Wiring switching device and method for transformer energy efficiency test

Abstract

The present invention provides a wiring switching device and method for transformer energy efficiency tests, which includes a hybrid group of relays and AC contactors, a test power input interface, test cables, a PLC5, a communication control interface, and a measurement interface; wherein, the hybrid group of relays and AC contactors is electrically connected to a test power supply through the test power input interface and is electrically connected to a transformer under test through the test cables; the PLC is signal-connected to a computer control system through the communication control interface, the computer control system is used to control the operation of the PLC, the PLC is used to control the opening and closing of the relays in the hybrid group of relays and AC contactors, and the disconnection and closing of the AC contactors; the hybrid group of relays and AC contactors is electrically connected to a measurement system through the measurement interface. The present invention realizes automatic wiring switching between different transformer energy efficiency tests and improves the wiring switching efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer testing, and particularly to a wiring switching device and method for transformer energy efficiency tests. Background Art

[0002] Transformer energy efficiency test items include winding resistance measurement, no-load loss and no-load current measurement tests, short-circuit impedance and load loss measurement tests.

[0003] In these transformer energy efficiency tests, the line connections of the test power supply, measuring equipment, and the transformer under test are involved. The wiring methods for different energy efficiency tests are different, and different wiring methods require different wiring pliers, connecting cables, connecting copper plates, etc. During the process of conducting multiple energy efficiency tests, it is necessary to switch the wiring method, that is, switch from one wiring method for an energy efficiency test to another wiring method for an energy efficiency test.

[0004] Currently, the wiring switching during the transformer energy efficiency test process is completed manually. The line switching work is time-consuming and laborious, and requires technicians to be familiar with the wiring methods of various energy efficiency tests. Summary of the Invention

[0005] The present invention provides a wiring switching device and method for transformer energy efficiency tests to solve the defect that the wiring switching during the transformer energy efficiency test process in the prior art is completed manually, which is time-consuming, laborious, and requires professional knowledge, and realizes automatic switching of various wirings for transformer energy efficiency tests.

[0006] The present invention provides a wiring switching device for transformer energy efficiency tests, including a relay and AC contactor hybrid group, a test power supply input interface, test cables, a PLC5, a communication control interface, and a measurement interface;

[0007] Among them, the relay and AC contactor hybrid group is electrically connected to the test power supply through the test power supply input interface and is electrically connected to the transformer under test through the test cables;

[0008] The PLC is signal-connected to the computer control system through the communication control interface. The computer control system is used to control the operation of the PLC, and the PLC is used to control the opening and closing of the relays in the relay and AC contactor hybrid group and the disconnection and closing of the AC contactors;

[0009] The relay and AC contactor hybrid group is electrically connected to the measurement system through the measurement interface.

[0010] According to the wiring switching device for transformer energy efficiency tests provided by the present invention, the test cables include primary side cables and secondary side cables;

[0011] The relay and AC contactor hybrid group is electrically connected to the primary side terminals of the transformer under test through the primary side cable;

[0012] The relay and AC contactor hybrid group is electrically connected to the secondary side terminals of the transformer under test through the secondary side cable.

[0013] According to a wiring switching device for transformer energy efficiency test provided by the present invention, the relay and AC contactor hybrid group includes three first relay and AC contactor hybrid groups, three second relay and AC contactor hybrid groups and a relay group;

[0014] Among them, the three first relay and AC contactor hybrid groups are electrically connected to the primary side A-phase, B-phase and C-phase terminals of the transformer under test through the primary side cable respectively, and are electrically connected to the primary side A-phase, B-phase and C-phase terminal blocks of the measurement interface respectively, and are electrically connected to the U-phase, V-phase and W-phase terminals of the test power input interface respectively;

[0015] The three second relay and AC contactor hybrid groups are electrically connected to the secondary side A-phase, B-phase and C-phase terminals of the transformer under test through the secondary side cable respectively, and are electrically connected to the secondary side A-phase, B-phase and C-phase terminal blocks of the measurement interface respectively, and are electrically connected to the U-phase, V-phase and W-phase terminals of the test power input interface respectively;

[0016] The relay group is electrically connected to the secondary side N-phase terminal of the transformer under test through the secondary side cable, and is electrically connected to the secondary side N-phase terminal block of the measurement interface.

