Knife switch position correction method and system

Abstract

The invention discloses a disconnecting link position correction method and system. The method comprises the steps that the three-phase current amplitude of each branch on a bus, a switch position switching-in signal, a first female disconnecting link position switching-in signal, a second female disconnecting link position switching-in signal, a bus coupler switch position switching-in signal and a bus interconnection pressing plate switching-in signal are collected; calculating a bus large-difference three-phase current amplitude, and small-difference three-phase current amplitudes and phases of a bus 1 and a bus 2; and based on the acquired input signal, the current amplitude and the state logic relationship between the branch switches and the disconnecting links connected with the branches and the buses, combining the calculation results of the large difference, the small difference of the first bus and the small difference of the second bus, judging the abnormal state of the position of the disconnecting link of the first bus / the second bus, and correcting the abnormal state of the disconnecting link. According to the method, the application range of disconnecting link position correction is expanded, the accuracy of disconnecting link position correction is improved, correction of the reverse connection condition of the disconnecting link position is achieved, and the correctness of busbar differential protection action behaviors when faults occur in a busbar area is guaranteed.

Description

Technical Field

[0001] The present invention belongs to the technical field of relay protection, and particularly relates to a knife switch position correction method and system. Background Art

[0002] At present, the busbars of voltage levels of 220 kV and above are mostly of the double-bus type. Various types of equipment need to be switched between the two busbars. The bus protection needs to access the knife switch positions of each branch to realize the automatic switching of the differential current loop and the tripping outlet loop, and keep consistent with the primary operation mode. The abnormal knife switch position directly affects the correctness of the differential protection action behavior.

[0003] From the perspective of bus protection, an abnormal knife switch position refers to the situation where the knife switch position input sensed by the bus protection is inconsistent with the primary position of the knife switch, including the case where the primary position is closed and the secondary position is open caused by poor contact of the knife switch auxiliary contact, and the case where the primary position is open and the secondary position is closed caused by adhesion of the knife switch auxiliary contact. In addition, the reverse connection of the knife switch input in the bus protection panel will also cause the inconsistency between the primary and secondary positions of the knife switch. When the primary position of the knife switch is closed and the secondary position is open, it may lead to the problem that there is no knife switch input for the operating branch. When the primary position of the knife switch is open and the secondary position is closed, it may lead to the interconnection operation of the two busbars, and the problem that the faulty bus cannot be distinguished when a bus fault occurs.

[0004] For the treatment scheme of the abnormal knife switch position problem, the paper "Optimal Scheduling Strategy for Electric Vehicle Charging and Discharging Considering User Responsiveness" (Li Jun, Liang Jiacheng, Liu Ketian, etc., "Southern Power Grid Technology", No. 8, 2023) and the paper "Adaptive Scheme for Bus Operating Mode of Microcomputer Bus Protection" (Lu Zhengjun, Li Dong, Mao Yasheng, etc., "Automation of Electric Power Systems", Vol. 23, No. 10, May 30, 1999) propose a scheme that combines the advantages of the two methods of knife switch auxiliary contact and current recognition. The paper "Adaptive Correction of Knife Switch Position in Bus Protection" (Huang Jidong; Xiao Feng; Wang Zhiyong, etc., "Power System Protection and Control", Vol. 44, No. 6, March 14, 2016) proposes an intelligent correction scheme for abnormal knife switch positions based on the principle of conservation of the vector sum of the inflowing and outflowing currents calculated from the knife switch position.

[0005] CN111509672A discloses a fast adaptive correction method for knife switch position based on the sampling value algorithm, which proposes to compare the sampled value of the differential current with the differential current balance setting value to judge whether the current knife switch position meets the correctness requirement; however, the calculation amount in this patent scheme is large and the sensitivity is low.

[0006] CN101227082A discloses an automatic correction method for bus knife switch auxiliary contacts. This patent proposes to fit the knife switch for the branch with current but no knife switch and the branch with double-span knife switch, and correct the knife switch by judging whether the differential currents of the large difference and the small difference are balanced.

[0007] The above - mentioned various methods all have a high degree of dependence on the branch - current amplitude, do not incorporate the branch - switch position and the bus - interconnection pressure plate into the disconnector - calibration criterion, and do not consider the problem of disconnector correction when the disconnector input is reversed. Summary of the Invention

[0008] To solve the deficiencies in the prior art, such as a high degree of dependence on the branch - current amplitude, not incorporating the branch - switch position and the bus - interconnection pressure plate into the disconnector - calibration criterion, and not considering the problem of disconnector correction when the disconnector input is reversed, the present invention provides a disconnector - position calibration method and system.

[0009] The present invention adopts the following technical solutions.

[0010] On the one hand, the present invention discloses a disconnector - position calibration method, including:

[0011] Collect the three - phase current amplitudes of each branch on the bus, the switch - position input signal, the No.1 - bus disconnector - position input signal, the No.2 - bus disconnector - position input signal, the switch - position input signal of the bus coupler, and the bus - interconnection pressure - plate input signal;

[0012] Calculate the three - phase current amplitudes of the bus differential, the No.1 - bus and No.2 - bus differential, and the phase;

[0013] Based on the collected input signals, current amplitudes, and the state - logic relationship between each branch - switch and the disconnectors connected to each branch and the bus, combined with the calculation results of the bus differential, No.1 - bus differential, and No.2 - bus differential, judge the abnormal state of the No.1 - bus / No.2 - bus disconnector position, and perform disconnector - state abnormal correction.

