Testing device and method for carrying out partial discharge measurement on double-body phase-shifting transformer

Abstract

The invention relates to a test device and method for partial discharge measurement of a double-body phase-shifting transformer. The testing device relates to the technical field of power transformer testing. The test device comprises a series transformer T1 and an exciting transformer T2, the series transformer T1 and the exciting transformer T2 are connected with each other, the middle of a high-voltage winding of the series transformer T1 is connected with a high-voltage winding of the exciting transformer T2 in series, a high-voltage neutral point is led out from three phases, a low-voltage winding of the series transformer T1 is in corner joint, and a phase modulation winding is externally connected to the exciting transformer T2. The metal conductive sleeve is of a conductive structure, conductive connection between the two wires can be guaranteed, the wires can smoothly stretch into the metal conductive sleeve in the mode that the adhesion layer is arranged, a conventional wiring mode is replaced, and operation is easy.

Description

Technical Field

[0001] The invention belongs to the technical field of power transformer testing, and in particular relates to a testing device and method for partial discharge measurement of a double-body phase-shifting transformer. Background Art

[0002] The power system refers to a system of electric energy production and consumption composed of power plants, transmission lines, distribution lines and loads. When the power system is in steady-state operation, the voltage and power distribution of each node of the power grid is called the power flow distribution of the power system. Changes in the impedance and phase angle of the parallel loads in the branch of the power grid will lead to changes in the steady-state power flow of the power system, thereby affecting the reliable and stable output of electric energy. Therefore, the power system introduces a power flow control device - a phase-shifting transformer, which adjusts the distribution of the power system power flow by changing the size of the phase angle. However, the phase-shifting transformer has many windings, a complex outgoing line structure, and a wide range of winding voltage distribution. The product is the most difficult to test in the acceptance test, especially the induced voltage test with partial discharge measurement, because its enhanced voltage is high and there are many terminals for monitoring partial discharge. Testing the line and monitoring the voltage are a major problem. Summary of the invention

[0003] The purpose of the present invention is to provide a test device for partial discharge measurement of a dual-body phase-shifting transformer with a simple structure and reasonable design in order to solve the above problems, thereby solving the test problems caused by high voltage.

[0004] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0005] A first aspect of the present invention provides a test device for partial discharge measurement of a double-body phase-shifting transformer, comprising a series transformer T1 and an excitation transformer T2, wherein the series transformer T1 and the excitation transformer T2 are connected to each other, and the middle part of the high-voltage winding of the series transformer T1 is connected in series with the high-voltage winding of the excitation transformer T2, and the high-voltage neutral point is led out in three phases, and the low-voltage winding of the series transformer T1 is delta-connected and externally connected to the phase-adjusting winding of the excitation transformer T2.

[0006] As a further optimization solution of the present invention, the series transformer T1 and the excitation transformer T2 are connected by an auxiliary tool;

[0007] The auxiliary tool includes a metal conductive sleeve, an insulating layer and an adhesion layer. The metal conductive sleeve is a circular sleeve structure. Adhesion layers are fixedly provided at both ends of the metal conductive sleeve, and the adhesion layer and the outer ring surface of the metal conductive sleeve are fixedly coated with an insulation layer. Small teeth are fixedly provided at the inner ring of the adhesion layer.

[0008] As a further optimization solution of the present invention, a plurality of small teeth are provided, and the tips of the plurality of small teeth are all distributed toward the middle of the metal conductive sleeve.

[0009] As a further optimization solution of the present invention, the end of the adhesion layer away from the metal conductive sleeve has a larger opening.

[0010] As a further optimization solution of the present invention, exhaust grooves are further provided on the inner wall of the metal conductive sleeve, and the exhaust grooves are distributed along the length direction of the metal conductive sleeve.

[0011] A second aspect of the present invention provides a test method for partial discharge measurement of a dual-body phase-shifting transformer, comprising the test device as described above, the method comprising:

[0012] The low-voltage winding of the series transformer is delta-connected and connected to the phase-modulating winding of the excitation transformer to obtain the voltage of the corresponding tapped low-voltage winding of the series transformer, and to obtain and record the excitation side voltage of the partial discharge test.

[0013] The beneficial effects of the present invention are as follows: the present invention applies a lower excitation voltage to the low-voltage winding of the series transformer by temporarily leading out the test terminal, thereby completing the partial discharge test of the complex double-body phase-shifting transformer, and can conveniently process the power-on line to complete the measurement of the partial discharge test of the high-voltage 6 terminals.

[0014] The metal conductive sleeve is a conductive structure, which can ensure the conductive connection between the two wires. In the present invention, an adhesive layer is provided so that the wires can be smoothly inserted, replacing the conventional wiring method, and the operation is simple.

