switch 62, the seventh 10kV switch 63 and the second 10kV bus 64; the second gas turbine generator 31 is connected to the second 110kV line 53 via the second outlet switch 32, the second main transformer 33, the fifth 110kV knife switch 34, the third 110kV circuit breaker 35, the sixth 110kV knife switch 36, the fourteenth 110kV knife switch 50, the sixth 110kV circuit breaker 51 and the fifteenth 110kV knife switch 52; the third gas turbine generator 61 is connected to the second 110kV bus 49 via the third main transformer 59, the nineteenth 110kV knife switch 58, the seventh 110kV circuit breaker 57 and the eighteenth 110kV knife switch 56 The second 10kV bus 64 is connected to the common point between the third main transformer 59 and the third outlet switch 60 via the seventh 10kV switch 63 and the sixth 10kV switch 62 in sequence; one end of the seventeenth 110kV knife switch 55 is connected to the 110kV bypass bus 46, and the other end is connected to the common point between the nineteenth 110kV knife switch 58 and the third main transformer 59; one end of the sixteenth 110kV knife switch 54 is connected to the second 110kV line 53, and the other end is connected to the 110kV bypass bus 46; one end of the fourth 110kV circuit breaker 38 is connected to the second 110kV bus 49, and the other end is connected to the first 110kV bus 45;The 110kV voltage transformer 41 is connected to the first 110kV bus 45 via the ninth 110kV knife switch 40; the tenth 110kV knife switch 42, the fifth 110kV circuit breaker 43, and the eleventh 110kV knife switch 44 are connected in series and both ends are connected in parallel between the first 110kV bus 45 and the 110kV bypass bus 46; one end of the thirteenth 110kV knife switch 48 is connected to the 110kV bypass bus 46, and the other end is connected to the common point between the first main transformer 3 and the first 110kV knife switch 4; one end of the twelfth 110kV knife switch 47 is connected to the first 110kV line 10, and the other end is connected to the 110kV bypass bus 46; the fifth 10kV One end of the switch 30 is connected to the common point between the second outlet switch 32 and the second main transformer 33, and the other end is connected to the second 400V common bus 23 via the second common transformer 29 and the second common 400V incoming line switch 25 in sequence; one end of the second 10kV switch 16 is connected to the common point between the first outlet switch 2 and the first main transformer 3, and the other end is connected to the first 400V common bus 19 via the first common transformer 17 and the first common 400V incoming line switch 18 in sequence; one end of the third 10kV switch 26 is connected to the common point between the first outlet switch 2 and the first main transformer 3, and the other end is connected to the first 10kV bus 28 via the fourth 10kV switch 27. ;

[0068] like Figure 2As shown, before the first combustion engine generator 1 and the first main transformer 3 are black-started with the first 110kV line 10, the first 110kV knife switch 4, the first 110kV circuit breaker 5, the second 110kV knife switch 6, the third 110kV knife switch 7, the second 110kV circuit breaker 8, the fourth 110kV knife switch 9, the second 10kV switch 16, the first public 400V incoming line switch 18, the 400V public contact switch 22, the third 10kV switch 26, the fourth 10kV switch 27, the ninth 110kV knife switch 40, the fourteenth 110kV knife switch 50, the sixth 110kV circuit breaker 51, the fifteenth 110kV knife switch 52, the eighteenth 110kV knife switch 56, the seventh 110kV circuit breaker 57, the nineteenth 110kV knife switch 58, the sixth 10kV switch 62, and the seventh 10kV switch 63 are all In the closed state; the first outlet switch 2, the first 10kV switch 11, the plant 400V incoming line switch 13, the first 400V feeder switch 20, the second 400V feeder switch 24, the second public 400V incoming line switch 25, the fifth 10kV switch 30, the second outlet switch 32, the fifth 110kV knife switch 34, the third 110kV circuit breaker 35, the sixth 110kV knife switch 36, the seventh 110kV knife switch 37, the fourth 110kV circuit breaker 38, the eighth 110kV knife switch 39, the tenth 110kV knife switch 42, the fifth 110kV circuit breaker 43, the eleventh 110kV knife switch 44, the twelfth 110kV knife switch 47, the thirteenth 110kV knife switch 48, the sixteenth 110kV knife switch 54, the seventeenth 110kV knife switch 55, and the third outlet switch 60 are all in the open state. Figure 3 As shown,.

