Double-sided pressurization circuit and method for out-of-step closing and breaking tests of medium voltage circuit breakers

Abstract

The application relates to a double-side pressurizing circuit for step-out closing and breaking test of a medium-voltage circuit breaker, belonging to the technical field of circuit breaker test, which comprises a generator system G for providing three-phase power supply for a tested product SP; the generator system G is connected with an adjusting impedance Z through an operating circuit breaker QF, and is further connected with the tested product SP through an option switch HK, an isolating switch QS1 and an isolating switch QS2; the isolating switch QS1 is connected in parallel with a transformer T. The application introduces a double-side pressurizing scheme to realize 2.5 / sqrt(3)Un, 0.25In power supply required by step-out closing and breaking capacity test, and has the advantages of simple structure, perfect function and low cost.

Description

Technical Field

[0001] This invention belongs to the field of circuit breaker testing technology, and relates to a double-sided pressurization circuit and method for out-of-step closing and opening tests of medium-voltage circuit breakers. Background Technology

[0002] Out-of-synchronization closing and opening tests of medium-voltage circuit breakers are a special performance test for medium-voltage circuit breakers used in power systems. These tests are designed to simulate an extreme operating condition that occurs in the power grid, where two parts of the grid lose synchronization (out-of-synchronization) due to frequency or phase difference, and the circuit breaker needs to perform closing or opening operations under such conditions.

[0003] The out-of-synchronization closing test simulates the operation of a circuit breaker closing when two systems lose synchronization. This typically occurs after a grid fault is repaired, when two asynchronous systems need to be reconnected. The test verifies whether the circuit breaker can successfully close and maintain stable operation without re-breakdown or damage under the high voltage and high current caused by system out-of-synchronization.

[0004] Out-of-step breaking test evaluates the circuit breaker's ability to disconnect the circuit when the system is out of step. When the systems at both ends of the circuit breaker become independent due to frequency or phase differences, their voltage and current characteristics change rapidly, potentially leading to high recovery voltages and overvoltages. The test simulates this scenario to check whether the circuit breaker can quickly and safely interrupt the current during breaking, preventing insulation breakdown or damage under the impact of high voltage and high current.

[0005] These types of tests are crucial for ensuring the stability and safety of power systems because, although out-of-step events are relatively rare, they pose an extremely severe test to circuit breakers when they occur. The test conditions are demanding, requiring circuit breakers to withstand currents and voltages far exceeding normal operating conditions while ensuring the reliability of their mechanical and electrical performance. Therefore, out-of-step making and breaking capabilities are considered key indicators for evaluating the performance of medium-voltage circuit breakers. However, the withstand voltage and current handling capabilities of the test equipment limit the scale and accuracy of the tests, sometimes necessitating compromises that may affect the comprehensiveness and representativeness of the test results. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a double-sided pressurization circuit and method for out-of-step closing and opening tests of medium-voltage circuit breakers.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] On one hand, the present invention provides a double-sided pressurized circuit for out-of-step closing and opening tests of medium-voltage circuit breakers, including a generator system G for providing three-phase power to the test object SP; the generator system G is connected to the regulating impedance Z through the operating circuit breaker QF, and then connected to the test object SP through the optional switch HK, the disconnecting switch QS1 and the disconnecting switch QS2; the disconnecting switch QS1 is connected in parallel with a transformer T.

[0009] Furthermore, the transformer T consists of two single-phase step-down transformers, with its primary side connected to the line voltage of the generator system G, and its secondary side connected in series with the intermediate point grounded.

[0010] Furthermore, the transformer T includes a first single-phase step-down transformer and a second single-phase step-down transformer; the primary side of the first single-phase step-down transformer is connected to phase A of the generator system G via disconnector QS3 and to phase C of the generator system G via disconnector QS4; the primary side of the second single-phase step-down transformer is connected to phase A of the generator system G via disconnector QS5 and to phase C of the generator system G via disconnector QS6; the secondary sides of the first single-phase step-down transformer and the second single-phase step-down transformer are connected in series and then connected to phase C of the generator system G via disconnector QS7 and to phase A of the generator system G via disconnector QS8.

[0011] Furthermore, the rated voltage of the three-phase power supply is Un = 12kV, and the maximum voltage is Um = 13.2kV.

[0012] Furthermore, the transformer T turns ratio is Secondary output is U AC This represents the line voltage of two phases of AC.

[0013] On the other hand, the present invention provides a bilateral pressurization method for out-of-step closing and breaking tests of medium-voltage circuit breakers, comprising the following steps:

[0014] S1: Close the circuit breaker QF, the optional switch HK, the disconnecting switch QS1 and the disconnecting switch QS2 to connect the main circuit generator system G, the circuit breaker QF, the regulating impedance Z, the optional switch HK, the disconnecting switch QS1, the disconnecting switch QS2 and the test object SP. By adjusting the generator G voltage and the regulating impedance Z, short-circuit closing and opening tests are performed on the test object SP of 12kV and below.

[0015] S2: Close the operating circuit breaker QF, the optional switch HK, and the disconnecting switch QS2; open the disconnecting switch QS1, connecting the experimental circuit generator system G, the operating circuit breaker QF, the regulating impedance Z, the optional switch HK, the transformer T, the disconnecting switch QS2, and the test object SP, making the secondary output voltage of the transformer T... The test sample SP was subjected to out-of-step closing and breaking capability tests, in which U AC This represents the line voltage of two phases of AC.

