CN213423386U

CN213423386U - Transformer induction withstand voltage test circuit

Info

Publication number: CN213423386U
Application number: CN202022555280.6U
Authority: CN
Inventors: 董景义; 沈花林; 李国旗; 费旭城
Original assignee: Wujiang Transformer Co Ltd
Current assignee: Wujiang Transformer Co Ltd
Priority date: 2020-11-06
Filing date: 2020-11-06
Publication date: 2021-06-11
Anticipated expiration: 2030-11-06

Abstract

The utility model relates to the technical field of transformers, and discloses a transformer induction withstand voltage test circuit, which comprises a voltage regulator, an intermediate transformer and a transformer test article which are connected in sequence; the device also comprises a power analyzer and a local discharge tester; the output end of the voltage regulator is connected with the low-voltage side of the intermediate transformer; the high-voltage end of the intermediate transformer is connected with the low-voltage end of the transformer test article; a voltage transformer, a current transformer and a series filter are arranged between the intermediate transformer and the transformer sample; the partial discharge tester is connected with the high-voltage side of the transformer test article; the output end of the voltage regulator is provided with a compensation reactor; the voltage transformer and the current transformer are both connected with the power analyzer; the voltage regulator, the intermediate transformer and the transformer test sample are all connected by adopting high-voltage shielded cables. The transformer induction voltage withstand test method and the circuit have the advantages of small investment of test circuits, simple wiring, convenience in operation and strong practicability, and can effectively reduce power supply interference during transformer test.

Description

Transformer induction withstand voltage test circuit

Technical Field

The utility model relates to a transformer testing arrangement, in particular to transformer response withstand voltage test circuit.

Background

Along with the rapid increase of the installed capacity of the generator in China, the single capacity and the high-voltage level of the transformer are gradually improved; at present, high-voltage, ultrahigh-voltage and extra-high-voltage generators and transformers for power grids become standardized products in China, and the capacity of the transformers is increased from hundreds of thousands of kVA to millions of kVA. However, with the increase of the capacity of the transformer, the rated voltage of the low-voltage winding of the transformer is also improved, and the rated voltage of the low-voltage winding of some products is 66kV or even higher.

In order to ensure the quality of the transformer and to operate the transformer smoothly, it is necessary to perform an induction withstand voltage test before the transformer is put into operation and measure the partial discharge amount thereof during the test. However, in the process of performing partial discharge test on the transformer operation site, the number of interference sources is large, the signal types are complex, and the shielding or isolation is difficult. Years of analysis and research find that the interference of a power supply for testing is a main factor, and the influence is more obvious when the applied power supply voltage is higher, so that sometimes test detection personnel cannot distinguish whether the partial discharge quantity is from a transformer body or from external background interference, and the misjudgment of the transformer fault is easily caused. Therefore, a new test scheme is needed to be sought for reducing the test power supply interference, which is beneficial to saving the consumption of manpower and material resources and shortening the construction period of the transformer substation.

SUMMERY OF THE UTILITY MODEL

The utility model provides a technical problem provide a transformer response withstand voltage test circuit, test equipment investment is little, the wiring is simple, convenient operation, practicality are strong, can effectively reduce transformer response withstand voltage test method and circuit of power disturbance when experimental.

The utility model provides a technical scheme that its technical problem adopted is: a transformer induction voltage withstand test circuit comprises a voltage regulator, an intermediate transformer and a transformer test article which are connected in sequence; the device also comprises a power analyzer and a local discharge tester; the output end of the voltage regulator is connected with the low-voltage side of the intermediate transformer; the high-voltage end of the intermediate transformer is connected with the low-voltage end of the transformer test article; a voltage transformer, a current transformer and a series filter are arranged between the intermediate transformer and the transformer sample; the partial discharge tester is connected with the high-voltage side of the transformer test article.

Further, the method comprises the following steps: and the output end of the voltage regulator is provided with a compensation reactor.

Further, the method comprises the following steps: and the voltage transformer and the current transformer are both connected with the power analyzer.

Further, the method comprises the following steps: the voltage regulator, the intermediate transformer and the transformer test sample are connected by adopting high-voltage shielded cables.

The utility model has the advantages that: by installing a series filter in the transformer induced withstand voltage test line, an interference signal from a power supply is greatly attenuated; by adopting a non-tested phase excitation and non-tested phase support mode, the power supply voltage acting on the transformer test article is reduced to one half of that during the tested phase excitation, the acting voltage on a test line is effectively reduced, and the background interference level is further weakened; the measures effectively ensure the authenticity of the test result of the partial discharge capacity of the transformer and are beneficial to the analysis and judgment of the quality state of the transformer. The method has the advantages of low investment, simple wiring, convenient operation, strong practicability and the like. The test scheme is suitable for test projects of induction withstand voltage and partial discharge measurement of all three-phase power transformers with 66kV levels and above.