[0069] like Figure 3As shown, after the first gas turbine generator 1 and the first main transformer 3 are black-started and isolated from the first 110kV line 10, the first 110kV knife switch 4, the first 110kV circuit breaker 5, the second 110kV knife switch 6, the third 110kV knife switch 7, the second 110kV circuit breaker 8, the fourth 110kV knife switch 9, the 400V public tie switch 22, the second public 400V incoming line switch 25, The fifth 10kV switch 30, the fifth 110kV knife switch 34, the third 110kV circuit breaker 35, the sixth 110kV knife switch 36, the ninth 110kV knife switch 40, the fourteenth 110kV knife switch 50, the sixth 110kV circuit breaker 51, the fifteenth 110kV knife switch 52, the eighteenth 110kV knife switch 56, the seventh 110kV circuit breaker 57, the nineteenth 110kV knife switch 58, the sixth 10 kV switch 62 and the seventh 10kV switch 63 are all in a closed state; the first outlet switch 2, the first 10kV switch 11, the plant 400V incoming line switch 13, the second 10kV switch 16, the first public 400V incoming line switch 18, the first 400V feeder switch 20, the second 400V feeder switch 24, the third 10kV switch 26, the fourth 10kV switch 27, the second outlet switch 32, the seventh 110kV knife switch 37, the fourth 110kV circuit breaker 38, the eighth 110kV knife switch 39, the tenth 110kV knife switch 42, the fifth 110kV circuit breaker 43, the eleventh 110kV knife switch 44, the twelfth 110kV knife switch 47, the thirteenth 110kV knife switch 48, the sixteenth 110kV knife switch 54, the seventeenth 110kV knife switch 55, and the third outlet switch 60 are all in an open state.

[0070] like Figure 4 As shown, when the first gas turbine generator 1 and the first main transformer 3 charge the first 110kV line 10 during black start, the first outlet switch 2, the first 400V feeder switch 20, and the second 400V feeder switch 24 are all in a closed state, the second public 400V incoming line switch 25 is in a disconnected state, and the non-common end of the 400V plant power supply transfer switch 14 is connected to the second 400V feeder switch 24.

[0071] like Figure 5 As shown, when the first gas turbine generator 1 is in black start island operation with the first main transformer 3, the first 110kV line 10, and the plant transformer 12, the first 10kV switch 11 and the plant 400V incoming line switch 13 are in a closed state, and the non-common end of the 400V plant power supply switching switch 14 is connected to the plant 400V incoming line switch 13.

[0072] like Figure 6As shown, after the black start of the first gas turbine generator 1 and the first main transformer 3 with the first 110kV line 10 is completed, the first outlet switch 2, the first 400V feeder switch 20, and the second 400V feeder switch 24 are in the disconnected state, the non-common end of the 400V plant power supply transfer switch 14 is connected to the second 400V feeder switch 24, and the second public 400V incoming line switch 25 is in the closed state.

