CN112072773A

CN112072773A - Main transformer spare power automatic switching implementation method adaptive to 10kV bus operation mode change

Info

Publication number: CN112072773A
Application number: CN202010776497.1A
Authority: CN
Inventors: 李新海; 曾令诚; 范德和; 肖星; 孟晨旭; 梁景明; 刘国民; 卢泳茵; 邱天怡; 凌霞; 罗海鑫
Original assignee: Guangdong Power Grid Co Ltd; Zhongshan Power Supply Bureau of Guangdong Power Grid Co Ltd
Current assignee: Guangdong Power Grid Co Ltd; Zhongshan Power Supply Bureau of Guangdong Power Grid Co Ltd
Priority date: 2020-08-05
Filing date: 2020-08-05
Publication date: 2020-12-11
Anticipated expiration: 2040-08-05
Also published as: CN112072773B

Abstract

The invention provides a main transformer spare power automatic switching implementation method adaptive to 10kV bus operation mode change, which solves the problem that the existing main transformer spare power automatic switching cannot meet the requirements of a single-bus single-section two-section bus and the main transformer becomes any branch operation to realize the main transformer spare power automatic switching function under the condition that one section of the bus is a double branch incoming line mode, and comprises the following steps of: s1, collecting a bus wiring mode and determining a main transformer to be put into operation; s2, collecting related electrical quantity and switching value parameters; s3, judging whether the main transformer spare power automatic switching is completed or not, if so, executing S4, otherwise, not processing; s4, judging whether the main transformer spare power automatic switching action condition is met, if so, starting a delay fixed value time, tripping off a main transformer low-voltage switch of a main power supply, and executing S5, otherwise, the main transformer spare power automatic switching does not act; s5, judging whether a main transformer variable-low switch of the main supply is in the off position within the time of the delay set value, if so, switching on the main transformer variable-low switch of the backup supply after the time of the switching-on delay set value of the backup switch, and successfully acting; otherwise, the main transformer spare power automatic switching discharges, and the main transformer spare power automatic switching action fails.

Description

Main transformer spare power automatic switching implementation method adaptive to 10kV bus operation mode change

Technical Field

The invention relates to the technical field of main transformer spare power automatic switching self-adaptive switching of a 10kV bus, in particular to a main transformer spare power automatic switching implementation method adaptive to the change of a 10kV bus operation mode.

Background

The automatic standby power supply switching device (hereinafter referred to as a standby automatic switching device) is a key device for improving the power supply reliability of a power system, and when a system bus working power supply loses voltage due to a fault, the standby automatic switching device quickly cuts off the working power supply and switches the standby power supply, so that the normal operating voltage of the system bus is restored, and the reliable power supply for a user is guaranteed.

As a typical design of a wiring mode of a single-bus double-section four-section bus shown in fig. 1 is generally adopted as a 10kV bus of a transformer substation for collecting, distributing and directly transmitting electric energy to a power supply load, an existing 10kV main transformer automatic backup switching device has a main transformer change-over switch function, two main transformer change-over switches are mutually standby, a hot standby main transformer change-over switch can be automatically switched on after two parallel 10kV buses lose working power, a standby power supply is switched on, power loss of a user is avoided, and the requirement of power supply reliability operation is met. However, during investment and construction of the transformer substation, most transformer substations adopt a staged construction mode, only two main transformers are put into operation at the first stage (one of the main transformers becomes a single branch, the other main transformer becomes a double branch), a bus ii AM and a bus ii BM which supply 10kV through the double branch second main transformer are communicated to a bus ii M, the 10kV bus forms a connection mode of a single-bus single-section two-section bus and one of the buses is a double branch incoming line as shown in fig. 2 and 3, wherein fig. 2 shows a connection mode diagram of the 10kV bus in which the single-bus single-section two-section bus and one of the buses is the double branch incoming line when the first main transformer and the second main transformer are put into operation, and fig. 3 shows a connection mode diagram of the 10kV bus in which the single-bus single-section two-section bus and one of the bus is the double branch incoming line when the third main transformer and the second main. Taking fig. 2 as an example, if the second main-transformer-low first branch switch 2DL is out of operation due to a defect and is switched to be powered or hot standby by the second main-transformer-low second branch switch 4DL, the existing 10kV main-transformer automatic backup switching device cannot realize the main-transformer automatic backup switching function that the second main-transformer-low second branch switch 4DL and the first main-transformer-low branch switch 1DL are mutually standby, at this time, the parallel 10kV bus i M and bus ii M lose working power, which causes a power safety event that the total station 10kV bus is voltage-lost, thereby causing a large area power failure in the power supply area. Taking fig. 3 as an example, if the second main-transformer-low second branch switch 4DL is out of operation due to a defect and is switched to be powered or hot standby by the second main-transformer-low first branch switch 2DL, the existing 10kV main-transformer automatic backup switching device cannot realize the main-transformer automatic backup switching function in which the second main-transformer-low first branch switch 2DL and the third main-transformer-low branch switch 5DL are mutually standby, at this time, the parallel 10kV bus iii M and bus ii M lose working power, which causes a power safety event of voltage loss of the total station 10kV bus, thereby causing a large area power failure in the power supply area.

The utility model discloses a be CN204578206U, disclose in the chinese utility model patent that the publication date is 2015 8 months 19 days a main change spare power automatic switching system based on 10kV female allies oneself with spare power automatic switching, including female allies oneself with spare power automatic switching device, two generating lines and two main changes, two main changes respectively connect the generating line of the same kind, can select the best running mode, make the light load transformer trund into reserve operation, when satisfying the electric wire netting reliability, reach the purpose that reduces the net loss, nevertheless can not satisfy two branch owner and become arbitrary branch switch of step-down and all can realize the main change spare power automatic switching function at operation or hot standby state.

Disclosure of Invention

The invention provides a main transformer spare power automatic switching implementation method adaptive to 10kV bus operation mode change, which overcomes the defects and ensures the power supply reliability of a 10kV distribution network, and aims to solve the problem that the existing 10kV main transformer spare power automatic switching technology cannot meet the requirement that the main transformer spare power automatic switching function can be implemented by the operation of any branch of a double-branch main transformer when the 10kV bus connection mode is changed into a single-bus single-section two-section bus and one section of the bus is a double-branch incoming line connection mode.

In order to achieve the technical effects, the technical scheme of the invention is as follows:

a main transformer spare power automatic switching implementation method adapting to 10kV bus operation mode change at least comprises the following steps:

s1, collecting a 10kV bus wiring mode and determining a main transformer to be put into operation;

s2, acquiring the switching value of the low-voltage main transformer, the switching value of a section switch, the bus voltage and the low-voltage current electrical quantity parameter of the main transformer in operation;

s3, judging whether the charging of the spare power automatic switching of the 10kV main transformer is finished or not, if so, executing a step S4; otherwise, not processing;

s4, judging whether the main transformer low-level switching value, the sectional switch switching value, the bus voltage and the main transformer low-level current electrical quantity parameter in operation meet the main transformer spare power automatic switching action condition, if so, starting the delay fixed value time t1, then tripping off the main transformer low-level switch of the main power supply, and executing the step S5; otherwise, the spare power automatic switching of the 10kV main transformer does not act;

s5, judging whether a main transformer of main supply is in a position separation state or not within the time td of the time delay setting of the tripping of the lower transformer switch, if so, switching on a main transformer lower transformer switch of standby supply after the time t2 of the time delay setting of the switching-on of the standby switch, and successfully performing the standby automatic switching action of the 10kV main transformer; otherwise, the 10kV main transformer is subjected to spare power automatic switching discharge, and the 10kV main transformer is subjected to spare power automatic switching failure.