[0017] According to a wiring switching device for transformer energy efficiency test provided by the present invention, the first relay and AC contactor hybrid group includes a first AC contactor, a second AC contactor, a third AC contactor and a first relay;

[0018] Among them, one contact of the first AC contactor is electrically connected to the primary side terminal of the transformer under test through the primary side cable, and the other contact is electrically connected to the primary side terminal block of the measurement interface through a set of contacts of the first relay;

[0019] One contact of the second AC contactor is electrically connected to the primary side terminal of the transformer under test through the primary side cable, and the other contact is electrically connected to the primary side terminal block of the measurement interface through another set of contacts of the first relay, and is electrically connected to one contact of the third AC contactor;

[0020] The other contact of the third AC contactor is electrically connected to the primary side terminal block of the measurement interface and is electrically connected to the terminal of the test power input interface.

[0021] According to a wiring switching device for transformer energy efficiency test provided by the present invention, the measurement system includes a transformer loss measurement system and a DC resistance tester;

[0022] One set of contacts of the first relay is connected to the terminal in the primary side terminal block of the measurement interface for connecting the voltage line of the DC resistance tester;

[0023] Another set of contacts of the first relay is connected to the terminal in the primary side terminal block of the measurement interface for connecting the current line of the DC resistance tester;

[0024] Another contact of the third AC contactor is connected to the terminal in the primary side terminal block of the measurement interface for connecting the voltage measurement line of the transformer loss measurement system.

[0025] According to a wiring switching device for transformer energy efficiency test provided by the present invention, the second relay and AC contactor hybrid group includes a fourth AC contactor, a fifth AC contactor and a second relay;

[0026] Wherein, one contact of the fourth AC contactor and one contact of the fifth AC contactor are electrically connected to the secondary side terminals of the transformer under test through the secondary side cable;

[0027] Another contact of the fourth AC contactor is electrically connected to the load test short-circuit copper bar, and another contact of the fifth AC contactor is electrically connected to the secondary side terminal block of the measurement interface and is electrically connected to the terminal of the test power input interface; wherein, another contact of the fourth AC contactor in the three second relay and AC contactor hybrid groups is connected to the same load test short-circuit copper bar;

[0028] The secondary side terminal block of the measurement interface is electrically connected to the secondary side terminals of the transformer under test through a set of contacts of the second relay and the secondary side cable;

[0029] The secondary side terminal block of the measurement interface is electrically connected to the secondary side terminals of the transformer under test through another set of contacts of the second relay and the sandwich wire of the secondary side cable.

[0030] According to a wiring switching device for transformer energy efficiency test provided by the present invention, the measurement system includes a transformer loss measurement system and a DC resistance tester;

[0031] Another contact of the fifth AC contactor is connected to the terminal in the secondary side terminal block of the measurement interface for connecting the voltage measurement line of the transformer loss measurement system;

[0032] One set of contacts in the second relay is connected to a terminal in the secondary terminal block of the measurement interface for connecting the current line of the DC resistance tester;

[0033] Another set of contacts in the second relay is connected to a terminal in the secondary terminal block of the measurement interface for connecting the voltage line of the DC resistance tester.

[0034] According to a wiring switching device for transformer energy efficiency test provided by the present invention, the relay group includes a third relay;

[0035] The secondary N-phase terminal block of the measurement interface is electrically connected to the secondary N-phase terminal of the transformer under test through two sets of contacts of the third relay.

[0036] The present invention also provides a wiring switching method for transformer energy efficiency test based on the above-mentioned wiring switching device for transformer energy efficiency test, including:

[0037] Based on the computer control system, control the operation of the PLC;

[0038] Based on the running PLC, control the opening and closing of the relays in the relay and AC contactor hybrid group, and the opening and closing of the AC contactors.