[0073] A black start method for a gas turbine power station with a single busbar segmentation and a side busbar connection comprises the following steps:

[0074] 1) Check and confirm the status of the first gas turbine generator 1 and the first main transformer 3 with the first 110kV line 10 before black start, and proceed to step 2);

[0075] 2) performing isolation and switching operations before black start of the first combustion engine generator 1 and the first main transformer 3 with the first 110 kV line 10, and proceeding to step 3);

[0076] 3) Start the diesel generator 21, measure the outlet voltages Uab, Uac, Ubc, and frequency f, confirm that the phase sequence is correct, and proceed to step 4);

[0077] 4) Closing the first 400V feeder switch 20 to supply power to the first 400V common bus 19 and the second 400V common bus 23, and proceeding to step 5);

[0078] 5) Switch the 400V plant power supply switch 14 to connect to the second 400V feeder switch 24 to supply power to the 400V plant bus 15, and proceed to step 6);

[0079] 6) Close the first outlet switch 2, check that the closing indication state of the first outlet switch 2 is normal, and proceed to step 7);

[0080] 7) Operate the first gas turbine generator 1 at a constant speed of 2950 r / min, check that the first gas turbine generator 1 is operating normally at a constant speed, and proceed to step 8);

[0081] 8) Manually operate the first gas turbine generator 1 to build up the voltage to 50% of the rated voltage, check that the voltage indications of the first 110 kV bus 45 and the first 110 kV line 10 are correct, and proceed to step 9);

[0082] 9) Operate the first gas turbine generator 1 to build up voltage to 10.04 kV and frequency to 49.0 Hz, the voltage of the first 110 kV bus 45 is 114.5 kV, observe at the line protection of the first 110 kV line 10, the line secondary voltage and current parameters are correct, the secondary phase voltage is about 58 V and the three phases are balanced, the secondary phase current is 35 mA, and enter step 10);

[0083] 10) Check and confirm that the voltage indication on the opposite side of the first 110 kV line 10 is correct, and proceed to step 11);

[0084] 11) The 400V plant power switch 14 is switched to the plant 400V incoming line switch 13, the first gas turbine generator 1 is operated with its own plant transformer 12, the output voltage and frequency of the first gas turbine generator 1 are displayed correctly, and the process goes to step 12);

[0085] 12) switching the 400V factory power supply switch 14 to the second 400V feeder switch 24, stopping the first gas turbine generator 1, disconnecting the first outlet switch 2, confirming that the first gas turbine generator 1 is shut down, and proceeding to step 13);

[0086] 13) The second 400V feeder switch 24 is opened, and the second public 400V incoming line switch 25 is closed. The first 400V public bus 19 and the second 400V public bus 23 are powered by the second main transformer 33. The black start of the first gas turbine generator 1 and the first main transformer 3 with the first 110kV line 10 is completed.

[0087] In this embodiment, the status check and confirmation work before black start in step 1) includes: confirming that the first gas turbine generator 1, the second gas turbine generator 31, and the third gas turbine generator 61 are all in a shutdown standby state; confirming that the first 110kV line 10 and the second 110kV line 53 are all in an operating state; confirming that the first 110kV bus 45, the second 110kV bus 49, the first main transformer 3, and the third main transformer 59 are all in an operating state; confirming that the first 10kV bus 28, the second 10kV bus 64, the first 400V common bus 19, and the second 400V common bus 23 are in an operating state; confirming that the diesel generator 21 is in a shutdown state; the isolation switching operation in step 2) includes: operating the second main transformer 33 to switch to operation, switching the first main transformer 3 from operation to hot standby, switching the first 10kV bus 28 from operation to cold standby, switching the first 4 100KV common bus 19 and the second 400KV common bus 23 are powered by the second common transformer 29; the first 110KV line 10 and the first 110KV bus 45 are converted to hot standby state; check and confirm that the fourth 110KV circuit breaker 38 and the fifth 110KV circuit breaker 43 are in cold standby state, the second 110KV circuit breaker 8 and the first 110KV circuit breaker 5 are in hot standby state, check that the ninth 110KV knife switch 40 is in the closed position, and the secondary circuit breaker of the 110KV voltage transformer 41 is in the closed state; close the second 110KV circuit breaker 8, check and confirm that the first 110KV line 10 and the first 110KV bus 45 have no voltage, and close the first 110KV circuit breaker 5; disconnect the second common 400V incoming line switch 25, and confirm that the first 400KV common bus 19 and the second 400KV common bus 23 have no voltage.