The 10kV bus operation mode in the step S1 and the switching value parameters, the current and voltage electrical parameters in the step S2 are collected by a corresponding collection unit in the technical field, and whether the bus in the step S4 is under voltage loss is tested by a corresponding test unit in the technical field.

Preferably, the implementation method is applied to main transformer spare power automatic switching of a 10kV distribution network, as shown in fig. 1, the 10kV distribution network comprises a first main transformer, a second main transformer, a third main transformer, a bus im connected with the first main transformer substation single branch a, a bus iiam connected with the second main transformer substation first branch B, a bus iibm connected with the second main transformer substation second branch C, and a bus iiim connected with the third main transformer substation single branch D, a first section switch 3DL is connected in series between the bus im and the bus iiam, a second section switch 6DL is connected in series between the bus iibm and the bus iiim, and a switch 1DL is arranged on a line connecting the first main transformer substation single branch a and the bus im; a switch 2DL is arranged on a circuit connecting the first branch B of the second main transformer with the bus II AM; a switch 4DL is arranged on a circuit connecting the second main transformer variable-low second branch C with the bus II BM; a switch 5DL is arranged on a circuit connecting the third main transformer variable-low single branch D with the bus IIIM, and I1-I4 represent current values collected by the current transformers; the 10kV bus wiring mode comprises a single-bus single-section two-section bus wiring mode and a single-bus double-section four-section bus wiring mode, wherein one section of the bus is a double-branch incoming line wiring mode.

Here, switch 1DL is used for controlling the break-make of the connecting line between first main transformer and low level single branch a and bus im, switch 2DL is used for controlling the break-make of the connecting line between second main transformer and low level first branch B and bus iiam, switch 4DL is used for controlling the break-make of the connecting line between second main transformer and low level second branch C and bus iibm, and switch 5DL is used for controlling the break-make of the connecting line between third main transformer and low level single branch D and bus iiim.

Preferably, when the 10kV bus connection mode is a single-bus single-section two-section bus connection mode, and one section of bus is a double-branch incoming line connection mode, a first main transformer is put into operation, a second main transformer is put into operation, a third main transformer is not put into operation, or the second main transformer is put into operation, the third main transformer is put into operation, and the first main transformer is not put into operation, and a bus II AM is communicated with a bus II BM to form a bus II M; when the 10kV bus connection mode is a single-bus double-section four-section bus connection mode, the first main transformer, the second main transformer and the third main transformer are all put into operation, and the bus II AM is not communicated with the bus II BM.

When the 10kV bus connection mode is a single-bus single-section two-section bus connection mode, and one section of bus is a double-branch incoming line connection mode, namely when only two main transformers are put into operation at the first stage of transformer substation construction; when the 10kV bus connection mode is a single-bus double-section four-section bus connection mode, namely when three main transformers are all put into operation in the corresponding transformer substation construction final stage.

Preferably, the 10kV bus connection mode is switched and changed by one of control word switching, hard pressure plate switching, soft pressure plate switching or operation handle switching.

Preferably, the acquired parameters of step S2 include:

when the 10kV bus wiring mode is a single-bus single-section two-section bus wiring mode, and one section of bus is a double-branch incoming line wiring mode, the collected parameters are as follows: the switch position, the closed position or the hand jump signal of the switch 1DL or the switch 5DL, and the switching value of a backup protection action locking signal; the switch position switching amount of the first section switch 3DL or the switch position switching amount of the second section switch 6 DL; the switch positions, the closed positions or the hand jump signals of the switch 2DL and the switch 4DL, and the switching values of the backup protection action locking signals; the voltage of the bus IIM; the voltage of the bus I M or the bus III M; current of switch 1DL or switch 5 DL; switch 2DL and switch 4 DL.

When the 10kV bus connection mode is a single-bus double-section four-section bus connection mode, the collected parameters are as follows: the switching position switching amount of the first section switch 3DL and the switching position switching amount of the second section switch 6 DL; the switch positions, the closed positions or the hand jump signals of the switch 1DL and the switch 5DL, and the switching values of the backup protection action locking signals; current of switch 1DL and switch 5 DL; the switch positions, the closed positions or the hand jump signals of the switch 2DL and the switch 4DL, and the switching values of the backup protection action locking signals; current of switch 2DL and switch 4 DL; the voltage of the buses IIAM and IIBM; bus im and bus iiim.

Preferably, the standard for completing the charging of the main backup power automatic switching device in step S3 is as follows: the main transformer spare power automatic switching meets all charging conditions and finishes charging after charging delay fixed value time t 0;

the charging conditions include: A. the main transformer spare power automatic switching function hard pressing plate is switched; B. the main transformer spare power automatic switching function soft pressing plate is switched; C. the main transformer spare power automatic switching mode controls the character switching; D. the switch position of the section switch is closed; E. the three-phase voltage of two sections of buses connected with the section switch in series is more than or equal to a bus voltage fixed value Uy; F. one main transformer has at least one low-voltage switch in the running state, the other main transformer has no low-voltage switch in the running state and has at least one low-voltage switch in the hot standby state;

the conditions of main transformer spare power automatic switching discharge are as follows: A. withdrawing the main transformer spare power automatic switching function soft pressing plate or the main transformer spare power automatic switching function hard pressing plate; B. the low switch of any hot standby state of the main transformer is turned on and goes through the discharge delay fixed value time t 4; C. when the main transformer spare power automatic switching is not started, a position signal after the switch in the running state is closed is from 1 → 0 or a hand jump signal is from 0 → 1; D. when the main transformer backup power automatic switching is not started, a switch backup protection action blocking signal in the running state is from 0 → 1; E. receiving other external blocking signals; F. PT (potential transformer) disconnection occurs in two sections of buses connected with the section switch in series; when any one of the conditions of the main transformer spare power automatic switching discharge is met, the main transformer spare power automatic switching discharge is carried out.

Here, when the above charging conditions are all satisfied, it can be further determined whether charging is completed, and the two segments of buses connected in series with the sectionalizing switch refer to: when the 10kV bus wiring mode is a single-bus single-section two-section bus wiring mode, one section of bus is a double-branch incoming line wiring mode, a first main transformer and a second main transformer are put into operation, and a third main transformer is not put into operation, a bus I M and a bus II M; when the 10kV bus wiring mode is a single-bus single-section two-section bus wiring mode, one section of bus is a double-branch incoming line wiring mode, the second main transformer and the third main transformer are put into operation, and the first main transformer is not put into operation, the bus II M and the bus III M; when the 10kV bus connection mode is a single-bus double-section four-section bus connection mode and the first main transformer, the second main transformer and the third main transformer are all put into operation, the bus I M, the bus II AM, the bus II BM and the bus III M are connected in series.

When the 10kV bus wiring mode is a single-bus single-section two-section bus and one section of bus is a wiring mode of a double-branch incoming line, a first main transformer and a second main transformer are put into operation, a third main transformer is not put into operation, the main transformer is fully charged by automatic switching, and the main transformer is fully charged by automatic switching action conditions and action logics, wherein the operation modes comprise:

under the operation mode of 'the switch 1DL is in an operation state, the switch 2DL is in a hot standby state, the switch 4DL is in an overhaul state and the sectional switch 3DL is in an on position', if the conditions that 'the three-phase voltages of the bus I M and the bus II M are both smaller than a non-voltage fixed value Uw, the current of the switch 1DL is smaller than a non-current fixed value Iw, the switch 2DL is in the hot standby state and the switch 4DL is in the overhaul state' are simultaneously met, the first main transformer step-down switch 1DL is tripped after the starting delay fixed value time t1 of the 10kV main transformer backup automatic switching, if the switch 1DL is in an off position within the delay fixed value time td of the trip of the step-down switch, the first branch switch 2DL of the second main transformer is switched after the switching delay fixed value time t2 of the backup automatic switching, and the action of the main; if the switch 1DL is still in the on position after the time td of waiting for the delay fixed value by the tripping of the low-voltage switch, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails.

