A multi-voltage pre-magnetizing short circuit test transformer and a short circuit test detection system

Abstract

This invention belongs to the field of transformers and transformer testing, specifically a multi-voltage pre-magnetized anti-rotation test transformer and anti-rotation test system. It includes: a tank cover fixed to the top of the tank with bolts; an oil conservator vertically installed above the tank cover to form a closed oil circulation system; an iron core is located inside the tank, with a lower concentric winding, a magnetizing winding, and an upper concentric winding coaxially mounted on the three core columns; the lower concentric winding consists of three lower secondary windings mounted on the three core columns and a lower primary winding sleeved on its outer side; the upper concentric winding consists of three upper secondary windings mounted on the three core columns and an upper primary winding sleeved on its outer side; output terminals are located on the tank and the tank cover, with each winding's output terminal electrically connected to its corresponding terminal group. This invention uses an upper and lower winding in parallel structure on the primary side, reducing the manufacturing cost of the anti-rotation test transformer while meeting the requirements of the anti-rotation test system.

Description

Technical Field

[0001] This invention belongs to the field of transformers and transformer testing, specifically a multi-voltage pre-magnetized transformer and a transformer testing system for transformer testing. Background Technology

[0002] In recent years, new energy sources have developed rapidly, especially photovoltaic, wind power, and energy storage. However, the poor quality of new energy power sources has significantly impacted grid stability. As inverter system capacity increases and its proportion rises year by year, the poor quality of new energy power sources continues to pose a challenge to grid stability. Furthermore, the wide variety of inverter models and parameters necessitates the use of multiple transformers with different output voltages to meet factory testing requirements. This significantly increases both investment costs and floor space requirements.

[0003] The lack of effective and low-cost testing equipment among complete equipment manufacturers to fully test the performance and functions of their products has led to frequent failures in new energy power generation systems.

[0004] During testing, the test transformer is frequently subjected to closing shocks. Influenced by the DC component of the inverter unit and higher-order harmonics, excessive inrush current may lead to a high failure rate, transformer protection tripping, and inability to operate. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-voltage pre-magnetized transformer and a transformer testing system for testing and inspecting transformers, so as to effectively check the relevant performance indicators and functions of integrated substation units, inverters and other systems, and avoid potential product quality problems.

[0006] The technical solution adopted by the present invention to achieve the above objectives is: a multi-voltage pre-magnetized pair test transformer, characterized in that it includes: an oil tank, a tank cover, an oil conservator, an iron core, a lower concentric winding, a magnetizing winding, an upper concentric winding, and outgoing terminals;

[0007] The top of the oil tank is fixedly connected to the tank cover by bolts, and the oil storage tank is installed vertically above the tank cover to form a closed oil circulation system;

[0008] The oil tank contains an iron core, which adopts a three-phase three-column laminated structure. The lower concentric winding, the magnetized winding, and the upper concentric winding are coaxially mounted on the three columns in sequence.

[0009] The lower concentric winding consists of three lower secondary windings mounted on three core columns and a lower primary winding mounted on the outside of them.

[0010] The upper concentric winding consists of three upper secondary windings mounted on three core columns and an upper primary winding mounted on the outside of them.

[0011] The outgoing terminals are located on the oil tank and the tank cover, wherein each winding outgoing terminal is electrically connected to the corresponding terminal group.

[0012] The outgoing terminals are provided in multiple sets, including: magnetized winding outgoing terminal set, primary outgoing terminal set, 800V secondary outgoing terminal set A, 800V secondary outgoing terminal set B, 630V secondary outgoing terminal set A and 630V secondary outgoing terminal set B;

[0013] The magnetizing winding output terminal group is connected to the first end of the magnetizing winding via a copper busbar;

[0014] The primary output terminal group is connected to the parallel terminals of the upper primary winding and the lower primary winding respectively via wires;

[0015] The 800V secondary output terminal group A and the 800V secondary output terminal group B are respectively connected to the positive and negative phase sequence output terminals of the upper secondary winding;

[0016] The 630V secondary output terminal group A and 630V secondary output terminal group B are respectively connected to the positive and negative phase sequence output terminals of the lower secondary winding.

[0017] The winding arrangement structure of each core column of the iron core, from top to bottom, is as follows:

[0018] The upper secondary winding, the upper primary winding, the magnetizing winding, the lower primary winding, and the lower secondary winding are all separated by an insulating layer.

[0019] The winding directions of each winding are as follows:

[0020] The lower secondary winding and the upper secondary winding are wound in opposite spirals; the lower primary winding and the upper primary winding are wound in opposite spirals; the magnetizing winding is wound in a segmented disc shape.

[0021] The magnetized winding is independently arranged between the upper concentric winding and the lower concentric winding to form a layered structure;

[0022] The magnetizing winding consists of three independent coils, each mounted on one of three core columns.

[0023] A pre-magnetized test system for a test specimen includes: a test transformer, a magnetization control circuit, and a test specimen connection structure.