[0088] The present invention provides a reference for the black start of gas turbine power plants in coastal areas lacking hydropower, enhances the ability of coastal areas to cope with natural disasters, provides security for power grids in coastal areas, and reduces power outage losses. The above is only a preferred embodiment of the patent of the present invention, and does not limit the patent of the present invention. Any simple modification, change and equivalent structural change made to the above embodiment according to the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A black start system for a gas turbine power station with single busbar segmentation and side busbar connection, characterized in that: It comprises a first combustion engine generator (1), a first 110 kV busbar (45), a third 110 kV knife switch (7), a first 110 kV line (10), a 400 V plant power supply transfer switch (14), a 400 V plant busbar (15), a first 400 V common busbar (19), a first 400 V feeder switch (20), a diesel generator (21), a 400 V common contact switch (22) and a second 400 V common busbar (23); The first combustion engine generator (1) is connected to the first 110 kV busbar (45) via a first outlet switch (2), a first main transformer (3), a first 110 kV knife switch (4), a first 110 kV circuit breaker (5), and a second 110 kV knife switch (6) in sequence; One end of the third 110 kV knife switch (7) is connected to the first 110 kV busbar (45), and the other end is connected to the first 110 kV line (10) via the second 110 kV circuit breaker (8) and the fourth 110 kV knife switch (9) in sequence; The common end of the 400V plant power switch (14) is connected to the 400V plant bus (15); one end of the non-common end of the 400V plant power switch (14) is connected to the common point of the first outlet switch (2) and the first main transformer (3) via the plant 400V incoming line switch (13), the plant transformer (12), and the first 10kV switch (11); the other end of the non-common end of the 400V plant power switch (14) is connected to the second 400V common bus (23) via the second 400V feeder switch (24); The diesel generator (21) is connected to the first 400V common bus (19) via a first 400V feeder switch (20); one end of the 400V common contact switch (22) is connected to the first 400V common bus (19), and the other end is connected to the second 400V common bus (23); It also includes a second 10kV switch (16), a third 10kV switch (26), a first 10kV busbar (28), a fifth 10kV switch (30), a second gas turbine generator (31), a fourth 110kV circuit breaker (38), a 110kV voltage transformer (41), a tenth 110kV knife switch (42), a fifth 110kV circuit breaker (43), an eleventh 110kV knife switch (44), a 110kV side busbar (46), a twelfth 110kV knife switch (47), a thirteenth 110kV knife switch (48), a second 110kV busbar (49), a second 110kV line (53), a sixteenth 110kV knife switch (54), a seventeenth 110kV knife switch (55), a third outlet switch (60), a third gas turbine generator (61) and a second 10kV busbar (64); The second combustion engine generator (31) is connected to the second 110 kV line (53) via the second outlet switch (32), the second main transformer (33), the fifth 110 kV knife switch (34), the third 110 kV circuit breaker (35), the sixth 110 kV knife switch (36), the fourteenth 110 kV knife switch (50), the sixth 110 kV circuit breaker (51), and the fifteenth 110 kV knife switch (52) in sequence; The third combustion engine generator (61) is connected to the second 110 kV busbar (49) via the third main transformer (59), the nineteenth 110 kV knife switch (58), the seventh 110 kV circuit breaker (57), and the eighteenth 110 kV knife switch (56) in sequence; The second 10kV busbar (64) is connected to a common point between the third main transformer (59) and the third outlet switch (60) via a seventh 10kV switch (63) and a sixth 10kV switch (62) in sequence; One end of the seventeenth 110 kV knife switch (55) is connected to the 110 kV bypass bus (46), and the other end is connected to the common point between the nineteenth 110 kV knife switch (58) and the third main transformer (59); One end of the sixteenth 110 kV knife switch (54) is connected to the second 110 kV line (53), and the other end is connected to the 110 kV bypass bus (46); one end of the fourth 110 kV circuit breaker (38) is connected to the second 110 kV bus (49) via the seventh 110 kV knife switch (37), and the other end is connected to the first 110 kV bus (45) via the eighth 110 kV knife switch (39); The 110 kV voltage transformer (41) is connected to the first 110 kV busbar (45) via a ninth 110 kV switch (40); The tenth 110kV knife switch (42), the fifth 110kV circuit breaker (43), and the eleventh 110kV knife switch (44) are connected in series and then both ends are connected in parallel between the first 110kV busbar (45) and the 110kV side busbar (46); One end of the thirteenth 110 kV knife switch (48) is connected to the 110 kV bypass bus (46), and the other end is connected to the common point between the first main transformer (3) and the first 110 kV knife switch (4); One end of the twelfth 110 kV knife switch (47) is connected to the first 110 kV line (10), and the other end is connected to the 110 kV bypass bus (46); One end of the fifth 10kV switch (30) is connected to the common point between the second outlet switch (32) and the second main transformer (33), and the other end is connected to the second 400V common bus (23) via the second common transformer (29) and the second common 400V incoming line switch (25) in sequence; One end of the second 10kV switch (16) is connected to the common point between the first outlet switch (2) and the first main transformer (3), and the other end is connected to the first 400V common busbar (19) via the first common transformer (17) and the first common 400V incoming line switch (18) in sequence; One end of the third 10kV switch (26) is connected to the common point between the first outlet switch (2) and the first main transformer (3), and the other end is connected to the first 10kV busbar (28) via the fourth 10kV switch (27).