[0015] The adhesion layer has a certain viscosity and can be elastically deformed. It is usually made of plastic film. When the two ends of the wires are inserted into the metal conductive sleeve at the same time, the inner wall of the adhesion layer can be baked with fire to melt the inner wall of the adhesion layer to a certain extent. Then, the outer circle of the adhesion layer can be manually pinched to adhere the adhesion layer to the outer circle surface of the wire, which plays a sealing and waterproof role, and realizes a quick connection between the two wires, thereby improving the connection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a test circuit diagram used in a partial discharge test of a double-body phase-shifting transformer of the present invention;

[0017] Figure 2 It is a schematic diagram of the structure of the series transformer T1 and the excitation transformer T2 of the present invention;

[0018] Figure 3 It is a schematic diagram of the auxiliary tool structure of the present invention;

[0019] Figure 4 is a schematic diagram of the structure of the auxiliary tool of the present invention when it is in use;

[0020] Figure 5 It is a schematic diagram of the structure of the auxiliary tool of the present invention after connecting two wires.

[0021] In the figure: a metal conductive sleeve 1, an insulating layer 2, an adhesive layer 3, small teeth 4, a conductor 5, a folded portion 21, and a conductor skin 51. DETAILED DESCRIPTION

[0022] The present application is further described in detail below in conjunction with the accompanying drawings. It is necessary to point out here that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technical personnel in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0023] The invention provides a test device and method for partial discharge measurement of a double-body phase-shifting transformer.

[0024] The technical solution of the present invention is: the product leads out the test terminal on the low-voltage side of the series transformer, and calculates the voltage of the corresponding low-voltage side winding according to the voltage of the high-voltage side winding of the series transformer. Since the number of turns of the phase-adjusting winding of the excitation transformer is small, the voltage is low. The method of partial discharge measurement is carried out by excitation of the low-voltage winding, so that the appropriate power-on method can be flexibly selected to complete the partial discharge measurement test of the product, that is, the circuit can be optimized, and the partial discharge assessment of each high-voltage terminal is carried out at the same time.

[0025] Working principle: Reference Figure 1 As shown in the figure, the double-body phase-shifting transformer is composed of a series transformer T1 and an excitation transformer T2 connected to each other. The high-voltage winding of the series transformer is connected in series with the high-voltage winding of the excitation transformer in the middle, and the three-phase high-voltage neutral point is drawn out. The low-voltage winding of the series transformer is angle-connected and externally connected to the phase-adjusting winding of the excitation transformer. The excitation side voltage of the partial discharge test is determined by calculating the voltage of the corresponding tapped low-voltage winding of the series transformer. This voltage is low and the wiring is simple and convenient.

[0026] The voltage applied to the low-voltage winding of the series transformer under the partial discharge measurement line is calculated using the following formula: (induction multiple K)

[0027]

[0028] Note:U H is the high voltage rated voltage of the series transformer; θ is the half phase shift angle of the phase shift transformer;

[0029] N H N is the number of turns of the high-voltage coil of the series transformer; L is the number of turns of the low-voltage coil of the series transformer.

[0030] Wiring is performed according to the test circuit diagram, voltage correction is performed on the high-voltage terminal S and low-voltage terminals EF, G, H of the series transformer of the test product, and the voltages of the high-voltage terminal and the low-voltage terminal are checked to see whether they are consistent with the calculated values. Partial discharge measurement is performed according to standard procedures.

[0031] Here are some examples:

[0032] Calculate the high voltage turn voltage of the series winding of the phase-shifting transformer:

[0033] Parameters of the tested phase shifter: Rated voltage Ur: 115kV

[0034] Coil turns: Series transformer high voltage winding: 190, low voltage winding 219

[0035] Series transformer turn voltage:

[0036] Calculate the voltage applied to the low voltage winding for partial discharge test:

[0037] Low voltage winding excitation side voltage: 1.58×489.4 / 1000×219=16.93kV

[0038] High voltage side voltage:

[0039] Voltage correction: When the potential of the S side to ground is 100 kV, the potential between EF, G, and H is 9.3 kV, which is consistent with the calculated tap voltage value.

[0040] In summary, when conducting partial discharge measurements on double-body phase-shifting transformers with voltage levels of 110kV and below, choosing an appropriate power-on method based on the existing test equipment and power supply in the laboratory can make the line more optimized and the test method more flexible.

[0041] refer to Figure 3 As shown in the figure, the present invention also proposes an auxiliary tool for connecting the series transformer T1 and the excitation transformer T2, specifically comprising: a metal conductive sleeve 1, an insulating layer 2 and an adhesion layer 3. The metal conductive sleeve 1 is a circular sleeve structure. Adhesion layers 3 are fixedly provided at both ends of the metal conductive sleeve 1. The end of the adhesion layer 3 away from the metal conductive sleeve 1 has a large opening, and the outer ring surfaces of the adhesion layer 3 and the metal conductive sleeve 1 are fixedly coated with the insulation layer 2. Small teeth 4 are fixedly provided at the inner ring of the adhesion layer 3. A plurality of small teeth 4 are provided, and the tips of the plurality of small teeth 4 are all distributed toward the middle of the metal conductive sleeve 1.

