CN111123172B

CN111123172B - Consistency checking method for polarity of each interval CT secondary winding of bus differential protection

Info

Publication number: CN111123172B
Application number: CN201911363219.7A
Authority: CN
Inventors: 乔中伟; 钱敏; 王世祥; 谷斌; 苏靖
Original assignee: Shenzhen Power Supply Co ltd
Current assignee: Shenzhen Power Supply Co ltd
Priority date: 2019-12-26
Filing date: 2019-12-26
Publication date: 2022-01-25
Anticipated expiration: 2039-12-26
Also published as: CN111123172A

Abstract

The invention provides a method for checking the consistency of the polarity of each interval CT secondary winding of bus differential protection, which is realized in bus protection configured in a double-bus wiring substation. The method comprises selecting an outgoing line interval as an interval to be checked, and disconnecting the bus-coupled interval from the double buses; controlling the switches on the reference interval and the outgoing line interval to be switched on or switched off to realize the conduction of the reference interval and the outgoing line interval with the same bus; controlling the grounding knife connected with the reference interval to be closed, outputting primary current through the current generator to truly simulate the secondary current condition of primary equipment after load, and if the bus protection large difference and the single bus small difference are both detected to be 0, the polarity of the CT secondary winding on the same phase of the reference interval and the outlet interval is consistent; otherwise, they are not consistent. By implementing the method, the secondary current condition of the primary equipment after being loaded is truly simulated by a primary current rising method, and the polarity consistency of the secondary windings of the CT at intervals of the protection of the accessed bus is ensured.

Description

Consistency checking method for polarity of each interval CT secondary winding of bus differential protection

Technical Field

The invention relates to the technical field of substation relay protection tests, in particular to a method for verifying the consistency of the polarity of each interval CT secondary winding of bus differential protection.

Background

The bus is a key device of the transformer substation, the bus differential protection is used as the main protection of the bus, and both misoperation and refusal of the bus can cause immeasurable influence on the transformer substation and even the whole power grid, and the stable operation of the power grid is seriously influenced. According to the constitution principle of the bus differential protection, the key factor influencing the correct action of the bus protection is the correctness of the connection of each interval CT secondary circuit accessed into the bus differential protection, and the key factor determining the correctness of the connection of the CT secondary circuit is the consistency of the polarity of each interval CT secondary winding accessed into the bus differential protection. Therefore, in the checking and accepting work of the infrastructure substation, the checking of the consistency of the polarity of each interval CT secondary winding of the bus differential protection is an extremely important work.

The traditional method for checking the consistency of the polarity of each interval CT secondary winding of the bus differential protection is to check whether the polarity of each interval CT secondary winding is consistent with a CT nameplate or not and then check whether the secondary circuit of each access interval is normal or not one by one in a secondary current rising mode. However, the consistency check method is inefficient and not intuitive, and in addition, the real situation of the equipment after loading cannot be simulated.

Therefore, there is a need for a method for checking the polarity consistency of the secondary windings of the CT intervals of the bus differential protection, which can ensure the polarity consistency of the secondary windings of the CT intervals of the access bus protection by truly simulating the secondary current condition of the loaded primary equipment in the checking and accepting stage, and effectively avoid the phenomenon that the polarity consistency of the secondary windings of the CT intervals of the access bus protection cannot be judged due to the fact that the loaded primary equipment cannot be effectively loaded by new commissioning equipment, and further the large-range power failure fault of the power grid may be caused.

Disclosure of Invention

The technical problem to be solved by the embodiments of the present invention is to provide a method for checking the consistency of the polarities of every interval CT secondary winding of bus differential protection, which can truly simulate the secondary current situation of a primary device after being loaded by a primary current rising method, and ensure the consistency of the polarities of every interval CT secondary winding of an access bus protection, thereby effectively avoiding the occurrence of a phenomenon that the consistency of the secondary winding polarities of an access bus protection CT cannot be judged due to the fact that a new commissioning device cannot be loaded effectively, and further causing a large-scale power failure fault of a power grid.

In order to solve the above technical problem, an embodiment of the present invention provides a method for checking the consistency of polarities of every interval CT secondary winding of bus differential protection, which is implemented in bus protection configured in a double-bus connection substation; wherein,

a reference interval, an outgoing line interval and a bus connection interval are formed on the bus protection configured on the double-bus wiring substation;

one end of the reference interval is correspondingly connected with the double buses through two first knife switches respectively, and the other end of the reference interval is connected with a current generator in the bus protection screen through one of ABC three phases of a ground knife in the bus protection screen and then is grounded;

one end of the outgoing line interval is correspondingly connected with the double buses through two second disconnecting links respectively, and the other end of the outgoing line interval is connected with the other grounding switch which is used for grounding the ABC three phases in the bus protection screen;

one end of the bus-tie interval is connected with one of the double buses through a third disconnecting link, and the other end of the bus-tie interval is connected with the other of the double buses through another third disconnecting link and is also directly connected into the bus protection screen;

the method comprises the following steps:

selecting the outgoing line interval as an interval to be verified, and disconnecting two third disconnecting links on the bus coupling interval from the double buses;

controlling one of the two first knife switches on the reference interval to be closed and the other to be opened, and controlling one of the second knife switches on the outgoing line interval to be closed and the other to be opened, so that the reference interval and the outgoing line interval are communicated with the same bus;

controlling the grounding knife connected with the reference interval to be closed, outputting primary current through the current generator, and obtaining a bus protection large difference and a single bus small difference formed by phase angles of the secondary current of the reference interval and the outgoing line interval in the bus protection screen after truly simulating the secondary current condition of primary equipment after load, and further judging that the polarities of CT secondary windings of the reference interval and the outgoing line interval on the connection of the grounding knife ABC three phases corresponding to the current generator are consistent if the obtained bus protection large difference and the obtained single bus small difference are both 0; otherwise, the polarity of the CT secondary windings of the reference interval and the outlet interval on the phase connected with the three phases ABC corresponding to the current generator is judged to be inconsistent.

Wherein the method further comprises:

sequentially adjusting the current generator to be correspondingly connected with three phases of the grounding knife ABC and controlling the grounding knife connected with the current generator to be closed, outputting primary current through the current generator in sequence, really simulating the secondary current condition of primary equipment after load, obtaining a bus protection large difference and a single bus small difference formed by phase angles of the secondary current of the reference interval and the outgoing line interval in the bus protection screen after each adjustment, and further judging that the polarities of CT secondary windings of the reference interval and the outgoing line interval are consistent if all the bus protection large differences and the single bus small differences are 0; otherwise, the polarity of the CT secondary windings of the reference interval and the outgoing line interval is judged to be inconsistent.