[0024] The output terminals of the magnetizing winding are connected to the magnetizing transformer T0 via the magnetizing control circuit;

[0025] The test specimen connection architecture includes: test specimen PCS and test specimen inverter;

[0026] The AC outgoing copper busbar of the test specimen PCS is connected to the corresponding voltage group in the 800V secondary outgoing terminal group A or the 630V secondary outgoing terminal group A of the test transformer.

[0027] The AC output copper busbar of the test inverter is connected to the corresponding voltage group in the 800V or 630V secondary output terminal group B of the test transformer.

[0028] The positive DC terminal of the test PCS is connected to the positive DC terminal of the test inverter; the negative DC terminal of the test PCS is connected to the negative DC terminal of the test inverter, so that the test PCS can transmit DC power to the DC side of the test inverter.

[0029] The magnetization control circuit includes: magnetization transformer T0, time relay JS1, magnetization contactor KM1, intermediate relay KM2, circuit breaker 1QF, molded case switch 2QF, and indicator light circuit.

[0030] The magnetizing transformer T0 has its input end connected to a three-phase power supply via a molded case switch 2QF, and its output end connected to the output terminal of the magnetizing winding via the main contact of the magnetizing contactor KM1.

[0031] The time relay JS1 and the intermediate relay KM2 form a timing control unit. The delay contact of JS1 is connected in series in the coil circuit of the intermediate relay KM2. The normally open contact of the intermediate relay KM2 is used to control the closing operation of the circuit breaker 1QF.

[0032] The time relay JS1 and the circuit breaker 1QF form an interlock control. When the pre-magnetization time reaches the set value, the delayed contact of JS1 closes to trigger the intermediate relay KM2 to operate. The normally open contact of KM2 drives the circuit breaker 1QF to close, and at the same time cuts off the power supply circuit of the magnetizing contactor KM1.

[0033] The main contacts of the magnetizing contactor KM1 are connected in parallel to the magnetizing circuit, and its auxiliary contacts are connected in series with the coil of the time relay JS1 to form a self-locking circuit.

[0034] The indicator light circuit includes a trip indicator light 1HG, a closing indicator light 1HR, a pre-magnetization status indicator light 2HR, and a pre-magnetization exit indicator light 2HG, which are controlled to turn on and off by the contact status of the circuit breaker 1QF and the magnetizing contactor KM1, respectively.

[0035] The indicator light circuit includes:

[0036] The trip indicator light 1HG is connected in series across the normally closed contact of circuit breaker 1QF;

[0037] The closing indicator light 1HR is connected in series across the normally open contact of circuit breaker 1QF;

[0038] The pre-magnetization status indicator light 2HR is connected in series in the auxiliary contact circuit of the magnetization contactor KM1;

[0039] The pre-charge exit indicator light 2HG is connected in series in the normally closed contact circuit of the magnetizing contactor KM1.

[0040] The magnetization control circuit performs the following steps:

[0041] a) After the control power supply is closed, the circuit breaker 1QF is in the open state and the open indicator light 1HG is lit.

[0042] b) Close the plastic case switch 2QF and trigger the start button SB3 to energize the magnetizing contactor KM1. The main contacts of KM1 close, and the magnetizing transformer T0 supplies power to the magnetizing winding (13). At the same time, the auxiliary contacts of KM1 self-lock and light up the pre-magnetization status indicator 2HR.

[0043] c) When the magnetizing contactor KM1 contacts are closed, the timing relay JS1 starts counting;

[0044] d) After the preset delay is reached, the delay contact of JS1 closes. If the magnetizing contactor KM1 is still in the closed state at this time, the intermediate relay KM2 will be energized.

[0045] e) After the intermediate relay KM2 is activated, its normally open contact closes to drive the circuit breaker 1QF to close, the closing indicator light 1HR lights up, and at the same time the delayed contact of JS1 opens, cutting off the power supply circuit of the magnetizing contactor KM1.

[0046] f) After the magnetizing contactor KM1 loses power, its main contacts disconnect the magnetizing circuit, and the normally closed contacts reset to illuminate the pre-magnetizing exit indicator 2HG, thus completing the pre-magnetizing process.

[0047] The method for testing the torsion test includes the following steps:

[0048] 1) Pre-magnetization stage: Close the molded case switch 2QF to trigger the start of the magnetization control circuit, and supply power to the magnetization winding through the magnetization transformer T0 to pre-magnetize the iron core;

[0049] 2) Main circuit closing: When the pre-magnetization time reaches the set value, the time relay JS1 triggers the intermediate relay KM2 to operate, driving the circuit breaker 1QF to close, cutting off the magnetization circuit and connecting the main power supply;

[0050] 3) Test specimen connection: Connect the AC output copper busbar of the test specimen PCS to the designated voltage secondary output terminal group of the test transformer, and connect the AC output copper busbar of the test specimen inverter to the corresponding voltage secondary output terminal group; at the same time, the DC side of the test specimen PCS and the DC side of the test specimen inverter are interconnected through copper busbars.

[0051] 4) Energy cycle test:

[0052] 4-1) The test transformer supplies AC power to the test PCS through the secondary output terminals. The test PCS converts the AC power to DC power and inputs it to the test inverter.

[0053] 4-2) The test inverter converts DC power into AC power and feeds it back to the secondary side of the test transformer.