[0014] Further preferably,

[0015] The branch - switch position input and the disconnector - position input can be normally - open or normally - closed single - contact inputs, or can be normally - open and normally - closed double - contact inputs.

[0016] Further preferably,

[0017] When the switch position of a certain branch is in the closed position, the No.1 - bus / No.2 - bus disconnector position is in the closed position, and the No.2 - bus / No.1 - bus disconnector position is in the open position, if the No.1 - bus / No.2 - bus disconnector - position input of this branch indicates that the No.1 - bus / No.2 - bus disconnector changes from closed to open, report the abnormal open - position signal of the No.1 - bus / No.2 - bus disconnector of this branch, and correct the No.1 - bus / No.2 - bus disconnector position of this branch to the closed position.

[0018] Further preferably,

[0019] When reporting the abnormal open - position of the No.1 - bus / No.2 - bus disconnector of a certain branch, if the No.1 - bus / No.2 - bus disconnector - position input of this branch indicates that the disconnector changes from open to closed, or the switch - position input of this branch indicates that the switch changes from closed to open, then the abnormal open - position signal of the No.1 - bus / No.2 - bus disconnector of this branch is returned, and no disconnector correction is performed.

[0020] Further preferably,

[0021] When the busbar interconnection pressure plate is not put in or the position of the bus-coupler switch is in the off position, and the incoming signal of the 2nd bus / 1st bus disconnector position of a certain branch is in the on position while the incoming signal of the 1st bus / 2nd bus disconnector position is in the off position, if the incoming signal of the 1st bus / 2nd bus disconnector position of this branch indicates that the 1st bus / 2nd bus disconnector changes from off to on, report the abnormal on-position signal of the 1st bus / 2nd bus disconnector position of this branch, and correct the position of the 1st bus / 2nd bus disconnector of this branch to the off position.

[0022] Further preferably,

[0023] When reporting the abnormal on-position of the 1st bus / 2nd bus disconnector position of a certain branch, if the busbar interconnection pressure plate is put in and the position of the bus-coupler switch is in the on position, then the abnormal on-position signal of the 1st bus / 2nd bus disconnector position of this branch returns, and no disconnector correction is performed.

[0024] Further preferably,

[0025] When reporting the abnormal on-position of the 1st bus / 2nd bus disconnector position of a certain branch, if the incoming signal of the 1st bus / 2nd bus disconnector position of this branch indicates that the disconnector changes from on to off, then the abnormal on-position signal of the 1st bus / 2nd bus disconnector position of this branch returns, and no disconnector correction is performed.

[0026] Further preferably,

[0027] When the magnitudes of the three-phase currents of the main bus differential are all less than the first set threshold, the magnitudes of the three-phase currents of the 1st bus and 2nd bus differentials are all greater than the second set threshold, the magnitudes of the three-phase currents of the 1st bus differential are equal to the corresponding phase currents of the 2nd bus differential, and the phases of the three-phase currents of the 1st bus differential are opposite to the corresponding phase currents of the 2nd bus differential, when there is only one branch whose three-phase current magnitudes are equal to the corresponding phase current magnitudes of the 1st bus differential, report the signal that the incoming connection of the disconnector position of this branch is reversed, and reverse the positions of the two disconnectors of this branch.

[0028] Further preferably,

[0029] Both the first set threshold and the second set threshold are set based on the secondary rated value of the current transformer.

[0030] Further preferably,

[0031] When reporting that the incoming connection of the disconnector position of a certain branch is reversed, if the differential current of the three-phase main bus is less than the first set threshold and the magnitudes of the three-phase currents of the 1st bus and 2nd bus differentials are both less than the second set threshold, then the signal that the incoming connection of the disconnector position of the branch returns, and no disconnector correction is performed.

[0032] On the other hand, the present invention discloses a disconnector position correction system based on a disconnector position correction method, including a signal acquisition module, a differential current calculation module, and a disconnector abnormality correction module:

[0033] The signal acquisition module collects the three-phase current amplitudes of each branch on the bus, the switch position input signal, the incoming signal of the No. 1 bus disconnector position, the incoming signal of the No. 2 bus disconnector position, the switch position input signal of the bus coupler, and the incoming signal of the bus interconnection pressure plate.

[0034] The differential current calculation module is used to calculate the three-phase current amplitudes of the large differential of the bus, the three-phase current amplitudes and phases of the small differentials of the No. 1 bus and the No. 2 bus.

[0035] The disconnector abnormal correction module determines the abnormal state of the No. 1 bus / No. 2 bus disconnector position based on the collected input signals, current amplitudes, and the state logic relationship between the switches of each branch and the disconnectors connected to each branch and the bus, and combines the calculation results of the large differential, the small differential of the No. 1 bus, and the small differential of the No. 2 bus, and performs disconnector state abnormal correction.