Under the operation mode of ' the switch 1DL is in an operation state, the switch 2DL is in an overhaul state, the switch 4DL is in a hot standby state and the sectional switch 3DL is in an on position ', if the conditions that three-phase voltages of a bus I M and a bus II M are both smaller than a non-voltage fixed value Uw, the current of the switch 1DL is smaller than a non-current fixed value Iw, the switch 2DL is in the overhaul state and the switch 4DL is in the hot standby state ' are simultaneously met, the first main transformer low-voltage switch 1DL is tripped after the starting delay fixed value time t1 of the 10kV main transformer backup power automatic switching, if the switch 1DL is in an off position within the delay fixed value time td of the trip of the low-voltage switch, the second main transformer low-voltage second branch switch 4DL is switched after the switching delay fixed value time t2 of the backup power automatic switching, and the main transformer backup; if the switch 1DL is still in the on position after the time td of waiting for the delay fixed value by the tripping of the low-voltage switch, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails.

Under the operation mode of 'the switch 1DL is in an operation state, the switch 2DL is in a hot standby state, the switch 4DL is in a hot standby state and the sectional switch 3DL is in an on position', if the conditions that 'the three-phase voltages of the bus I M and the bus II M are both smaller than a non-voltage fixed value Uw, the current of the switch 1DL is smaller than a non-current fixed value Iw, the switch 2DL is in a hot standby state and the switch 4DL is in a hot standby state' are simultaneously met, the first main transformer low-voltage switch 1DL is jumped after the delay fixed value time t1 of the starting of the 10kV main transformer low-voltage automatic switching, and if the switch 1DL is in an off position in the delay fixed value time td of the low-voltage switch tripping waiting, the first main transformer low-voltage branch switch 2DL and the second main transformer low-voltage branch switch 4DL are switched after the delay fixed value time t2 of the standby; if the switch 1DL is still in the on position after the time td of waiting for the delay fixed value by the tripping of the low-voltage switch, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails.

Under the operation modes of 'the switch 1DL is in a hot standby state, the switch 2DL is in an operation state, the switch 4DL is in an overhaul state and the sectional switch 3DL is in an on position', if the conditions that three-phase voltages of a bus I M and a bus II M are all smaller than a non-voltage fixed value Uw, the current of the switch 1DL is in the hot standby state, the current of the switch 2DL is smaller than a non-current fixed value Iw and the current of the switch 4DL is in the overhaul state are simultaneously met, the second main transformer low-voltage first branch switch 2DL is jumped after the time delay fixed value time t1 is started, if the switch 2DL is in an off position in the low-voltage switch tripping waiting time delay fixed value time td, the first main transformer low-voltage switch 1DL is switched on after the time delay fixed value time t2 of the low-voltage switch, and the main transformer low-voltage; if the switch 2DL is still in the on position after the time td of waiting for the delay fixed value by the tripping of the low-voltage switch, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails.

Under the operation modes of ' the switch 1DL is in a hot standby state, the switch 2DL is in an overhaul state, the switch 4DL is in an operation state and the sectional switch 3DL is in an on position ', if the conditions that three-phase voltages of a bus I M and a bus II M are all smaller than a non-voltage fixed value Uw, the switch 1DL is in the hot standby state, the switch 2DL is in the overhaul state and the current of the switch 4DL is smaller than a non-current fixed value Iw ' are simultaneously met, the second main transformer low-voltage switch 4DL is tripped after the starting delay fixed value time t1 of the 10kV main transformer backup power automatic switching, if the switch 4DL is in an off position in the low-voltage switch tripping waiting delay fixed value time td, the first main transformer low-voltage switch 1DL is switched on after the switching delay fixed value time t2 of the backup power automatic switching, and the main transformer backup power automatic switching action; if the switch 4DL is still in the on position after the time td of waiting for the delay fixed value by the tripping of the low-voltage switch, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails.

Under the operation modes of ' the switch 1DL is in a hot standby state, the switch 2DL is in an operation state, the switch 4DL is in an operation state and the sectional switch 3DL is in an on position ', if the conditions that three-phase voltages of a bus I M and a bus II M are all smaller than a non-voltage fixed value Uw, the current of the switch 1DL is in a hot standby state, the current of the switch 2DL is smaller than a non-current fixed value Iw and the current of the switch 4DL is smaller than a non-current fixed value Iw ' are simultaneously met, the second main transformer becomes lower after the standby power automatic switching is started for a delayed fixed value time t1, the first main transformer becomes lower, the second main transformer becomes lower, the first main transformer becomes lower, the standby power automatic switching is switched after the delayed fixed value time t2, and the main transformer becomes lower power automatic switching is successful; if any one of the switch 2DL and the switch 4DL is still in the on position after the time td of the delay fixed value is waited for by the tripping of the low-level switch, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails.

Under the operation modes of ' the switch 1DL is in a hot standby state, the switch 2DL is in an operation state, the switch 4DL is in a hot standby state and the sectional switch 3DL is in an on position ', if the conditions that three-phase voltages of a bus I M and a bus II M are all smaller than a non-voltage fixed value Uw, the switch 1DL is in a hot standby state, the current of the switch 2DL is smaller than a non-current fixed value Iw and the switch 4DL is in a hot standby state ' are simultaneously met, the second main transformer becomes the first branch switch 2DL and the second branch switch 4DL after the standby automatic switching of 10kV is started for a delay fixed value time t1, if the main transformers 2DL and the switch 4DL are in an off position in a delay fixed value time td for the tripping of the main transformers, the first main transformer becomes the low switch 1DL is switched after a switching-on delay fixed value time t2, and the standby automatic switching action succeeds; if any one of the switch 2DL and the switch 4DL is still in the on position after the time td of the delay fixed value is waited for by the tripping of the low-level switch, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails.

Under the operation modes of ' the switch 1DL is in a hot standby state, the switch 2DL is in a hot standby state, the switch 4DL is in an operation state and the sectional switch 3DL is in an on position ', if the conditions that three-phase voltages of a bus I M and a bus II M are all smaller than a non-voltage fixed value Uw, the switch 1DL is in the hot standby state, the switch 2DL is in the hot standby state and the current of the switch 4DL is smaller than a non-current fixed value Iw ' are simultaneously met, the second main transformer becomes the first branch switch 2DL and the second branch switch 4DL after the standby automatic switching of 10kV is started within a delay fixed value time t1, if the main transformers 2DL and the switch 4DL are in the off position within a delay fixed value time td of the tripping of the main transformers, the first main transformer becomes the low switch 1DL is switched after a switching-on delay fixed value time t2, and the standby automatic switching action succeeds; if any one of the switch 2DL and the switch 4DL is still in the on position after the time td of the delay fixed value is waited for by the tripping of the low-level switch, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails.

