Electronic current transformer calibration system and method

Abstract

The present invention provides an electronic current transformer calibration system and method, the electronic current transformer calibration system comprises: a standard current transformer, a current booster, a calibration device, and a two-thirds wiring for accessing the electronic current transformer under test; three strings of the two-thirds wiring are connected in series, connected in series with the output end of the current booster and the standard current transformer, and the output end of the standard current transformer is connected to the secondary analog input end of the calibration device. Through the configuration of the primary wiring, high-voltage switch electrical appliance operation, and calibration equipment of the present invention, the electronic current transformer is calibrated on-site, thereby improving the efficiency of the on-site calibration of the electronic current transformer.

Description

Technical Field

[0001] The invention relates to electric power technology, and in particular to an electronic current transformer calibration system and method. Background Art

[0002] With the continuous development of key technologies of smart grid and smart substation, my country's smart substation has experienced explosive growth, and the number of smart devices in smart substations is increasing. For the transformers in the substation, on-site verification is required before commissioning. The on-site verification of electronic transformers in smart substations is more complicated and takes more time than the on-site verification of electromagnetic transformers in traditional substations. The on-site verification of transformers requires power outages, and cross-operation cannot be performed during this period. Therefore, improving the efficiency of on-site verification of electronic transformers in smart substations is of great significance to the construction, commissioning, and maintenance of smart substations.

[0003] In the prior art, the electronic current transformer calibration wiring diagram given in the State Grid Enterprise Standard Q / GDW 690-2011 "Electronic Current Transformer Field Calibration Specification" is as follows: Figure 1 As shown, using Figure 1 The transformer calibration scheme shown can only perform on-site calibration on one electronic current transformer at a time. Each on-site calibration of an electronic current transformer requires disconnecting the primary test line and the secondary test line, and at the same time, the test equipment and auxiliary equipment must be moved according to the location of the test product. Summary of the invention

[0004] In order to solve the problem of cumbersome test process in the on-site verification of electronic current transformers in existing smart substations, an embodiment of the present invention provides an electronic current transformer verification system, including: a standard current transformer, a current booster, a verification device, and a two-thirds connection for connecting to the electronic current transformer under test; wherein,

[0005] The three strings of the two-thirds connection are connected in series, and are connected in series with the output end of the current booster and the standard current transformer. The output end of the standard current transformer is connected to the secondary analog input end of the verification device.

[0006] In the embodiment of the present invention, each of the intervals of two-thirds of the wiring corresponds to a merging unit.

[0007] In the embodiment of the present invention, the merging unit is connected to the synchronization signal output terminal of the verification device for the time period, or the merging unit and the verification device are connected to the whole station time synchronization signal as well as the input terminal of the verification device at the same time.

[0008] In the embodiment of the present invention, the electronic current transformer calibration system further comprises: a voltage regulator;

[0009] The output end of the voltage regulator is connected to the input end of the current booster.

[0010] At the same time, the present invention also provides an electronic current transformer calibration method, using the aforementioned electronic current transformer calibration system to calibrate the electronic current transformer under test, the method comprising:

[0011] Disconnect the two-thirds connection bays from the busbar, and close the circuit breakers and disconnectors of each phase in each bay;

[0012] Connect the electronic current transformer under test in the two-thirds wiring form in series to the verification circuit;

[0013] Connect the merging unit corresponding to the interval of the tested electronic current transformer to the verification device, turn on the test voltage, adjust the voltage regulator, and verify the tested electronic current transformer connected in each phase in each interval.

[0014] In the embodiment of the present invention, the electronic mutual inductor to be tested is connected in series with a circuit breaker and a disconnector of one phase in one bay.

[0015] The present invention performs on-site verification of an electronic current transformer in a two-thirds wiring form, performs on-site verification of the electronic current transformer through the configuration of primary wiring, high-voltage switch electrical appliance operation, and verification equipment of the scheme, and improves the on-site verification efficiency of the electronic current transformer.