2. A black start system for a gas turbine power station with single busbar segmentation and bypass busbar connection according to claim 1, characterized in that: Before the first combustion engine generator (1) and the first main transformer (3) are started with the first 110 kV line (10), the first 110 kV knife switch (4), the first 110 kV circuit breaker (5), the second 110 kV knife switch (6), the third 110 kV knife switch (7), the second 110 kV circuit breaker (8), the fourth 110 kV knife switch (9), the second 10 kV switch (16), the first public 400 V incoming line switch (18), the 400 V public contact switch The switch (22), the third 10kV switch (26), the fourth 10kV switch (27), the ninth 110kV knife switch (40), the fourteenth 110kV knife switch (50), the sixth 110kV circuit breaker (51), the fifteenth 110kV knife switch (52), the eighteenth 110kV knife switch (56), the seventh 110kV circuit breaker (57), the nineteenth 110kV knife switch (58), the sixth 10kV switch (62), and the seventh 10kV switch (63) are all in in a closed state; the first outlet switch (2), the first 10 kV switch (11), the plant 400 V incoming line switch (13), the first 400 V feeder switch (20), the second 400 V feeder switch (24), the second public 400 V incoming line switch (25), the fifth 10 kV switch (30), the second outlet switch (32), the fifth 110 kV knife switch (34), the third 110 kV circuit breaker (35), the sixth 110 kV knife switch (36), the seventh The 110 kV knife switch (37), the fourth 110 kV circuit breaker (38), the eighth 110 kV knife switch (39), the tenth 110 kV knife switch (42), the fifth 110 kV circuit breaker (43), the eleventh 110 kV knife switch (44), the twelfth 110 kV knife switch (47), the thirteenth 110 kV knife switch (48), the sixteenth 110 kV knife switch (54), the seventeenth 110 kV knife switch (55), and the third outlet switch (60) are all in the disconnected state.