Wherein the method further comprises:

after the reference interval and the outgoing line interval are judged to be consistent in the polarity of the CT secondary winding connected with the three phases of the grounding switch ABC corresponding to the current generator, selecting the bus connection interval as an interval to be checked;

controlling one of the two first disconnecting switches on the reference interval to be closed, the other one of the two first disconnecting switches on the reference interval to be opened, controlling one of the second disconnecting switches on the outgoing line interval to be closed, the other one of the two first disconnecting switches on the outgoing line interval to be opened, further closing the connection between the two third disconnecting switches on the bus coupling interval and the double buses, and realizing the connection and conduction of the reference interval, the bus coupling interval and the outgoing line interval through the double buses;

controlling the grounding knife connected with the reference interval to be closed, outputting primary current through the current generator, really simulating the secondary current condition of primary equipment after load, obtaining a bus protection large difference and a double-bus small difference formed by phase angles of the secondary current of the reference interval, the outgoing line interval and the bus connection interval in the bus protection screen, and further judging that the polarities of CT secondary windings of the reference interval, the outgoing line interval and the bus connection interval on the phase connected with the grounding knife ABC corresponding to the current generator are consistent if the obtained bus protection large difference and the double-bus small difference are all 0; otherwise, the polarity of the CT secondary windings of the reference interval, the outgoing line interval and the bus connection interval on the phase connected with the corresponding grounding switch ABC of the current generator is judged to be inconsistent.

Wherein the method further comprises:

sequentially adjusting the current generator to be correspondingly connected with three phases of the grounding knife ABC and controlling the grounding knife connected with the current generator to be closed, after the current generator sequentially outputs primary current, truly simulating the secondary current condition of primary equipment after load, obtaining a bus protection large difference and a double-bus small difference formed by phase angles of the secondary current of the reference interval, the outgoing line interval and the bus-coupled interval in the bus protection screen, wherein the phase angles of the secondary current of the reference interval, the outgoing line interval and the bus-coupled interval are adjusted each time, and further judging that the polarities of CT secondary windings of the reference interval, the outgoing line interval and the bus-coupled interval are consistent if all the obtained bus protection large differences and the double-bus small differences are 0; otherwise, the polarity of the CT secondary windings of the reference interval, the outgoing line interval and the bus-tie interval is judged to be inconsistent.

The embodiment of the invention also provides a method for checking the consistency of the polarity of each interval CT secondary winding of the bus differential protection, which is realized in the bus protection configured in the transformer substation in a double-bus-section wiring mode; wherein,

a reference interval, a subsection interval, an adjacent bus outgoing line interval and an adjacent bus-bar connection interval are formed on the bus protection configured on the double-bus subsection connection transformer substation;

one end of the reference interval is correspondingly connected with the first group of double buses through two first knife switches respectively, and the other end of the reference interval is connected with a current generator in the first bus protection screen through one of ABC three phases of a ground knife in the first bus protection screen and then grounded;

one end of the adjacent bus outgoing line interval is correspondingly connected with a second group of double buses through two second disconnecting links, and the other end of the adjacent bus outgoing line interval is connected with a grounding switch which is used for grounding ABC three phases in a second bus protection screen;

two ends of the subsection interval are respectively provided with two third disconnecting switches, the two third disconnecting switches are bridged between one bus in the first group of double buses and one bus in the second group of double buses, one end facing the first group of double buses is also directly connected into the second bus protection screen, and one end facing the second group of double buses is also directly connected into the first bus protection screen;

one end of the adjacent bus busbar connection interval is connected with one of the second group of double buses through a fourth disconnecting link, and the other end of the adjacent bus busbar connection interval is connected with the other of the second group of double buses through another fourth disconnecting link and is also directly connected into the second bus protection screen;

the method comprises the following steps:

selecting the section interval as an interval to be checked, and disconnecting two fourth disconnecting switches on the adjacent bus-bar connection interval from the second group of double buses;

controlling one of the two first knife switches on the reference interval to be closed, controlling the other one of the two first knife switches on the reference interval to be opened, controlling both the two third knife switches on the sectional interval to be closed, and controlling one of the second knife switches on the adjacent bus outgoing line interval to be closed and the other one of the two third knife switches on the adjacent bus outgoing line interval to be opened, so that the reference interval, the sectional interval and the adjacent bus outgoing line interval are conducted;

controlling the grounding knife connected with the reference interval to be closed, outputting a primary current through the current generator, really simulating the secondary current condition of primary equipment after loading, obtaining a bus protection large difference and a single bus small difference formed by phase angles of the secondary currents of the reference interval and the sectional intervals in the first bus protection screen, obtaining a bus protection large difference and a single bus small difference formed by phase angles of the secondary currents of the sectional intervals and the adjacent bus outgoing line intervals in the second bus protection screen, and further judging that the polarities of CT secondary windings of the reference interval, the sectional intervals and the adjacent bus outgoing line intervals on the phase connected with the grounding knife ABC corresponding to the current generator are consistent if all the bus protection large differences and the single bus small differences are 0; otherwise, the reference interval, the subsection interval and the adjacent bus outgoing line interval are judged to be inconsistent in the polarity of the CT secondary winding connected with the three phases of the grounding switch ABC corresponding to the current generator.

Wherein the method further comprises:

sequentially adjusting the current generator to be correspondingly connected with the grounding switch ABC and controlling the grounding switch connected with the current generator to be closed, after the primary current is output by the current generator in sequence and the secondary current condition of the primary equipment after load is truly simulated, obtaining a bus protection large difference and a single bus small difference formed by phase angles of the secondary currents of the reference interval and the subsection interval in each adjustment in the first bus protection screen, and obtaining the bus protection large difference and the single bus small difference formed by adjusting the phase angle of the secondary current of the subsection interval and the adjacent bus outgoing line interval each time in the second bus protection screen, and further if all the obtained bus protection large differences and the obtained single bus small differences are 0, judging that the polarities of the CT secondary windings of the reference interval, the subsection interval and the adjacent bus outgoing line interval are consistent; otherwise, the polarities of the CT secondary windings of the reference interval, the subsection interval and the adjacent bus outgoing line interval are judged to be inconsistent.

Wherein the method further comprises:

after the reference interval, the subsection interval and the adjacent bus outgoing line interval are judged to be consistent in the polarity of the CT secondary winding connected with the three phases of the grounding switch ABC corresponding to the current generator, the adjacent bus connection interval is selected as an interval to be verified;

controlling one of the two first disconnecting switches on the reference interval to be closed, controlling the other one of the two first disconnecting switches on the reference interval to be opened, controlling both the two third disconnecting switches on the subsection interval to be closed, controlling one of the second disconnecting switches on the adjacent bus outgoing line interval to be closed, and controlling the other one of the second disconnecting switches on the adjacent bus buscouple interval to be opened, and controlling the two fourth disconnecting switches on the adjacent bus buscouple interval to be closed, so that the reference interval, the subsection interval, the adjacent bus outgoing line interval and the adjacent bus buscouple interval are connected and conducted through a first group of double buses and a second group of double buses;

controlling the ground knife connected with the reference interval to be closed, outputting primary current through the current generator, and after truly simulating the secondary current condition of primary equipment after loading, obtaining a bus protection large difference and a single bus small difference formed by phase angles of the secondary currents of the reference interval and the subsection interval in the first bus protection screen, and obtaining a bus protection large difference and a double-bus small difference formed by the phase angles of the secondary currents of the subsection intervals, the adjacent bus outlet intervals and the adjacent bus-bar connection intervals in the second bus protection screen, and further if all the bus protection large differences, the single bus small differences and the double bus small differences are 0, judging that the polarities of the CT secondary windings of the reference interval, the subsection interval, the adjacent bus outlet interval and the adjacent bus coupler interval on the phase connected by the three phases ABC corresponding to the current generator are consistent; otherwise, the polarities of the CT secondary windings of the reference interval, the subsection interval, the adjacent bus outgoing line interval and the adjacent bus connection interval on the phase connected by the three phases ABC corresponding to the current generator are judged to be inconsistent.

