Method for testing power apparatus

Abstract

To easily determine whether discharge has occurred in a target power apparatus in a withstand voltage test.SOLUTION: When discharge is detected during application of a test voltage, whether discharge has occurred in a power apparatus or in an adapter is determined on the basis of a current detected by a first ammeter (A1) provided on a first grounding line (100) for grounding a housing (11) of the power apparatus (transformer 10) and a current detected by a second ammeter (2A) provided on a second grounding line (200) for grounding a metal container (21) of the adapter (20).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for testing electric power equipment. [Background technology]

[0002] Adapters are known that are used for individual testing of electric power equipment that is directly connected to gas-insulated equipment. Such adapters are equipped with a container filled with an insulating medium such as SF6, and are connection devices that enable the main circuit of the electric power equipment to be connected to a test circuit inside the container filled with the insulating medium.

[0003] In other words, such an adapter allows the terminals of the main circuit of the electric power equipment to be connected in an insulating medium in place of the gas-insulated equipment, thereby enabling the required tests to be performed on the electric power equipment. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-224818 Summary of the Invention [Problem to be solved by the invention]

[0005] As a test of electric power equipment, a withstand voltage test is performed in which a predetermined high test voltage is applied to the main circuit to confirm that no discharge occurs from the main circuit. If a discharge is observed when a high voltage is applied in the withstand voltage test, the electric power equipment must be disassembled to investigate and identify the location of the discharge and repair it. However, in the case of a withstand voltage test using the above-mentioned adapter, even if a discharge is detected, it may occur on the adapter side and not in the electric power equipment, and disassembly, investigation, and repair of the electric power equipment may not be necessary.

[0006] In view of these circumstances, one aspect of the present disclosure aims to realize a test method that can easily determine whether a discharge occurs in the power equipment or the adapter during a withstand voltage test of power equipment that is used in direct connection with gas-insulated equipment. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, one aspect of the present disclosure is a method for testing electric power equipment connected to gas-insulated equipment, comprising: connecting an adapter having a metal container that encloses an insulating medium and a lead for applying a test voltage to a main circuit outlet of the electric power equipment instead of the gas-insulated equipment; grounding the housing of the electric power equipment through a first grounding wire and arranging a first ammeter on the first grounding wire; grounding the metal container of the adapter through a second grounding wire and arranging a second ammeter on the second grounding wire; applying a predetermined test voltage to the main circuit of the electric power equipment through the lead of the adapter to perform a voltage withstand test of the electric power equipment; and, if a discharge is detected during application of the test voltage, determining whether the discharge occurred in the electric power equipment or the adapter based on the current detected by the first ammeter and the current detected by the second ammeter. [Effects of the Invention]

[0008] According to one aspect of the present disclosure, a test method can be realized that can easily determine whether a discharge occurs in the power equipment or the adapter during a withstand voltage test of power equipment that is used in direct connection with gas-insulated equipment. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram for explaining a test method according to the first embodiment of the present disclosure. [Figure 2] 1 is a circuit diagram showing a circuit configuration for a test method according to a first embodiment of the present disclosure. [Figure 3]FIG. 10 is a circuit diagram showing a case where a discharge occurs on the transformer side during a withstand voltage test. [Figure 4] FIG. 10 is a circuit diagram showing a case where a discharge occurs on the adapter side during a withstand voltage test. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Embodiment] Hereinafter, an embodiment of the present disclosure will be described in detail. In this embodiment, a transformer 10 is used as an example of electric power equipment to be tested for a withstand voltage test. However, other types of electric power equipment connected to gas-insulated equipment, such as a transformer, a switchgear, a reactor, or a capacitor, may also be used as such electric power equipment.

[0011] <Outline of equipment configuration for conducting voltage withstand tests> Fig. 1 is a schematic diagram illustrating the configuration of equipment for conducting a withstand voltage test on a transformer 10. Fig. 2 is a circuit diagram showing an overview of a test circuit for conducting a withstand voltage test on a transformer 10. In Figs. 1 and 2, the transformer 10 is, for example, a three-phase transformer.

[0012] Transformer 10 includes a housing 11, which houses the core 12 and the main components of the transformer, including windings 13. Insulating oil is sealed in housing internal space 11S. Connection terminals 142 for three phases of the main circuit of transformer 10 are drawn out of the housing through main circuit outlet 14.

[0013] Transformer 10 is a transformer connected to gas-insulated equipment, and its main circuit outlet 14 has a partition 141. Transformer 10 is connected to the gas-insulated equipment at partition 141, and its main circuit is connected to the circuit on the gas-insulated equipment side for use.

[0014] 1 and 2, during a voltage withstand test, an adapter 20 is connected to the main circuit outlet 14 of the transformer 10 in place of gas-insulated equipment. The adapter 20 has a partition 241 that is connected to the partition 141 of the main circuit outlet 14. The adapter 20 is also composed of a metal container 21 that is a high-pressure tank as a whole, and an insulating gas similar to the gas sealed in the gas-insulated equipment is sealed in the container internal space 21S of the metal container 21 that is connected to the housing 11 of the transformer 10.

[0015] Adapter 20 is provided with three-phase leads 22 inside metal container 21, which are connected to connection terminals 142 of the main circuit of transformer 10 and are used to introduce a test voltage into the main circuit of transformer 10. Leads 22 are also configured so that a test voltage can be introduced through charging bushings 31 joined to charging cables 32 electrically connected to test voltage application device 30.

[0016] In this way, the adapter 20 makes it possible to apply a test voltage to the transformer 10 under test through the connection terminal 142, which cannot be connected in air, even if the transformer 10 to be connected to the gas-insulated equipment is in a standalone state.