[0036] The beneficial effect of the present invention is that, compared with the prior art:

[0037] The present invention provides a disconnector position correction method and system, which corrects the disconnector position of the branch based on the branch switch position state and the bus interconnection pressure plate state, is not affected by the magnitude of the branch current, and determines whether the disconnector position of the branch is reversed based on analog quantities such as the large differential current amplitude, the bus small differential current amplitude and phase, and the branch current amplitude, and performs disconnector position correction. The above method expands the applicable range of disconnector position correction, improves the accuracy of disconnector position correction, and realizes the correction of the reversed disconnector position, ensuring the correctness of the differential protection action behavior during bus internal faults.

[0038] In addition, the present invention also has the advantage of low dependence on the branch current amplitude. Description of the Drawings

[0039] Figure 1 is a schematic diagram of a double bus connection;

[0040] Figure 2 is the abnormal and correction logic diagram of the No. 1 bus disconnector in the open position of interval X;

[0041] Figure 3 is the abnormal and correction logic diagram of the No. 2 bus disconnector in the open position of interval X;

[0042] Figure 4 is the abnormal and correction logic diagram of the No. 1 bus disconnector in the closed position of interval X;

[0043] Figure 5 is the abnormal and correction logic diagram of the No. 2 bus disconnector in the closed position of interval X;

[0044] Figure 6 is the abnormal and correction logic diagram of the disconnector input connection reversed in interval X. Detailed Embodiments

[0045] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. The embodiments described in this application are only a part of the embodiments of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0046] This application provides a method for correcting the position of a knife switch, including:

[0047] See the attached Figure 1 , which is a schematic diagram of a double-busbar connection adopted by the present invention. Each of the branches 1-4 is connected to busbar 1 or busbar 2 through a No. 1 busbar knife switch or a No. 2 busbar knife switch; busbar 1 and busbar 2 are connected through a bus-coupling breaker, and a current transformer is serially configured in the breaker circuit; each branch is configured with a switch CB, and each CB is serially connected to a current transformer CT; the switches and breakers in the present invention.

[0048] The bus protection accesses the switch position input signals of branches 1, 2, 3, and 4, the position input signals of the No. 1 and No. 2 busbar knife switches, the three-phase currents, and the switch position input signal of the bus-coupling, and sets a bus interconnection pressure plate.

[0049] Collect the three-phase current amplitudes, switch position input signals, No. 1 busbar knife switch position input signals, and No. 2 busbar knife switch position input signals of each branch on the busbar, the switch position input signal of the bus-coupling, and the bus interconnection pressure plate input signal; among them, the No. 1 busbar knife switch is the knife switch connecting the branch to busbar 1; the No. 2 busbar knife switch is the knife switch connecting the branch to busbar 2.

[0050] The input of the branch switch position and the input of the knife switch position can be a normally open or normally closed single-contact input, or a normally open and normally closed double-contact input.

[0051] Those skilled in the art should know that if the input of a certain branch switch position or the input of a certain knife switch position is a normally open and normally closed double-contact input, it means that the switch / knife switch has a total of two auxiliary contacts, one of which is normally open and the other is normally closed. The signals of the two auxiliary contacts are collected to the bus protection device to determine whether the switch / knife switch is conducting.

[0052] Calculate the large differential current D I and the small differential currents D I1 , D I2 .

[0053] Calculate the large differential current D I according to the following formula:

[0054] D I =I 1 +I2 +I 3 +I 4 ;

[0055] where I 1 represents the current phasor of branch 1, I 2 represents the current phasor of branch 2, I 3 represents the current phasor of branch 3, I 4 represents the current phasor of branch 4.

[0056] Calculate the differential current D of bus 1 according to the following formula I1 :

[0057] D I1 = K 11 ×I 1 + K 21 ×I 2 + K 31 ×I 3 + K 41 ×I 4 + I BC

[0058] where, I BC represents the current phasor of the bus tie, K N1 (N = 1, 2, 3, 4) represents the closing position of the No. 1 bus knife switch of branch N. Specifically, when K 11 = 1, it means the No. 1 bus knife switch of branch 1 is in the closing position; when K 11 = 0, it means the No. 1 bus knife switch of branch 1 is in the opening position; when K 21 = 1, it means the No. 1 bus knife switch of branch 2 is in the closing position; when K 21 = 0, it means the No. 1 bus knife switch of branch 2 is in the opening position; when K 31 = 1, it means the No. 1 bus knife switch of branch 3 is in the closing position; when K 31 = 0, it means the No. 1 bus knife switch of branch 3 is in the opening position; when K 41 = 1, it means the No. 1 bus knife switch of branch 4 is in the closing position; when K 41 = 0, it means the No. 1 bus knife switch of branch 4 is in the opening position.

[0059] Calculate the differential current D of bus 2 according to the following formula I2 :

[0060] D I2 = K 12 ×I 1 + K 22 ×I 2 + K 32 ×I 3 + K 42 ×I 4 - I BC

[0061] Among them, K N2 (N = 1, 2, 3, 4) indicates that the 2-bus disconnecting switch position of branch N is closed. Specifically, when K 12 = 1, it indicates that the 2-bus disconnecting switch position of branch 1 is closed; when K 12 = 0, it indicates that the 2-bus disconnecting switch position of branch 1 is open; when K 22 = 1, it indicates that the 2-bus disconnecting switch position of branch 2 is closed; when K 22 = 0, it indicates that the 2-bus disconnecting switch position of branch 2 is open; when K 32 = 1, it indicates that the 2-bus disconnecting switch position of branch 3 is closed; when K 32 = 0, it indicates that the 2-bus disconnecting switch position of branch 3 is open; when K 42 = 1, it indicates that the 2-bus disconnecting switch position of branch 4 is closed; when K 42 = 0, it indicates that the 2-bus disconnecting switch position of branch 4 is open.

