A multi-winding current transformer test device

Abstract

The utility model discloses a multi-winding current transformer test device, including a current output device and an input detection device, wherein the current output device has a primary current output interface P1, P2 and a first communication interface, and the input detection device has a four-winding secondary current input interface, a four-winding direct resistance input interface and a second communication interface; the first communication interface and the second communication interface are connected for communication, and the input detection device tests the secondary current and the loop direct resistance while acquiring a square wave signal output by the current output device, which is used for polarity discrimination and loop direct resistance test of the CT four-winding three-phase. The utility model integrates multi-interface input, primary wiring, multi-channel transformer multi-winding test, and automatically analyzes and displays the test results, with simple operation and high test efficiency.

Description

Technical Field

[0001] The utility model relates to the field of transformer operation and maintenance detection, and in particular to a multi-winding current transformer testing device. Background Art

[0002] The polarity of the current transformer (CT) does not correspond, the CT secondary circuit is open, or the connection is virtual, resulting in excessive DC resistance, which does not meet the requirements of on-site protection and measurement error; or causes relay protection and safety automatic devices to malfunction or refuse to operate, posing a safety hazard. Therefore, it is necessary to regularly measure the CT polarity and secondary circuit DC resistance, and determine whether it exceeds the maximum allowable load.

[0003] In the prior art, when measuring the internal resistance of a CT, a multimeter is still mostly used to measure the single-phase winding. Since the resistance value to be measured is different and the fixed resistors used are different, it is usually necessary to adjust the gear before testing, and it takes a long time to obtain a stable value, and accurate measurement results cannot be obtained quickly. It is impossible to measure the internal resistance of a multi-branch CT loop winding at the same time, and it takes a lot of time to measure multiple windings one by one.

[0004] Chinese patent CN2020105016586 discloses a current transformer internal resistance measuring instrument, which adds multiple winding internal resistance measurement displays. However, the measurement is controlled by the gear paddles and reading switches on the device, which is inconvenient to operate. Each measured value corresponds to an LCD display, and it is impossible to quickly and uniformly view the data and automatically analyze whether there is a data tolerance problem. Utility Model Content

[0005] Aiming at the problems in the prior art that the instrument is inconvenient to operate in the test of multi-branch current transformer windings and the efficiency of testing multiple windings one by one is low, the utility model proposes a multi-winding current transformer testing device, which integrates multi-interface input, one-time wiring, multi-branch testing and automatic analysis and display of test results, with simple operation and high testing efficiency.

[0006] The utility model provides the following technical solutions:

[0007] A multi-winding current transformer test device comprises a current output device and an input detection device, wherein the current output device has primary current output interfaces P1 and P2 and a first communication interface, and the input detection device has a four-winding secondary current input interface, a four-winding direct resistance input interface and a second communication interface; the first communication interface and the second communication interface are connected for communication, and the input detection device tests the secondary current and the loop direct resistance while acquiring a square wave signal output by the current output device, which is used for polarity discrimination of the three-phase of the CT four-winding and the loop direct resistance test.

[0008] Optionally, the primary current output interface P1 is connected to the outgoing line of the primary current loop of the CT, and the primary current output interface P2 is connected to the incoming line of the primary current loop, so as to inject the test current into the primary side of the CT;

[0009] The four-winding secondary current input interface includes a secondary current inflow interface of winding 1, a secondary current inflow interface of winding 2, a secondary current inflow interface of winding 3, a secondary current inflow interface of winding 4 and a secondary current outflow interface; the input detection device obtains the square wave signal output by the current output device and measures the polarity of the four windings of the CT at one time.