Preferably, when the 10kV bus connection mode is a single-bus single-section two-section bus and one section of the bus is a connection mode of a double branch incoming line, the second main transformer and the third main transformer are put into operation, the first main transformer is not put into operation, the main transformer backup power automatic switching completes charging, and the main transformer backup power automatic switching action conditions and the action logic are as follows:

under the operation mode of 'the switch 5DL is in an operation state, the switch 2DL is in a hot standby state, the switch 4DL is in an overhaul state and the sectional switch 6DL is in an on position', if the conditions that 'the three-phase voltages of the bus III M and the bus II M are both smaller than a non-voltage fixed value Uw, the current of the switch 5DL is smaller than a non-current fixed value Iw, the switch 2DL is in the hot standby state and the switch 4DL is in the overhaul state' are simultaneously met, the third main transformer step-down switch 5DL is tripped after the starting delay fixed value time t1 of the 10kV main transformer backup automatic switching, if the switch 5DL is in an off position within the delay fixed value time td of the trip of the step-down switch, the second main transformer step-down first branch switch 2DL is switched after the switching-on delay fixed value time t2 of the backup automatic switching, and the main; if the switch 5DL is still in the on position after the time td of waiting for the delay fixed value by the tripping of the low-voltage switch, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails.

Under the operation mode of 'the switch 5DL is in an operation state, the switch 2DL is in an overhaul state, the switch 4DL is in a hot standby state and the sectional switch 6DL is in an on position', if the conditions that 'the three-phase voltages of the bus III M and the bus II M are both smaller than a non-voltage fixed value Uw, the current of the switch 5DL is smaller than a non-current fixed value Iw, the switch 2DL is in the overhaul state and the switch 4DL is in the hot standby state' are simultaneously met, the third main transformer low-voltage switch 5DL is tripped after the starting delay fixed value time t1, if the switch 5DL is in an off position in the low-voltage switch tripping waiting delay fixed value time td, the second main transformer low-voltage second branch switch 4DL is switched after the closing delay fixed value time t2 of the low-voltage switch, and the main transformer low-voltage automatic switching action is successful; if the switch 5DL is still in the on position after the time td of waiting for the delay fixed value by the tripping of the low-voltage switch, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails.

Under the operation mode of 'the switch 5DL is in an operation state, the switch 2DL is in a hot standby state, the switch 4DL is in a hot standby state and the sectional switch 6DL is in an on position', if the conditions that 'three-phase voltages of a bus III M and a bus II M are both smaller than a non-voltage fixed value Uw, the current of the switch 5DL is smaller than a non-current fixed value Iw, the switch 2DL is in a hot standby state and the switch 4DL is in a hot standby state' are simultaneously met, the third main transformer low-voltage switch 5DL is jumped after the time delay fixed value time t1 of starting of the 10kV main transformer low-voltage automatic switching, and if the switch 5DL is in an off position in the time delay fixed value time td of waiting for the trip of the low-voltage switch, the first branch switch 2DL and the second branch switch 4DL of the second main transformer are switched after the time delay fixed value time t2 of the switching of; if the switch 5DL is still in the on position after the time td of waiting for the delay fixed value by the tripping of the low-voltage switch, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails.

Under the operation modes of ' the switch 5DL is in a hot standby state, the switch 2DL is in an operation state, the switch 4DL is in an overhaul state and the sectional switch 6DL is in an on position ', if the conditions that three-phase voltages of a bus III M and a bus II M are all smaller than a non-voltage fixed value Uw, the switch 5DL is in the hot standby state, the current of the switch 2DL is smaller than a non-current fixed value Iw and the switch 4DL is in the overhaul state ' are simultaneously met, the second main transformer low-voltage first branch switch 2DL is jumped after the time delay fixed value t1 is started for the 10kV main transformer low-voltage backup automatic switching, and if the switch 2DL is in an off position in the time delay fixed value td waiting for the low-voltage switch tripping, the third main transformer low-voltage switch 5DL is switched after the time delay fixed value t2 for the low-voltage backup switching; if the switch 2DL is still in the on position after the time td of waiting for the delay fixed value by the tripping of the low-voltage switch, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails.

Under the operation modes of ' the switch 5DL is in a hot standby state, the switch 2DL is in an overhaul state, the switch 4DL is in an operation state and the sectional switch 6DL is in an on position ', if the conditions that three-phase voltages of a bus III M and a bus II M are all smaller than a non-voltage fixed value Uw, the switch 5DL is in the hot standby state, the switch 2DL is in the overhaul state and the current of the switch 4DL is smaller than a non-current fixed value Iw ' are simultaneously met, the second main transformer low-voltage switch 4DL is jumped after the starting delay fixed value time t1 of the 10kV main transformer backup power automatic switching, if the switch 4DL is in an off position in the low-voltage switch tripping waiting delay fixed value time td, the third main transformer low-voltage switch 5DL is switched on after the switching delay fixed value time t2 of the backup power automatic switching, and the main transformer backup power automatic switching; if the switch 4DL is still in the on position after the time td of waiting for the delay fixed value by the tripping of the low-voltage switch, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails.

Under the operation modes of ' the switch 5DL is in a hot standby state, the switch 2DL is in an operation state, the switch 4DL is in an operation state and the sectional switch 6DL is in an on position ', if the conditions that three-phase voltages of a bus III M and a bus II M are all smaller than a non-voltage fixed value Uw, the current of the switch 5DL is in a hot standby state, the current of the switch 2DL is smaller than a non-current fixed value Iw and the current of the switch 4DL is smaller than a non-current fixed value Iw ' are simultaneously met, the second main transformer becomes lower by jumping the first branch switch 2DL and the second branch switch 4DL after the 10kV main transformer automatic switching is started for a delay fixed value time t1, and if the switch 2DL and the switch 4DL are in an off position in a standby main transformer trip waiting delay fixed value time td, the third main transformer automatic switching becomes lower by switching on the delay fixed value time t2, and the main transformer automatic switching action succeeds; if any one of the switch 2DL and the switch 4DL is still in the on position after the time td of the delay fixed value is waited for by the tripping of the low-level switch, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails.

Under the operation modes of ' the switch 5DL is in a hot standby state, the switch 2DL is in an operation state, the switch 4DL is in a hot standby state and the sectional switch 6DL is in an on position ', if the conditions that three-phase voltages of a bus III M and a bus II M are all smaller than a non-voltage fixed value Uw, the switch 5DL is in a hot standby state, the current of the switch 2DL is smaller than a non-current fixed value Iw and the switch 4DL is in a hot standby state ' are simultaneously met, the second main transformer becomes the first branch switch 2DL and the second branch switch 4DL after the standby automatic switching of 10kV is started for a delay fixed value time t1, if the main transformers 2DL and the switch 4DL are in an off position in a delay fixed value time td for the tripping of the main transformers, the third main transformer becomes the low switch 5DL is switched after a switching-on delay fixed value time t2, and the standby automatic switching action succeeds; if any one of the switch 2DL and the switch 4DL is still in the on position after the time td of the delay fixed value is waited for by the tripping of the low-level switch, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails.

Under the operation mode of ' the switch 5DL is in a hot standby state, the switch 2DL is in a hot standby state, the switch 4DL is in an operation state and the sectional switch 6DL is in an on position ', if the conditions that three-phase voltages of a bus III M and a bus II M are all smaller than a non-voltage fixed value Uw, the switch 5DL is in the hot standby state, the switch 2DL is in the hot standby state and the current of the switch 4DL is smaller than a non-current fixed value Iw ' are simultaneously met, the second main transformer becomes the first branch switch 2DL and the second branch switch 4DL after the standby automatic switching of 10kV is started for a delay fixed value time t1, if the main transformers 2DL and the switch 4DL are in the off position within a delay fixed value time td for the trip of the main transformers, the third main transformer becomes the low switch 5DL is switched after a switch on delay fixed value time t2, and the standby automatic switching action succeeds; if any one of the switch 2DL and the switch 4DL is still in the on position after the time td of the delay fixed value is waited for by the tripping of the low-level switch, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails.