[0062] Those skilled in the art should know that the large differential current is used to calculate the phasor sum of the currents of the outgoing line units on two buses; the small differential current is used to calculate the phasor sum of the currents of the outgoing line units on a certain bus. In the present invention, there are two buses, so it includes the small differential current calculated for bus 1, that is, the small differential current of bus 1, and the small differential current calculated for bus 2, that is, the small differential current of bus 2.

[0063] Based on the collected input signals, current amplitudes, and the logical relationships of the disconnector positions of each branch switch and the disconnectors connecting each branch to the bus in the open and closed states, combined with the calculation results of the large differential, the small differential of bus 1, and the small differential of bus 2, determine the abnormal state of the 1-bus / 2-bus disconnector position and perform correction of the disconnector state abnormality. The disconnectors connecting each branch to the bus include the 1-bus disconnector and the 2-bus disconnector.

[0064] Embodiment 1

[0065] A method for correcting the disconnector position.

[0066] See Appendix Figure 2 , which is the logic diagram of the abnormal open position and correction of the 1-bus disconnector of bay X. Denote the logical operation represented by this logic diagram as the first logical operation;

[0067] See Appendix Figure 3 , which is the logic diagram of the abnormal open position and correction of the 2-bus disconnector of bay X. Denote the logical operation represented by this logic diagram as the second logical operation;

[0068] According to the first / second logical operation, first collect the input signals of the positions of each branch switch on the bus, the input signal of the 1-bus disconnector position, and the input signal of the 2-bus disconnector position;

[0069] See Appendix Figure 2, According to the first logical operation, when the switch position of a certain branch is in the closed position, the disconnector position of bus 2 is in the open position, and the disconnector position of bus 1 is in the closed position, if the incoming signal of the disconnector position of bus 1 of this branch indicates that the disconnector of bus 1 changes from closed to open, report the abnormal open position signal of the disconnector of bus 1 of this branch, correct the disconnector position of bus 1 of this branch to the closed position, and include it in the first logical operation.

[0070] Assume that branch 1 is connected to bus 1. At this time, the switch of branch 1 is in the closed position, that is, CB1 is 1, the disconnector position of bus 1 of branch 1 is in the closed position, that is, K11 is 1, and the disconnector position of bus 2 of branch 1 is in the open position, that is, K12 is 0;

[0071] When K11 becomes 0 and other conditions remain unchanged, the judgment result of the switch of bay 1 being closed is 1, the judgment result of the disconnector of bay 1 to bus 2 being open is 1, and the judgment result of the disconnector of bay 1 to bus 1 being closed changes from 1 to 0. Output the judgment result of the switch of bay 1 being closed and the judgment result of the disconnector of bay 1 to bus 2 being open to the first AND gate in the first logical operation, and the output of the first AND gate in the first logical operation is 1; among them, if a certain condition is judged correctly, the judgment result signal is 1, otherwise it is 0. Among them, bay X represents the Xth branch.

[0072] At this time, the judgment result of the disconnector of bay 1 to bus 1 being closed after T delay is still 1, while the current judgment result of the disconnector of bay 1 to bus 1 being closed is 0; output the judgment result 1 of the disconnector of bay 1 to bus 1 being closed after T delay to the OR gate in the first logical operation, and the output of the OR gate in the first logical operation is 1,

[0073] Transmit the output of the first AND gate in the first logical operation and the output of the OR gate in the first logical operation to the second AND gate in the first logical operation, and the output of the second AND gate in the first logical operation is 1;

[0074] Transmit the output of the second AND gate in the first logical operation and the inverse signal 1 of the current judgment result of the disconnector of bay 1 to bus 1 being closed to the third AND gate in the first logical operation, and the output of the third AND gate in the first logical operation is 1, that is, the first logical operation result is 1. At this time, the bus protection reports the abnormal open position signal of the disconnector of bus 1 of branch 1, corrects the disconnector position of bus 1 of branch 1 to the closed position, that is, corrects K11 to 1, and includes K11 being 1 in the first logical operation, that is, transmits the signal 1 to the OR gate in the first logical operation, so that the output of the OR gate remains 1. The so-called bus 1 is busbar 1.

[0075] See Appendix Figure 3 , According to the second logical operation, when the switch position of a certain branch is in the closed position, the disconnector position of bus 1 is in the open position, and the disconnector position of bus 2 is in the closed position, if the incoming signal of the disconnector position of bus 2 of this branch indicates that the disconnector of bus 2 changes from closed to open, report the abnormal open position signal of the disconnector of bus 2 of this branch, correct the disconnector position of bus 2 of this branch to the closed position, and include it in the second logical operation.

[0076] Similar to the first logic operation, assume that branch circuit 3 is connected to bus 2. At this time, the switch of branch circuit 3 is in the closed position, K31 is 0, and K32 is 1. When K32 becomes 0, according to the second logic operation, the bus protection reports an abnormal open position signal of the bus 2 disconnector of branch circuit 3. At this time, correct K32 to 1 and include it in the second logic operation. The so-called bus 2 refers to busbar 2.