3. The black start system of a gas turbine power station with single busbar segmentation and side busbar connection according to claim 1 is characterized in that: After the first combustion engine generator (1) and the first main transformer (3) are black-started and isolated from the first 110 kV line (10), the first 110 kV knife switch (4), the first 110 kV circuit breaker (5), the second 110 kV knife switch (6), the third 110 kV knife switch (7), the second 110 kV circuit breaker (8), the fourth 110 kV knife switch (9), the 400 V public tie switch (22), the second public 400 V incoming line switch (25), the fifth 110 kV knife switch (9), the 400 V public tie switch (22), the second public 400 V incoming line switch (25), the fifth 110 kV knife switch (10 ... 10 kV switch (30), the fifth 110 kV knife switch (34), the third 110 kV circuit breaker (35), the sixth 110 kV knife switch (36), the ninth 110 kV knife switch (40), the fourteenth 110 kV knife switch (50), the sixth 110 kV circuit breaker (51), the fifteenth 110 kV knife switch (52), the eighteenth 110 kV knife switch (56), the seventh 110 kV circuit breaker (57), the nineteenth 110 kV knife switch (58), the sixth 110 kV switch The first outlet switch (2), the first 10kV switch (11), the plant 400V incoming line switch (13), the second 10kV switch (16), the first public 400V incoming line switch (18), the first 400V feeder switch (20), the second 400V feeder switch (24), the third 10kV switch (26), the fourth 10kV switch (27), the second outlet switch (3 ... first 10kV switch (11), the plant 400V incoming line switch (13), the second 10kV switch (16), the first public 400V incoming line switch (18), the first 400V feeder switch (20), the second 400V feeder switch (24), the third 10kV switch (26), the fourth 10kV switch (27), the second outlet switch (32), the first The seventh 110 kV knife switch (37), the fourth 110 kV circuit breaker (38), the eighth 110 kV knife switch (39), the tenth 110 kV knife switch (42), the fifth 110 kV circuit breaker (43), the eleventh 110 kV knife switch (44), the twelfth 110 kV knife switch (47), the thirteenth 110 kV knife switch (48), the sixteenth 110 kV knife switch (54), the seventeenth 110 kV knife switch (55), and the third outlet switch (60) are all in the disconnected state.

4. A black start system for a gas turbine power station with single busbar segmentation and bypass busbar connection according to claim 3, characterized in that: When the first combustion engine generator (1) and the first main transformer (3) charge the first 110 kV line (10) during black start, the first outlet switch (2), the first 400 V feeder switch (20), and the second 400 V feeder switch (24) are all in a closed state, the second public 400 V incoming line switch (25) is in an open state, and the non-common end of the 400 V plant power supply switch (14) is connected to the second 400 V feeder switch (24).

5. A black start system for a gas turbine power station with single busbar segmentation and side busbar connection according to claim 4, characterized in that: When the first gas turbine generator (1) is in black start island operation with the first main transformer (3), the first 110kV line (10) and the plant transformer (12), the first 10kV switch (11) and the plant 400V incoming line switch (13) are in a closed state, and the non-common end of the 400V plant power supply switch (14) is connected to the plant 400V incoming line switch (13).

6. A black start system for a gas turbine power station with single busbar segmentation and bypass busbar connection according to claim 5, characterized in that: After the black start of the first gas turbine generator (1) and the first main transformer (3) with the first 110 kV line (10) is completed, the first outlet switch (2), the first 400 V feeder switch (20), and the second 400 V feeder switch (24) are in an open state, the non-common end of the 400 V plant power supply switch (14) is connected to the second 400 V feeder switch (24), and the second public 400 V incoming line switch (25) is in a closed state.