[0016] In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A wiring diagram for checking an electronic current transformer in the prior art;

[0019] Figure 2 It is a block diagram of the electronic current transformer calibration system disclosed in the present invention;

[0020] Figure 3 It is a flow chart of the electronic current transformer calibration method disclosed in the present invention;

[0021] Figure 4 FIG. 1 is a schematic diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] like Figure 2 As shown, it is a block diagram of an electronic current transformer calibration system disclosed in the present invention, comprising: a standard current transformer 101, a current booster 102, a calibration device 103, and a two-thirds connection 104 for connecting to the electronic current transformer under test; wherein,

[0024] The three strings of the two-thirds connection 104 are connected in series to the output ends of the standard current transformer 101 and the current booster 102 . The output end of the standard current transformer 101 is connected to the secondary analog input end of the verification device 103 .

[0025] In the embodiment of the present invention, the merging unit is connected to the synchronization signal output terminal of the verification device for the time period, or the merging unit and the verification device 103 and the input terminal of the verification device are simultaneously connected to the whole station time synchronization signal;

[0026] Each of the two-thirds wiring intervals corresponds to a merging unit.

[0027] At the same time, the present invention also provides an electronic current transformer calibration method, using the above-mentioned electronic current transformer calibration system to calibrate the electronic current transformer under test, such as Figure 3 As shown, the method includes:

[0028] Step S201, disconnect the two-thirds wiring bay from the busbar, and close the circuit breaker and disconnector of each phase in each bay;

[0029] Step S202, connecting the electronic current transformer under test in the two-thirds wiring form in series to the verification circuit;

[0030] Step S203, linking the merging unit corresponding to the interval of the electronic current transformer under test with the verification device, connecting the test voltage, and adjusting the voltage regulator to verify the electronic current transformer under test connected to each phase in each interval.

[0031] The present invention verifies the electronic current transformer on-site in the two-thirds wiring form, and verifies the electronic current transformer on-site through the configuration of the primary wiring, high-voltage switchgear operation, and verification equipment of the present solution, thereby improving the efficiency of the on-site verification of the electronic current transformer. The technical solution of the present invention is described in detail below in conjunction with specific embodiments.

[0032] In order to solve the problem of cumbersome testing procedures in the on-site verification of electronic current transformers in smart substations, it is necessary to continuously disconnect the primary test lines and secondary test lines one by one and repeatedly move the test equipment and auxiliary equipment. A scheme and device for high-efficiency on-site verification is provided to reduce the number of repeated wiring, reduce the number of voltage / current increases, reduce the repeated movement of experimental equipment, verify multiple error channels of multiple transformers at the same time, and automatically determine and identify verification points. This embodiment provides an efficient on-site testing scheme for electronic current transformers with a 3 / 2 wiring format.

[0033] The 3 / 2 wiring form is widely used in the primary electrical wiring of the power system. There are several strings of circuit breakers between the two sets of busbars. Each string has 3 circuit breakers. The middle one is called the connecting circuit breaker. A circuit is connected between every two circuit breakers, and there are two circuits in total. On average, each circuit is equipped with one and a half (3 / 2) circuit breakers, so it is called one and a half circuit breaker wiring, also known as two-thirds wiring. The main advantages of 3 / 2 wiring are high reliability, good operational flexibility, and convenient operation and maintenance. It is also widely used in smart substations. Each string of the 3 / 2 wiring form is equipped with 3 sets of current transformers or 4 sets of current transformers.

[0034] In order to facilitate the demonstration of the scheme, this embodiment is analyzed and explained with a 500kV interval of 3 / 2 connection, but the application of the technical solution of the present invention is not limited to the 500kV voltage level. In order to calibrate multiple electronic current transformers at one time, for a structure with a main connection form of 3 / 2 connection, consider connecting 12 electronic current transformers in a complete "string" of three phases according to the order of their spatial arrangement positions.

[0035] like Figure 4 As shown, it is a schematic diagram of the efficient on-site test scheme of the 3 / 2 wiring form electronic current transformer in this embodiment. Among them, the three phases of the 5051 interval each contain a tested electronic current transformer, that is, 5051A, 5051B, and 5051C each contain a tested electronic current transformer, wherein the tested electronic current transformer is connected in series with the disconnector and the circuit breaker therein; wherein the middle interval 5052 contains 6 tested electronic current transformers, because the current flowing through the middle interval 5052 is bidirectional, current transformers are usually configured on both sides of the middle interval, so the middle interval 5052 contains 2 groups, i.e. 6 current transformers.