Preferably, when the 10kV bus connection mode is a single-bus double-section four-section bus connection mode, the first main transformer, the second main transformer and the third main transformer are all put into operation, the bus iiam and the iibm bus are not communicated, the main transformer is fully charged by the fully automatic switch, and the fully automatic switch operation conditions and the operation logic of the main transformers include: the main transformer spare power automatic switching function is characterized in that the first main transformer and the second main transformer are mutually standby main transformers, and the second main transformer and the third main transformer are mutually standby main transformers.

When the first main transformer, the second main transformer and the third main transformer are all put into operation, the bus IIAM and the IIBM bus are not communicated, and the main transformer spare power automatic switching function can be realized by the conventional main transformer spare power automatic switching technology.

Preferably, the switch in the operating state satisfies: when the maintenance pressing plate corresponding to the switch is in an exit state, the switch is in a closed position or the switch current is greater than or equal to a current constant value Iy;

the switch is in a hot standby state to meet the following conditions: the maintenance pressing plate corresponding to the switch is in an exit state, the switch is in a position division state, and the switch current is smaller than the no-current fixed value Iw;

the switch is in the maintenance state and satisfies: the maintenance pressing plate corresponding to the switch is in a putting-in state.

Compared with the prior art, the technical scheme of the invention has the beneficial effects that:

the invention provides a method for realizing the spare power automatic switching of a main transformer adaptive to the change of a 10kV bus operation mode, which determines the main transformer to be operated according to the 10kV bus wiring mode, collects relevant switching value and current and voltage electrical quantity parameters, realizes the spare power automatic switching function of the 10kV main transformer by adapting to the 10kV bus wiring mode and the change of the variable switching state of a double-branch main transformer, solves the problem that the existing 10kV main transformer spare power automatic switching technology cannot meet the requirement of the spare power automatic switching function of the main transformer on the operation of any branch of the double-branch main transformer when the 10kV bus wiring mode is changed into a single-bus single-section two-section bus and one section of the bus is a double-branch incoming line wiring mode, meets the functional requirement of the 10kV bus on a 10kV spare power automatic switching device by adopting a single-bus single-section two-section bus and one section of the main transformer is a double-branch incoming line wiring mode and adopting a single-bus double-section four, main transformer spare power automatic switching logic is succinct and clear, has ensured the reliable operation of 10kV generating line.

Drawings

FIG. 1 is a wiring structure diagram of the operation mode of a single-bus double-section four-section bus according to the present invention;

fig. 2 shows a single-bus single-section two-section bus of the transformer substation provided by the invention, which is only put into operation in the first stage of construction of the first main transformer and the second main transformer, wherein one section of the bus is a double-branch incoming line wiring mode structure diagram.

Fig. 3 shows a single-bus single-section two-section bus of the transformer substation provided by the invention, which is only put into operation in the first stage of construction of the second main transformer and the third main transformer, wherein one section of the bus is a double-branch incoming line wiring mode structure diagram.

Fig. 4 is a schematic flow chart of a main transformer backup power automatic switching implementation method adapted to a change in a 10kV bus operation mode according to an embodiment of the present invention.

Fig. 5 is a logic diagram of the backup automatic switching operation of the main transformers in the connection mode of the double branch incoming line, wherein the single bus is a single-section two-section bus only for operating the first main transformer and the second main transformer, and one section of the bus is provided in the embodiment of the present invention.

Fig. 6 is a logic diagram of the backup automatic switching operation of the main transformers in the connection mode of the double branch incoming line, wherein the single bus is a single-section two-section bus only for operating the second main transformer and the third main transformer, and one section of the bus is provided in the embodiment of the present invention.

Detailed Description

The drawings are for illustrative purposes only and are not to be construed as limiting the patent;

for better illustration of the present embodiment, certain parts of the drawings may be omitted, enlarged or reduced, and do not represent actual dimensions;

it will be understood by those skilled in the art that certain well-known descriptions of the figures may be omitted.

The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.

Example 1

As shown in fig. 4, the flow diagram of the main transformer spare power automatic switching implementation method adapted to the change of the operation mode of the 10kV bus provided by the invention is applied to the main transformer spare power automatic switching of a 10kV distribution network, and referring to fig. 1, the 10kV distribution network comprises a first main transformer, a second main transformer, a third main transformer, a bus im connected with a first main transformer change-down single branch a, a bus iiam connected with a first branch B of the second main transformer change-down, a bus iibm connected with a second branch C of the second main transformer change-down, and a bus iiim connected with a third main transformer change-down single branch D, a first section switch 3DL is connected in series between the bus im and the bus iiam, a second section switch 6DL is connected in series between the bus iibm and the bus iiim, and a line connected with the bus im is provided with a switch 1 DL; a switch 2DL is arranged on a circuit connecting the first branch B of the second main transformer with the bus II AM; a switch 4DL is arranged on a circuit connecting the second main transformer variable-low second branch C with the bus II BM; a switch 5DL is arranged on a circuit connecting the third main transformer variable-low single branch D with the bus IIIM, and I1-I4 represent current values collected by the current transformers; the 10kV bus wiring mode comprises a single-bus single-section two-section bus wiring mode and a single-bus double-section four-section bus wiring mode, wherein one section of the bus is a double-branch incoming line wiring mode. The method comprises the following steps:

s1, collecting a 10kV bus wiring mode and determining a main transformer to be put into operation; when the 10kV bus wiring mode is a single-bus single-section two-section bus and one section of the bus is a double-branch incoming line wiring mode, a first main transformer and a second main transformer are put into operation, a third main transformer is not put into operation or the second main transformer and the third main transformer are put into operation, the first main transformer is not put into operation, a bus II AM and an II BM bus are communicated to form a bus II M, and only two main transformers are put into operation at the first stage of the construction of a corresponding transformer substation; when the 10kV bus connection mode is a single-bus double-section four-section bus connection mode, the first main transformer, the second main transformer and the third main transformer are all put into operation, the bus IIAM and the IIBM bus are not communicated, and when the three main transformers are all put into operation in the corresponding transformer substation construction final stage; the wiring mode of the 10kV bus is switched by one of the modes of controlling character input and output, hard pressing plate input and output, soft pressing plate input and output or operating handle switching.

S2, acquiring the switching value of the low-voltage main transformer, the switching value of a section switch, the bus voltage and the low-voltage current electrical quantity parameter of the main transformer in operation; the collected parameters of step S2 include:

S3, judging whether the charging of the spare power automatic switching of the 10kV main transformer is finished or not, if so, executing a step S4; otherwise, not processing; the standard for completing the charging of the main transformer spare power automatic switching is as follows: the main transformer spare power automatic switching meets all charging conditions and finishes charging after charging delay fixed value time t 0;

the charging conditions include: A. the main transformer spare power automatic switching function hard pressing plate is switched; B. the main transformer spare power automatic switching function soft pressing plate is switched; C. the main transformer spare power automatic switching mode controls the character switching; D. the switch position of the section switch is closed; E. the three-phase voltage of two sections of buses connected with the section switch in series is more than or equal to a bus voltage fixed value Uy; F. one main transformer has at least one low-voltage switch in the running state, the other main transformer has no low-voltage switch in the running state and has at least one low-voltage switch in the hot standby state; when the charging conditions are all satisfied, whether charging is completed or not can be further judged. Whether the bus is pressureless can be directly detected by the existing measuring device.

s5, judging whether a main transformer of main supply is in a position separation state or not within the time td of the time delay setting of the tripping of the lower transformer switch, if so, switching on a main transformer lower transformer switch of standby supply after the time t2 of the time delay setting of the switching-on of the standby switch, and successfully performing the standby automatic switching action of the 10kV main transformer; otherwise, the 10kV main transformer is subjected to spare power automatic switching discharge, and the 10kV main transformer is subjected to spare power automatic switching failure. The conditions of main transformer spare power automatic switching discharge are as follows: A. withdrawing the main transformer spare power automatic switching function soft pressing plate or the main transformer spare power automatic switching function hard pressing plate; B. the low switch of any hot standby state of the main transformer is turned on and goes through the discharge delay fixed value time t 4; C. when the main transformer spare power automatic switching is not started, a position signal after the switch in the running state is closed is from 1 → 0 or a hand jump signal is from 0 → 1; D. when the main transformer backup power automatic switching is not started, a switch backup protection action blocking signal in the running state is from 0 → 1; E. receiving other external blocking signals; F. PT (potential transformer) disconnection occurs in two sections of buses connected with the section switch in series; when any one of the conditions of the main transformer spare power automatic switching discharge is met, the main transformer spare power automatic switching discharge is carried out.