[0054] 5) Through circulating energy transfer, the DC output ripple of the test PCS, the AC output harmonic distortion rate of the test inverter, and the temperature rise data of the test transformer are collected by external monitoring equipment to evaluate the system stability.

[0055] The voltage matching rule for the energy cycling test is as follows:

[0056] If the test PCS is connected to the 800V secondary output terminal group A, then the test inverter needs to be connected to the 800V secondary output terminal group B.

[0057] If the test PCS is connected to the 630V secondary output terminal group A, then the test inverter needs to be connected to the 630V secondary output terminal group B.

[0058] The present invention has the following beneficial effects and advantages:

[0059] 1. According to the system requirements and the test system, the primary winding and secondary winding capacities of the transformer of the present invention are inconsistent. After calculation and performance reserve analysis, the primary side capacity is 1 / 3 of the secondary side capacity.

[0060] 2. The primary winding of this invention adopts an upper winding and a lower winding, with the upper and lower windings connected in parallel, which reduces the manufacturing cost of the transformer for the test while meeting the requirements of the test system.

[0061] 3. The present invention provides an excitation winding in the middle of the test transformer. The excitation winding is magnetized by a pre-magnetizing system to achieve pre-magnetization of the test transformer, which can significantly reduce the inrush current during no-load closing and eliminate the impact of frequent excitation inrush current on the test transformer.

[0062] 4. By adjusting the position of the low-voltage turns draw-out line, the present invention enables a transformer to input one voltage on the primary winding and output multiple voltages on the secondary and tertiary sides, thereby meeting the customer's needs for different voltages during use and reducing investment costs and floor space. Attached Figure Description

[0063] Figure 1 This is a schematic diagram of the pre-magnetized pair test detection system of the present invention;

[0064] Figure 2 This is a schematic diagram of the pre-magnetization control principle system for the test transformer of the present invention;

[0065] Figure 3 This is the formal drawing of the test transformer of the present invention;

[0066] Figure 4 This is a top view of the test transformer of the present invention;

[0067] Figure 5 This is a side view of the transformer body for the test of the present invention;

[0068] Figure 6 This is a front view of the transformer body for the test of the present invention;

[0069] Figure 7 This is a front view of the experimental PCS;

[0070] Figure 8 This is a top view of the experimental PCS;

[0071] Figure 9 This is a side view of the experimental PCS;

[0072] Figure 10 This is a side view of the experimental inverter;

[0073] Figure 11 This is a front view of the experimental inverter;

[0074] Figure 12 This is a top view of the experimental inverter;

[0075] Wherein: 1 is the oil tank, 2 is the tank cover, 3 is the oil conservator, 4 is the magnetizing winding output terminal, 5 is the primary output terminal, 6 is the 800V secondary output terminal group A; 7 is the secondary 800V output terminal group B, 8 is the 630V secondary output terminal group A, 9 is the 630V secondary output terminal group B, 10 is the test transformer, 11 is the upper primary winding, 12 is the lower primary winding, 13 is the magnetizing winding, 14 is the core, 15 is the clamp, 16 is the upper secondary winding, 17 is the lower secondary winding, 18 is the upper secondary winding neutral busbar, and 19 is the upper secondary winding 800V output copper busbar. 20 is the 630V output copper busbar of the upper secondary winding; 21 is the neutral busbar of the lower secondary winding; 22 is the 800V output copper busbar of the lower secondary winding; 23 is the 630V output copper busbar of the lower secondary winding; 24 is the transformer body; 25 is the test PCS; 26 is the DC positive terminal of the test PCS; 27 is the DC negative terminal of the test PCS; 28 is the AC output copper busbar of the test PCS; 29 is the test inverter; 30 is the DC positive terminal of the test inverter; 31 is the DC negative terminal of the test inverter; 32 is the AC output copper busbar of the test inverter. Detailed Implementation

[0076] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0077] like Figures 3-4 The diagram shown is a structural schematic of the multi-voltage pre-magnetized pair test transformer of the present invention. The multi-voltage pre-magnetized pair test transformer of the present invention includes: an oil tank 1, a tank cover 2, an oil conservator 3, an iron core 14, a lower concentric winding, a magnetizing winding 13, an upper concentric winding, and outgoing terminals.

[0078] The top of the oil tank 1 is fixedly connected to the tank cover 2 by bolts, and the oil storage tank 3 is vertically installed above the tank cover 2 to form a closed oil circulation system;

[0079] The oil tank 1 is equipped with an iron core 14. The iron core 14 adopts a three-phase three-column laminated structure. The lower concentric winding, the magnetized winding 13 and the upper concentric winding are coaxially mounted on the three columns in sequence.

[0080] The lower concentric winding consists of three lower secondary windings 17 mounted on three core columns and a lower primary winding 12 mounted on its outer side.

[0081] The upper concentric winding consists of three upper secondary windings 16 mounted on three core columns and an upper primary winding 11 mounted on its outer side.

[0082] The output terminals are located on the oil tank 1 and the tank cover 2, wherein each winding output terminal is electrically connected to the corresponding terminal group.