[0016] The beneficial effects of this invention are as follows: This invention achieves the requirements for out-of-step closing and breaking capacity testing by introducing a bilateral pressurization scheme. The 0.25In power supply has a simple structure, complete functions, and low cost.

[0017] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0019] Figure 1 This is the electrical schematic diagram of a double-sided pressurized circuit used for out-of-step closing and opening tests of medium-voltage circuit breakers. Detailed Implementation

[0020] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0021] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0022] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0023] This invention provides a double-sided pressurized circuit for out-of-step closing and opening tests of medium-voltage circuit breakers, including a generator system G for providing three-phase power to the test object SP. In this embodiment, the rated voltage Un = 12kV and the maximum voltage Um = 13.2kV. The generator system G is connected to the adjustable impedance Z via the operating circuit breaker QF, and then connected to the test object SP via the optional switch HK, disconnecting switches QS1 and QS2; the disconnecting switch QS1 is connected in parallel with a transformer T. The main circuit G—QF—Z—HK—QS1—QS2—SP is a conventional test circuit. At this time, disconnecting switches QS1 and QS2 are closed, QS3 to QS8 are open, and the transformer is not in use. Short-circuit closing and opening tests can be performed on the test object SP of 12kV and below by adjusting the generator G voltage and the adjustable impedance Z.

[0024] Because the out-of-step closing and breaking capacity tests require the provision of... For a 0.25In power supply, the generator capacity is sufficient for a 12kV circuit breaker, but the voltage is insufficient. This solution introduces a double-sided voltage boosting scheme. Transformer T consists of two single-phase step-down transformers with a turns ratio of [formula missing]. The primary side is connected to the line voltage of the generator power supply. In this embodiment, it is connected to two phases of AC, and the corresponding line voltage is U. AC The secondary windings are connected in series, with the intermediate point grounded. Therefore, the output of the secondary side of transformer T is... The test circuit is G—QF—Z—HK—T—QS2—SP. At this time, disconnecting switch QS1 is open and QS2 is closed.

[0025] Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium. When the program is executed, it can implement the steps of the method. The storage medium may be, for example, ROM / RAM, magnetic disk, optical disk, etc.

[0026] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A double-sided pressurized circuit for out-of-step closing and breaking tests of medium-voltage circuit breakers, characterized in that: The device includes a generator system G, which provides three-phase power to the test object SP. The generator system G is connected to the regulating impedance Z via an operating circuit breaker QF, and then connected to the test object SP via an option switch HK, a disconnect switch QS1, and a disconnect switch QS2. A transformer T is connected in parallel to the disconnect switch QS1. The transformer T includes a first single-phase step-down transformer and a second single-phase step-down transformer; the primary side of the first single-phase step-down transformer is connected to phase A of the generator system G via disconnector QS3 and phase C of the generator system G via disconnector QS4; the primary side of the second single-phase step-down transformer is connected to phase A of the generator system G via disconnector QS5 and phase C of the generator system G via disconnector QS6; the secondary sides of the first single-phase step-down transformer and the second single-phase step-down transformer are connected in series and then connected to phase C of the generator system G via disconnector QS7 and phase A of the generator system G via disconnector QS8.

2. The double-sided pressurized circuit for out-of-step closing and opening tests of medium-voltage circuit breakers according to claim 1, characterized in that: The transformer T consists of two single-phase step-down transformers. Its primary side is connected to the line voltage of the generator system G, and its secondary side is connected in series with the intermediate point grounded.

3. The double-sided pressurized circuit for out-of-step closing and opening tests of medium-voltage circuit breakers according to claim 1, characterized in that: The three-phase power supply has a rated voltage Un=12kV and a maximum voltage Um=13.2kV.

4. The double-sided pressurized circuit for out-of-step closing and opening tests of medium-voltage circuit breakers according to claim 1, characterized in that: The transformer T turns ratio is / 1.25, secondary output is 2.5 / U AC U AC This represents the line voltage of two phases of AC.

5. A bilateral pressurization method for out-of-step closing and breaking tests of medium-voltage circuit breakers, characterized in that: Based on the double-sided pressurized circuit for out-of-step closing and opening tests of medium-voltage circuit breakers as described in claim 1, the method includes the following steps: S1: Close the circuit breaker QF, the optional switch HK, the disconnecting switch QS1 and the disconnecting switch QS2 to connect the main circuit generator system G, the circuit breaker QF, the regulating impedance Z, the optional switch HK, the disconnecting switch QS1, the disconnecting switch QS2 and the test object SP. By adjusting the generator G voltage and the regulating impedance Z, short-circuit closing and opening tests are performed on the test object SP of 12kV and below. S2: Close the operating circuit breaker QF, the optional switch HK, and the disconnecting switch QS2; open the disconnecting switch QS1, connecting the experimental circuit generator system G, operating circuit breaker QF, regulating impedance Z, optional switch HK, transformer T, disconnecting switch QS2, and the tested object SP, making the secondary output voltage of transformer T 2.5 / U AC The test sample SP was subjected to out-of-step closing and breaking capability tests, in which U AC This represents the line voltage of two phases of AC.

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