[0039] According to a wiring switching method for transformer energy efficiency test provided by the present invention, the control of the opening and closing of the relays in the relay and AC contactor hybrid group and the opening and closing of the AC contactors based on the running PLC includes:

[0040] When performing an open-circuit test on the transformer under test, based on the running PLC, control all the relays in the relay and AC contactor hybrid group to be disconnected, all the AC contactors in the three first relay and AC contactor hybrid groups to be disconnected, the fourth AC contactor in the three second relay and AC contactor hybrid groups to be disconnected, and the fifth AC contactor to be closed;

[0041] When performing a load test on the transformer under test, based on the running PLC, control all the relays in the relay and AC contactor hybrid group to be disconnected, the second and third AC contactors in the three first relay and AC contactor hybrid groups to be closed, the first AC contactor to be disconnected, the fourth AC contactor to be closed, and the fifth AC contactor to be disconnected;

[0042] When performing a DC resistance test on the transformer under test, based on the running PLC, control all the relays in the relay and AC contactor hybrid group to be closed, the first and second AC contactors to be closed, the third AC contactor to be disconnected, and the fourth and fifth AC contactors to be disconnected.

[0043] The wiring switching device and method for transformer energy efficiency test provided by the present invention are controlled by an external computer control system through the wiring switching device. The on-off of each relay and AC contactor in the relay and AC contactor hybrid group is controlled by a PLC, and the wiring between different transformer energy efficiency tests can be automatically switched after one wiring, improving the efficiency of wiring switching. Brief Description of the Drawings

[0044] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0045] Figure 1 is one of the structural schematic diagrams of the wiring switching device for transformer energy efficiency test provided by the present invention;

[0046] Figure 2 is the second structural schematic diagram of the wiring switching device for transformer energy efficiency test provided by the present invention;

[0047] Figure 3 is the flow schematic diagram of the wiring switching method for transformer energy efficiency test provided by the present invention. Detailed Embodiments

[0048] To make the objectives, technical solutions and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention in conjunction with the drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments in 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.

[0049] The following will describe in conjunction with Figure 1 a wiring switching device for transformer energy efficiency test of the present invention, including a relay and AC contactor hybrid group, a test power input interface, a test cable, a PLC (Programmable Logic Controller), a communication control interface, and a measurement interface;

[0050] Among them, the relay and AC contactor hybrid group is electrically connected to the test power supply through the test power input interface and is electrically connected to the transformer under test through the test cable;

[0051] The relay and AC contactor hybrid group includes a relay and an AC contactor. Optionally, the type of the relay is DPST.

[0052] The test power input interface is a set of connection terminals for connecting an external test power supply, such as a three-phase alternating current (AC) power supply like a generator set, a voltage regulator, or a digital power supply.

[0053] The test power input interface is electrically connected to the relay and AC contactor hybrid group inside the wiring switching device. The external test power supply is connected to the wiring switching device through the test power input interface to provide a three-phase AC power supply for the transformer energy efficiency test.

[0054] The test cable is electrically connected to the relay and AC contactor hybrid group inside the wiring switching device and is used to connect the transformer under test.

[0055] The PLC is signal-connected to the computer control system through the communication control interface. The computer control system is used to control the operation of the PLC, and the PLC is used to control the opening and closing of the relay in the relay and AC contactor hybrid group, as well as the disconnection and closing of the AC contactor.

[0056] The communication control interface is used to connect the external computer control system and the PLC to enable communication between the external computer control system and the PLC. The operation of the program in the PLC is controlled by the external computer control system. Optionally, the communication control interface is an RJ45 network port or an RS485 serial interface.

[0057] The IO (Input and Output) points of the PLC are connected to the control coils of the relay and AC contactor hybrid group, and the relay and AC contactor hybrid group is connected to the test power input interface, the test cable, and the measurement interface.

[0058] The PLC controls each relay and AC contactor in the relay and AC contactor hybrid group to close or open according to a preset logic, realizing different connections between the test power input interface, the test cable, and the measurement interface, thereby automatically switching various wiring methods for the transformer energy efficiency test.

[0059] The relay and AC contactor hybrid group is electrically connected to the measurement system through the measurement interface.

[0060] The measurement interface is a terminal block connected to the relay and AC contactor hybrid group and is used to connect the measurement cables of the external transformer measurement system to collect various data in the transformer energy efficiency test. The transformer energy efficiency test includes transformer winding resistance measurement, no-load loss and no-load current measurement tests, and short-circuit impedance and load loss measurement tests.

