A device for detecting phase shift angle of transformer and detection method thereof

Abstract

The invention discloses a device for detecting a phase shift angle of a transformer and a detection method thereof, and belongs to the field of transformer detection. The device for detecting a phase shift angle of a transformer comprises a lead wire, a terminal bolt, a base and a plurality of isolation transformers, wherein the plurality of isolation transformers are fixedly mounted on the base in sequence, and lead wires are respectively arranged at both ends of the primary winding of the isolation transformer, and the lead wires are connected by a Y-type connection method. One end of the secondary windings of the plurality of isolation transformers is used to be connected to an interface end of a multi-channel power analyzer, and the other ends of the secondary windings of the plurality of isolation transformers are connected together to form a common ground reference point N, and the free ends of the lead wires are all fixed to the base. The device for detecting a phase shift angle of a transformer of the invention cooperates with a detection instrument, and can intuitively read out the phase shift angle degrees of multiple groups at the output end of the transformer at the same time, thereby reducing the proficiency requirements of the operator, improving the detection accuracy, and shortening the detection time.

Description

Technical Field

[0001] The invention belongs to the field of transformer detection, and more specifically relates to a device for detecting a transformer phase shift angle and a detection method thereof. Background Art

[0002] With the rapid development of power electronics technology, DC voltage is widely used, and rectifiers are indispensable. Since the sine wave of the rectifier on the grid side contains a large number of harmonics, the electromagnetic compatibility of the equipment is reduced, which brings harm to the grid and other electrical equipment and affects the power factor. In order to avoid the harmonics of these rectifier products, more and more methods of multi-pulse phase-shifting rectification are used. From 6-pulse rectification to 12-pulse rectification, high-order harmonics cannot be suppressed well. Many transformer manufacturers have designed 18-pulse and 24-pulse phase-shifting transformers according to market demand, and their phase shift angles are -20 degrees, 0 degrees, positive 20 degrees, -15 degrees, 0 degrees, and positive 15 degrees. However, there is currently no detection equipment that can intuitively detect the phase shift angle between each end.

[0003] At present, the line voltage of my country's low-voltage three-phase four-wire power supply lines is 380V, the phase voltage is 220V, the frequency is 50HZ, the frequency is 360 degrees per cycle, and the phase difference between the three phases ABC is 120 degrees. The output side of the 18-pulse transformer is three groups, namely a1-b1-c1; a2-b2-c2; a3-b3-c3, a total of nine outlets, and the phase difference between each outlet is 20 degrees. The output side of the 24-pulse transformer is four groups, with a4-b4-c4 more than the 18-pulse transformer, a total of 12 outlets, and the phase difference between each outlet is 15 degrees, forming a total of 360 degrees in the first half and the second half.

[0004] The existing detection method is to use an oscilloscope to capture the instantaneous waveform at each end, and judge whether it is ahead or behind based on the waveform. This requires the detection personnel to be very professional and is time-consuming. Another method is to use an electric power analyzer for direct detection, which also takes a long time to wire, and can only read the phase shift angle of one output terminal at a time, which requires very high professionalism in instrument setting and wiring operation.

[0005] These phase shift angles are calculated during the design. When the transformer is produced, the phase shift angle needs to be verified to determine whether the actual phase shift angle is consistent with the designed phase shift angle. However, there is currently no device that can simply and quickly detect the phase shift angle. Summary of the invention

[0006] The purpose of the present invention is to propose a device for detecting the phase shift angle of a transformer and a detection method thereof. The principle is to use a sampling voltage to read the phase shift angle. The device is equipped with a multi-channel power analyzer display screen to intuitively read the phase shift angle, which can play a role in safety isolation. High voltage will not damage the multi-channel power analyzer. The present invention can simply and conveniently verify whether the phase shift angle of the transformer meets the design requirements.