Wherein the method further comprises:

sequentially adjusting the current generator to correspond to and control the grounding knife connected with the current generator to be closed, after the current generator outputs primary current in sequence and truly simulates the secondary current condition of primary equipment after load is carried out, obtaining a bus protection large difference and a single bus small difference formed by phase angles of the secondary current of the reference interval and the subsection interval in each adjustment in the first bus protection screen, obtaining a bus protection large difference and a double bus small difference formed by the subsection interval, the adjacent bus outlet interval and the phase angle of the secondary current of the adjacent bus coupler interval in each adjustment in the second bus protection screen, and further judging the reference interval, the subsection interval if all the bus protection large differences, the single bus small difference and the double bus small differences are 0, The polarities of the CT secondary windings of the adjacent bus outgoing line interval and the adjacent bus connection interval are consistent; otherwise, the polarities of the CT secondary windings of the reference interval, the subsection interval, the adjacent bus outlet interval and the adjacent bus connection interval are judged to be inconsistent.

The double-bus small difference formed by the phase angles of the secondary currents of the subsection interval, the adjacent bus outlet interval and the adjacent bus coupling interval is obtained in the second bus protection screen, and comprises a bus small difference of one bus in a second group of buses formed by the phase angles of the secondary currents of the subsection interval and the adjacent bus outlet interval and a bus small difference of the other bus in the second group of buses formed by the phase angles of the secondary currents of the adjacent bus outlet interval and the adjacent bus coupling interval.

The embodiment of the invention has the following beneficial effects:

the invention can truly simulate the secondary current condition of primary equipment after being loaded by a primary current rising method and ensure the consistency of the polarity of the CT secondary windings at intervals of the protection of the accessed bus, thereby effectively avoiding the phenomenon that the consistency of the secondary winding polarity of the CT secondary windings of the protection of the accessed bus cannot be judged because new operation equipment cannot be loaded effectively, and further causing the large-scale power failure fault of the power grid.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is within the scope of the present invention for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

Fig. 1 is a flowchart of a method for checking consistency of polarities of every interval CT secondary winding of bus differential protection according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a bus protection system configured in a dual bus connection substation in a method for checking consistency of polarities of respective interval CT secondary windings of bus differential protection according to an embodiment of the present invention;

FIG. 3 is a diagram of an exemplary implementation of FIG. 2;

FIG. 4 is a diagram of another embodiment of FIG. 2;

fig. 5 is a flowchart of a method for checking consistency of polarities of every interval CT secondary winding of bus differential protection according to a second embodiment of the present invention;

fig. 6 is a schematic structural diagram of a bus protection system configured in a dual bus segment connection substation in the method for checking the polarity consistency of the polarities of the respective interval CT secondary windings of the bus differential protection according to the second embodiment of the present invention;

FIG. 7 is a diagram illustrating an exemplary implementation scenario of FIG. 6;

fig. 8 is a diagram of another specific application scenario of fig. 6.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.

As shown in fig. 1, a method for checking the consistency of the polarity of each interval CT secondary winding of bus differential protection according to a first embodiment of the present invention is implemented in bus protection configured in a dual bus connection substation; wherein,

as shown in fig. 2, a reference interval 1, an outgoing line interval 2 and a bus-tie interval 3 are formed on the bus protection configured in the double bus-connection substation;

one end of the reference interval 1 is correspondingly connected with double buses (such as 1M and 2M) through two first knife gates 11 respectively, and the other end of the reference interval is connected with a current generator I (such as a current rising instrument) in a bus protection screen (such as a 1M and 2M bus protection device protection screen) through a certain phase (such as an A phase) in ABC three phases of a ground knife 12 in the bus protection screen and then is grounded;

one end of the outgoing line interval 2 is correspondingly connected with the double buses (such as 1M and 2M) through two second disconnecting links 21 respectively, and the other end of the outgoing line interval is connected with another grounding switch 22 which is in the bus protection screen (such as the 1M and 2M bus protection device protection screen) and is grounded at the ABC three phases;

one end of the bus-tie interval 3 is connected with one (such as 1M) of the double buses through a third disconnecting link 31, and the other end of the bus-tie interval is connected with the other (such as 2M) of the double buses through another third disconnecting link 31 and is also directly connected into a bus protection screen (such as a 1M and 2M bus protection device protection screen);

the method comprises the following steps:

step S11, selecting the outgoing line interval as an interval to be verified, and disconnecting two third disconnecting links on the bus connection interval from the double buses;

step S12, controlling one of the two first knife switches on the reference interval to be closed and the other to be opened, and controlling one of the second knife switches on the outgoing line interval to be closed and the other to be opened, so as to realize that the reference interval and the outgoing line interval are communicated with the same bus;

step S13, controlling the grounding knife connected with the reference interval to be closed, outputting a primary current through the current generator, and after the secondary current condition of primary equipment after loading is truly simulated, obtaining a bus protection large difference and a single bus small difference formed by phase angles of the secondary currents of the reference interval and the outgoing line interval in the bus protection screen, and further judging that the polarities of the CT secondary windings of the reference interval and the outgoing line interval on the phase connected with the three phases ABC of the grounding knife corresponding to the current generator are consistent if the obtained bus protection large difference and the obtained single bus small difference are both 0; otherwise, the polarity of the CT secondary windings of the reference interval and the outlet interval on the phase connected with the three phases ABC corresponding to the current generator is judged to be inconsistent.

Specifically, before step S11, a reference interval is selected, and an up-flow operation is ready, taking phase a as an example. It should be noted that the polarity of the CT secondary winding of the reference bay access bus protection is confirmed as correctly wired by the single bay polarity test and the secondary loop check.

In step S11, the outgoing line interval is selected as the interval to be verified, and the bus tie interval is disconnected and connected to the double bus.

In step S12, determining that the outgoing line interval is connected to the bus protection CT secondary winding polarity check primary up-flow connection, so that the reference interval and the outgoing line interval are conducted with the same bus to form a passage; for example, the reference interval and the outgoing line interval are connected into the 1M bus, and the current generator I is connected into the phase a of the grounding knife 12 connected with the reference interval.

In step S13, first, the grounding switch 12 connected to the current generator I is closed, and the current generator I outputs a primary current (the current value can reach 200A) to truly simulate the secondary current condition of the primary device after being loaded; then, secondary currents (phase currents) of a reference interval and an outgoing line interval are obtained in a bus protection screen (such as a 1M bus protection device protection screen and a 2M bus protection device protection screen), and a bus protection large difference (such as a 1M bus protection large difference and a 2M bus protection large difference) and a single bus small difference (such as a 1M bus small difference when the reference interval is connected to 1M) are formed according to phase angles of the secondary currents of the reference interval and the outgoing line interval; finally, if the obtained bus protection large difference and the single bus small difference are both 0, the polarities of the CT secondary windings of the reference interval and the outlet interval on the ABC three-phase connected phase (A phase) of the grounding knife 12 corresponding to the current generator I are judged to be consistent; on the contrary, if only one of the obtained bus protection large difference and the single bus small difference is not 0, the polarities of the CT secondary windings of the reference interval and the outgoing line interval on the phase (phase a) connected with the ABC three phases of the grounding switch 12 corresponding to the current generator I are judged to be inconsistent.