[0061] The wiring switching device in this embodiment is controlled by an external computer control system. Through the PLC, the on / off of each relay and AC contactor in the relay and AC contactor hybrid group is controlled. After one wiring, the wiring between different transformer energy efficiency tests can be automatically switched, improving the efficiency of wiring switching.

[0062] Based on the above embodiment, in this embodiment, the test cable includes a primary side cable and a secondary side cable;

[0063] The relay and AC contactor hybrid group is electrically connected to the primary side terminals of the transformer under test through the primary side cable;

[0064] The relay and AC contactor hybrid group is electrically connected to the secondary side terminals of the transformer under test through the secondary side cable.

[0065] The test cable in this embodiment is divided into a primary side cable and a secondary side cable according to the terminals connected to the transformer to be tested, and are respectively connected to the primary terminals and secondary terminals of the transformer under test before the energy efficiency test, and the wiring is not changed or switched during the energy efficiency test.

[0066] Based on the above embodiment, as Figure 2 shown, in this embodiment, the relay and AC contactor hybrid group includes three first relay and AC contactor hybrid groups, three second relay and AC contactor hybrid groups and a relay group;

[0067] Among them, the three first relay and AC contactor hybrid groups are electrically connected to the primary side A-phase, B-phase and C-phase terminals of the transformer under test through the primary side cable one by one, and are electrically connected to the primary side A-phase, B-phase and C-phase terminal blocks of the measurement interface one by one, and are electrically connected to the U-phase, V-phase and W-phase terminals of the test power input interface one by one;

[0068] The primary side cable includes high-voltage cables 1 to 6. Among them, high-voltage cables 1 and 2 are connected to the primary side A-phase terminal of the transformer under test, high-voltage cables 3 and 4 are connected to the primary side B-phase terminal of the transformer under test, and high-voltage cables 5 and 6 are connected to the primary side C-phase terminal of the transformer under test.

[0069] The relay and AC contactor hybrid group connected to the primary side cable is used as the first relay and AC contactor hybrid group, and the structures of the three first relay and AC contactor hybrid groups are the same.

[0070] In the wiring switching device, the first relay and AC contactor hybrid group connected to the primary side A-phase terminal of the transformer under test through the primary side cable is regarded as group A, the first relay and AC contactor hybrid group connected to the primary side B-phase terminal of the transformer under test through the primary side cable is regarded as group B, and the first relay and AC contactor hybrid group connected to the primary side C-phase terminal of the transformer under test through the primary side cable is regarded as group C.

[0071] The three second relay and AC contactor hybrid groups are electrically connected to the secondary side A-phase, B-phase, and C-phase terminals of the transformer under test through the secondary side cable in a one-to-one correspondence, and are electrically connected to the secondary side A-phase, B-phase, and C-phase terminal blocks of the measurement interface in a one-to-one correspondence, and are electrically connected to the U-phase, V-phase, and W-phase terminals of the test power input interface in a one-to-one correspondence;

[0072] The relay group is electrically connected to the secondary side N-phase terminal of the transformer under test through the secondary side cable, and is electrically connected to the secondary side N-phase terminal block of the measurement interface.

[0073] The secondary side cable includes a large current cable 1, a large current cable 2, a large current cable 3, and a two-core wire, which are respectively used to connect the secondary side A-phase, B-phase, C-phase, and N-phase terminals of the transformer under test. The large current cable is a sandwich cable with a thin wire sandwiched in the middle of the cable.

[0074] The relay and AC contactor hybrid group connected to the secondary side cable is regarded as the second relay and AC contactor hybrid group, and the structures of the three second relay and AC contactor hybrid groups are the same.

[0075] In the wiring switching device, the second relay and AC contactor hybrid group connected to the secondary side A-phase terminal of the transformer under test through the secondary side cable is regarded as group a, the second relay and AC contactor hybrid group connected to the secondary side B-phase terminal of the transformer under test through the secondary side cable is regarded as group b, the second relay and AC contactor hybrid group connected to the secondary side C-phase terminal of the transformer under test through the secondary side cable is regarded as group c, and the relay group connected to the secondary side N-phase terminal of the transformer under test through the secondary side cable is regarded as group n.

[0076] In this embodiment, by setting corresponding relay and AC contactor hybrid groups for the primary side A-phase, B-phase, and C-phase terminals of the transformer under test, and a corresponding relay group for the secondary side N-phase of the transformer under test, fine wiring switching for the energy efficiency test of the transformer is realized.