[0007] In order to achieve the above-mentioned purpose, the present invention is implemented by adopting the following technical scheme: the device for detecting the phase shift angle of a transformer comprises a lead wire, a terminal bolt, a base and a plurality of isolation transformers, wherein the plurality of isolation transformers are fixedly installed on the base in sequence, the lead wires are respectively provided at both ends of the primary winding of the isolation transformer, the primary winding of the isolation transformer is used to be connected to any in-phase sequence end of the output winding of the phase shift transformer to be detected, the lead wires are respectively provided at both ends of the secondary winding of the isolation transformer, the lead wires of the secondary windings of the plurality of isolation transformers are connected by a Y-type connection, wherein the free ends of the secondary windings of the plurality of isolation transformers are used to be connected to the interface end of the multi-channel power analyzer, and the other ends of the secondary windings of the plurality of isolation transformers are connected together to form a common ground reference point N, the common ground reference point N is used for grounding, and the free ends of the lead wires of each are fixed to the base by corresponding terminal bolts.

[0008] Furthermore, when detecting 18-pulse waves, three independent isolation transformers are installed on the base, which are numbered as isolation transformer I, isolation transformer II and isolation transformer III.

[0009] Furthermore, when detecting 24 pulses, four independent isolation transformers are installed on the base, which are numbered as isolation transformer I, isolation transformer II, isolation transformer III and isolation transformer IV.

[0010] Furthermore, the isolation transformer is an EI type isolation transformer, which includes a frame, an iron core, the primary winding and the secondary winding. The primary winding and the secondary winding are respectively wound on the outer wall of the frame, and the iron core is installed inside the frame.

[0011] Furthermore, the two ends of the primary winding of the isolation transformer I are respectively the phase-shifting transformer test end a and the phase-shifting transformer test end n1; the two ends of the primary winding of the isolation transformer II are respectively the phase-shifting transformer test end b and the phase-shifting transformer test end n2; the two ends of the primary winding of the isolation transformer III are respectively the phase-shifting transformer test end c and the phase-shifting transformer test end n3; one end of the secondary winding of the isolation transformer I is the multi-channel power analyzer interface end A, one end of the secondary winding of the isolation transformer II is the multi-channel power analyzer interface end B, and one end of the secondary winding of the isolation transformer III is the multi-channel power analyzer interface end C. The other ends of the secondary windings of the isolation transformer I, the isolation transformer II and the isolation transformer III are connected together to form the common ground reference point N, and the primary windings of the isolation transformer I, the isolation transformer II and the isolation transformer III are respectively connected to any in-phase sequence end of the three groups of output windings of the 18-pulse phase-shifting transformer to be detected.

[0012] Furthermore, the two ends of the primary winding of the isolation transformer I are respectively the phase-shifting transformer test terminal a and the phase-shifting transformer test terminal n1; the two ends of the primary winding of the isolation transformer II are respectively the phase-shifting transformer test terminal b and the phase-shifting transformer test terminal n2; the two ends of the primary winding of the isolation transformer III are respectively the phase-shifting transformer test terminal c and the phase-shifting transformer test terminal n3; the two ends of the primary winding of the isolation transformer IV are respectively the phase-shifting transformer test terminal d and the phase-shifting transformer test terminal n4; one end of the secondary winding of the isolation transformer I is the multi-channel power analyzer interface terminal A, and the secondary winding of the isolation transformer II is One end of the primary winding is the multi-channel power analyzer interface terminal B, one end of the secondary winding of the isolation transformer III is the multi-channel power analyzer interface terminal C, one end of the secondary winding of the isolation transformer IV is the multi-channel power analyzer interface terminal D, the other ends of the secondary windings of the isolation transformer I, the isolation transformer II, the isolation transformer III and the isolation transformer IV are connected together to form the common ground reference point N connection, and the primary windings of the isolation transformer I, the isolation transformer II, the isolation transformer III and the isolation transformer IV are respectively connected to any in-phase sequence end of the three groups of output windings of the 24-pulse phase-shifting transformer to be detected.