7. A black start method for a gas turbine power station with single busbar segmentation and side busbar connection, characterized in that: The system according to any one of claims 1 to 6 comprises the following steps: 1) Performing a status check and confirmation work before black start of the first combustion engine generator (1) and the first main transformer (3) with the first 110 kV line (10), and proceeding to step 2); 2) performing isolation and switching operations before black start of the first combustion engine generator (1) and the first main transformer (3) with the first 110 kV line (10), and proceeding to step 3); 3) Start the diesel generator (21), measure the outlet voltages Uab, Uac, Ubc, and frequency f, confirm that the phase sequence is correct, and proceed to step 4); 4) Closing the first 400V feeder switch (20) to supply power to the first 400V common bus (19) and the second 400V common bus (23), and proceeding to step 5); 5) Switching the 400V plant power supply switch (14) to connect to the second 400V feeder switch (24) to supply power to the 400V plant bus (15), and proceeding to step 6); 6) Close the first outlet switch (2), check that the closing indication state of the first outlet switch (2) is normal, and proceed to step 7); 7) operating the first combustion engine generator (1) at a constant speed of 2950 r / min, checking that the first combustion engine generator (1) is operating normally at a constant speed, and proceeding to step 8); 8) Manually operate the first gas turbine generator (1) to build up the voltage to 50% of the rated voltage, check that the voltage indications of the first 110 kV busbar (45) and the first 110 kV line (10) are correct, and proceed to step 9); 9) Operate the first gas turbine generator (1) to build up voltage to 10.04 kV and frequency to 49.0 Hz, the voltage of the first 110 kV bus (45) is 114.5 kV, observe at the line protection of the first 110 kV line (10), the line secondary voltage and current parameters are correct, the secondary phase voltage is about 58 V and the three phases are balanced, the secondary phase current is 35 mA, and proceed to step 10); 10) Check and confirm that the voltage indication on the opposite side of the first 110 kV line (10) is correct, and proceed to step 11); 11) The 400V factory power switch (14) is switched to be connected to the factory 400V incoming line switch (13), the first gas turbine generator (1) is operated with its own factory transformer (12), the output voltage and frequency of the first gas turbine generator (1) are displayed correctly, and the process proceeds to step 12); 12) switching the 400V factory power supply switch (14) to the second 400V feeder switch (24), stopping the first gas turbine generator (1), disconnecting the first outlet switch (2), confirming that the first gas turbine generator (1) is shut down, and proceeding to step 13); 13) The second 400V feeder switch (24) is opened, and the second common 400V incoming line switch (25) is closed. The first 400V common bus (19) and the second 400V common bus (23) are powered by the second main transformer (33). The black start of the first gas turbine generator (1) and the first main transformer (3) with the first 110kV line (10) is completed.

8. A black start method for a gas turbine power plant with single busbar segmentation and bypass busbar connection according to claim 7, characterized in that: The status check and confirmation work before black start in step 1) includes: confirming that the first gas turbine generator (1), the second gas turbine generator (31), and the third gas turbine generator (61) are all in a shutdown standby state; confirming that the first 110kV line (10) and the second 110kV line (53) are all in an operating state; confirming that the first 110kV bus (45), the second 110kV bus (49), the first main transformer (3), and the third main transformer (59) are all in an operating state; confirming that the first 10kV bus (28), the second 10kV bus (64), the first 400V common bus (19), and the second 400V common bus (23) are in an operating state; and confirming that the diesel generator (21) is in a shutdown state. The isolation switching operation in step 2) includes: operating the second main transformer (33) to switch to operation, switching the first main transformer (3) from operation to hot standby, switching the first 10kV bus (28) from operation to cold standby, switching the first 400V common bus (28) from operation to cold standby, and switching the first 400V common bus (28) from operation to cold standby. The busbar (19) and the second 400V common busbar (23) are powered by the second common transformer (29); the first 110kV line (10) and the first 110kV busbar (45) are converted to a hot standby state; the fourth 110kV circuit breaker (38) and the fifth 110kV circuit breaker (43) are checked and confirmed to be in a cold standby state, the second 110kV circuit breaker (8) and the first 110kV circuit breaker (5) are in a hot standby state, and the ninth 110kV knife switch is checked and confirmed to be in a cold standby state. (40) In the closed position, the secondary circuit breaker of the 110kV voltage transformer (41) is in the closed state; the second 110kV circuit breaker (8) is closed, and it is checked and confirmed that the first 110kV line (10) and the first 110kV bus (45) have no voltage, and the first 110kV circuit breaker (5) is closed; the second public 400V incoming line switch (25) is disconnected, and it is confirmed that the first 400V public bus (19) and the second 400V public bus (23) have no voltage.

Images