[0077] On the basis of the above embodiment, as Figure 2 shown, in this embodiment, the first relay and AC contactor hybrid group includes a first AC contactor, a second AC contactor, a third AC contactor, and a first relay;

[0078] For the first relay and AC contactor hybrid group of Group A, the first AC contactor is Figure 2 the AC contactor 1 in Figure 2 the AC contactor 2 in Figure 2 the AC contactor 3 in Figure 2 and the first relay is the relay 1 in

[0079] The three first relay and AC contactor hybrid groups altogether include AC contactors 1 to 9 and relays 1 to 3.

[0080] Wherein, one contact of the first AC contactor is electrically connected to the primary side terminal of the transformer under test through the primary side cable, and the other contact is electrically connected to the primary side terminal row of the measurement interface through a set of contacts of the first relay;

[0081] The high-voltage cable 1 is connected to one contact of the AC contactor 1, and the other contact of the AC contactor 1 is connected to the primary side A-phase terminal row of the measurement interface through a set of contacts of the relay 1, for connecting the high-voltage A-phase voltage line of the external DC resistance tester.

[0082] One contact of the second AC contactor is electrically connected to the primary side terminal of the transformer under test through the primary side cable, and the other contact is electrically connected to the primary side terminal row of the measurement interface through another set of contacts of the first relay and is electrically connected to one contact of the third AC contactor;

[0083] The high-voltage cable 2 is connected to one contact of the AC contactor 2, and the other contact of the AC contactor 2 is respectively connected to another set of contacts of the relay 1 and the AC contactor 3. The another set of contacts of the relay 1 is connected to the primary side A-phase terminal row of the measurement interface, for connecting the high-voltage A-phase current line of the external DC resistance tester.

[0084] The other contact of the third AC contactor is electrically connected to the primary side terminal row of the measurement interface and is electrically connected to the terminal of the test power input interface.

[0085] The other contact of the AC contactor 3 is connected to the primary side A-phase terminal row of the measurement interface, for connecting the A-phase voltage measurement line of the external measurement system. The other contact of the AC contactor 3 is also connected to the U-phase terminal of the test power input interface, for wiring during the load test.

[0086] Optionally, the AC contactor 1 and the AC contactor 2 are high-voltage AC contactors, such as 10 kV voltage class AC contactors, and the operating voltages of the AC contactor 3 and the relay 1 are 690 V.

[0087] The structure of the first relay and AC contactor hybrid group in Group B and Group C is the same as that in Group A.

[0088] Based on the above embodiments, as Figure 2 shown, in this embodiment, the measurement system described includes a transformer loss measurement system and a DC resistance tester;

[0089] One set of contacts of the first relay is connected to the terminal in the primary side terminal block of the measurement interface for connecting the voltage line of the DC resistance tester;

[0090] Another set of contacts of the first relay is connected to the terminal in the primary side terminal block of the measurement interface for connecting the current line of the DC resistance tester;

[0091] Another contact of the third AC contactor is connected to the terminal in the primary side terminal block of the measurement interface for connecting the voltage measurement line of the transformer loss measurement system.

[0092] Based on the above embodiments, as Figure 2 shown, in this embodiment, the second relay and AC contactor hybrid group described includes a fourth AC contactor, a fifth AC contactor, and a second relay;

[0093] For the second relay and AC contactor hybrid group in Group A, the fourth AC contactor is Figure 2 the AC contactor 10 in Figure 2 the fifth AC contactor is Figure 2 the AC contactor 11 in, and the second relay is

[0094] the relay 4 in.

[0095] Among them, one contact of the fourth AC contactor and one contact of the fifth AC contactor are electrically connected to the secondary side terminals of the transformer under test through the secondary side cable;

[0096] The large current cable 1 is respectively connected to a set of contacts of the AC contactor 10, the AC contactor 11, and the relay 4 inside the switching device. The sandwich wire of the large current cable 1 is then connected to another set of contacts of the relay 4.