[0013] Furthermore, a system for detecting a transformer phase-shift angle comprises a multi-channel power analyzer and the device for detecting a transformer phase-shift angle, wherein the free ends of the secondary windings of the multiple isolation transformers of the device for detecting a transformer phase-shift angle are respectively connected one-to-one with the multiple interface ends of the multi-channel power analyzer through corresponding connecting bolts.

[0014] Furthermore, the detection method of the transformer phase shift angle detection system comprises the following steps:

[0015] Step 1: the common ground reference point N of the transformer phase shift angle detection device is grounded;

[0016] Step 2: The primary winding of the isolation transformer of the device for detecting the phase shift angle of the transformer is connected to any in-phase sequence end of the output winding of the phase shift transformer to be detected through a corresponding connecting bolt;

[0017] Step 3, the input side of the phase-shifting transformer to be tested is switched on and energized;

[0018] Step 4: Turn on the switch of the multi-channel power analyzer. At this time, the output voltage of each isolation transformer and the phase shift angle of the secondary winding will be displayed on the display screen of the multi-channel power analyzer.

[0019] Beneficial effects of the present invention:

[0020] The device is equipped with a multi-channel power analyzer display screen to intuitively read the phase shift angle, which can play a role in safety isolation. High voltage will not damage the multi-channel power analyzer. The present invention can simply and conveniently verify whether the phase shift angle of the transformer meets the design requirements.

[0021] The device is relatively small in size and light in weight. The input side can be designed according to the voltage of the transformer being tested, and high voltage is also acceptable. The output side can reduce the voltage by multiples, which makes the test process safer and ensures that the multi-channel power analyzer will not be damaged by high voltage.

[0022] The device cooperates with the detection instrument to intuitively read out multiple groups of phase shift angles at the output end of the transformer at the same time, which reduces the requirements on the proficiency of the operator, improves the detection accuracy and shortens the detection time. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A side view of a device for detecting a phase shift angle of a transformer according to one embodiment of the present invention;

[0024] Figure 2 A top view of a third isolation transformer of a device for detecting a phase shift angle of a transformer according to one embodiment of the present invention;

[0025] Figure 3 A top view of a fourth isolation transformer of a device for detecting a transformer phase shift angle according to one embodiment of the present invention;

[0026] Figure 4 A front view of a device for detecting a phase shift angle of a transformer according to one embodiment of the present invention;

[0027] Figure 5 This is a wiring diagram of three isolation transformers of a device for detecting a transformer phase shift angle according to one embodiment of the present invention;

[0028] Figure 6It is a wiring diagram of an 18-pulse phase-shifting transformer and a detection device for detecting the phase-shifting angle of the transformer according to one embodiment of the present invention;

[0029] Figure 7 The figure is a schematic diagram of the angle relationship between a triangle and an edge of an embodiment of the present invention.

[0030] In the figure, 1- isolation transformer, 2- frame, 3- lead wire, 4- terminal bolt, 5- iron core, 6- base. DETAILED DESCRIPTION

[0031] The following will disclose the embodiments of the present invention with the accompanying drawings. For the purpose of clear description, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present disclosure. That is, in some embodiments of the present disclosure, these practical details are not necessary. In addition, in order to simplify the drawings, some conventional structures and elements will be shown in the drawings in a simple schematic manner.

[0032] like Figure 1-4 As shown, a device for detecting a phase shift angle of a transformer in this embodiment comprises a lead wire 3, a terminal bolt 4, a base 6 and a plurality of isolation transformers 1, wherein the plurality of isolation transformers 1 are fixedly mounted on the base 6 in sequence, the lead wires 3 are respectively provided at both ends of the primary winding of the isolation transformer 1, the primary winding of the isolation transformer 1 is used to be connected to any in-phase sequence end of the output winding of the phase-shifting transformer to be detected, the lead wires 3 are respectively provided at both ends of the secondary winding of the isolation transformer 1, the lead wires 3 of the secondary windings of the plurality of isolation transformers 1 are connected by a Y-type connection, wherein a free end of the secondary windings of the plurality of isolation transformers 1 is used to be connected to an interface end of a multi-channel power analyzer, and the other ends of the secondary windings of the plurality of isolation transformers 1 are connected together to form a common ground reference point N, the common ground reference point N is used for grounding, and the free end of each of the lead wires 3 is fixed to the base 6 by a corresponding terminal bolt 4.