[0083] The output terminals are provided in multiple groups, including: magnetized winding output terminal group 4, primary output terminal group 5, 800V secondary output terminal group A6, 800V secondary output terminal group B7, 630V secondary output terminal group A8 and 630V secondary output terminal group B9.

[0084] The magnetizing winding output terminal group 4 is connected to the first end of the magnetizing winding 13 via a copper busbar;

[0085] The primary output terminal group 5 is connected to the parallel terminals of the upper primary winding 11 and the lower primary winding 12 respectively via wires;

[0086] The 800V secondary output terminal group A6 and the 800V secondary output terminal group B7 are respectively connected to the positive and negative phase sequence output terminals of the upper secondary winding 16;

[0087] The 630V secondary output terminal group A8 and the 630V secondary output terminal group B9 are respectively connected to the positive and negative phase sequence output terminals of the lower secondary winding 17.

[0088] like Figures 5-6 The image shows different views of the transformer body for the test transformer of the present invention; the winding arrangement structure of each core column of the core 14 from top to bottom is as follows:

[0089] The upper secondary winding 16, the upper primary winding 11, the magnetizing winding 13, the lower primary winding 12, and the lower secondary winding 17 are all separated by an insulation layer.

[0090] The winding directions of each winding are as follows:

[0091] The lower secondary winding 17 and the upper secondary winding 16 are wound in opposite spirals; the lower primary winding 12 and the upper primary winding 11 are wound in opposite spirals; the magnetizing winding 13 is wound in a segmented disc shape.

[0092] The magnetized winding 13 is independently set between the upper concentric winding and the lower concentric winding to form a layered structure;

[0093] The magnetizing winding 13 uses three independent coils, each mounted on one of the three core columns.

[0094] like Figure 1 The diagram shown is a schematic of the pre-magnetized test system of the present invention. The pre-magnetized test system of the present invention includes: a test transformer 10, a magnetization control circuit, and a test specimen connection structure.

[0095] The output terminals of the magnetizing winding 14 are connected to the magnetizing transformer T0 via the magnetizing control circuit;

[0096] like Figures 7-12The diagram shown is a structural schematic of the experimental PCS and the experimental inverter of the present invention; wherein, the experimental connection architecture includes: experimental PCS25 and experimental inverter 29;

[0097] The AC output copper busbar 28 of the test specimen PCS25 is connected to the corresponding voltage group in the 800V secondary output terminal group A6 or the 630V secondary output terminal group A8 of the test transformer 10.

[0098] The AC output copper busbar 32 of the test inverter 29 is connected to the corresponding voltage group in the 800V secondary output terminal group B7 or the 630V secondary output terminal group B9 of the test transformer 10.

[0099] The positive DC terminal 26 of the test PCS25 is connected to the positive DC terminal 30 of the test inverter 29; the negative DC terminal 27 of the test PCS25 is connected to the negative DC terminal 31 of the test inverter 29, so that the test PCS25 can transmit DC power to the DC side of the test inverter.

[0100] like Figure 2 The diagram shown is a schematic of the pre-magnetization control principle system of the test transformer of the present invention. The magnetization control circuit of the present invention includes: magnetization transformer T0, time relay JS1, magnetization contactor KM1, intermediate relay KM2, circuit breaker 1QF, molded case switch 2QF, and indicator light circuit.

[0101] The magnetizing transformer T0 has its input end connected to a three-phase power supply via a molded case switch 2QF, and its output end connected to the output terminal of the magnetizing winding 13 via the main contacts of the magnetizing contactor KM1.

[0102] The time relay JS1 and the intermediate relay KM2 form a timing control unit. The delay contact of JS1 is connected in series in the coil circuit of the intermediate relay KM2. The normally open contact of the intermediate relay KM2 is used to control the closing operation of the circuit breaker 1QF.

[0103] The time relay JS1 and the circuit breaker 1QF form an interlock control. When the pre-magnetization time reaches the set value, the delayed contact of JS1 closes to trigger the intermediate relay KM2 to operate. The normally open contact of KM2 drives the circuit breaker 1QF to close, and at the same time cuts off the power supply circuit of the magnetizing contactor KM1.

[0104] The main contacts of the magnetizing contactor KM1 are connected in parallel in the magnetizing circuit, and its auxiliary contacts are connected in series with the coil of the time relay JS1 to form a self-locking circuit.

[0105] The indicator light circuit includes a trip indicator light 1HG, a closing indicator light 1HR, a pre-magnetization status indicator light 2HR, and a pre-magnetization exit indicator light 2HG, which are controlled to turn on and off by the contact status of the circuit breaker 1QF and the magnetizing contactor KM1, respectively.

[0106] Indicator light circuit, including:

[0107] The trip indicator light 1HG is connected in series across the normally closed contact of circuit breaker 1QF;

[0108] The closing indicator light 1HR is connected in series across the normally open contact of circuit breaker 1QF;

[0109] The pre-magnetization status indicator light 2HR is connected in series in the auxiliary contact circuit of the magnetization contactor KM1;

[0110] The pre-charge exit indicator light 2HG is connected in series in the normally closed contact circuit of the magnetizing contactor KM1.