[0010] Optionally, the four-winding direct resistance input interface includes a winding 1 input interface, a winding 2 input interface, a winding 3 input interface, and a winding 4 input interface;

[0011] Further, the input detection device has a built-in relay switching unit and a DC source measurement unit, and the relay switches the four-winding DC resistance input interface to be connected to the DC source measurement unit to perform a four-loop DC resistance test;

[0012] The relay switching unit includes the positive ends of the winding 1 input interface, the winding 2 input interface, the winding 3 input interface and the winding 4 input interface, and selects one S1 for access; the negative ends of the winding 1 input interface, the winding 2 input interface, the winding 3 input interface and the winding 4 input interface, and selects one S2 for access;

[0013] The DC source measurement unit includes a DC power supply unit, a precision resistance test unit and an S1, S2 access detection unit. The DC power supply unit is connected to the precision resistance test unit and the S1, S2 access detection unit. By detecting the voltage of the DC power supply unit and the voltage of the precision resistance test unit, the resistance value measured by the S1, S2 access detection unit is obtained.

[0014] Optionally, the first communication interface and the second communication interface are wired communication or wireless communication;

[0015] Furthermore, the first communication interface and the second communication interface are wired communications, and are used for connection communication when the primary side and the secondary side are in close proximity;

[0016] Furthermore, the first communication interface and the second communication interface are wireless communications, and are used for connection and communication when the primary side and the secondary side are at a long distance.

[0017] Optionally, the input detection device includes a human-computer interaction module, including a wire resistance setting unit and an automatic alarm unit, and the touch operation controls the measurement process, sets the wire resistance, stores the measurement results, and directly checks the test results through the display;

[0018] Further, the wire resistance setting unit short-circuits the four-winding direct resistance input interface with a test line to obtain the wire resistance and set it to adjust the test accuracy;

[0019] Furthermore, the automatic alarm unit starts an automatic alarm prompt when the deviation of the measurement result of the direct resistance input of the four-winding is too large.

[0020] Compared with the prior art, the utility model has the following remarkable effects:

[0021] The utility model, while the input detection device tests the secondary current and the loop direct resistance, obtains the square wave signal output by the current output device, which is used for polarity discrimination of the three-phase of the CT four-winding and the loop direct resistance test, with one-time wiring and simple operation;

[0022] The input detection device of the utility model includes a relay switching circuit and a DC source, which automatically switches to measure different windings, and the test results of multiple windings are intuitively displayed;

[0023] The input detection device of the utility model includes a wire resistance setting unit, and the wire resistance is not included in the measurement of the secondary circuit direct resistance, thereby improving the accuracy of CT current circuit measurement and reducing measurement errors;

[0024] The utility model can be used for multi-branch testing of different phases of the same winding or different windings of the same phase, effectively solving the problem of easy errors and omissions in manual switching during multi-branch CT winding testing, ensuring the normal operation of CT and improving the "four properties" of relay protection devices; through multi-branch testing, it enriches the maintenance means of maintenance personnel and makes measurement and maintenance lean, standardized and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the accompanying drawings required for describing the embodiments are introduced below.

[0026] In the attached picture:

[0027] Figure 1 This is a schematic diagram of the connection and measurement of an embodiment of the utility model;

[0028] Figure 2 This is a structural diagram of an embodiment of the utility model;

[0029] Figure 3 Input detection device module structure diagram for one embodiment of the utility model;

[0030] Figure 4 A relay switching circuit and a DC source circuit diagram of an embodiment of the utility model;

[0031] Figure 5 This is a schematic diagram of multi-branch polarity and direct resistance test connections in one embodiment of the utility model.