[0097] Another contact of the fourth AC contactor is electrically connected to the load test short - circuit copper bar, and another contact of the fifth AC contactor is electrically connected to the secondary - side terminal block of the measurement interface and electrically connected to the terminal of the test power input interface; wherein, another contact of the fourth AC contactor in the three second - relay and AC - contactor hybrid groups is connected to the same load test short - circuit copper bar;

[0098] Another contact of the AC contactor 10 is connected to the load test short - circuit copper bar, which is used for short - circuit wiring of the secondary - side terminals during the transformer load test,

[0099] Another contact of the AC contactor 11 is respectively connected to the U - phase of the test power input interface and the A - phase terminal block of the secondary side of the measurement interface, which are respectively used for wiring during the transformer no - load test and measuring the system voltage.

[0100] The secondary - side terminal block of the measurement interface is electrically connected to the secondary - side terminals of the transformer under test through a set of contacts of the second relay and the secondary - side cable;

[0101] The secondary - side terminal block of the measurement interface is electrically connected to the secondary - side terminals of the transformer under test through another set of contacts of the second relay and the sandwich wire of the secondary - side cable.

[0102] Two sets of contacts of the relay 4 are connected to the A - phase terminal block of the secondary side of the measurement interface, which are respectively used for connecting the low - voltage - side A - phase voltage and current lines of the external DC resistance tester.

[0103] The structures of the second - relay and AC - contactor hybrid groups in group b and group c are the same as those in group a.

[0104] On the basis of the above - mentioned embodiments, as Figure 2 shown, in this embodiment, the measurement system includes a transformer loss measurement system and a DC resistance tester;

[0105] Another contact of the fifth AC contactor is connected to the terminal in the secondary - side terminal block of the measurement interface for connecting the voltage measurement line of the transformer loss measurement system;

[0106] A set of contacts in the second relay is connected to the terminal in the secondary - side terminal block of the measurement interface for connecting the current line of the DC resistance tester;

[0107] Another set of contacts in the second relay is connected to the terminal in the secondary - side terminal block of the measurement interface for connecting the voltage line of the DC resistance tester.

[0108] On the basis of the above - mentioned embodiments, as Figure 2 shown, in this embodiment, the relay group includes a third relay;

[0109] For n groups of relay sets, the third relay is Figure 2 relay 7 in

[0110] The secondary N-phase terminal block of the measurement interface is electrically connected to the secondary N-phase terminal of the transformer under test through two sets of contacts of the third relay.

[0111] In the n groups of relay sets, two core wires are respectively connected to two sets of contacts of relay 7, and the two sets of contacts of the relay are connected to the secondary N-phase terminal block of the measurement interface, and are respectively used to connect the neutral voltage and current wires on the low-voltage side of an external DC resistance tester.

[0112] This embodiment provides a wiring switching method for transformer energy efficiency test based on the wiring switching device for transformer energy efficiency test in any of the above embodiments, as Figure 3 shown, including: Step 301, controlling the operation of the PLC based on a computer control system; Step 302, controlling the opening and closing of the relays and the opening and closing of the AC contactors in the relay and AC contactor hybrid group based on the running PLC.

[0113] The wiring switching device in this embodiment is controlled by an external computer control system, and the on / off of each relay and AC contactor in the relay and AC contactor hybrid group is controlled by the PLC. After one wiring, the wiring between different transformer energy efficiency tests can be automatically switched, improving the efficiency of wiring switching.

[0114] Based on the above embodiments, as Figure 2 shown, the controlling the opening and closing of the relays and the opening and closing of the AC contactors in the relay and AC contactor hybrid group based on the running PLC in this embodiment includes: when performing an open-circuit test on the transformer under test, based on the running PLC, all the relays in the relay and AC contactor hybrid group are disconnected, all the AC contactors in the three first relay and AC contactor hybrid groups are disconnected, the fourth AC contactor in the three second relay and AC contactor hybrid groups is disconnected, and the fifth AC contactor is closed;

[0115] When performing an open-circuit test on the transformer, all AC contactors from contactor 1 to contactor 9 are disconnected, contactor 10, contactor 12, and contactor 14 are disconnected, all relays from relay 1 to relay 7 are disconnected, and contactor 11, contactor 13, and contactor 15 are closed. The U, V, and W three phases of the test power supply are respectively connected to the secondary A, B, and C phase terminals of the transformer under test through contactor 11, contactor 13, contactor 15, and large current cables 1, large current cables 2, and large current cables 3.