[0036] Operation of high-voltage switchgear: disconnect the connection between the interval and the busbar; close the circuit breakers and disconnectors of the three phases A, B, and C of the 5051, 5052, and 5053 intervals; disconnect the grounding switches of the three phases A, B, and C of the 5051, 5052, and 5053 intervals.

[0037] Primary wiring: Figure 3 As shown, connect the primary current line "head to tail", lead out the "head" and "tail" of phase A and phase C, connect them in series with the output end of the booster and the standard current transformer; connect the output end of the voltage regulator to the input end of the booster;

[0038] Secondary wiring: The secondary outputs S1 and S2 of the standard current transformer are connected to the secondary analog input terminals of the verification device; the output optical fiber of the merging unit is connected to the data input terminal of the verification device; the timing terminal of the merging unit is connected to the synchronization signal output terminal of the verification device, or the synchronization signal input terminals of the merging unit and the verification device are simultaneously connected to the timing signal of the entire station.

[0039] On-site verification process:

[0040] 1. Perform high-voltage switchgear operation, primary current wiring, and secondary wiring in accordance with the above requirements;

[0041] 2. Connect the merging unit corresponding to the 5051 bay to the calibration device, turn on the test voltage, adjust the voltage regulator, and calibrate the three phases and three electronic current transformers of the 5051 bay at the same time. After recording the calibration data, return the voltage regulator to zero and cut off the power.

[0042] 3. Connect the merging unit corresponding to the 5052 bay to the calibration device, turn on the test voltage, adjust the voltage regulator, and calibrate the 6 electronic current transformers of the 5052 bay 3 phases at the same time. After recording the calibration data, return the voltage regulator to zero and cut off the power.

[0043] 4. Connect the merging unit corresponding to the 5053 bay to the calibration device, turn on the test voltage, adjust the voltage regulator, and calibrate the three phases and three electronic current transformers of the 5053 bay at the same time. After recording the calibration data, return the voltage regulator to zero and cut off the power.

[0044] 5. Remove the primary and secondary wires and restore the high-voltage switchgear to its original position.

[0045] When the traditional verification scheme verifies the 12 electronic current transformers equipped with the "A set + B set" combined unit configuration in this embodiment, for these 24 sets of error data, the experimental equipment requires a total of 1 voltage regulator, 1 current booster, 1 standard current transformer, a set of verification equipment, 2 primary high current lines, 2 secondary test lines, and 2 optical fibers; in terms of the test process, at least 12 primary connections, 24 secondary connections, and 24 current boosts are required, accompanied by the continuous movement of the equipment.

[0046] When adopting the scheme proposed by the present invention, in terms of experimental equipment, a total of 1 voltage regulator, 1 current booster, 1 standard current transformer, a set of calibration equipment, 4 primary large current lines, 2 secondary test lines, and 2 optical fibers are required, which only adds 2 large current lines compared to the traditional calibration scheme. In terms of the test process, if the calibration equipment can only connect to one merging unit, the test only requires one wiring, one secondary wiring, and 6 current boosts, and the equipment does not need to be moved during the test. If the calibration equipment can connect to multiple merging units and can be calibrated at the same time, the number of current boosts can be reduced. If 2 merging units can be connected when calibrating the equipment, the number of current boosts is reduced to 3 times. If 6 merging units can be connected when calibrating the equipment, the number of current boosts is reduced to 1 time. It can achieve a full calibration of 24 sets of error parameters corresponding to 12 electronic current transformers connected at one time.

[0047] This embodiment requires a total of 4 primary current lines, among which ② and ③ respectively connect the outgoing line of phase A 5051 interval with the outgoing line of phase B 5053 interval, and connect the outgoing line of phase B 5051 interval with the outgoing line of phase C 5051 interval, so that a total of 12 electronic current transformers on the three intervals 5051, 5052, and 5053 are connected in series, achieving the goal of 12 electronic current transformers passing through a single connection.