[0077] According to the first / second logic operation, when reporting an abnormal open position of the bus 1 disconnector or an abnormal open position of the bus 2 disconnector of a branch circuit, if the position input of the bus 1 disconnector or the position input of the bus 2 disconnector indicates that the disconnector changes from open to closed, or the switch position indication of the corresponding branch circuit changes from closed to open, making the result of the first / second logic operation 0, then the abnormal open position signal of the bus 1 disconnector or the abnormal open position signal of the bus 2 disconnector of the branch circuit is returned, and no disconnector correction is performed. The original position input of the bus 1 disconnector and the original position input of the bus 2 disconnector are included in the logic operation. Among them, the original position of the bus 1 disconnector refers to the position input signal of the bus 1 disconnector collected by the current bus protection; the original position of the bus 2 disconnector refers to the position input signal of the bus 2 disconnector collected by the current bus protection.

[0078] Embodiment 2

[0079] A method for correcting the position of a disconnector.

[0080] See Appendix Figure 4 , which is the logic diagram of the abnormal closed position and correction of the bus 1 disconnector of bay X. Denote the logic operation represented by this logic diagram as the third logic operation;

[0081] See Appendix Figure 5 , the logic diagram of the abnormal closed position and correction of the bus 2 disconnector of bay X. Denote the logic operation represented by this logic diagram as the fourth logic operation;

[0082] According to the third / fourth logic operation, collect the switch position input signals of each branch circuit on the busbar, the position input signals of the bus 1 disconnector and the bus 2 disconnector, the switch position input signal of the bus coupler, and the input signal of the bus interconnection pressure plate.

[0083] See Appendix Figure 4 , according to the third logic operation, when the bus interconnection pressure plate is not inserted or the bus coupler switch position is in the open position, and the position input of the bus 2 disconnector of a certain branch circuit is in the closed position and the position input of the bus 1 disconnector is in the open position, if the position input of the bus 1 disconnector of this branch circuit indicates that the bus 1 disconnector changes from open to closed, report an abnormal closed position signal of the bus 1 disconnector of this branch circuit, correct the position of the bus 1 disconnector of this branch circuit to the open position, and include it in the third logic operation.

[0084] Assume that branch circuit 3 is connected to bus 2, the bus interconnection pressure plate input is not turned on or the position of the bus coupler switch is in the off position. At this time, the switch of branch circuit 3 is in the on position, K31 is 0, and K32 is 1. When K31 becomes 1 and other conditions remain unchanged, among the judgment results of the withdrawal of the bus interconnection pressure plate and the off position of the bus coupler switch, at least one judgment is true, and signal 1 is output. The judgment result of the closing of the disconnector of bay 3_2 bus is 1, and the judgment result of the opening of the disconnector of bay 3_1 bus changes from 1 to 0.

[0085] Output the judgment result of the withdrawal of the bus interconnection pressure plate and the judgment result of the off position of the bus coupler switch to the first OR gate in the third logical operation, and the output of the first OR gate in the third logical operation is 1;

[0086] Transmit the output of the first OR gate in the three logical operations and the judgment result of the closing of the disconnector of bay 3_2 bus to the first AND gate in the third logical operation, and the output of the first AND gate in the third logical operation is 1;

[0087] At this time, the judgment result of the closing of the disconnector of bay 3_1 bus after T delay is still 1, while the current judgment result of the closing of the disconnector of bay 3_1 bus is 0; Output the judgment result 1 of the closing of the disconnector of bay 3_1 bus after T delay to the second OR gate in the third logical operation, and the output of the second OR gate in the third logical operation is 1;

[0088] Transmit the output of the first AND gate in the third logical operation and the output of the second OR gate in the third logical operation to the second AND gate in the third logical operation, and the output of the second AND gate in the third logical operation is 1;

[0089] Transmit the output of the second AND gate in the third logical operation and the inverse signal 1 of the current judgment result of the closing of the disconnector of bay 3_1 bus to the third AND gate in the third logical operation, and the output of the third AND gate in the third logical operation is 1, that is, the result of the third logical operation is 1. At this time, the bus protection reports the abnormal closing signal of the disconnector position of bay 3's 1 bus, corrects the position of the disconnector of bay 3's 1 bus to the off position, that is, corrects K31 to 0, and includes it in the third logical operation. That is, when K31 is 0, the judgment result 1 of the opening of the disconnector of bay 3_1 bus is transmitted to the second OR gate in the third logical operation, so that the output of the second OR gate remains 1.

[0090] See Appendix Figure 5 , according to the fourth logical operation, when the bus interconnection pressure plate is not turned on or the position of the bus coupler switch is in the off position, and the input of the disconnector position of a certain branch circuit to bus 1 is in the on position and the input of the disconnector position to bus 2 is in the off position, if the input of the disconnector position of this branch circuit to bus 2 indicates that the disconnector of bus 2 changes from off to on, report the abnormal closing signal of the disconnector position of this branch circuit to bus 2, correct the position of the disconnector of this branch circuit to bus 2 to the off position, and include it in the fourth logical operation.