In one embodiment, the phase angle of the reference interval phase current I1 is I1 ═ Im 0, and the phase angle of the outgoing line interval secondary current I2 is I2 ═ Im 180, so that the 1M, 2M bus protection large difference Id ═ I1+ I2 and the 1M small difference Id1 ═ I1+ I2.

In the first embodiment of the present invention, since the polarity of the CT secondary winding needs to verify the ABC three phases, after the phase (a phase) connected to the ABC three phases of the blade 12 corresponding to the current generator I needs to be detached, the other unverified phases are connected, and then the steps S12 and S13 are repeated until the ABC three-phase verification is completed. Accordingly, the method further comprises:

sequentially adjusting the current generator to be correspondingly connected with the grounding knife ABC three phases and controlling the grounding knife connected with the current generator to be closed, outputting primary current through the current generator in sequence, really simulating the secondary current condition of primary equipment after load, obtaining a bus protection large difference and a single bus small difference formed by phase angles of secondary current of a reference interval and an outgoing line interval in a bus protection screen, and further judging that the polarities of CT secondary windings of the reference interval and the outgoing line interval are consistent if all the bus protection large differences and the single bus small differences are 0; otherwise, the polarities of the CT secondary windings of the reference interval and the outgoing line interval are judged to be inconsistent.

The specific process is that the current generator I is adjusted to correspond to the phase (such as phase B) connected with the ABC three phases of the grounding knife 12, primary current (the current value can reach 200A) is output through the current generator I, after the secondary current condition of a primary device after load is truly simulated, a bus protection large difference and a single bus small difference formed by phase angles of the secondary current of a reference interval and an outgoing line interval are obtained in a bus protection screen, and further if all the bus protection large differences and the single bus small differences are 0, the polarity of CT secondary windings of the reference interval and the outgoing line interval on the phase (phase B) connected with the ABC three phases of the grounding knife 12 corresponding to the current generator I is judged to be consistent; on the contrary, if only one of the obtained bus protection large difference and the single bus small difference is not 0, the polarities of the CT secondary windings of the reference interval and the outgoing line interval on the ABC three-phase connected phase (phase B) of the grounding knife 12 corresponding to the current generator I are judged to be inconsistent;

similarly, adjusting the phase (such as the phase C) connected by the ABC three phases of the current generator I corresponding to the ground knife 12, outputting a primary current (the current value can reach 200A) through the current generator I, truly simulating the secondary current condition of the primary equipment after loading, and judging whether the polarities of the CT secondary windings of the reference interval and the outlet interval on the phase (the phase C) connected by the ABC three phases of the ground knife 12 corresponding to the current generator I are the same;

finally, if all the bus protection large differences and the single bus small differences are 0 (obtained by respectively measuring A, B, C phases), judging that the polarities of the CT secondary windings of the reference interval and the outlet interval are consistent; otherwise, the polarities of the CT secondary windings of the reference interval and the outgoing line interval are judged to be inconsistent.

It can be understood that, for the consistency check method of the polarities of the secondary windings of the respective intervals CT of the bus differential protection in the bus protection configured in the single bus connection substation, the consistency check method is similar to the consistency check method of the polarities of the secondary windings of the respective intervals CT of the bus differential protection in the bus protection configured in the double bus connection substation in the first embodiment of the present invention, and details are not described here again.

As shown in fig. 3, an application scenario (at this time, a bus tie interval is not accessed) of polarity verification of the secondary winding of the bus differential protection in the bus protection configured in the double-bus connection substation according to the first embodiment of the present invention is further described in which the polarity of the secondary winding of the bus differential protection at the bus interval is accessed to the bus protection CT at the outgoing line interval by using the method for verifying the consistency of the polarity of the secondary winding at each interval (CT) of the bus differential protection:

a primary current path is formed through a 220kV1M bus, and a grounding end of 2201C0 ground knife A, B, C three phases is disconnected from a grounding copper bar, taking phase a as an example.

Prepare 1 current generator (current boost) and output current range: 0-300A, connecting the current output end of a current generator to the phase A grounding end of a 2201C0 grounding knife, connecting the current flow-back end of the current generator (a current rising instrument) to a grounding copper bar, closing a 2201 switch, a 22011 disconnecting link, a 2201C0 grounding knife, a 22021 disconnecting link, a 2202 switch and a 2202C0 grounding knife to form a current path, wherein the current passing method can simulate the passing of primary current through 2201 (reference interval) and 2202 (outgoing line interval), and the polarity of the CT secondary winding of the reference interval access bus protection is confirmed to be correct in wiring through single interval polarity test and secondary circuit check. Since the primary current flows through the

interval

2201 and 2202 in a penetrating manner, in the 220kV1M and 2M bus protection device, if the 2201 switch a phase current I1 is taken as a reference, I1 is equal to Im 0, the 2202 switch a phase current I2 should be equal to I2 equal to Im 180, so that the 220kV1M and 2M bus protection large difference Id is equal to I1+ I2 equal to 0 and the 1M small difference Id1 is equal to I1+ I2 equal to 0.

In the first embodiment of the invention, the single-phase polarity of the CT secondary winding at the outgoing line interval is successfully verified, and on the basis, the single-phase polarity of the CT secondary winding at the bus-tie interval can be verified. Therefore, in addition to repeating the above steps S11 to S13, the following steps are added:

step S14, after the reference interval and the outgoing line interval are judged to be consistent in the polarity of the CT secondary winding connected with the three phases ABC of the grounding switch corresponding to the current generator, selecting the bus connection interval as an interval to be checked;

step S15, controlling one of the two first switches on the reference interval to be closed and the other to be opened, controlling one of the second switches on the outgoing line interval to be closed and the other to be opened, and further closing the connection between the two third switches on the bus tie interval and the double buses, so as to realize the connection and conduction of the reference interval, the bus tie interval and the outgoing line interval through the double buses;

step S16, controlling the grounding knife connected with the reference interval to be closed, outputting a primary current through the current generator, really simulating the secondary current condition of primary equipment after loading, obtaining a bus protection big difference and a double-bus small difference formed by the reference interval, the outgoing line interval and the phase angle of the secondary current of the bus tie interval in the bus protection screen, and further judging that the CT secondary windings of the reference interval, the outgoing line interval and the bus tie interval on the phase connected with the grounding knife ABC corresponding to the current generator have consistent polarity if the obtained bus protection big difference and the double-bus small difference are all 0; otherwise, the polarity of the CT secondary windings of the reference interval, the outgoing line interval and the bus connection interval on the phase connected with the corresponding grounding switch ABC of the current generator is judged to be inconsistent.

The specific process is that please refer to the above contents in steps S11-S13, which are not described herein again. In step S14, after the polarity verification of the single-phase (e.g., a-phase) of the CT secondary winding based on the outgoing line interval is successful, the bus-coupled interval is selected as the interval to be verified.

In step S15, determining that the bus tie interval is connected to the bus protection CT secondary winding polarity check primary up-flow connection, so that the reference interval, the outgoing line interval and the bus tie interval are connected and conducted to form a passage through the double bus; for example, the reference interval is connected into a 1M bus, the bus-tie interval is bridged between the 1M bus and the 2M bus, and the outgoing line interval is connected into the 2M bus, at this time, the current generator I is connected into the a phase of the grounding knife 12 connected with the reference interval.