[0116] When performing a load test on the transformer to be tested, based on the operating PLC, control all the relays in the relay and AC contactor hybrid group to disconnect, close the second and third AC contactors in the three first relay and AC contactor hybrid groups, open the first AC contactor, close the fourth AC contactor, and open the fifth AC contactor;

[0117] When performing a transformer load test, AC contactors 2, 3, 5, 6, 8, and 9 are closed, AC contactors 10, 12, and 14 are closed, and other AC contactors and relays are open. The three phases U, V, and W of the test power supply are respectively connected to the primary side A, B, and C phase terminals of the transformer under test through AC contactors 2, 3, AC contactors 5, AC contactors 6, AC contactors 8, AC contactors 9, and high-voltage cables 2, high-voltage cable 4, and high-voltage cable 6; the load test short-circuit copper bar is connected to the secondary side A, B, and C phase terminals of the transformer under test through AC contactors 10, AC contactors 12, and AC contactors 14.

[0118] When performing a DC resistance test on the transformer to be tested, based on the operating PLC, control all the relays in the relay and AC contactor hybrid group to close, close the first and second AC contactors, open the third AC contactor, and open the fourth and fifth AC contactors.

[0119] When performing a transformer DC resistance test, AC contactors 1, 2, 4, 5, 7, 8 and relays 1, 2, 3 are closed, and AC contactors 3, 6, and 9 are open to achieve the wiring for the primary side DC resistance test of the transformer under test; AC contactors 10, 11, 12, 13, 14, and 15 are open, and relays 4, 5, 6, and 7 are closed to achieve the wiring for the secondary side DC resistance test of the transformer under test.

[0120] In this embodiment, the coils of the AC contactors and relays in the wiring switching device are controlled through the output points of the PLC, and the corresponding AC contactors and relays are controlled to open or close according to the preset logic, realizing different connections between the test power input interface, test cables, and measurement interface, so as to automatically switch various wirings for the transformer energy efficiency test.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wiring switching device for transformer energy efficiency test, characterized in that, It includes a hybrid group of relays and AC contactors, a test power input interface, test cables, a PLC, a communication control interface, and a measurement interface; Among them, the hybrid group of relays and AC contactors is electrically connected to the test power supply through the test power input interface and is electrically connected to the transformer under test through the test cables; The PLC is signal-connected to the computer control system through the communication control interface. The computer control system is used to control the operation of the PLC, and the PLC is used to control the opening and closing of the relays and the disconnection and closing of the AC contactors in the hybrid group of relays and AC contactors; The hybrid group of relays and AC contactors is electrically connected to the measurement system through the measurement interface; The hybrid group of relays and AC contactors includes three first hybrid groups of relays and AC contactors, three second hybrid groups of relays and AC contactors, and a relay group; The three first hybrid groups of relays and AC contactors are electrically connected to the primary side A-phase, B-phase, and C-phase terminals of the transformer under test through the primary side cables one by one, and are electrically connected to the primary side A-phase, B-phase, and C-phase terminal blocks of the measurement interface one by one, and are electrically connected to the U-phase, V-phase, and W-phase terminals of the test power input interface one by one; The three second hybrid groups of relays and AC contactors are electrically connected to the secondary side A-phase, B-phase, and C-phase terminals of the transformer under test through the secondary side cables one by one, and are electrically connected to the secondary side A-phase, B-phase, and C-phase terminal blocks of the measurement interface one by one, and are electrically connected to the U-phase, V-phase, and W-phase terminals of the test power input interface one by one; The relay group is electrically connected to the secondary side N-phase terminal of the transformer under test through the secondary side cable and is electrically connected to the secondary side N-phase terminal block of the measurement interface; The first hybrid group of relays and AC contactors includes a first AC contactor, a second AC contactor, a third AC contactor, and a first relay; One contact of the first AC contactor is electrically connected to the primary side terminal of the transformer under test through the primary side cable, and the other contact is electrically connected to the primary side terminal block of the measurement interface through a set of contacts of the first relay; One contact of the second AC contactor is electrically connected to the primary side terminal of the transformer under test through the primary side cable, and the other contact is electrically connected to the primary side terminal block of the measurement interface through another set of contacts of the first relay and is electrically connected to one contact of the third AC contactor; The other contact of the third AC contactor is electrically connected to the primary side terminal block of the measurement interface and is electrically connected to the terminal of the test power input interface; The second hybrid group of relays and AC contactors includes a fourth AC contactor, a fifth AC contactor, and a second relay; One contact of the fourth AC contactor and one contact of the fifth AC contactor are electrically connected to the secondary side terminal of the transformer under test through the secondary side cable; Another contact of the fourth AC contactor is electrically connected to the load test shorting copper bar, and another contact of the fifth AC contactor is electrically connected to the secondary terminal block of the measurement interface and electrically connected to the terminal of the test power input interface; wherein, another contact of the fourth AC contactor in the three second relay and AC contactor hybrid group is connected to the same load test shorting copper bar; The secondary terminal block of the measurement interface is electrically connected to the secondary terminal of the transformer under test through a set of contacts of the second relay and the secondary cable; The secondary terminal block of the measurement interface is electrically connected to the secondary terminal of the transformer under test through another set of contacts of the second relay and the sandwich wire of the secondary cable.