[0091] Similarly to the third logical operation, assume that branch 1 is connected to bus 1, the bus interconnection pressure plate input is not enabled, or the bus coupler switch position is in the off position. At this time, the switch of branch 1 is in the on position, K11 is 1, and K12 is 0. When K12 becomes 1, according to the fourth logical operation, the bus protection reports an abnormal on-position signal for the busbar disconnector of branch 1 on bus 2, corrects K12 to 0, and records it in the fourth logical operation.

[0092] Further, according to the third / fourth logical operation, when reporting an abnormal on-position of the busbar disconnector of branch 1 or an abnormal on-position of the busbar disconnector of bus 2, if the bus interconnection pressure plate is enabled and the bus coupler switch position is in the on position, the output of the first OR gate in the third / fourth logical operation is 0, resulting in the result of the third / fourth logical operation being 0. Then, the abnormal on-position signal of the busbar disconnector of branch 1 or the abnormal on-position signal of the busbar disconnector of bus 2 is returned, and no disconnector correction is performed. The original on-position input of busbar disconnector 1 or the original on-position input of busbar disconnector 2 is recorded in the logical operation. Among them, the original on-position of busbar disconnector 1 refers to the on-position input signal of busbar disconnector 1 collected by the current bus protection; the original on-position of busbar disconnector 2 refers to the on-position input signal of busbar disconnector 2 collected by the current bus protection.

[0093] Further, according to the third / fourth logical operation, when reporting an abnormal on-position of the busbar disconnector of branch 1 or an abnormal on-position of the busbar disconnector of bus 2, if the on-position input of busbar disconnector 1 or the on-position input of busbar disconnector 2 indicates that the disconnector changes from on to off, making the inverted signal of the judgment result of the disconnector off of bay 3_1 busbar / disconnector off of bay 3_2 busbar in the third / fourth logical operation be 0, resulting in the result of the third / fourth logical operation being 0. Then, the abnormal on-position signal of the busbar disconnector of branch 1 or the abnormal on-position signal of the busbar disconnector of bus 2 is returned, and no disconnector correction is performed. The original on-position input of busbar disconnector 1 or the original on-position input of busbar disconnector 2 is recorded in the logical operation.

[0094] Embodiment 3

[0095] A method for correcting the position of a disconnector.

[0096] See the appendix Figure 6 , which is the logic diagram of the reverse connection and correction of the disconnector input of bay X. Denote the logical operation represented by this logic diagram as the fifth logical operation;

[0097] According to the fifth logical operation, collect the three-phase current amplitudes, switch position input signals, on-position input signals of busbar disconnector 1 and on-position input signals of busbar disconnector 2 of each branch on the bus, the on-position input signal of the bus coupler, and the on-position input signal of the bus interconnection pressure plate;

[0098] Calculate the three-phase current amplitude of the main bus differential, the three-phase current amplitudes and phases of the small differentials of bus 1 and bus 2;

[0099] See the appendix Figure 6 , according to the fifth logical operation, when the three-phase current amplitudes of the main bus differential are all less than the first set threshold IT1 When the magnitudes of the three-phase currents of the differential protection for both Bus 1 and Bus 2 are greater than the second set threshold I T2 and the magnitudes of the three-phase currents of the differential protection for Bus 1 are equal to the corresponding phase currents of the differential protection for Bus 2, and the phases of the three-phase currents of the differential protection for Bus 1 are opposite to the corresponding phase currents of the differential protection for Bus 2, when the magnitudes of the three-phase currents of only one branch are equal to the corresponding phase currents of the differential protection for Bus 1, report the signal that the incoming signal of the disconnector position of this branch is connected reversely, reverse the positions of the two disconnectors of this branch, and include it in the fifth logical operation. The first set threshold I T1 and the second set threshold I T2 are both set based on the secondary rated value of the current transformer. The preferred value range of the set values of I T1 and I T2 is both 0.02 to 0.04 times the secondary rated value of the current transformer CT, and I T1 >I T2 . Reversing the positions of the two disconnectors of this branch means correcting the signal of the closed disconnector position in this branch to the open position and correcting the signal of the open disconnector position to the closed position.

[0100] Assume that Branch 1 is connected to Bus 1 and the disconnector position is connected reversely. At this time, the switch of Branch 1 is closed, K11 is 0, and K12 is 1. At this time, the magnitudes of the three-phase currents of the main differential protection of the bus are all less than the internal set threshold I T1 . The differential current of Bus 1 undercounts the current of Branch 1, and the differential current of Bus 2 overcounts the current of Branch 1, resulting in the magnitudes of the three-phase currents of the differential protection for Bus 1 being equal to the corresponding phase currents of the differential protection for Bus 2, and the phases of the three-phase currents of the differential protection for Bus 1 being opposite to the corresponding phase currents of the differential protection for Bus 2. The magnitudes of the three-phase currents of the differential protection for Bus 1 are equal to the three-phase currents of Branch 1. At this time, the judgment result that the three-phase differential current of the main differential protection <I T1 is 1, that is, true; the judgment result that the three-phase differential current of Bus 1 >I T2 is 1; the judgment result that the magnitudes of the three-phase differential currents of Bus 1 and Bus 2 are equal is 1; the judgment result that the phases of the three-phase differential currents of Bus 1 and Bus 2 are opposite is 1; the judgment result that the three-phase differential current of Bus 1 = the three-phase currents of Interval 1 is 1. Among them, if a certain condition is judged correctly, the judgment result signal is 1, otherwise it is 0.