[0032] Description of main reference numerals:

[0033] S1, current output device; S2, input detection device; 1, primary current output P1 interface; 2, primary current output P2 interface; 3, first communication interface; 4, winding 1 direct resistance S1 input interface; 5, winding 1 direct resistance S2 input interface; 6, winding 2 direct resistance S1 input interface; 7, winding 2 direct resistance S2 input interface; 8, winding 3 direct resistance S1 input interface; 9, winding 3 direct resistance S2 input interface; 10, winding 4 direct resistance S1 input interface; 11, winding 4 direct resistance S2 input interface; 12, winding 1 secondary current output Input interface; 13, winding 2 secondary current input interface; 14, winding 3 secondary current input interface; 15, winding 4 secondary current input interface; 16, winding secondary current input N-terminal interface; 17, second communication interface; 301, four-winding polarity measurement module; 302, four-winding DC resistance input detection; 303, relay switching unit; 304, DC source measurement unit; 305, analysis and processing module; 306, communication module; 307, human-computer interaction module; 308, touch display unit; 309, automatic alarm unit. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0035] The utility model discloses a multi-winding current transformer test device, comprising a current output device S1 and an input detection device S2. Figure 1 The current output device S1 is connected to the primary side of the CT and injects a square wave signal into the CT circuit; the input detection device S2 is connected to the secondary side of the CT and the two ends of the secondary circuit terminal block to measure the secondary current and circuit direct resistance of the CT secondary circuit; the current output device S1 is connected to the input detection device S2, and the input detection device S2 simultaneously obtains the square wave signal injected into the CT circuit by the current output device S1, and measures the secondary current of the CT secondary circuit to determine the CT polarity.

[0036] Specifically, refer to Figure 2 , the current output device S1 comprises: a primary current output P1 interface 1, a primary current output P2 interface 2 and a first communication interface 3;

[0037] The input detection device S2 includes: a winding 1 direct resistance S1 input interface 4, a winding 1 direct resistance S2 input interface 5, a winding 2 direct resistance S1 input interface 6, a winding 2 direct resistance S2 input interface 7, a winding 3 direct resistance S1 input interface 8, a winding 3 direct resistance S2 input interface 9, a winding 4 direct resistance S1 input interface 10, a winding 4 direct resistance S2 input interface 11, a winding 1 secondary current input interface 12, a winding 2 secondary current input interface 13, a winding 3 secondary current input interface 14, a winding 4 secondary current input interface 15, a winding secondary current input N-terminal interface 16 and a second communication interface 17;

[0038] Further, the primary current output P1 interface 1 is connected to the outgoing line of the primary current loop of the CT, and the primary current output P2 interface 2 is connected to the incoming line of the primary current loop, and a square wave signal is injected into the CT loop;

[0039] Further, the winding 1 secondary current input interface 12, the winding 2 secondary current input interface 13, the winding 3 secondary current input interface 14, the winding 4 secondary current input interface 15, and the winding secondary current input N-terminal interface 16 are connected to each winding loop of the CT, and the winding 1 secondary current input interface 12 and the winding secondary current input N-terminal interface 16 are used to measure the secondary current of the winding 1; the winding 2 secondary current input interface 13 and the winding secondary current input N-terminal interface 16 are used to measure the secondary current of the winding 2; the winding 3 secondary current input interface 14 and the winding secondary current input N-terminal interface 16 are used to measure the secondary current of the winding 3; the winding 4 secondary current input interface 15 and the winding secondary current input N-terminal interface 16 are used to measure the secondary current of the winding 4;

[0040] Furthermore, the first communication interface 3 and the second communication interface 17 are connected for communication, and wired communication can be selected, and the first communication interface 3 and the second communication interface 17 are directly connected by a data communication line, and are used for connection and communication when the primary side and the secondary side of the CT are in close proximity; wireless communication can be selected, and 2.4G wireless transmission can be used for connection and communication when the primary side and the secondary side of the CT are in long proximity; the input detection device S1 obtains the square wave signal output by the current output device S1, and measures the polarity of the four windings of the CT at one time.