In step S16, first, the grounding switch 12 connected to the current generator I is closed, and the current generator I outputs a primary current (the current value can reach 200A) to truly simulate the secondary current condition of the primary device after being loaded; then, secondary currents (phase currents) of a reference interval, an outgoing line interval and a bus coupling interval are obtained in the bus protection screen, and a bus protection large difference (such as a 1M bus protection large difference and a 2M bus protection large difference) and a double-bus small difference (such as a 1M bus small difference and a 2M bus small difference) are formed according to phase angles of the reference interval, the outgoing line interval and the bus coupling interval secondary currents; finally, if the obtained bus protection large difference and the double-bus small difference are both 0, judging that the polarities of the CT secondary windings of the reference interval, the outgoing line interval and the bus tie interval on the ABC three-phase connected phase (phase A) of the current generator I corresponding to the grounding switch 12 are consistent; on the contrary, if only one of the obtained bus protection large difference and the single bus small difference is not 0, the polarity of the CT secondary windings of the reference interval, the outgoing line interval and the bus-tie interval on the ABC three-phase connected phase (phase a) of the current generator I corresponding to the grounding switch 12 is determined to be inconsistent.

In one embodiment, the phase angle of the reference interval phase current I1 is I1 ═ Im 0, the phase angle of the outgoing line interval secondary current I2 is I2 ═ Im 180, and the phase angle of the bus-coupled interval secondary current Iml is Iml ═ Im 0, so that 1M, 2M bus protection large difference Id ═ I1+ I2, 1M small difference Id1 ═ I1-Iml, and 2M small difference Id2 ═ I2+ Iml.

Similarly, in the first embodiment of the present invention, since the polarity of the CT secondary winding needs to verify the ABC three phases, after the phase (a phase) connected to the ABC three phases of the blade 12 corresponding to the current generator I needs to be detached, the other unverified phases are connected, and then the steps S12 to S16 are repeated until the ABC three-phase verification is completed. Accordingly, the method further comprises:

sequentially adjusting a current generator to be correspondingly connected with three phases of the grounding knife ABC and controlling the grounding knife connected with the current generator to be closed, outputting primary current through the current generator in sequence, really simulating the condition of secondary current of primary equipment after load, and then obtaining a bus protection large difference and a double-bus small difference which are formed by phase angles of the secondary current of a reference interval, an outgoing line interval and a bus-tie interval and are adjusted each time in a bus protection screen, and further judging that the polarities of CT secondary windings of the reference interval, the outgoing line interval and the bus-tie interval are consistent if all the bus protection large differences and the double-bus small differences are 0; otherwise, the polarities of the CT secondary windings of the reference interval, the outgoing line interval and the bus-tie interval are judged to be inconsistent.

It can be understood that, since the other two-phase polarity check of the bus-coupled interval CT secondary winding is similar to the other two-phase polarity check of the outgoing line interval CT secondary winding, the details are not repeated. Certainly, the checking of the other two-phase polarities of the bus-connected spaced CT secondary winding is optimal on the basis of the successful checking of the other two-phase polarities of the outgoing line spaced CT secondary winding, so that the situation that the other two-phase polarities of the outgoing line spaced CT secondary winding need to be checked again when the polarities are inconsistent in checking is avoided.

As shown in fig. 4, an application scenario (at this time, the bus tie interval is not accessed) of the bus differential protection CT secondary winding polarity check in the bus protection configured in the double bus connection substation according to the first embodiment of the present invention is further described in the method for checking the consistency of the polarities of the secondary windings of the respective intervals CT of the bus differential protection in the bus protection:

selecting a reference interval and an outgoing line interval which is subjected to polarity verification as an auxiliary test interval, wherein the auxiliary test interval comprises the following steps: 2201 (reference interval) and 2202 (outgoing line interval) are checked to be intervals with consistent polarity, 2201 is hung on 1M and 2202 is hung on 2M at intervals, and the grounding ends of 2201C0 grounding knife A, B, C three phases are detached from the grounding copper bar, taking phase A as an example.

The current outflow end of a current generator (a current rising instrument) is connected to the phase A ground end of a 2201C0 ground knife, the current outflow end of the current generator (the current rising instrument) is connected to a ground copper bar, the 2201C0 and 2201C0 ground knives are closed, the 2201, 2202 and 2012 switches are closed, the 22011, 20121, 20122 and 22022 knife switches are closed to form a current path, and the current passing method can simulate the passing of primary current through 2201 (reference interval), 2012 (bus tie interval) and 2202 (auxiliary test interval). Since the primary current flows through the bus protection device 220kV1M and 2M, if the switching a phase current I1 2201 is taken as a reference, i.e., I1 equals Im 0, the switching a phase current I2 2202 should be taken as I2 equals Im 180, and the switching a phase current (for example, with the polarity end facing 2M) Iml equals Im 0, so that the bus protection large difference Id 220kV1M and 2M is taken as I1+ I2 equals 0, the bus protection small difference Id1 equals I1-Iml equals 0, and the bus protection small difference Id2 equals I2+ Iml equals 0.

As shown in fig. 5, another method for checking the consistency of the polarity of the secondary winding of each interval CT of the bus differential protection provided in the second embodiment of the present invention is implemented in the bus protection configured in the substation in the form of dual bus segment connection; wherein,

as shown in fig. 6, a reference interval 1, a section interval 4, an adjacent bus outgoing line interval 2 and an adjacent bus coupler interval 3 are formed on the bus protection configured in the double-bus section wiring substation;

one end of a reference interval 1 is correspondingly connected with a first group of double buses (such as 1M and 2M) through two first knife gates 11 respectively, and the other end of the reference interval is connected with a current generator I (such as a current rising instrument) in a first bus protection screen (such as a 1M and 2M bus protection device protection screen) through a certain phase (such as an A phase) in ABC three phases of a ground knife 12 in the first bus protection screen (such as the 1M and 2M bus protection device protection screen) and then is grounded;

one end of the adjacent bus outgoing line interval 2 is correspondingly connected with a second group of double buses (such as 5M and 6M) through two second disconnecting links 21 respectively, and the other end is connected with a grounding switch 22 which is in ABC three-phase grounding in a second bus protection screen (such as 5M and 6M bus protection device protection screens);

two ends of the sectional partition 4 are respectively provided with two third disconnecting links 41, and the two third disconnecting links 41 are bridged between one bus (such as 1M or 2M) in the first group of double buses and one bus (such as 5M or 6M) in the second group of double buses, one end facing the first group of double buses is also directly connected into a second bus protection screen (such as a 5M or 6M bus protection device protection screen), and one end facing the second group of double buses is also directly connected into the first bus protection screen (such as a 1M or 2M bus protection device protection screen);

one end of the adjacent bus busbar interval 3 is connected with one (such as 5M) of the second group of double buses through a fourth knife switch 31, and the other end is connected with the other (such as 6M) of the second group of double buses through another fourth knife switch 31 and is also directly connected into a second bus protection screen (such as 5M and 6M bus protection device protection screens);

the method comprises the following steps:

step S21, selecting the section interval as an interval to be checked, and disconnecting two fourth disconnecting links on the adjacent bus coupler interval from the second group of double buses;

step S22, controlling one of the two first switches on the reference interval to be closed and the other to be opened, controlling both the two third switches on the sectional interval to be closed, and controlling one of the second switches on the adjacent bus outgoing line interval to be closed and the other to be opened, so as to realize the conduction of the reference interval, the sectional interval and the adjacent bus outgoing line interval;

step S23, controlling the grounding knife connected with the reference interval to be closed, outputting a primary current through the current generator, really simulating the secondary current condition of primary equipment after loading, obtaining a bus protection large difference and a single bus small difference formed by phase angles of the secondary currents of the reference interval and the sectional intervals in the first bus protection screen, obtaining a bus protection large difference and a single bus small difference formed by phase angles of the secondary currents of the sectional intervals and the adjacent bus outgoing line intervals in the second bus protection screen, and further judging that the polarities of CT secondary windings of the reference interval, the sectional intervals and the adjacent bus outgoing line intervals on a phase connected with the grounding knife ABC corresponding to the current generator are consistent if all the bus protection large differences and the single bus small differences are 0; otherwise, the reference interval, the subsection interval and the adjacent bus outgoing line interval are judged to be inconsistent in the polarity of the CT secondary winding connected with the three phases of the grounding switch ABC corresponding to the current generator.

Specifically, before step S21, a reference interval is selected, and an up-flow operation is ready, taking phase a as an example. It should be noted that the reference interval and the polarity of the CT secondary winding of the adjacent bus outgoing line interval access bus protection can be confirmed as the correct wiring through the single interval polarity test and the secondary loop check.

In step S21, the section interval is selected as the interval to be verified, and the connection between the two fourth disconnecting switches on the adjacent bus buscouple interval and the second group of double buses is disconnected.

In step S22, determining that the segment interval is accessed to the bus bar protection CT secondary winding polarity check primary up-flow connection line, so that the reference interval, the segment interval and the adjacent bus bar outgoing line interval are conducted to form a passage; for example, the reference interval is connected into the 1M bus, the segment interval is bridged between the 1M bus and the 5M bus, and the outgoing line interval of the adjacent bus is connected into the 5M bus, at this time, the current generator I is connected into the a phase of the grounding knife 12 connected with the reference interval.

In step S23, first, the grounding switch 12 connected to the current generator I is closed, and the current generator I outputs a primary current (the current value can reach 200A) to truly simulate the secondary current condition of the primary device after being loaded; then, a reference interval secondary current (such as phase current) and a subsection interval secondary current are obtained in a first bus protection screen (such as a 1M bus protection device protection screen and a 2M bus protection device protection screen), a bus protection large difference and a single bus small difference are formed according to phase angles of the reference interval secondary current and the subsection interval secondary current, a subsection interval secondary current (such as phase current) and an adjacent bus outgoing line interval secondary current are obtained in a second bus protection screen (such as a 5M bus protection device protection screen and a 6M bus protection device protection screen), and a bus protection large difference and a single bus small difference are formed according to the subsection interval secondary current phase angles and the adjacent bus outgoing line interval secondary current phase angles; finally, if all the bus protection large differences and the single bus small differences are 0, judging that the polarities of the CT secondary windings of the reference interval, the subsection interval and the adjacent bus outgoing line interval on the phase (such as A phase) connected with the ABC three phases corresponding to the current generator are consistent; otherwise, the reference interval, the subsection interval and the adjacent bus outlet interval are judged to be inconsistent in the polarity of the CT secondary winding on the phase (such as A phase) connected with the ABC three phases of the grounding switch corresponding to the current generator.

In one embodiment, in a 1M and 2M bus protection device protection screen, the phase angle of the reference interval phase current I1 is I1 ═ Im 0, and the phase angle of the segment interval phase current Ifd is Ifd ═ Im 180, so that 220kV1M and 2M bus protection large difference is Id ═ I1+ Ifd, and 1M small difference Id1 is I1+ Ifd; meanwhile, in the protection screen of the 5M and 6M busbar protection device, the phase angle of the subsection interval phase current Ifd is Ifd & ltim & gt 0, the phase angle of the adjacent busbar outgoing interval phase current I3 is I3 & ltim & gt 0, and then

220kV

5M and 6M busbar protection large difference Id & ltI 3+ Ifd, and 5M small difference Id5 & ltI 3+ Ifd.

In the second embodiment of the present invention, since the polarity of the CT secondary winding needs to verify the ABC three phases, after the phase (a phase) connected to the ABC three phases of the blade 12 corresponding to the current generator I needs to be detached, the other unverified phases are connected, and then the steps S22 and S23 are repeated until the ABC three-phase verification is completed. Accordingly, the method further comprises:

sequentially adjusting a current generator to be correspondingly connected with three phases of an earthing switch ABC and controlling the earthing switch connected with the current generator to be closed, outputting primary current through the current generator in sequence, really simulating the condition of secondary current after primary equipment is loaded, obtaining a bus protection large difference and a single bus small difference formed by phase angles of secondary current of a reference interval and a subsection interval in each adjustment in a first bus protection screen, obtaining a bus protection large difference and a single bus small difference formed by phase angles of the secondary current of the subsection interval and an adjacent bus outgoing line interval in each adjustment in a second bus protection screen, and further judging that the polarities of CT secondary windings of the reference interval, the subsection interval and the adjacent bus outgoing line interval are consistent if all the obtained bus protection large differences and the single bus small differences are 0; otherwise, the polarities of the CT secondary windings of the reference interval, the subsection interval and the adjacent bus outgoing line interval are judged to be inconsistent.

The specific process is that firstly, a current generator I is adjusted to correspond to the phase (such as phase B) connected with ABC three phases of the grounding knife 12, primary current (the current value can reach 200A) is output through the current generator I, after the secondary current condition of primary equipment after load is truly simulated, a bus protection large difference and a single bus small difference formed by phase angles of secondary current of reference intervals and sectional intervals are obtained in a first bus protection screen (such as a 1M bus protection device protection screen and a 2M bus protection device protection screen), and a bus protection large difference and a single bus small difference formed by phase angles of secondary current of sectional intervals and adjacent bus outlet intervals are obtained in a second bus protection screen (such as a 5M bus protection device protection screen and a 6M bus protection screen); secondly, if all the bus protection large differences and the single bus small differences are 0, judging that the polarities of CT secondary windings of the reference interval, the subsection interval and the adjacent bus outgoing line interval on the ABC three-phase connected phase (phase B) of the current generator I corresponding to the grounding switch 12 are consistent; on the contrary, if only one of the obtained bus protection large difference and the single bus small difference is not 0, the polarity of the CT secondary windings of the reference interval, the sectional interval and the adjacent bus outlet interval on the ABC three-phase connected phase (phase B) of the current generator I corresponding to the grounding switch 12 is judged to be inconsistent;

similarly, adjusting the phase (such as the C phase) connected by the ABC three phases of the current generator I corresponding to the ground knife 12, outputting a primary current (the current value can reach 200A) through the current generator I, truly simulating the secondary current condition of the primary equipment after loading, and judging whether the polarities of the CT secondary windings of the reference interval, the segmentation interval and the adjacent bus outgoing line interval of the three phases connected by the ABC three phases (the C phase) of the current generator I corresponding to the ground knife 12 are consistent;

finally, if all bus protection large differences and single bus small differences are 0 (obtained by respectively measuring A, B, C phases), judging that the polarities of the CT secondary windings of the reference interval, the subsection interval and the adjacent bus outgoing line interval are consistent; otherwise, the polarities of the CT secondary windings of the reference interval, the subsection interval and the adjacent bus outgoing line interval are judged to be inconsistent.