[0101] Output the judgment result that the three-phase differential current of the main differential protection <I T1 , the judgment result that the three-phase differential current of Bus 1 >I T2 , and the judgment result that the magnitudes of the three-phase differential currents of Bus 1 and Bus 2 are equal to the first AND gate in the fifth logical operation, and the output of the first AND gate in the fifth logical operation is 1;

[0102] Output the judgment result that the phases of the three-phase differential currents of Bus 1 and Bus 2 are opposite, and the judgment result that the three-phase differential current of Bus 1 = the three-phase currents of Interval 1 to the second AND gate in the fifth logical operation, and the output of the second AND gate in the fifth logical operation is 1;

[0103] The outputs of the first AND gate in the fifth logical operation and the second AND gate in the fifth logical operation are transmitted to the third AND gate in the fifth logical operation. The output of the third AND gate in the fifth logical operation is 1, that is, the result of the fifth logical operation is 1. At this time, the bus protection reports that the incoming signal of the disconnector position of branch 1 is reversed. Correct K11 to 1, correct K12 to 0, and include them in the fifth logical operation. Among them, the large differential three-phase current is the large differential three-phase current; the first and second bus three-phase currents are the small differential three-phase currents of bus 1 and bus 2.

[0104] Further, according to the fifth logical operation, when it is reported that the incoming signal of the disconnector position is reversed, if the large differential three-phase current is less than the first set threshold, and the amplitudes of the small differential three-phase currents of bus 1 and bus 2 are both less than the second set threshold, making the result of the fifth logical operation 0, then the incoming signal of the disconnector position reversal of this branch is returned, and no disconnector correction is performed. The original incoming signal of the disconnector position of bus 1 or the original incoming signal of the disconnector position of bus 2 is included in the logical operation. Among them, the original incoming signal of the disconnector position of bus 1 refers to the incoming signal of the disconnector position of bus 1 collected by the current bus protection; the original incoming signal of the disconnector position of bus 2 refers to the incoming signal of the disconnector position of bus 2 collected by the current bus protection.

[0105] Further, according to the fifth logical operation, when the large differential three-phase currents are all less than the first set threshold I T1 , and the amplitudes of the three-phase currents of bus 1 and the small differential three-phase currents of bus 2 are both greater than the second set threshold I T2 , when the amplitudes of the three-phase currents of more than 1 branch are equal to the amplitudes of the corresponding differential currents of bus 1 and bus 2, only report the incoming signal of the disconnector position reversal of the branch, do not perform disconnector correction, and set the bus to be interconnected.

[0106] This application also discloses a disconnector position correction system based on the disconnector position correction method, including a signal acquisition module, a differential current calculation module, and a disconnector abnormality correction module:

[0107] The signal acquisition module collects the amplitudes of the three-phase currents of each branch on the bus, the incoming signal of the switch position, the incoming signal of the disconnector position of bus 1 and the incoming signal of the disconnector position of bus 2, the incoming signal of the switch position of the bus coupler, and the incoming signal of the bus interconnection pressure plate;

[0108] The differential current calculation module is used to calculate the amplitude, phase of the large differential three-phase current of the bus, and the amplitudes of the small differential three-phase currents of bus 1 and bus 2;

[0109] The disconnector abnormality correction module, based on the collected incoming signals, current amplitudes, and the state logical relationship between each branch switch and the disconnectors connected to each branch and the bus, combines the calculation results of the large differential, small differential of bus 1, and small differential of bus 2 to judge the abnormal state of the disconnector position of bus 1 / bus 2, and perform disconnector state abnormality correction.

[0110] The present disclosure may be a system, a method, and / or a computer program product. The computer program product may include a computer-readable storage medium having computer-readable program instructions thereon for causing a processor to implement aspects of the present disclosure.

[0111] A computer-readable storage medium may be a tangible device that can retain and store instructions for use by an instruction execution device. A computer-readable storage medium may be, for example—but not limited to—an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer-readable storage medium would include: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as a punch card or raised structures in grooves having instructions stored thereon, and any suitable combination of the foregoing. The computer-readable storage medium as used herein is not to be construed as a transitory signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through an optical fiber cable), or an electrical signal transmitted through a wire.

[0112] The computer-readable program instructions described herein may be downloaded to respective computing / processing devices from a computer-readable storage medium or may be downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network may include copper transmission cables, optical fiber transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in a computer-readable storage medium in each computing / processing device.