In this embodiment, referring to fig. 5, a logic schematic diagram of a main transformer backup automatic switching operation in a double branch incoming line connection mode of a single-bus single-section two-section bus only running a first main transformer and a second main transformer, that is,:

when the 10kV bus connection mode is a single bus single-section two-section bus and one section of bus is a double branch incoming line connection mode, as shown in fig. 2, the first main transformer and the second main transformer are put into operation, and the third main transformer is not put into operation, referring to fig. 5, the main transformer spare power automatic switching operation conditions and operation logics include:

Referring to fig. 6, a schematic diagram of a main transformer backup automatic switching operation logic when only a single bus single-section two-section bus of the second main transformer and the third main transformer is operated and one section of the bus is in a double-branch incoming line connection mode is shown, when a 10kV bus connection mode is a single bus single-section two-section bus and one section of the bus is in a double-branch incoming line connection mode, as shown in fig. 3, the second main transformer and the third main transformer are operated, the first main transformer is not operated, and the main transformer backup automatic switching logic is:

Above, the switch is in the operating state and satisfies: when the maintenance pressing plate corresponding to the switch is in an exit state, the switch is in a closed position or the switch current is greater than or equal to a current constant value Iy;

When the 10kV bus wiring mode is a single-bus double-section four-section bus wiring mode, a first main transformer, a second main transformer and a third main transformer are all put into operation, buses II AM and II BM buses are not communicated, the main transformer spare power automatic switching completes charging, the first main transformer and the second main transformer are mutually standby main transformer spare power automatic switching functions, the second main transformer and the third main transformer are mutually standby main transformer automatic switching functions, and at the moment, the existing main transformer spare power automatic switching technology can realize the main transformer spare power automatic switching functions.

The positional relationships depicted in the drawings are for illustrative purposes only and are not to be construed as limiting the present patent;

it should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A main transformer spare power automatic switching implementation method adapting to 10kV bus operation mode change is characterized by at least comprising the following steps:

s5, judging the time t of the trip waiting delay of the low-level switch_dWhether a main transformer variable-low switch of the main supply is in a separating position or not is judged, if yes, after the time t2 of a closing delay fixed value of the spare power switching switch, the spare power switching main transformer variable-low switch is closed, and the spare power switching action of the 10kV main transformer is successful; otherwise, the 10kV main transformer is subjected to spare power automatic switching discharge, and the 10kV main transformer is subjected to spare power automatic switching failure.

2. The method for realizing the main transformer automatic backup power switching adapting to the change of the operation mode of the 10kV bus according to claim 1, wherein the method is applied to the main transformer automatic backup power switching of a 10kV distribution network, the 10kV distribution network comprises a first main transformer, a second main transformer, a third main transformer, a bus IM connected with a first main transformer-lower single branch A, a bus IIAM connected with a second main transformer-lower first branch B, a bus IIBM connected with a second main transformer-lower branch C, and a bus IIIM connected with a third main transformer-lower single branch D, a first section switch 3DL is connected between the bus IM and the bus IIAM in series, a second section switch 6DL is connected between the bus IIBM and the bus IIIM in series, and a switch 1DL is arranged on a line connected with the first main transformer-lower single branch A and the bus IM; a switch 2DL is arranged on a circuit connecting the first branch B of the second main transformer with the bus II AM; a switch 4DL is arranged on a circuit connecting the second main transformer variable-low second branch C with the bus II BM; a switch 5DL is arranged on a circuit connecting the third main transformer variable-low single branch D with the bus IIIM; the 10kV bus wiring mode comprises the following steps: the single-bus single-section two-section bus adopts a wiring mode of a double-branch incoming line and a wiring mode of a single-bus double-section four-section bus.

3. The method for realizing the spare power automatic switching of the main transformer adapting to the change of the operation mode of the 10kV bus according to claim 2, wherein when the connection mode of the 10kV bus is a single-bus single-section two-section bus and one section of the bus is a connection mode of a double branch incoming line, a first main transformer is switched on, a second main transformer is switched on, a third main transformer is not switched on or the second main transformer, the third main transformer is switched on, the first main transformer is not switched on, and a bus IIAM is communicated with a bus IIBM to form a bus IIM; when the 10kV bus connection mode is a single-bus double-section four-section bus connection mode, the first main transformer, the second main transformer and the third main transformer are all put into operation, and the bus II AM is not communicated with the bus II BM.

4. The method for realizing the automatic main transformer automatic switching adapting to the operation mode change of the 10kV bus according to any one of claims 1 to 3, wherein the wiring mode of the 10kV bus is switched by one of control word switching, hard pressure plate switching, soft pressure plate switching or operating handle switching.

5. The method for realizing the main transformer spare power automatic switching device adapting to the change of the 10kV bus operation mode according to claim 4, wherein the acquired parameters in the step S2 comprise:

when the 10kV bus wiring mode is a single-bus single-section two-section bus wiring mode, and one section of bus is a double-branch incoming line wiring mode, the collected parameters are as follows: the switch position, the closed position or the hand jump signal of the switch 1DL or the switch 5DL, and the switching value of a backup protection action locking signal; the switch position switching amount of the first section switch 3DL or the switch position switching amount of the second section switch 6 DL; the switch positions, the closed positions or the hand jump signals of the switch 2DL and the switch 4DL, and the switching values of the backup protection action locking signals; the voltage of the bus IIM; the voltage of the bus I M or the bus III M; current of switch 1DL or switch 5 DL; current of switch 2DL and switch 4 DL;

6. The method for realizing the main transformer automatic backup power switching adapting to the change of the operation mode of the 10kV bus according to claim 5, wherein the standard of the completion of the main transformer automatic backup power switching charging in the step S3 is as follows: the main transformer spare power automatic switching meets all charging conditions and finishes charging after charging delay fixed value time t 0;

the conditions of main transformer spare power automatic switching discharge are as follows: A. withdrawing the main transformer spare power automatic switching function soft pressing plate or the main transformer spare power automatic switching function hard pressing plate; B. the low switch of any hot standby state of the main transformer is turned on and goes through the discharge delay fixed value time t 4; C. when the main transformer spare power automatic switching is not started, a position signal after the switch in the running state is closed is from 1 → 0 or a hand jump signal is from 0 → 1; D. when the main transformer backup power automatic switching is not started, a switch backup protection action blocking signal in the running state is from 0 → 1; E. receiving other external blocking signals; F. PT disconnection occurs on two sections of buses connected with the section switch in series. When any one of the conditions of the main transformer spare power automatic switching discharge is met, the main transformer spare power automatic switching discharge is carried out.