It can be understood that, for the consistency check method of the polarities of the CT secondary windings in each interval of the bus differential protection in the bus protection configured in the single bus segment connection substation, the consistency check method is similar to the consistency check method of the polarities of the CT secondary windings in each interval of the bus differential protection in the bus protection configured in the double bus segment connection substation in the second embodiment of the present invention, and details are not described here again.

As shown in fig. 7, an application scenario (at this time, adjacent bus buscouple intervals are not accessed) of polarity verification of a CT secondary winding of a bus differential protection in a sectionalized access bus protection according to the method for verifying consistency of polarities of each CT secondary winding of a bus differential protection in bus protection configured in a double-bus section wiring substation in the second embodiment of the present invention is further described:

grounding ends of 2201C0 ground blade A, B, C three phases are disconnected from the grounding copper bars, taking phase A as an example.

The current outflow end of a current generator (current rising instrument) is connected to the phase A grounding end of a 2201C0 ground blade, the current outflow end of the current generator (current rising instrument) is connected to a grounding copper bar, switches 2201, 2015 and 2203 are closed, switches 22011, 20151, 20156 and 22035 are closed, ground blades 2201C0 and 2203C0 are closed to form a current path, and the current flowing method can simulate that a one-time current passes through 2201(1M and 2M reference intervals), 2015(1M and 5M segment intervals) and 2203(5M and 6M auxiliary test intervals, namely adjacent bus outlet intervals).

Since the primary current flows in a penetrating manner.

Therefore, in the 220kV1M and 2M bus protection device, if the 2201 switch a phase current I1 is taken as a reference, i.e., I1 is equal to Im 0, then 2015 switch a phase current Ifd should be equal to Im 180, and if the large difference of 220kV1M and 2M bus protection is Id equal to I1+ Ifd, and the small difference of 1M Id1 is equal to I1+ Ifd;

in a

220kV

5M and 6M bus protection device, a 2015 switch A phase current Ifd should be Ifd equal to Im < 0, and a 2203 switch A phase current I3 equal to Im < 0, so that a

220kV

5M and 6M bus protection large difference Id is I3+ Ifd, and a 5M small difference Id5 is I3+ Ifd.

In the second embodiment of the invention, the single-phase polarity of the CT secondary winding at the sectional interval is successfully verified, and on the basis, the single-phase polarity of the CT secondary winding at the adjacent bus-bar connection interval can be verified. Therefore, in addition to repeating the above steps S21 to S23, the following steps are added:

step S24, after the reference interval, the subsection interval and the adjacent bus outgoing line interval are judged to be consistent in the polarity of the CT secondary winding connected with the current generator corresponding to the three phases ABC, the adjacent bus connection interval is selected as an interval to be verified;

step S25, controlling one of the two first switches on the reference interval to be closed and the other to be opened, controlling both the two third switches on the segment interval to be closed, controlling one of the second switches on the adjacent bus outgoing line interval to be closed and the other to be opened, and controlling two fourth switches on the adjacent bus buscouple interval to be closed, so as to realize that the reference interval, the segment interval, the adjacent bus outgoing line interval and the adjacent bus buscouple interval are connected and conducted through a first group of double buses and a second group of double buses;

step S26, controlling the earthing knife connected with the reference interval to close, and after the primary current is output by the current generator and the secondary current condition of the primary equipment after loading is truly simulated, obtaining a bus protection large difference and a single bus small difference formed by phase angles of the secondary currents of the reference interval and the subsection interval in the first bus protection screen, and obtaining a bus protection large difference and a double-bus small difference formed by the phase angles of the secondary currents of the subsection intervals, the adjacent bus outlet intervals and the adjacent bus-bar connection intervals in the second bus protection screen, and further if all the bus protection large differences, the single bus small differences and the double bus small differences are 0, judging that the polarities of the CT secondary windings of the reference interval, the subsection interval, the adjacent bus outlet interval and the adjacent bus coupler interval on the phase connected by the three phases ABC corresponding to the current generator are consistent; otherwise, the polarities of the CT secondary windings of the reference interval, the subsection interval, the adjacent bus outgoing line interval and the adjacent bus connection interval on the phase connected by the three phases ABC corresponding to the current generator are judged to be inconsistent.

The specific process is that please refer to the above contents in steps S21-S23, which are not described herein again. In step S24, after the polarity verification of the single-phase (e.g., a-phase) of the CT secondary winding based on the segment interval is successful, the adjacent bus bar bus-bar connection interval is selected as the interval to be verified.

In step S25, it is determined that the adjacent bus bar linkage interval is connected to the bus bar protection CT secondary winding polarity check primary up-flow connection line, so that the reference interval, the segment interval, the adjacent bus bar outgoing line interval and the adjacent bus bar linkage interval are connected and conducted to form a passage through the first group of double buses and the second group of double buses; for example, the reference interval is connected into the 1M bus, the segment interval is bridged between the 1M bus and the 5M bus, the outgoing line interval of the adjacent bus is bridged between the 5M bus and the 6M bus, and the outgoing line interval of the adjacent bus is connected into the 6M bus, at this time, the current generator I is connected into the a phase of the grounding knife 12 connected to the reference interval.

In step S26, first, the grounding switch 12 connected to the current generator I is closed, and the current generator I outputs a primary current (the current value can reach 200A) to truly simulate the secondary current condition of the primary device after being loaded; then, a reference interval secondary current (such as phase current) and a subsection interval secondary current are obtained in a first bus protection screen (such as a 1M bus protection device protection screen and a 2M bus protection device protection screen), a bus protection large difference and a single bus small difference are formed according to phase angles of the reference interval secondary current and the subsection interval secondary current, a subsection interval secondary current (such as phase current) and an adjacent bus busbar interval secondary current are obtained in a second bus protection screen (such as a 5M bus protection device protection screen and a 6M bus protection device protection screen), and a bus protection large difference and a double bus small difference are formed according to the subsection interval, an adjacent bus outlet interval and the phase angle of the adjacent bus busbar interval secondary current; finally, if all the bus protection large differences, the single bus small differences and the double bus small differences are 0, judging that the polarities of CT secondary windings of the reference interval, the subsection interval, the adjacent bus outgoing line interval and the adjacent bus coupler interval are consistent on a phase (such as an A phase) connected with the ABC three phases corresponding to the current generator; otherwise, the polarities of the CT secondary windings of the reference interval, the subsection interval, the adjacent bus outlet interval and the adjacent bus connection interval on the phase (such as A phase) connected with the ABC three phases corresponding to the current generator are judged to be inconsistent. The double-bus small difference formed by the phase angles of the secondary currents of the sectional interval, the outgoing line interval of the adjacent bus and the bus coupling interval of the adjacent bus is obtained in the second bus protection screen, and comprises a bus small difference of one bus (such as 5M) in the second group of buses formed by the phase angles of the secondary currents of the sectional interval and the outgoing line interval of the adjacent bus and a bus small difference of the other bus (such as 6M) in the second group of buses formed by the phase angles of the secondary currents of the outgoing line interval of the adjacent bus and the bus coupling interval of the adjacent bus.