[0048] The present invention performs on-site verification of an electronic current transformer with a 3 / 2 wiring form, including pre-commissioning verification, first inspection after commissioning, periodic inspection, temporary inspection, etc. The electronic current transformer can be verified on-site through the primary wiring, high-voltage switchgear operation, and configuration of the verification equipment of the solution of the present application, thereby improving the on-site verification efficiency of the electronic current transformer.

[0049] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. An electronic current transformer calibration system, characterized in that: The electronic current transformer calibration system comprises: a standard current transformer, a current booster, a calibration device and two-thirds of the wiring of the electronic current transformer to be tested; wherein, Three strings of two-thirds wiring are connected in series, connected in series with the output end of the current booster and the standard current transformer, and the output end of the standard current transformer is connected to the secondary analog input end of the verification device; Among them, each interval of two-thirds of the wiring corresponds to a merging unit; Wherein, the merging unit is connected to the synchronization signal output terminal of the verification device for the time period; or the merging unit and the verification device and the input terminal of the verification device are simultaneously connected to the whole station time synchronization signal; Wherein, the electronic current transformer calibration system further comprises: a voltage regulator; the output end of the voltage regulator is connected to the input end of the current booster; The intervals of the two-thirds connection include a first interval (5051), a second interval (5052) and a third interval (5053), the three phases of the first interval each include one electronic current transformer under test, the second interval includes six electronic current transformers under test, and the three phases of the third interval each include one electronic current transformer under test; The three-quarter wiring includes 4 primary high current wires, 2 secondary test wires and 2 optical fibers; If the verification device is connected to one merging unit, it needs to be wired once, wired once, and increased current six times; if the verification device is connected to two merging units, the number of times of increasing current is reduced to three times; if the verification device is connected to six merging units, the number of times of increasing current is reduced to one time; The primary wiring is as follows: connecting the primary large current line head to tail, leading out the head and tail of phase A and phase C and connecting them in series with the output end of the current booster and the standard current transformer; and connecting the output end of the voltage regulator to the input end of the current booster; The secondary wiring is as follows: the secondary outputs S1 and S2 of the standard current transformer are connected to the secondary analog input terminals of the verification device; the output optical fiber of the merging unit is connected to the data input terminal of the verification device; the timing terminal of the merging unit is connected to the synchronization signal output terminal of the verification device, or the synchronization signal input terminal of the merging unit and the verification device are simultaneously connected to the whole station timing signal.

2. A method for calibrating an electronic current transformer, characterized in that: The method uses the electronic current transformer calibration system according to any one of claims 1 to calibrate the electronic current transformer under test, and the method comprises: Disconnect the two-thirds connection bays from the busbar, and close the circuit breakers and disconnectors of each phase in each bay; Connect the electronic current transformer under test in the two-thirds wiring form in series to the verification circuit; Connect the merging unit corresponding to the interval of the tested electronic current transformer to the verification device, turn on the test voltage, adjust the voltage regulator, and verify the tested electronic current transformer connected to each phase in each interval; The method specifically includes: Performing high-voltage switchgear operation, primary wiring and secondary wiring, wherein the high-voltage switchgear operation includes: disconnecting the connection between the interval and the busbar; closing the circuit breakers and disconnecting switches of the A, B and C phases of the first interval, the second interval and the third interval; disconnecting the grounding switches of the A, B and C phases of the first interval, the second interval and the third interval; Connect the merging unit corresponding to the first interval to the verification device, turn on the test voltage, adjust the voltage regulator, and verify the three electronic current transformers of the three phases of the first interval at the same time. After recording the verification data, return the voltage regulator to zero and cut off the power; Connect the merging unit corresponding to the second interval to the verification device, turn on the test voltage, adjust the voltage regulator, and verify the three-phase six electronic current transformers of the second interval at the same time. After recording the verification data, return the voltage regulator to zero and cut off the power; Connect the merging unit corresponding to the third interval to the verification device, turn on the test voltage, adjust the voltage regulator, and verify the three-phase three electronic current transformers of the third interval at the same time. After recording the verification data, the voltage regulator is reset to zero and the power is turned off; Remove the primary and secondary wires and restore the high-voltage switchgear to its original position.

3. The electronic current transformer calibration method according to claim 2, characterized in that: The electronic transformer under test is connected in series with the circuit breakers and disconnectors of each phase in a bay.

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