7. The method for realizing the main transformer automatic backup power switching adapting to the change of the operation mode of the 10kV bus according to claim 6, wherein when the connection mode of the 10kV bus is a single-bus single-section two-section bus and one section of the bus is a connection mode of a double branch incoming line, a first main transformer and a second main transformer are put into operation, a third main transformer is not put into operation, the main transformer automatic backup power switching finishes charging, and the main transformer automatic backup power switching operation conditions and the operation logic comprise:

under the operation mode of 'the switch 1DL is in an operation state, the switch 2DL is in a hot standby state, the switch 4DL is in an overhaul state and the sectional switch 3DL is in an on position', if the conditions that 'the three-phase voltages of the bus I M and the bus II M are both smaller than a non-voltage fixed value Uw, the current of the switch 1DL is smaller than a non-current fixed value Iw, the switch 2DL is in the hot standby state and the switch 4DL is in the overhaul state' are simultaneously met, the first main transformer step-down switch 1DL is tripped after the starting delay fixed value time t1 of the 10kV main transformer backup automatic switching, if the switch 1DL is in an off position within the delay fixed value time td of the trip of the step-down switch, the first branch switch 2DL of the second main transformer is switched after the switching delay fixed value time t2 of the backup automatic switching, and the action of the main; if the switch 1DL is still in the on position after the tripping of the low-voltage switch waits for the delay fixed value time td, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails;

under the operation mode of ' the switch 1DL is in an operation state, the switch 2DL is in an overhaul state, the switch 4DL is in a hot standby state and the sectional switch 3DL is in an on position ', if the conditions that three-phase voltages of a bus I M and a bus II M are both smaller than a non-voltage fixed value Uw, the current of the switch 1DL is smaller than a non-current fixed value Iw, the switch 2DL is in the overhaul state and the switch 4DL is in the hot standby state ' are simultaneously met, the first main transformer low-voltage switch 1DL is tripped after the starting delay fixed value time t1 of the 10kV main transformer backup power automatic switching, if the switch 1DL is in an off position within the delay fixed value time td of the trip of the low-voltage switch, the second main transformer low-voltage second branch switch 4DL is switched after the switching delay fixed value time t2 of the backup power automatic switching, and the main transformer backup; if the switch 1DL is still in the on position after the tripping of the low-voltage switch waits for the delay fixed value time td, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails;

under the operation mode of 'the switch 1DL is in an operation state, the switch 2DL is in a hot standby state, the switch 4DL is in a hot standby state and the sectional switch 3DL is in an on position', if the conditions that 'the three-phase voltages of the bus I M and the bus II M are both smaller than a non-voltage fixed value Uw, the current of the switch 1DL is smaller than a non-current fixed value Iw, the switch 2DL is in a hot standby state and the switch 4DL is in a hot standby state' are simultaneously met, the first main transformer low-voltage switch 1DL is jumped after the delay fixed value time t1 of the starting of the 10kV main transformer low-voltage automatic switching, and if the switch 1DL is in an off position in the delay fixed value time td of the low-voltage switch tripping waiting, the first main transformer low-voltage branch switch 2DL and the second main transformer low-voltage branch switch 4DL are switched after the delay fixed value time t2 of the standby; if the switch 1DL is still in the on position after the tripping of the low-voltage switch waits for the delay fixed value time td, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails;

under the operation modes of 'the switch 1DL is in a hot standby state, the switch 2DL is in an operation state, the switch 4DL is in an overhaul state and the sectional switch 3DL is in an on position', if the conditions that three-phase voltages of a bus I M and a bus II M are all smaller than a non-voltage fixed value Uw, the current of the switch 1DL is in the hot standby state, the current of the switch 2DL is smaller than a non-current fixed value Iw and the current of the switch 4DL is in the overhaul state are simultaneously met, the second main transformer low-voltage first branch switch 2DL is jumped after the time delay fixed value time t1 is started, if the switch 2DL is in an off position in the low-voltage switch tripping waiting time delay fixed value time td, the first main transformer low-voltage switch 1DL is switched on after the time delay fixed value time t2 of the low-voltage switch, and the main transformer low-voltage; if the switch 2DL is still in the on position after the tripping of the low-voltage switch waits for the delay fixed value time td, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails;

under the operation modes of ' the switch 1DL is in a hot standby state, the switch 2DL is in an overhaul state, the switch 4DL is in an operation state and the sectional switch 3DL is in an on position ', if the conditions that three-phase voltages of a bus I M and a bus II M are all smaller than a non-voltage fixed value Uw, the switch 1DL is in the hot standby state, the switch 2DL is in the overhaul state and the current of the switch 4DL is smaller than a non-current fixed value Iw ' are simultaneously met, the second main transformer low-voltage switch 4DL is tripped after the starting delay fixed value time t1 of the 10kV main transformer backup power automatic switching, if the switch 4DL is in an off position in the low-voltage switch tripping waiting delay fixed value time td, the first main transformer low-voltage switch 1DL is switched on after the switching delay fixed value time t2 of the backup power automatic switching, and the main transformer backup power automatic switching action; if the switch 4DL is still in the on position after the tripping of the low-voltage switch waits for the delay fixed value time td, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails;

under the operation modes of ' the switch 1DL is in a hot standby state, the switch 2DL is in an operation state, the switch 4DL is in an operation state and the sectional switch 3DL is in an on position ', if the conditions that three-phase voltages of a bus I M and a bus II M are all smaller than a non-voltage fixed value Uw, the current of the switch 1DL is in a hot standby state, the current of the switch 2DL is smaller than a non-current fixed value Iw and the current of the switch 4DL is smaller than a non-current fixed value Iw ' are simultaneously met, the second main transformer becomes lower after the standby power automatic switching is started for a delayed fixed value time t1, the first main transformer becomes lower, the second main transformer becomes lower, the first main transformer becomes lower, the standby power automatic switching is switched after the delayed fixed value time t2, and the main transformer becomes lower power automatic switching is successful; if any one of the switch 2DL and the switch 4DL is still in the on position after the tripping of the low-voltage switch waits for the delay fixed value time td, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails;

under the operation modes of ' the switch 1DL is in a hot standby state, the switch 2DL is in an operation state, the switch 4DL is in a hot standby state and the sectional switch 3DL is in an on position ', if the conditions that three-phase voltages of a bus I M and a bus II M are all smaller than a non-voltage fixed value Uw, the switch 1DL is in a hot standby state, the current of the switch 2DL is smaller than a non-current fixed value Iw and the switch 4DL is in a hot standby state ' are simultaneously met, the second main transformer becomes the first branch switch 2DL and the second branch switch 4DL after the standby automatic switching of 10kV is started for a delay fixed value time t1, if the main transformers 2DL and the switch 4DL are in an off position in a delay fixed value time td for the tripping of the main transformers, the first main transformer becomes the low switch 1DL is switched after a switching-on delay fixed value time t2, and the standby automatic switching action succeeds; if any one of the switch 2DL and the switch 4DL is still in the on position after the tripping of the low-voltage switch waits for the delay fixed value time td, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails;