In one embodiment, in a 1M and 2M bus protection device protection screen, the phase angle of the reference interval phase current I1 is I1 ═ Im 0, and the phase angle of the segment interval phase current Ifd is Ifd ═ Im 180, so that 220kV1M and 2M bus protection large difference is Id ═ I1+ Ifd, and 1M small difference Id1 is I1+ Ifd; meanwhile, in the protection screens of the 5M and 6M busbar protection devices, the phase angle of the subsection interval phase current Ifd is Ifd equal to Im 0, the phase angle of the adjacent busbar outlet interval phase current I3 is I3 equal to Im 0, the phase angle of the adjacent busbar inter-connection interval phase current Iml is Iml equal to Im 0, and then

220kV

5M and 6M busbar protection large difference Id equal to I3+ Ifd, 5M small difference Id5 equal to Ifd-Iml, and 6M small difference Id6 equal to I3+ Iml.

Similarly, in the second embodiment of the present invention, since the polarity of the secondary winding of the CT needs to verify the ABC three phases, after the phase (phase a) connected to the ABC three phases of the blade 12 corresponding to the current generator I needs to be detached, the other unverified phases are connected, and then the steps S12 to S16 are repeated until the ABC three-phase verification is completed. Accordingly, the method further comprises:

sequentially adjusting the current generator to be correspondingly connected with the grounding switch ABC and controlling the grounding switch connected with the current generator to be closed, after the primary current is output by the current generator in sequence and the secondary current condition of the primary equipment after load is truly simulated, obtaining the bus protection large difference and the single bus small difference formed by the phase angle of the secondary current of the reference interval and the subsection interval in each adjustment in the first bus protection screen, and obtaining the bus protection large difference and the double-bus small difference formed by the phase angle of the secondary current of the subsection interval, the adjacent bus outlet interval and the adjacent bus-bar connection interval each time of adjustment in the second bus protection screen, and further if all the bus protection large differences, the single bus small differences and the double bus small differences are 0, judging that the polarities of the CT secondary windings of the reference interval, the subsection interval, the adjacent bus outlet interval and the adjacent bus connection interval are consistent; otherwise, the polarities of the CT secondary windings of the reference interval, the subsection interval, the adjacent bus outgoing line interval and the adjacent bus connection interval are judged to be inconsistent.

It can be understood that, because the other two-phase polarity check of the CT secondary winding at the adjacent bus buscouple interval is similar to the other two-phase polarity check of the CT secondary winding at the segment interval, the details are not repeated. Certainly, the other two-phase polarity verification of the CT secondary winding at the adjacent bus-bar connection interval is optimal based on the successful verification of the other two-phase polarity verification of the CT secondary winding at the segment interval, so as to avoid the situation that the other two-phase polarity of the CT secondary winding at the segment interval needs to be verified again when the polarities are inconsistent during the verification.

As shown in fig. 8, an application scenario of the method for checking the consistency of the polarities of the secondary windings of the bus differential protection intervals in the bus protection configured in the double bus segment connection substation according to the second embodiment of the present invention for checking the polarities of the secondary windings of the bus differential protection intervals accessed to the bus protection CT in the adjacent bus buscouple intervals is further described:

The current outflow end of a current generator (a current rising instrument) is connected to the phase A ground terminal of a 2201C0 ground blade, the current outflow end of the current generator (the current rising instrument) is connected to a ground copper bar, 2201, 2015, 2056 and 2203 switches are closed, 22011, 20151, 20156, 20565, 20566 and 22035 are closed, 2201C0 and 2203C0 ground blades are closed to form a current path, and the current flowing method can simulate the situation that one-time current flows through 2201(1M and 2M reference intervals), 2015(1M and 5M segment intervals), 2056(5M and 6M bus-coupled intervals) and 2203(5M and 6M intervals). Since the primary current flows in a penetrating manner.

Therefore, in the 220kV1M and 2M bus protection device, if the 2201 switch a phase current I1 is taken as a reference, I1 is equal to Im 0, then 2015 switch a phase current Ifd should be Ifd equal to Im 180, and if the large difference of 220kV1M and 2M bus protection is Id equal to I1+ Ifd equal to 0, and 1M small difference Id1 is equal to I1+ Ifd equal to 0;

in a

220kV

5M and 6M bus protection device, a switch a phase current Ifd should be Ifd equal to Im 0, a switch a phase current 2056 (taking the polarity end facing 6M as an example) Iml equal to Im 0, a switch a phase current 2203I 3 should be I3 equal to Im 180, and if the bus protection of

220kV

5M and 6M is large, Id equal to I3+ Ifd equal to 0, a small difference Id5 equal to Ifd-Iml equal to 0, and a small difference Id6 equal to 6M equal to I3+ Iml equal to 0.

The embodiment of the invention has the following beneficial effects:

It will be understood by those skilled in the art that all or part of the steps in the method for implementing the above embodiments may be implemented by relevant hardware instructed by a program, and the program may be stored in a computer-readable storage medium, such as ROM/RAM, magnetic disk, optical disk, etc.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention, and it is therefore to be understood that the invention is not limited by the scope of the appended claims.

Claims

1. A method for checking the consistency of the polarity of each interval CT secondary winding of bus differential protection is characterized in that the method is realized in bus protection configured in a double-bus connection transformer substation; wherein,

the method comprises the following steps:

2. The method for verifying the consistency of the polarity of each interval CT secondary winding of bus bar differential protection as recited in claim 1, further comprising:

3. The method for verifying the consistency of the polarity of each interval CT secondary winding of bus bar differential protection as recited in claim 1, further comprising:

4. The method for verifying consistency of polarity of each interval CT secondary winding of bus bar differential protection as recited in claim 3, further comprising:

5. A method for checking the consistency of the polarity of each interval CT secondary winding of bus differential protection is characterized in that the method is realized in bus protection configured in a transformer substation in a double-bus-section wiring mode; wherein,

the method comprises the following steps:

6. The method for verifying consistency of polarity of each interval CT secondary winding of bus bar differential protection as recited in claim 5, further comprising:

7. The method for verifying consistency of polarity of each interval CT secondary winding of bus bar differential protection as recited in claim 5, further comprising:

8. The method for verifying consistency of polarity of each interval CT secondary winding of bus bar differential protection as recited in claim 7, further comprising:

9. The method for checking the polarity consistency of the secondary windings of the CT intervals of the bus differential protection according to claim 7 or 8, wherein the double bus bar small differences formed by the phase angles of the secondary currents of the segment intervals, the outgoing line intervals of the adjacent bus bars and the bus bar linkage intervals of the adjacent bus bars obtained in the second bus bar protection screen include a bus bar small difference of one bus bar in the second group of bus bars formed by the phase angles of the secondary currents of the segment intervals and the outgoing line intervals of the adjacent bus bars and a bus bar small difference of another bus bar in the second group of bus bars formed by the phase angles of the secondary currents of the outgoing line intervals of the adjacent bus bars and the bus bar linkage intervals of the adjacent bus bars.