2. The wiring switching device for transformer energy efficiency test according to claim 1, characterized in that, The test cable includes a primary cable and a secondary cable; The relay and AC contactor hybrid group is electrically connected to the primary terminal of the transformer under test through the primary cable; The relay and AC contactor hybrid group is electrically connected to the secondary terminal of the transformer under test through the secondary cable.

3. The wiring switching device for transformer energy efficiency test according to claim 1, characterized in that, The measurement system includes a transformer loss measurement system and a DC resistance tester; A set of contacts of the first relay is connected to the terminal in the primary terminal block of the measurement interface for connecting the voltage line of the DC resistance tester; Another set of contacts of the first relay is connected to the terminal in the primary terminal block of the measurement interface for connecting the current line of the DC resistance tester; Another contact of the third AC contactor is connected to the terminal in the primary terminal block of the measurement interface for connecting the voltage measurement line of the transformer loss measurement system.

4. The wiring switching device for transformer energy efficiency test according to claim 1, characterized in that The measurement system includes a transformer loss measurement system and a DC resistance tester; Another contact of the fifth AC contactor is connected to the terminal in the secondary terminal block of the measurement interface for connecting the voltage measurement line of the transformer loss measurement system; A set of contacts in the second relay is connected to the terminal in the secondary terminal block of the measurement interface for connecting the current line of the DC resistance tester; Another set of contacts in the second relay is connected to the terminal in the secondary terminal block of the measurement interface for connecting the voltage line of the DC resistance tester.

5. The wiring switching device for transformer energy efficiency test according to any one of claims 1, characterized in that, The relay group includes a third relay; The secondary N-phase terminal block of the measurement interface is electrically connected to the secondary N-phase terminal of the transformer under test through two sets of contacts of the third relay.

6. The wiring switching method for transformer energy efficiency test using the wiring switching device for transformer energy efficiency test according to any one of claims 1-5, characterized in that, Including: Controlling the operation of the PLC based on the computer control system; Based on the running PLC, controlling the opening and closing of the relays and the opening and closing of the AC contactors in the relay and AC contactor hybrid group; The controlling the opening and closing of the relays and the opening and closing of the AC contactors in the relay and AC contactor hybrid group based on the running PLC includes: When performing an open-circuit test on the transformer under test, based on the operating PLC, control all the relays in the relay and AC contactor hybrid group to open, all the AC contactors in the three first relay and AC contactor hybrid groups to open, the fourth AC contactor in the three second relay and AC contactor hybrid groups to open, and the fifth AC contactor to close; When performing a load test on the transformer under test, based on the operating PLC, control all the relays in the relay and AC contactor hybrid group to open, the second and third AC contactors in the three first relay and AC contactor hybrid groups to close, the first AC contactor to open, the fourth AC contactor to close, and the fifth AC contactor to open; When performing a DC resistance test on the transformer under test, based on the operating PLC, control all the relays in the relay and AC contactor hybrid group to close, the first and second AC contactors to close, the third AC contactor to open, and the fourth and fifth AC contactors to open.

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