[0111] according to Figure 2 As shown, the magnetization control circuit of this invention performs the following steps:

[0112] a) After the control power supply is closed, the circuit breaker 1QF is in the open state and the open indicator light 1HG is lit.

[0113] b) Close the molded case switch 2QF, trigger the start button SB3 to energize the magnetizing contactor KM1, the main contacts of KM1 close, the magnetizing transformer T0 supplies power to the magnetizing winding 13, and at the same time the auxiliary contacts of KM1 self-lock and the pre-magnetizing status indicator light 2HR is lit.

[0114] c) When the magnetizing contactor KM1 contacts are closed, the timing relay JS1 starts counting;

[0115] d) After the preset delay is reached, the delay contact of JS1 closes. If the magnetizing contactor KM1 is still in the closed state at this time, the intermediate relay KM2 will be energized.

[0116] e) After the intermediate relay KM2 is activated, its normally open contact closes to drive the circuit breaker 1QF to close, the closing indicator light 1HR lights up, and at the same time the delayed contact of JS1 opens, cutting off the power supply circuit of the magnetizing contactor KM1.

[0117] f) After the magnetizing contactor KM1 loses power, its main contacts disconnect the magnetizing circuit, and the normally closed contacts reset to illuminate the pre-magnetizing exit indicator 2HG, thus completing the pre-magnetizing process.

[0118] Combined with appendix Figures 1-2 As shown, the test method for the Torr test includes the following steps:

[0119] 1) Pre-magnetization stage: Close the plastic case switch 2QF to trigger the start of the magnetization control circuit, and supply power to the magnetization winding (13) through the magnetization transformer T0 to pre-magnetize the iron core (14);

[0120] 2) Main circuit closing: When the pre-magnetization time reaches the set value, the time relay JS1 triggers the intermediate relay KM2 to operate, driving the circuit breaker 1QF to close, cutting off the magnetization circuit and connecting the main power supply;

[0121] 3) Test specimen connection: Connect the AC output copper busbar (28) of the test specimen PCS (25) to the designated voltage secondary output terminal group of the test transformer (10), and connect the AC output copper busbar (32) of the test specimen inverter (29) to the corresponding voltage secondary output terminal group; at the same time, the DC side of the test specimen PCS and the DC side of the test specimen inverter are interconnected through copper busbars;

[0122] 4) Energy cycle test:

[0123] 4-1) The test transformer (10) supplies AC power to the test PCS (25) through the secondary output terminals. The test PCS (25) converts the AC power into DC power and inputs it into the test inverter (29).

[0124] 4-2) The test inverter (29) converts DC power into AC power and feeds it back to the secondary side of the test transformer (10);

[0125] The voltage matching rule for energy cycling testing is as follows:

[0126] If the test PCS (25) is connected to the 800V secondary output terminal group A (6), then the test inverter (29) needs to be connected to the 800V secondary output terminal group B (7);

[0127] If the test PCS (25) is connected to the 630V secondary output terminal group A (8), then the test inverter (29) needs to be connected to the 630V secondary output terminal group B (9).

[0128] 5) Through circulating energy transfer, the DC output ripple of the test PCS (25), the AC output harmonic distortion rate of the test inverter (29), and the temperature rise data of the test transformer (10) are collected by external monitoring equipment to evaluate the system stability.

[0129] Example 1:

[0130] According to the disclosure of the present invention, a test transformer according to a first aspect of the present invention includes: an oil tank and an oil tank cover. The oil tank contains one iron core, three high-voltage windings, and two low-voltage windings. Two sets of primary input terminals for 400V input are provided on the side wall of the oil tank. The oil tank cover has two sets of six secondary output terminals, with 630V and 800V output terminals on both sides of the cover, respectively. The primary winding consists of three sets of primary coils arranged vertically along the axial direction, where coils 1 and 3 are connected in parallel to form one primary winding, and coil 2 is an independent primary winding. The low-voltage windings are arranged vertically along the axial direction as an upper low-voltage winding and a lower low-voltage winding. The upper low-voltage winding is fitted onto the upper half of the core column, and the lower low-voltage winding is fitted onto the lower half of the core column. The upper and lower low-voltage windings are coaxially arranged and wound in opposite directions. The upper and lower low-voltage windings are identical in material, number of turns, voltage, and dimensions.

[0131] According to a second aspect of the present invention, a pre-magnetizing system for protecting a test transformer is provided. In order to protect the test transformer from the impact of inrush current, the magnetizing circuit needs to be started first to supply power to the magnetizing coil of the test transformer, magnetize the core of the test transformer, and then supply power to the main circuit to achieve successful switching of the transformer.

[0132] According to a third aspect of the present invention, a test system for a test PCS is provided. A test transformer supplies AC power to the PCS, which then inverts the AC power to DC power, inputting it to the DC side of the inverter. After further inversion, the DC power is input to the secondary side of the test transformer, and this process is repeated to test the performance and functionality of the test PCS and inverter. The secondary capacity of the test transformer needs to be greater than or equal to the full-load capacity of the test PCS. The primary capacity of the test transformer does not participate in operation; it only bears the reactive power loss and transformer no-load loss capacity of the test PCS and inverter. The required capacity is relatively small; calculations and performance reserve analysis show that the primary capacity is 1 / 3 of the secondary capacity.