[0042] like Figure 4As shown in the figure, when using the auxiliary tool, a part of the wire skin 51 at the end of the wire 5 on the series transformer T1 and the excitation transformer T2 is peeled off, and the peeled-off part of the wire skin 51 extends from the adhesive layer 3 to the inside of the metal conductive sleeve 1, and the ends of the two wires 5 extend from the adhesive layer 3 at both ends of the metal conductive sleeve 1 respectively, until the ends of the two wires 5 are attached to each other or are attached to the inner wall of the metal conductive sleeve 1 respectively.

[0043] The metal conductive sleeve 1 is a conductive structure, which can ensure the conductive connection between the two wires 5. In the present invention, the wires 5 can be smoothly inserted by providing an adhesive layer 3, which replaces the conventional wiring method and is easy to operate.

[0044] The adhesion layer 3 has a certain viscosity and can be elastically deformed. It is usually made of plastic film. When the ends of the two wires 5 are simultaneously extended into the metal conductive sleeve 1, the inner wall of the adhesion layer 3 can be baked with fire to melt the inner wall of the adhesion layer 3 to a certain extent. Then, the outer circle of the adhesion layer 3 is manually pinched to adhere the adhesion layer 3 to the outer circle surface of the wire 5, thereby playing a sealing and waterproof role, and realizing a quick connection between the two wires 5, thereby improving the connection efficiency.

[0045] Furthermore, when the adhesive layer 3 is bonded to the outer ring of the conductor 5, the small teeth 4 bite into the conductor skin 51 of the outer ring of the conductor 5, thereby achieving further bite fixation, making the connection difficult to come off and having high connection strength.

[0046] It should be noted that if Figure 4 As shown in FIG. 1 , only the wire skin 51 of a section of the outer circle of the wire 5 extending into the metal conductive sleeve 1 is peeled off, and the wire skin 51 of a section of the wire 5 located inside the adhesive layer 3 is retained for subsequent connection and use.

[0047] It should also be noted that the small teeth 4 can be set on the folded part 21, which is the insulating layer 2 of the outer circle of the adhesive layer 3. The method of setting the small teeth 4 on the folded part 21 avoids the problem of the small teeth 4 being detached due to subsequent baking of the inner wall of the adhesive layer 3.

[0048] like Figure 5 FIG. 4 is a final schematic diagram showing the metal conductive sleeve 1 being connected between two conductors 5 .

[0049] like Figure 3 As shown in the figure, exhaust grooves 11 are also provided on the inner wall of the metal conductive sleeve 1. The exhaust grooves 11 are distributed along the length direction of the metal conductive sleeve 1. When the wire 5 is inserted into the metal conductive sleeve 1, excess gas can be discharged through the exhaust grooves 11, avoiding the problem of excessive air inside the metal conductive sleeve 1 and enabling the two wires 5 to be smoothly connected.

[0050] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A test device for partial discharge measurement of a double-body phase-shifting transformer, comprising a series transformer T1 and an excitation transformer T2, characterized in that: The series transformer T1 and the excitation transformer T2 are connected to each other, and the middle part of the high-voltage winding of the series transformer T1 is connected in series with the high-voltage winding of the excitation transformer T2, and the three-phase high-voltage neutral point is led out. The low-voltage winding of the series transformer T1 is delta-connected and externally connected to the phase-adjusting winding of the excitation transformer T2.

2. The test device and method for partial discharge measurement of a dual-body phase-shifting transformer according to claim 1, characterized in that: The series transformer T1 and the excitation transformer T2 are connected by auxiliary tools; The auxiliary tool comprises a metal conductive sleeve (1), an insulating layer (2) and an adhesive layer (3); the metal conductive sleeve (1) is a circular sleeve-shaped structure; both ends of the metal conductive sleeve (1) are fixedly provided with an adhesive layer (3); the outer ring surfaces of the adhesive layer (3) and the metal conductive sleeve (1) are fixedly coated with an insulating layer (2); and small teeth (4) are fixedly provided at the inner ring of the adhesive layer (3).

3. A test device for partial discharge measurement of a double-body phase-shifting transformer according to claim 2, characterized in that: A plurality of small teeth (4) are provided, and the tips of the plurality of small teeth (4) are all distributed toward the middle of the metal conductive sleeve (1).

4. A test device for partial discharge measurement of a double-body phase-shifting transformer according to claim 2, characterized in that: The end of the adhesion layer (3) away from the metal conductive sleeve (1) has a larger opening.

5. The test device for partial discharge measurement of a double-body phase-shifting transformer according to claim 2, characterized in that: The inner wall of the metal conductive sleeve (1) is also provided with exhaust grooves (11), and the exhaust grooves (11) are distributed along the length direction of the metal conductive sleeve (1).

6. A test method for partial discharge measurement of a double-body phase-shifting transformer, characterized in that: Comprising the test device as claimed in claims 1-5, the method comprises: The low-voltage winding of the series transformer is delta-connected and connected to the phase-modulating winding of the excitation transformer to obtain the voltage of the corresponding tapped low-voltage winding of the series transformer, and to obtain and record the excitation side voltage of the partial discharge test.

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