[0033] The device for detecting the phase shift angle of the transformer reads the phase shift angle by sampling the voltage of the phase shift transformer to be detected through the isolation transformer 1. The device can intuitively read the phase shift angle when equipped with a multi-channel power analyzer display screen, which can play a role of safety isolation. High voltage will not damage the multi-channel power analyzer, and it can simply and conveniently verify whether the phase shift angle of the transformer meets the design requirements. In addition, the device for detecting the phase shift angle of the transformer realizes the pre-wiring function. Figure 2 and Figure 5It can be seen that, through the pre-wiring structure of multiple isolation transformers 1, there is no need to perform complicated wiring during detection to prevent wiring errors and improve detection accuracy. Instead, any in-phase sequence end of the output winding of the phase-shifting transformer to be detected is directly connected to the terminal plug 4 of the primary winding of the isolation transformer 1, and the interface end of the multi-channel power analyzer is connected to the terminal plug 4 at the free end of the secondary winding of the isolation transformer 1. Multiple isolation transformers 1 are set up so that the phase shift angles of all the output ends of the output winding of the phase-shifting transformer can be read out in one detection operation. The wiring is simple and fast, which greatly reduces the professional requirements for instrument setting and wiring operations.

[0034] The isolation transformer 1 is an EI type isolation transformer, the power is generally between 50VA-100VA, the size is relatively small, and the weight is relatively light. The input side of the isolation transformer 1 can be designed according to the voltage of the transformer to be tested, and high voltage is also possible. The output side of the isolation transformer 1 can reduce the voltage by multiples, so that the test process is safer and ensures that the multi-channel power analyzer will not be damaged by high voltage.

[0035] The isolation transformer 1 comprises a frame 2, an iron core 5, the primary winding and the secondary winding. The primary winding and the secondary winding are respectively wound on the outer wall of the frame 2, and the iron core 5 is installed inside the frame 2 to form the transformer body. The primary winding and the secondary winding are isolated by insulating materials. The isolation transformer 1 has a dielectric strength greater than 3000VAC and a leakage voltage less than 5mA. The primary winding and the secondary winding are internally connected with leads and solder, and the lead joints are inside the outer insulating material.

[0036] like Figure 5-6 As shown, when detecting the 18-pulse phase-shifting transformer, three independent isolation transformers 1 are installed on the base 6, which are numbered as isolation transformer I, isolation transformer II and isolation transformer III. The two ends of the primary winding of the isolation transformer I are respectively the phase-shifting transformer test end a and the phase-shifting transformer test end n1; the two ends of the primary winding of the isolation transformer II are respectively the phase-shifting transformer test end b and the phase-shifting transformer test end n2; the two ends of the primary winding of the isolation transformer III are respectively the phase-shifting transformer test end c and the phase-shifting transformer test end n3; one end of the secondary winding of the isolation transformer I is the multi-channel power analyzer interface end A, one end of the secondary winding of the isolation transformer II is the multi-channel power analyzer interface end B, and one end of the secondary winding of the isolation transformer III is the multi-channel power analyzer interface end C. The other ends of the secondary windings of the isolation transformer I, the isolation transformer II and the isolation transformer III are connected together to form the common ground reference point N connection, and the primary windings of the isolation transformer I, the isolation transformer II and the isolation transformer III are respectively connected to any in-phase sequence end of the three groups of output windings of the 18-pulse phase-shifting transformer to be detected.