[0133] like Figures 3-6As shown, the test transformer includes an oil tank 1, a tank cover 2, an oil conservator 3, magnetizing winding output terminals (A2, B2, C2) 4, primary output terminals (A1, B1, C1) 5, secondary 800V output terminals (a1, b1, c1) 6, secondary 800V output terminals (a2, b2, c2) 7, secondary 630V output terminals (a3, b3, c3) 8, secondary 630V output terminals (a4, b4, c4) 9, upper primary winding 11, lower primary winding 12, magnetizing winding 13, core 14, upper secondary winding 16, and lower secondary winding 17. The upper primary winding 11 is wound outside the upper secondary winding 16 to form an upper concentric winding, and a total of 3 upper concentric windings are wound; the lower primary winding 12 is wound outside the lower secondary winding 17 to form a lower concentric winding, and a total of 3 lower concentric windings are wound; the 3 lower concentric windings are respectively mounted on the three core posts of the iron core 14, and then the 3 magnetizing windings 12 are mounted on the three core posts of the iron core 14. Finally, the 3 upper concentric windings are respectively mounted on the three core posts of the iron core 14. The upper concentric windings, magnetizing windings and lower concentric windings are arranged in an upper, middle and lower arrangement and assembled into the transformer body 24. The transformer body 24 is hoisted into the oil tank 1. The leads of each winding of the transformer body 24 are connected and secured to the corresponding magnetizing winding terminals (A2, B2, C2) 4, primary winding terminals (A1, B1, C1) 5, secondary 800V winding terminals (a1, b1, c1) 6, secondary 800V winding terminals (a2, b2, c2) 7, secondary 630V winding terminals (a3, b3, c3) 8, and secondary 630V winding terminals (a4, b4, c4) 9. Finally, the upper part of the oil tank 1 is sealed with the tank cover 2, and the oil conservator 3 is installed on top of the tank cover 2. This assembles the test transformer T10.

[0134] like Figures 1-2 As shown, connect the output terminals (A2, B2, C2) 4 of the magnetizing winding to the output terminal of the magnetizing contactor KM1, connect the input terminal of the magnetizing contactor KM1 to the output terminal of the magnetizing transformer T0, and connect the input terminal of the magnetizing transformer T0 to the output terminal of the molded case switch 2QF. Assemble a pre-magnetized test transformer.

[0135] like Figures 7-12As shown, before testing the test PCS25 and test inverter 29 with the pre-magnetized test transformer, connect the AC output copper busbar 28 of the test PCS to one of the following sets of secondary 800V output terminals (a1, b1, c1) 6 or secondary 630V output terminals (a3, b3, c3) 8 of the pre-magnetized test transformer. Then connect the AC output copper busbar 32 of the test inverter to one of the following sets of secondary 800V output terminals (a2, b2, c2) 7 or secondary... Connect one set of the 630V output terminals (a4, b4, c4) 9. Next, connect the DC positive terminal 26 of the test PCS to the DC positive terminal 30 of the test inverter. Connect the DC negative terminal 27 of the test PCS to the DC negative terminal 31 of the test inverter. Finally, connect the working power supplies A, B, and C to the primary output terminals (A1, B1, C1) 5 of the pre-magnetized test transformer. Connect the input terminal of the molded case switch 2QF to the working power supplies A, B, and C. The test wiring is now complete.

[0136] The working process of this invention is as follows:

[0137] The test process was conducted in accordance with Figure 2 The schematic diagram of the pre-magnetization control for the test transformer is as follows: Pre-magnetizing the test transformer reduces the frequent impact of inrush current on the transformer. After connecting to AC220V control power, 1QF automatically stores energy, and the 1HG trip indicator light illuminates. When SB3 closes, the KM1 pre-magnetization relay coil is energized, and KM1 relay contacts 93 and 94 close, maintaining the pre-magnetization circuit. KM1 relay contacts 63 and 64 close, and the 2HR pre-magnetization closing indicator light illuminates. Simultaneously, KM1 relay contacts 53 and 54 close, energizing the pre-magnetization closing time relay JS and starting a timer. After 5 seconds, pre-magnetization closing time relay contacts 1 and 3 close, and KM1 relay contacts 33 and 34 close. When the following conditions are met, the KM2 relay coil is energized, and KM2 relay contacts L1 and L2 close, closing the 1QF circuit breaker. When the 1HR closing indicator light illuminates, magnetization is successful. When 1QF is closed, contacts 37 and 38 close, energizing the coil of time relay JS1, disconnecting contacts 4 and 1 of JS1, de-energizing the coil of pre-magnetizing relay KM1, disconnecting the pre-magnetizing circuit from the main circuit, closing contacts 101 and 102 of KM1 relay, and illuminating the 2HG pre-magnetizing exit indicator light. This completes the pre-magnetizing process for the test transformer.