[0041] As an optional implementation:

[0042] Reference Figure 3 , the input detection device of the utility model comprises: a four-winding polarity measurement module 301, a four-winding direct resistance input detection module 302, an analysis and processing module 305, a communication module 306 and a human-computer interaction module 307;

[0043] Specifically, the output of the four-winding polarity measurement module 301 is connected to the analysis and processing module 305, the four-winding direct resistance input detection module 302 is connected to the analysis and processing module 305, the analysis and processing module 305 is connected to the communication module 306 and the human-computer interaction module 307, and the four-winding secondary current input and the four-winding direct resistance input are simultaneously input, and the square wave signal output by the current output device is obtained through the communication module 306, and after analysis and processing, it is operated and displayed through the human-computer interaction module 307.

[0044] Further, the four-winding polarity measurement module 301 is respectively connected to the winding 1 secondary current input interface 12, the winding 2 secondary current input interface 13, the winding 3 secondary current input interface 14, the winding 4 secondary current input interface 15, and the winding secondary current input N-terminal interface 16.

[0045] Furthermore, the four-winding DC resistance input detection module 302 includes a relay switching unit 303 and a DC source measurement unit 304:

[0046] Reference Figure 4 The relay switching unit 303 is composed of 6 single-pole double-throw relays. The winding 1 direct resistance S1 input interface 4 and the winding 2 direct resistance S1 input interface 6 are connected to the relay K1, and one path is selected as the output of the relay K1. The winding 3 direct resistance S1 input interface 8 and the winding 4 direct resistance S1 input interface 10 are connected to the relay K2, and one path is selected as the output of the relay K2. The output of the relay K1 and the output of the relay K2 are used as the input of the relay K3. One path is selected as the output of the relay K3, and the positive end of the S1 of the direct resistance of the winding to be measured is connected to the DC source measurement. The measurement unit 304 is connected; the winding 1 direct resistance S2 input interface 5 and the winding 2 direct resistance S2 input interface 7 are connected to the relay K4, one path is selected as the output of the relay K4, the winding 3 direct resistance S2 input interface 9 and the winding 4 direct resistance S2 input interface 11 are connected to the relay K5, one path is selected as the output of the relay K5, the output of the relay K4 and the output of the relay K5 are used as the input of the relay K6, one path is selected as the output of the relay K6, and the negative end of S2 of the direct resistance of the winding to be measured is connected to the DC source measurement unit 304, and a four-loop direct resistance switching test is performed;

[0047] The DC power supply unit of the DC power supply measurement unit 304 is connected to the precision resistor R1 test unit and the S1 positive terminal and S2 negative terminal access detection unit. By detecting the voltage V1 of the DC power supply unit and the voltage V2 of the precision resistor R1 test unit, the DC resistance value R=(V1-V2)*R1 / V2 measured by the S1 and S2 access detection units is obtained.

[0048] Furthermore, the communication module is connected to the second communication interface 17 .

[0049] Furthermore, the human-computer interaction module 307 includes a wire resistance setting unit 308 and an automatic alarm unit 309, which controls the measurement process, sets the wire resistance, and stores the measurement results through touch operation, and directly checks the test results through display;

[0050] Optionally, the wire resistance setting unit 308 short-circuits the input interface corresponding to the four-winding direct resistance input detection module 301 with a test line to measure and set the wire resistance RL. During actual measurement, the test accuracy is adjusted through the analysis and processing module 305.

[0051] Optionally, the automatic alarm unit 309 starts an automatic alarm prompt if there is a large deviation in the measurement results of the direct resistance input of the four windings, and the deviation between the maximum and minimum values ​​exceeds 10%; the polarity of four windings is measured at one time, and the polarity of 12 windings in three phases can be measured three times, and a three-phase polarity comparison is performed. If the test is inconsistent, an automatic alarm prompt is started.