[0037] When testing the 24-pulse phase-shifting transformer, four independent isolation transformers 1 are installed on the base 6, which are numbered as isolation transformer I, isolation transformer II, isolation transformer III and isolation transformer IV. The two ends of the primary winding of the isolation transformer I are the phase-shifting transformer test terminal a and the phase-shifting transformer test terminal n1; the two ends of the primary winding of the isolation transformer II are the phase-shifting transformer test terminal b and the phase-shifting transformer test terminal n2; the two ends of the primary winding of the isolation transformer III are the phase-shifting transformer test terminal c and the phase-shifting transformer test terminal n3; the two ends of the primary winding of the isolation transformer IV are the phase-shifting transformer test terminal d and the phase-shifting transformer test terminal n4; one end of the secondary winding of the isolation transformer I is the multi-channel power analyzer interface terminal A, and the secondary winding of the isolation transformer II is the phase-shifting transformer test terminal n3. One end of the group is the multi-channel power analyzer interface terminal B, one end of the secondary winding of the isolation transformer III is the multi-channel power analyzer interface terminal C, one end of the secondary winding of the isolation transformer IV is the multi-channel power analyzer interface terminal D, the other ends of the secondary windings of the isolation transformer I, the isolation transformer II, the isolation transformer III and the isolation transformer IV are connected together to form the common ground reference point N connection, and the primary windings of the isolation transformer I, the isolation transformer II, the isolation transformer III and the isolation transformer IV are respectively connected to any in-phase sequence end of the three groups of output windings of the 24-pulse phase-shifting transformer to be detected.

[0038] In summary, the connection method and working process of the device are as follows: Take the detection of 18-pulse phase-shifting transformer as an example. Figure 6 As shown, the phase-shifting transformer test terminals a-n1 / b-n2 / c-n3 of the device are respectively connected to the output side terminals a1-b1, a2-b2 and a3-b3 of the 18-pulse phase-shifting transformer, or connected to the output side terminals b1-c1, b2-c2 and b3-c3, requiring the same phase sequence, and the clips of the external connecting wires of the multi-channel power analyzer are respectively clamped on the three terminal plugs 4 of the interface terminals ABC of the multi-channel power analyzer on the device for detecting the phase-shifting angle of the transformer;

[0039] Then the input side of the 18-pulse phase-shifting transformer is powered on, and the multi-channel power analyzer is turned on. At this time, the output voltage and the phase-shifting angle of the secondary winding of isolation transformer I, isolation transformer II and isolation transformer III will be displayed on the display screen of the multi-channel power analyzer. Since isolation transformer 1 has no phase shift, it can be regarded as a reference point; therefore, the phase-shifting angle of the secondary winding of isolation transformer 1 read by the multi-channel power analyzer is the phase-shifting angle of the same-phase sequence end of the output winding of the corresponding connected phase-shifting transformer.

[0040] This embodiment also proposes a system for detecting a transformer phase-shift angle, comprising a multi-channel power analyzer and the above-mentioned device for detecting a transformer phase-shift angle, wherein the free ends of the secondary windings of the multiple isolation transformers 1 of the device for detecting a transformer phase-shift angle are respectively connected one-to-one with the multiple interface ends of the multi-channel power analyzer through corresponding terminal plugs 4.

[0041] Based on this, this embodiment also proposes a detection method for the above-mentioned transformer phase shift angle detection system, comprising the following steps:

[0042] Step 1: the common ground reference point N of the transformer phase shift angle detection device is grounded;

[0043] Step 2: The primary winding of the isolation transformer 1 of the device for detecting the phase shift angle of the transformer is connected to any in-phase sequence end of the output winding of the phase shift transformer to be detected through the corresponding connecting bolt 4;

[0044] Step 3, the input side of the phase-shifting transformer to be tested is switched on and energized;

[0045] Step 4: Turn on the switch of the multi-channel power analyzer. At this time, the output voltage of each isolation transformer 1 and the phase shift angle of the secondary winding will be displayed on the display screen of the multi-channel power analyzer.