[0138] After the test transformer is energized, the test PCS25 and the test inverter 29 are tested. The test transformer connects the AC output copper busbar 28 of the test PCS to one set of the secondary 800V output terminals (a1, b1, c1) 6 or the secondary 630V output terminals (a3, b3, c3) 8 corresponding to the voltage of the pre-magnetized test transformer, thus energizing the test PCS and converting the AC power to DC power. The DC positive terminal 26 of the test PCS is connected to the DC positive terminal 30 of the test inverter; the DC negative terminal 27 of the test PCS is connected to... The test inverter's DC negative terminal 31 is connected, and the test PCS transmits DC power to the DC side of the test inverter. The inverter then converts the DC power into AC power. The test inverter's AC output copper busbar 32 is connected to one of the following sets of secondary 800V output terminals (a2, b2, c2) 7 or secondary 630V output terminals (a4, b4, c4) 9 corresponding to the voltage of the pre-magnetized test transformer. This process transmits the AC power converted by the test inverter to the secondary side of the test transformer, repeating the cycle to perform performance and functional testing on the test PCS and test inverter.

[0139] Those skilled in the art will understand that the above description is merely a preferred embodiment of the present invention, and the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. This is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0140] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if these modifications and modifications of the invention fall within the scope of the claims and their equivalents, the invention is also intended to include these modifications and modifications.

Claims

1. A multi-voltage pre-charged magnetized test transformer, characterized in that, include: Oil tank (1), tank cover (2), oil storage tank (3), iron core (14), lower concentric winding, magnetized winding (13), upper concentric winding and outgoing terminal; The top of the oil tank (1) is fixedly connected to the tank cover (2) by bolts, and the oil storage tank (3) is vertically installed above the tank cover (2) to form a closed oil circulation system; An iron core (14) is provided inside the oil tank (1). The iron core (14) adopts a three-phase three-column laminated structure. The lower concentric winding, the magnetized winding (13) and the upper concentric winding are coaxially mounted on the three columns in sequence. The lower concentric winding consists of three lower secondary windings (17) mounted on three core columns and a lower primary winding (12) mounted on its outer side; The upper concentric winding consists of three upper secondary windings (16) mounted on three core columns and an upper primary winding (11) mounted on its outer side; The output terminals are located on the oil tank (1) and the tank cover (2), wherein each winding output terminal is electrically connected to the corresponding terminal group.

2. The multi-voltage pre-charged magnetized test transformer according to claim 1, characterized in that, The outgoing terminals are provided in multiple groups, including: magnetized winding outgoing terminal group (4), primary outgoing terminal group (5), 800V secondary outgoing terminal group A (6), 800V secondary outgoing terminal group B (7), 630V secondary outgoing terminal group A (8) and 630V secondary outgoing terminal group B (9). The magnetizing winding output terminal group (4) is connected to the first end of the magnetizing winding (13) via a copper busbar; The primary output terminal group (5) is connected to the parallel terminals of the upper primary winding (11) and the lower primary winding (12) respectively by wires; The 800V secondary output terminal group A (6) and the 800V secondary output terminal group B (7) are respectively connected to the positive and negative phase sequence output terminals of the upper secondary winding (16); The 630V secondary output terminal group A (8) and the 630V secondary output terminal group B (9) are respectively connected to the positive and negative phase sequence output terminals of the lower secondary winding (17).

3. The multi-voltage pre-charged magnetized test transformer according to claim 1, characterized in that, The winding arrangement structure of each core column of the iron core (14) from top to bottom is as follows: The upper secondary winding (16), the upper primary winding (11), the magnetizing winding (13), the lower primary winding (12), and the lower secondary winding (17) are all separated by an insulating layer. The winding directions of each winding are as follows: The lower secondary winding (17) and the upper secondary winding (16) are wound in opposite spirals; the lower primary winding (12) and the upper primary winding (11) are wound in opposite spirals; the magnetized winding (13) is wound in a segmented disc shape.

4. A multi-voltage pre-charged magnetized test transformer according to claim 1, characterized in that, The magnetized winding (13) is independently arranged between the upper concentric winding and the lower concentric winding to form a layered structure; The magnetized winding (13) consists of three independent coils mounted on three core columns.

5. A pre-charged magnetic pair test detection system, characterized in that, include: The test transformer (10), magnetization control circuit, and test specimen connection structure as described in any one of claims 1-4; The output terminals of the magnetizing winding (14) are connected to the magnetizing transformer T0 via the magnetizing control circuit; The test specimen connection architecture includes: test specimen PCS (25) and test specimen inverter (29); The AC output copper busbar (28) of the test specimen PCS (25) is connected to the corresponding voltage group in the 800V secondary output terminal group A (6) or the 630V secondary output terminal group A (8) of the test transformer (10); The AC output copper busbar (32) of the test inverter (29) is connected to the corresponding voltage group in the 800V secondary output terminal group B (7) or 630V secondary output terminal group B (9) of the test transformer (10); The positive DC terminal (26) of the test PCS (25) is connected to the positive DC terminal (30) of the test inverter (29); the negative DC terminal (27) of the test PCS (25) is connected to the negative DC terminal (31) of the test inverter (29) so that the test PCS (25) can transmit DC power to the DC side of the test inverter.