[0052] As an optional implementation:

[0053] Reference Figure 5 , the current output device S1 is connected to AP1 and AP2 of the A-phase CT to inject a square wave signal. The secondary side of the A-phase CT has four winding branches. 12, 13, 14, 15, and 16 of the input detection device S2 are respectively connected to the loops of the secondary sides of the four windings. The current output device S1 is wirelessly connected to the input detection device S2. The current output device S1 outputs in the form of a square wave signal, which becomes a pair of positive and negative sharp pulses after passing through the current transformer and the four-winding polarity measurement module 301 inside the input detection device S2. The analysis and processing module 305 determines the positive and negative polarity of the current transformer according to the order of arrival of the detected positive and negative pulses, and once determines the polarity of the four windings of the A-phase CT;

[0054] The connecting pieces between the 101 interfaces, 201 interfaces, 301 interfaces and 401 interfaces of the terminal block are disconnected, and the 4 and 5 of the input detection device S2 are respectively connected to the two ends of the 101 interface of the terminal block, the 6 and 7 of the input detection device S2 are respectively connected to the two ends of the 201 interface of the terminal block, the 8 and 9 of the input detection device S2 are respectively connected to the two ends of the 301 interface of the terminal block, and the 10 and 11 of the input detection device S2 are respectively connected to the two ends of the 401 interface of the terminal block, and the direct resistance of the secondary circuit of the four-winding of the A-phase CT is measured once.

Claims

1. A multi-winding current transformer test device, characterized in that: Including current output device and input detection device: The current output device has a primary current output interface P1, P2 and a first communication interface; the input detection device has a four-winding secondary current input interface, a four-winding direct resistance input interface and a second communication interface; the first communication interface and the second communication interface are connected for communication, and the input detection device tests the secondary current and the loop direct resistance while obtaining the square wave signal output by the current output device, which is used for polarity determination of the three-phase of the CT four-winding and the loop direct resistance test.

2. A multi-winding current transformer testing device according to claim 1, characterized in that: The four-winding secondary current input interface includes a secondary current inflow interface of winding 1, a secondary current inflow interface of winding 2, a secondary current inflow interface of winding 3, a secondary current inflow interface of winding 4 and a secondary current outflow interface; the input detection device obtains the square wave signal output by the current output device and measures the polarity of the four windings of the CT at one time.

3. A multi-winding current transformer testing device according to claim 1, characterized in that: The four-winding direct resistance input interface includes a winding 1 input interface, a winding 2 input interface, a winding 3 input interface, and a winding 4 input interface, and each interface is connected to a four-winding direct resistance input detection module.

4. A multi-winding current transformer testing device according to claim 1, characterized in that: The first communication interface and the second communication interface are wired communications, and are used for connection communication when the primary side and the secondary side are in close proximity.

5. A multi-winding current transformer testing device according to claim 1, characterized in that: The first communication interface and the second communication interface are wireless communications, and are used for connection and communication when the primary side and the secondary side are at a long distance.

6. A multi-winding current transformer testing device according to claim 1, characterized in that: Each interface of the four-winding direct resistance input interface is connected to a four-winding direct resistance input detection module, including a relay switching unit and a DC source measurement unit. The relay switching four-winding direct resistance input interface is connected to the DC source measurement unit for four-loop direct resistance testing.

7. A multi-winding current transformer testing device according to claim 1, characterized in that: Each interface of the four-winding direct resistance input interface is connected to a four-winding direct resistance input detection module, and its relay switching unit includes the positive ends of the winding 1 input interface, the winding 2 input interface, the winding 3 input interface and the winding 4 input interface, and selects one S1 for access; the negative ends of the winding 1 input interface, the winding 2 input interface, the winding 3 input interface and the winding 4 input interface, select one S2 for access.

8. A multi-winding current transformer testing device according to claim 1, characterized in that: Each interface of the four-winding direct resistance input interface is connected to a four-winding direct resistance input detection module, and its DC source measurement unit includes a DC power supply unit, a precision resistance test unit and an S1, S2 access detection unit. The DC power supply unit is connected to the precision resistance test unit and the S1, S2 access detection unit. By detecting the voltage of the DC power supply unit and the voltage of the precision resistance test unit, the resistance value measured by the S1, S2 access detection unit is obtained.

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