[0046] The principle of the detection method of the present invention is as follows: to test the phase shift angle, a common reference point must be found, and the output low-voltage sides of multiple independent isolation transformers 1 are led out with leads, connected in parallel, and connected into multi-phase and multi-line, which is characterized by having a neutral line. The neutral line is used as the N line, which is the common ground reference point N. Therefore, the isolation transformer 1 on the phase shift angle detection device has no phase shift and can be regarded as a reference point. Therefore, the phase shift angle is read by using the sampling voltage through the isolation transformer 1, and then equipped with a multi-channel power analyzer to intuitively read the phase shift angle. The multi-channel power analyzer can be a 3169-20 multi-function clamp power meter. The multi-channel power analyzer can read the phase shift angle based on the detected sampling voltage. The specific principle is as follows:

[0047] The output side of the phase-shifting transformer adopts a multi-cake split structure. Each column of the 18-pulse phase-shifting transformer has three cakes, and each column of the 24-pulse phase-shifting transformer has four cakes. The calculation method of the 24-pulse phase-shifting angle is similar to that of the 18-pulse wave. The calculation of the phase-shifting angle of the 18-pulse phase-shifting transformer is as follows: the composite voltage of each line cake A2=Aab=Abc=Aca=B. The voltage of the phase-shifting winding Ay=Aax=Aby=Acz, in △ABC, according to the sine theorem, Ay=Aax=Aby=Acz=A2sinα / sin120°; the voltage of the main winding Az=A2×[sin(60°-α)-sinα] / sin120°, where α is (+20°, 0°, -20°).

[0048] like Figure 7 As shown, the multi-channel power analyzer can measure the angle relationship between the triangle and the extension through the angle measurement tool, and can calculate the phase shift of 20°. When the extension angle of 18 pulses is 20 degrees, the extension voltage can be calculated. Therefore, the phase shift angle is read by sampling voltage through the isolation transformer 1, and the phase shift angle can be read intuitively with the multi-channel power analyzer.

[0049] It should be understood that the detailed description of the technical solutions of the present invention by means of the preferred embodiments is illustrative rather than restrictive. A person skilled in the art may modify the technical solutions described in the embodiments, or replace some of the technical features by equivalents, based on reading the specification of the present invention; and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for detecting a phase shift angle of a transformer, characterized in that: The device for detecting the phase shift angle of a transformer comprises a lead wire (3), a terminal bolt (4), a base (6) and a plurality of isolation transformers (1), wherein the plurality of isolation transformers (1) are fixedly mounted on the base (6) in sequence, the lead wires (3) are respectively arranged at both ends of the primary winding of the isolation transformer (1), the primary winding of the isolation transformer (1) is used to be connected to any in-phase sequence end of the output winding of the phase shift transformer to be detected, the lead wires (3) are respectively arranged at both ends of the secondary winding of the isolation transformer (1), the lead wires (3) of the secondary windings of the plurality of isolation transformers (1) are connected by a Y-type connection, wherein a free end of the secondary windings of the plurality of isolation transformers (1) is used to be connected to an interface end of a multi-channel power analyzer, and the other ends of the secondary windings of the plurality of isolation transformers (1) are connected together to form a common ground reference point N, the common ground reference point N is used for grounding, and the free end of each of the lead wires (3) is fixed to the base (6) by a corresponding terminal bolt (4); The free ends of the secondary windings of the plurality of isolation transformers (1) of the transformer phase shift angle detection device are respectively connected to the plurality of interface ends of the multi-channel power analyzer in a one-to-one correspondence via corresponding connection bolts (4).

2. A device for detecting a phase shift angle of a transformer according to claim 1, characterized in that: When detecting 18 pulses, three independent isolation transformers (1) are installed on the base (6), which are numbered as isolation transformer I, isolation transformer II and isolation transformer III respectively.