[0113] Computer program instructions for performing the operations of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine - related instructions, microcode, firmware instructions, state - setting data, or source code or object code written in any combination of one or more programming languages, including object - oriented programming languages such as Smalltalk, C++, etc., and conventional procedural programming languages such as the "C" language or similar programming languages. The computer - readable program instructions may be executed entirely on the user's computer, partially on the user's computer, executed as a stand - alone software package, partially on the user's computer and partially on a remote computer, or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., through the Internet using an Internet service provider). In some embodiments, by using the state information of the computer - readable program instructions to customize an electronic circuit, such as a programmable logic circuit, a field - programmable gate array (FPGA), or a programmable logic array (PLA), the electronic circuit can execute the computer - readable program instructions to implement various aspects of the present disclosure.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: it is still possible to modify the specific implementation manners of the present invention or make equivalent substitutions. Any modification or equivalent substitution that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A method for correcting the position of a knife switch, characterized in that: Collect the three-phase current amplitude of each branch on the bus, the switch position input signal, the 1st mother knife switch position input signal and the 2nd mother knife switch position input signal, the bus coupler switch position input signal, and the bus interconnection pressure plate input signal; Calculate the busbar large difference three-phase current amplitude, bus 1 and bus 2 small difference three-phase current amplitude and phase; Based on the collected input signals and current amplitudes, the logical relationship between the states of the branch switches and the switches connected to the branches and busbars, and the calculation results of the large difference, the 1-bus small difference, and the 2-bus small difference, the abnormal position state of the 1-bus / 2-bus switch is judged, and the abnormal switch state correction is performed.

2. The method for correcting the position of a knife switch according to claim 1, characterized in that: The branch switch position input and the knife switch position input can be a normally open or normally closed single contact input, or a normally open and normally closed double contact input.

3. The method for correcting the position of a knife switch according to claim 1, characterized in that: When the switch position of a branch is in the closed position, the 1m / 2m knife switch position is in the closed position, and the 2m / 1m knife switch position is in the open position, if the 1m / 2m knife switch position input of the branch indicates that the 1m / 2m knife switch changes from closed to open, the abnormal open position signal of the 1m / 2m knife switch position of the branch is reported, and the 1m / 2m knife switch position of the branch is corrected to the closed position.

4. The knife switch position correction method according to claim 1 or 3, characterized in that: When an abnormal position of the 1m / 2m knife switch of a branch is reported, if the position input of the 1m / 2m knife switch of the branch indicates that the knife switch changes from open to closed, or the switch position of the branch indicates that the switch changes from closed to open, the abnormal position signal of the 1m / 2m knife switch of the branch is returned, and the knife switch correction is not performed.

5. The method for correcting the position of a knife switch according to claim 1, characterized in that: When the busbar interconnection pressure plate is not put into operation or the bus tie switch is in the open position, the 2m / 1m knife switch position of a branch is opened to the closed position, and the 1m / 2m knife switch position is opened to the open position, if the 1m / 2m knife switch position input of the branch indicates that the 1m / 2m knife switch changes from open to closed, the abnormal closed position signal of the 1m / 2m knife switch position of the branch is reported, and the 1m / 2m knife switch position of the branch is corrected to the open position.

6. The method for correcting the knife switch position according to claim 1 or 5, characterized in that: When it is reported that the position of the 1 mother / 2 mother knife switch of a branch is abnormally closed, if the busbar interconnection pressure plate is put into operation and the bus tie switch position is closed, the abnormal closed position signal of the 1 mother / 2 mother knife switch of the branch is returned and the knife switch correction is not performed.

7. The method for correcting the position of a knife switch according to claim 1 or 5, characterized in that: When it is reported that the position of the 1m / 2m knife switch of a branch is abnormally closed, if the position input of the 1m / 2m knife switch of the branch changes from closed to open, the abnormal closing signal of the 1m / 2m knife switch position of the branch is returned, and the knife switch correction is not performed.

8. The method for correcting the position of a knife switch according to claim 1, characterized in that: When the busbar large difference three-phase current amplitudes are all less than the first set threshold, the busbar 1 and 2 small difference three-phase current amplitudes are all greater than the second set threshold, the busbar 1 small difference three-phase current amplitude is equal to the corresponding phase current amplitude of the busbar 2 small difference, and the phase of the busbar 1 small difference three-phase current is opposite to the phase of the busbar 2 small difference current, when there is only one branch whose three-phase current amplitude is equal to the corresponding phase current amplitude of the busbar 1 small difference, the branch switch position is reported to be reversed, and the positions of the two switches of the branch are reversed.

9. The method for correcting the position of a knife switch according to claim 1, characterized in that: The first set threshold and the second set threshold are both set based on the secondary rated value of the current transformer.

10. The method for correcting the position of a knife switch according to claim 1, characterized in that: When it is reported that the switch position of a branch is reversed, if the large difference three-phase current is less than the first set threshold, and the small difference three-phase current amplitudes of 1 mother and 2 mother are both less than the second set threshold, the branch switch position reverse connection signal is returned and the switch correction is not performed.

11. A knife switch position correction system using the knife switch position correction method according to any one of claims 1 to 10, characterized in that: It includes signal acquisition module, differential current calculation module and switch abnormality correction module: The signal acquisition module collects the three-phase current amplitude of each branch on the bus, the switch position input signal, the 1st mother knife switch position input signal and the 2nd mother knife switch position input signal, the switch position input signal of the bus tie, and the bus interconnection pressure plate input signal; The differential current calculation module is used to calculate the busbar large differential three-phase current amplitude, bus 1 and bus 2 small differential three-phase current amplitude and phase; The switch abnormality correction module determines the abnormal position state of the 1 bus / 2 bus switch based on the collected input signal and current amplitude, the state logical relationship between each branch switch and the switch connected to each branch and bus, and the calculation results of the large difference, the 1 bus small difference, and the 2 bus small difference, and performs switch state abnormality correction.

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