Drawings

FIG. 1 is a schematic diagram of an induced voltage withstand test circuit of a transformer;

fig. 2 is a potential distribution diagram.

Labeled as: 1. a voltage regulator; 2. a compensation reactor; 3. an intermediate transformer; 4. a voltage transformer; 5. a current transformer; 6. a power analyzer; 7. a series filter; 8. testing a transformer; 9. partial discharge tester.

Detailed Description

In order to deepen the understanding of the present invention, the present invention will be described in further detail with reference to the accompanying drawings and embodiments, which are only used for explaining the present invention and are not limited to the protection scope of the present invention.

Examples

As shown in fig. 1, an induced voltage withstand test circuit of a transformer comprises a voltage regulator 1, an intermediate transformer 3 and a transformer test article 8 which are connected in sequence; the device also comprises a power analyzer 6 and a local discharge tester 9; the output end of the voltage regulator 1 is connected with the low-voltage side of the intermediate transformer 3; the high-voltage end of the intermediate transformer 3 is connected with the low-voltage end of the transformer test article 8; a voltage transformer 4, a current transformer 5 and a series filter 7 are arranged between the intermediate transformer 3 and the transformer sample 8; the partial discharge tester 9 is connected with the high-voltage side of the transformer test article 8.

On the basis, the output end of the voltage regulator 1 is provided with a compensation reactor 2; the voltage transformer 4 and the current transformer 5 are both connected with a power analyzer 6; the voltage regulator 1, the intermediate transformer 3 and the transformer test article 8 are all connected by adopting high-voltage shielding cables. The voltage regulator 1 may be replaced by a medium frequency generator.

Firstly, selecting the wire gauge size and the insulation level of the series filter 7 according to the current and the voltage which need to be applied to the transformer test sample 8; then, determining the inductance value of the series filter 7 according to the interference component in the field power supply signal of the transformer; next, the structural dimensions of the series filter 7 are determined on the basis of these parameters and the air-core reactor design principle. Finally, the output end of the voltage regulator 1 is connected to the low-voltage side of the intermediate transformer 3 through the compensating reactor 2 by using a high-voltage shielded cable; adjusting the tapping position of the intermediate transformer 3 according to the test voltage required to be applied by the transformer test article 8; a high-voltage output end of the intermediate transformer 3 is connected to a low-voltage line terminal corresponding to a transformer test product through a mutual inductor and a series filter 7 by using a high-voltage shielding cable, the pressurization mode is non-tested phase excitation, a tested winding adopts a non-tested phase supporting method, the voltage of a test line is effectively reduced, an experimental circuit potential diagram is shown in figure 2, U is tested phase end experimental voltage on the way, U is power supply voltage, and the power supply voltage in the traditional test line is 2U. And then the power analyzer 6, the partial discharge tester 9 and the like are respectively connected to a test line and a transformer test article 8 according to the requirements of the induction withstand voltage test scheme, and voltage is applied to the transformer according to the test standard GB1094.3 while the partial discharge amount of the transformer is monitored. The method has the characteristics of low investment, simple wiring, convenience in operation, high practicability and the like.

The above-mentioned embodiments should not limit the present invention in any way, and all the technical solutions obtained by adopting equivalent replacement or equivalent conversion fall within the protection scope of the present invention.

Claims

1. The utility model provides a transformer response withstand voltage test circuit which characterized in that: comprises a voltage regulator (1), an intermediate transformer (3) and a transformer test article (8) which are connected in sequence; the device also comprises a power analyzer (6) and a partial discharge tester (9); the output end of the voltage regulator (1) is connected with the low-voltage side of the intermediate transformer (3); the high-voltage end of the intermediate transformer (3) is connected with the low-voltage end of the transformer test article (8); a voltage transformer (4), a current transformer (5) and a series filter (7) are arranged between the intermediate transformer (3) and the transformer test article (8); the partial discharge tester (9) is connected with the high-voltage side of the transformer test article (8).

2. The transformer induction voltage withstand test circuit according to claim 1, wherein: and the output end of the voltage regulator (1) is provided with a compensation reactor (2).

3. The transformer induction voltage withstand test circuit according to claim 1, wherein: and the voltage transformer (4) and the current transformer (5) are both connected with the power analyzer (6).

4. The transformer induction voltage withstand test circuit according to claim 1, wherein: the voltage regulator (1), the intermediate transformer (3) and the transformer test article (8) are connected by adopting high-voltage shielding cables.