8. The method for realizing the main transformer automatic backup power switching adapting to the change of the operation mode of the 10kV bus according to claim 7, wherein when the connection mode of the 10kV bus is a single-bus single-section two-section bus and one section of the bus is a connection mode of a double branch incoming line, a second main transformer and a third main transformer are put into operation, the first main transformer is not put into operation, the main transformer automatic backup power switching is charged, and the main transformer automatic backup power switching operation conditions and the operation logic comprise:

under the operation mode of 'the switch 5DL is in an operation state, the switch 2DL is in a hot standby state, the switch 4DL is in an overhaul state and the sectional switch 6DL is in an on position', if the conditions that 'the three-phase voltages of the bus III M and the bus II M are both smaller than a non-voltage fixed value Uw, the current of the switch 5DL is smaller than a non-current fixed value Iw, the switch 2DL is in the hot standby state and the switch 4DL is in the overhaul state' are simultaneously met, the third main transformer step-down switch 5DL is tripped after the starting delay fixed value time t1 of the 10kV main transformer backup automatic switching, if the switch 5DL is in an off position within the delay fixed value time td of the trip of the step-down switch, the second main transformer step-down first branch switch 2DL is switched after the switching-on delay fixed value time t2 of the backup automatic switching, and the main; if the switch 5DL is still in the on position after the tripping of the low-voltage switch waits for the delay fixed value time td, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails;

under the operation mode of 'the switch 5DL is in an operation state, the switch 2DL is in an overhaul state, the switch 4DL is in a hot standby state and the sectional switch 6DL is in an on position', if the conditions that 'the three-phase voltages of the bus III M and the bus II M are both smaller than a non-voltage fixed value Uw, the current of the switch 5DL is smaller than a non-current fixed value Iw, the switch 2DL is in the overhaul state and the switch 4DL is in the hot standby state' are simultaneously met, the third main transformer low-voltage switch 5DL is tripped after the starting delay fixed value time t1, if the switch 5DL is in an off position in the low-voltage switch tripping waiting delay fixed value time td, the second main transformer low-voltage second branch switch 4DL is switched after the closing delay fixed value time t2 of the low-voltage switch, and the main transformer low-voltage automatic switching action is successful; if the switch 5DL is still in the on position after the tripping of the low-voltage switch waits for the delay fixed value time td, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails;

under the operation mode of 'the switch 5DL is in an operation state, the switch 2DL is in a hot standby state, the switch 4DL is in a hot standby state and the sectional switch 6DL is in an on position', if the conditions that 'three-phase voltages of a bus III M and a bus II M are both smaller than a non-voltage fixed value Uw, the current of the switch 5DL is smaller than a non-current fixed value Iw, the switch 2DL is in a hot standby state and the switch 4DL is in a hot standby state' are simultaneously met, the third main transformer low-voltage switch 5DL is jumped after the time delay fixed value time t1 of starting of the 10kV main transformer low-voltage automatic switching, and if the switch 5DL is in an off position in the time delay fixed value time td of waiting for the trip of the low-voltage switch, the first branch switch 2DL and the second branch switch 4DL of the second main transformer are switched after the time delay fixed value time t2 of the switching of; if the switch 5DL is still in the on position after the tripping of the low-voltage switch waits for the delay fixed value time td, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails;

under the operation modes of ' the switch 5DL is in a hot standby state, the switch 2DL is in an operation state, the switch 4DL is in an overhaul state and the sectional switch 6DL is in an on position ', if the conditions that three-phase voltages of a bus III M and a bus II M are all smaller than a non-voltage fixed value Uw, the switch 5DL is in the hot standby state, the current of the switch 2DL is smaller than a non-current fixed value Iw and the switch 4DL is in the overhaul state ' are simultaneously met, the second main transformer low-voltage first branch switch 2DL is jumped after the time delay fixed value t1 is started for the 10kV main transformer low-voltage backup automatic switching, and if the switch 2DL is in an off position in the time delay fixed value td waiting for the low-voltage switch tripping, the third main transformer low-voltage switch 5DL is switched after the time delay fixed value t2 for the low-voltage backup switching; if the switch 2DL is still in the on position after the tripping of the low-voltage switch waits for the delay fixed value time td, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails;

under the operation modes of ' the switch 5DL is in a hot standby state, the switch 2DL is in an overhaul state, the switch 4DL is in an operation state and the sectional switch 6DL is in an on position ', if the conditions that three-phase voltages of a bus III M and a bus II M are all smaller than a non-voltage fixed value Uw, the switch 5DL is in the hot standby state, the switch 2DL is in the overhaul state and the current of the switch 4DL is smaller than a non-current fixed value Iw ' are simultaneously met, the second main transformer low-voltage switch 4DL is jumped after the starting delay fixed value time t1 of the 10kV main transformer backup power automatic switching, if the switch 4DL is in an off position in the low-voltage switch tripping waiting delay fixed value time td, the third main transformer low-voltage switch 5DL is switched on after the switching delay fixed value time t2 of the backup power automatic switching, and the main transformer backup power automatic switching; if the switch 4DL is still in the on position after the tripping of the low-voltage switch waits for the delay fixed value time td, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails;

under the operation modes of ' the switch 5DL is in a hot standby state, the switch 2DL is in an operation state, the switch 4DL is in an operation state and the sectional switch 6DL is in an on position ', if the conditions that three-phase voltages of a bus III M and a bus II M are all smaller than a non-voltage fixed value Uw, the current of the switch 5DL is in a hot standby state, the current of the switch 2DL is smaller than a non-current fixed value Iw and the current of the switch 4DL is smaller than a non-current fixed value Iw ' are simultaneously met, the second main transformer becomes lower by jumping the first branch switch 2DL and the second branch switch 4DL after the 10kV main transformer automatic switching is started for a delay fixed value time t1, and if the switch 2DL and the switch 4DL are in an off position in a standby main transformer trip waiting delay fixed value time td, the third main transformer automatic switching becomes lower by switching on the delay fixed value time t2, and the main transformer automatic switching action succeeds; if any one of the switch 2DL and the switch 4DL is still in the on position after the tripping of the low-voltage switch waits for the delay fixed value time td, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails;

under the operation modes of ' the switch 5DL is in a hot standby state, the switch 2DL is in an operation state, the switch 4DL is in a hot standby state and the sectional switch 6DL is in an on position ', if the conditions that three-phase voltages of a bus III M and a bus II M are all smaller than a non-voltage fixed value Uw, the switch 5DL is in a hot standby state, the current of the switch 2DL is smaller than a non-current fixed value Iw and the switch 4DL is in a hot standby state ' are simultaneously met, the second main transformer becomes the first branch switch 2DL and the second branch switch 4DL after the standby automatic switching of 10kV is started for a delay fixed value time t1, if the main transformers 2DL and the switch 4DL are in an off position in a delay fixed value time td for the tripping of the main transformers, the third main transformer becomes the low switch 5DL is switched after a switching-on delay fixed value time t2, and the standby automatic switching action succeeds; if any one of the switch 2DL and the switch 4DL is still in the on position after the tripping of the low-voltage switch waits for the delay fixed value time td, the main transformer spare power automatic switching discharges and returns, and the main transformer spare power automatic switching action fails;

9. The method for realizing the main transformer automatic backup power switching adaptive to the change of the operation mode of the 10kV bus according to claim 6, wherein when the connection mode of the 10kV bus is a connection mode of a single-bus double-section four-section bus, a first main transformer, a second main transformer and a third main transformer are all operated, a bus II AM is not communicated with a bus II BM, the main transformer automatic backup power switching finishes charging, and the main transformer automatic backup power switching operation conditions and the operation logic comprise: the main transformer spare power automatic switching function is characterized in that the first main transformer and the second main transformer are mutually standby main transformers, and the second main transformer and the third main transformer are mutually standby main transformers.

10. The method for realizing the main transformer spare power automatic switching adapting to the change of the operation mode of the 10kV bus according to claim 7 or 8, wherein the switch in the operation state meets the following requirements: when the maintenance pressing plate corresponding to the switch is in an exit state, the switch is in a closed position or the switch current is greater than or equal to a current constant value Iy;