3. The device for detecting the phase shift angle of a transformer according to claim 1, characterized in that: When detecting 24 pulse waves, four independent isolation transformers (1) are installed on the base (6), which are numbered as isolation transformer I, isolation transformer II, isolation transformer III and isolation transformer IV.

4. The device for detecting the phase shift angle of a transformer according to claim 1, characterized in that: The isolation transformer (1) is an EI type isolation transformer, comprising a frame (2), an iron core (5), the primary winding and the secondary winding, the primary winding and the secondary winding being respectively wound on the outer wall of the frame (2), and the iron core (5) being installed inside the frame (2).

5. The device for detecting the phase shift angle of a transformer according to claim 2, characterized in that: The two ends of the primary winding of the isolation transformer I are respectively the phase-shifting transformer test end a and the phase-shifting transformer test end n1; the two ends of the primary winding of the isolation transformer II are respectively the phase-shifting transformer test end b and the phase-shifting transformer test end n2; the two ends of the primary winding of the isolation transformer III are respectively the phase-shifting transformer test end c and the phase-shifting transformer test end n3; one end of the secondary winding of the isolation transformer I is the multi-channel power analyzer interface end A, one end of the secondary winding of the isolation transformer II is the multi-channel power analyzer interface end B, and one end of the secondary winding of the isolation transformer III is the multi-channel power analyzer interface end C. The other ends of the secondary windings of the isolation transformer I, the isolation transformer II and the isolation transformer III are connected together to form the common ground reference point N. The primary windings of the isolation transformer I, the isolation transformer II and the isolation transformer III are respectively connected to any in-phase sequence end of the three groups of output windings of the 18-pulse phase-shifting transformer to be detected.

6. The device for detecting the phase shift angle of a transformer according to claim 3, characterized in that: The two ends of the primary winding of the isolation transformer I are respectively a phase-shifting transformer test end a and a phase-shifting transformer test end n1; The two ends of the primary winding of the isolation transformer II are respectively the phase-shifting transformer test end b and the phase-shifting transformer test end n2; the two ends of the primary winding of the isolation transformer III are respectively the phase-shifting transformer test end c and the phase-shifting transformer test end n3; the two ends of the primary winding of the isolation transformer IV are respectively the phase-shifting transformer test end d and the phase-shifting transformer test end n4; one end of the secondary winding of the isolation transformer I is the multi-channel power analyzer interface end A, one end of the secondary winding of the isolation transformer II is the multi-channel power analyzer interface end B, one end of the secondary winding of the isolation transformer III is the multi-channel power analyzer interface end C, one end of the secondary winding of the isolation transformer IV is the multi-channel power analyzer interface end D, the other ends of the secondary windings of the isolation transformer I, the isolation transformer II, the isolation transformer III and the isolation transformer IV are connected together to form the common ground reference point N connection, and the primary windings of the isolation transformer I, the isolation transformer II, the isolation transformer III and the isolation transformer IV are respectively connected to any in-phase sequence end of the three groups of output windings of the 24-pulse phase-shifting transformer to be detected.

7. A system for detecting a transformer phase shift angle, characterized in that: The invention comprises a multi-channel power analyzer and a device for detecting a phase shift angle of a transformer as claimed in any one of claims 1 to 6.

8. A detection method for detecting a transformer phase shift angle system according to claim 7, characterized in that: The following steps are involved: Step 1: the common ground reference point N of the transformer phase shift angle detection device is grounded; Step 2: the primary winding of the isolation transformer (1) of the device for detecting the phase shift angle of the transformer is connected to any in-phase sequence end of the output winding of the phase shift transformer to be detected through a corresponding connecting bolt (4); Step 3, the input side of the phase-shifting transformer to be tested is switched on and energized; Step 4: Turn on the switch of the multi-channel power analyzer. At this time, the output voltage of each isolation transformer (1) and the phase shift angle of the secondary winding will be displayed on the display screen of the multi-channel power analyzer.

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