6. The pre-charged magnetized pair test detection system according to claim 5, characterized in that, The magnetization control circuit includes: magnetization transformer T0, time relay JS1, magnetization contactor KM1, intermediate relay KM2, circuit breaker 1QF, molded case switch 2QF, and indicator light circuit. The magnetizing transformer T0 has its input end connected to a three-phase power supply via a molded case switch 2QF, and its output end connected to the output terminal of the magnetizing winding (13) via the main contact of the magnetizing contactor KM1. The time relay JS1 and the intermediate relay KM2 form a timing control unit. The delay contact of JS1 is connected in series in the coil circuit of the intermediate relay KM2. The normally open contact of the intermediate relay KM2 is used to control the closing operation of the circuit breaker 1QF. The time relay JS1 and the circuit breaker 1QF form an interlock control. When the pre-magnetization time reaches the set value, the delayed contact of JS1 closes to trigger the intermediate relay KM2 to operate. The normally open contact of KM2 drives the circuit breaker 1QF to close, and at the same time cuts off the power supply circuit of the magnetizing contactor KM1. The main contacts of the magnetizing contactor KM1 are connected in parallel to the magnetizing circuit, and its auxiliary contacts are connected in series with the coil of the time relay JS1 to form a self-locking circuit. The indicator light circuit includes a trip indicator light 1HG, a closing indicator light 1HR, a pre-magnetization status indicator light 2HR, and a pre-magnetization exit indicator light 2HG, which are controlled to turn on and off by the contact status of the circuit breaker 1QF and the magnetizing contactor KM1, respectively.

7. The pre-charged magnetized support test system according to claim 6, characterized in that, The indicator light circuit includes: The trip indicator light 1HG is connected in series across the normally closed contact of circuit breaker 1QF; The closing indicator light 1HR is connected in series across the normally open contact of circuit breaker 1QF; The pre-magnetization status indicator light 2HR is connected in series in the auxiliary contact circuit of the magnetization contactor KM1; The pre-charge exit indicator light 2HG is connected in series in the normally closed contact circuit of the magnetizing contactor KM1.

8. The pre-charged magnetic pair test detection system according to claim 6, characterized in that, The magnetization control circuit performs the following steps: a) After the control power supply is closed, the circuit breaker 1QF is in the open state and the open indicator light 1HG is lit. b) Close the plastic case switch 2QF and trigger the start button SB3 to energize the magnetizing contactor KM1. The main contacts of KM1 close, and the magnetizing transformer T0 supplies power to the magnetizing winding (13). At the same time, the auxiliary contacts of KM1 self-lock and light up the pre-magnetization status indicator 2HR. c) When the magnetizing contactor KM1 contacts are closed, the timing relay JS1 starts counting; d) After the preset delay is reached, the delay contact of JS1 closes. If the magnetizing contactor KM1 is still in the closed state at this time, the intermediate relay KM2 will be energized. e) After the intermediate relay KM2 is activated, its normally open contact closes to drive the circuit breaker 1QF to close, the closing indicator light 1HR lights up, and at the same time the delayed contact of JS1 opens, cutting off the power supply circuit of the magnetizing contactor KM1. f) After the magnetizing contactor KM1 loses power, its main contacts disconnect the magnetizing circuit, and the normally closed contacts reset to illuminate the pre-magnetizing exit indicator 2HG, thus completing the pre-magnetizing process.

9. A pre-charged magnetic pair test detection system according to any one of claims 5-8, characterized in that, The method for testing the torsion test includes the following steps: 1) Pre-magnetization stage: Close the plastic case switch 2QF to trigger the start of the magnetization control circuit, and supply power to the magnetization winding (13) through the magnetization transformer T0 to pre-magnetize the iron core (14); 2) Main circuit closing: When the pre-magnetization time reaches the set value, the time relay JS1 triggers the intermediate relay KM2 to operate, driving the circuit breaker 1QF to close, cutting off the magnetization circuit and connecting the main power supply; 3) Test specimen connection: Connect the AC output copper busbar (28) of the test specimen PCS (25) to the designated voltage secondary output terminal group of the test transformer (10), and connect the AC output copper busbar (32) of the test specimen inverter (29) to the corresponding voltage secondary output terminal group; at the same time, the DC side of the test specimen PCS and the DC side of the test specimen inverter are interconnected through copper busbars; 4) Energy cycle test: 4-1) The test transformer (10) supplies AC power to the test PCS (25) through the secondary output terminals. The test PCS (25) converts the AC power into DC power and inputs it into the test inverter (29). 4-2) The test inverter (29) converts DC power into AC power and feeds it back to the secondary side of the test transformer (10); 5) Through circulating energy transfer, the DC output ripple of the test PCS (25), the AC output harmonic distortion rate of the test inverter (29), and the temperature rise data of the test transformer (10) are collected by external monitoring equipment to evaluate the system stability.

10. The pre-charged magnetic pair test detection system according to claim 5, characterized in that, The voltage matching rule for the energy cycling test is as follows: If the test PCS (25) is connected to the 800V secondary output terminal group A (6), then the test inverter (29) needs to be connected to the 800V secondary output terminal group B (7); If the test PCS (25) is connected to the 630V secondary output terminal group A (8), then the test inverter (29) needs to be connected to the 630V secondary output terminal group B (9).

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