[0017] <Withstand voltage test circuit> Next, the test circuit for carrying out a withstand voltage test will be described with reference to Fig. 2. A test voltage application device 30 that generates a test voltage is connected so that the test voltage can be applied to the primary winding or secondary winding, which is the main circuit of the transformer 10, all three phases at once. As shown in Fig. 2, the three phases are short-circuited between the adapter 20 and the test voltage application device 30. For convenience, the following description will be given of a case where a withstand voltage test is performed on the primary side of transformer 10, but the same applies to a case where a withstand voltage test is performed on the secondary side. As shown in Fig. 2, when a withstand voltage test is performed on the primary side of transformer 10, each of the three phases of the secondary side of transformer 10 may be grounded.

[0018] The housing 11 of the transformer 10 is grounded via a first ground wire 100. A resistor R1 and a first ammeter A1 are provided on the first ground wire 100. The first ammeter A1 measures the current flowing through the first ground wire 100.

[0019] The metal container 21 of the adapter 20 is grounded via a second ground wire 200. A resistor R2 and a second ammeter A2 are provided on the second ground wire 200. The second ammeter A2 measures the current flowing through the second ground wire 200. Here, the resistance value of the resistor R1 and the resistance value of the resistor R2 are configured to be substantially the same.

[0020] The housing 11 of the transformer 10 and the metal container 21 of the adapter 20 are connected and in contact with each other at the partitions 141 and 241. However, as shown in the circuit diagram of Figure 2, there is a contact resistance R3 between the housing 11 of the transformer 10 and the metal container 21 of the adapter 20.

[0021] At least a portion of the contact resistance R3 is due to the application of anti-rust paint to the contact surface on at least one side of partition 141 of housing 11 or partition 241 of metal container 21. For example, an insulating paint for anti-rust purposes is applied to the outer surface of metal container 21 of adapter 20 or the outer surface of housing 11 of transformer 10, and such paint may be a factor in contact resistance R3.

[0022] <Test Method> In this embodiment, a withstand voltage test of the transformer 10 to be tested is carried out as follows: In the test circuit shown in Fig. 2, a predetermined test voltage is applied to the transformer 10 by a test voltage application device 30.

[0023] When a test voltage is applied to the transformer 10, a discharge due to dielectric breakdown is detected by a drop in the voltage output by the test voltage application device 30. The test voltage that the test voltage application device 30 should apply to the transformer 10 is determined by various standards and must comply with these. One example is the standard JEC-2200-2014 (Transformers) of the Institute of Electrical Engineers of Japan Electrical Standards Committee.

[0024] In this embodiment, the current measurement results by the first ammeter A1 of the first grounding wire 100 and the second ammeter A2 of the second grounding wire 200 are recorded during the withstand voltage test.

[0025] In this way, if no discharge is detected when the specified test voltage is applied to the transformer 10, the transformer 10 is determined to meet the voltage withstand performance requirements for the test items of the voltage withstand test.

[0026] On the other hand, Figure 3 shows a case where a discharge occurs in the transformer 10 during a withstand voltage test. At this time, a short-circuit current Is11, which becomes a ground fault current, flows from the housing 11 of the transformer 10 through the first grounding wire 100 and is detected by the first ammeter A1. In addition, a short-circuit current Is21, which also becomes a ground fault current, flows from the housing 11 of the transformer 10 through the metal container 21 of the adapter 20 and then through the second grounding wire 200. Therefore, the short-circuit current is also detected by the second ammeter A2.

[0027] The resistance values ​​of resistor R1 provided in first grounding wire 100 and resistor R2 provided in second grounding wire 200 are substantially the same, and there is contact resistance R3 between housing 11 of transformer 10 and metal container 21 of adapter 20. Therefore, in the case of Figure 3, short-circuit current Is11 detected by first ammeter A1 on the transformer 10 side becomes larger than short-circuit current Is21 detected by second ammeter A2, and it can be determined that a discharge has occurred in transformer 10 during the withstand voltage test.

[0028] If it is determined that a discharge has occurred in the transformer 10 during the withstand voltage test, the transformer 10 product is deemed to have a voltage withstand performance that does not meet the required performance. Furthermore, in order to ship the transformer 10 product, the transformer 10 must be disassembled, and the location of the discharge must be investigated, identified, and repaired.

[0029] 4 shows a case where a discharge occurs in the adapter 20 during a withstand voltage test. At this time, a short-circuit current Is22, which becomes a ground fault current, flows from the metal container 21 of the adapter 20 through the second grounding wire 200 and is detected by the second ammeter A2. In addition, a short-circuit current Is12, which also becomes a ground fault current, flows from the metal container 21 of the adapter 20 through the housing 11 of the transformer 10 and then through the first grounding wire 100. Therefore, the short-circuit current is also detected by the first ammeter A1.

[0030] In this case, the short-circuit current Is22 detected by the second ammeter A2 on the adapter 20 side becomes larger than the short-circuit current Is12 detected by the first ammeter A1, and it can be determined that a discharge occurred in the adapter 20 during the withstand voltage test. If a discharge occurs in the adapter 20 during the withstand voltage test, there is no need to disassemble the transformer 10 to investigate the location of the discharge. The adapter 20 can be repaired or replaced, and the withstand voltage test of the transformer 10 can be performed again to confirm the performance of the transformer 10 product.

[0031] As described above, according to the testing method of this embodiment, when a withstand voltage test of electric power equipment is performed using the adapter 20, it is possible to immediately determine whether the discharge occurred on the adapter 20 side or on the electric power equipment under test. Therefore, when a discharge is detected during a withstand voltage test, it is possible to reduce the possibility of a situation in which a complicated disassembly and inspection of the electric power equipment under test is carried out more than necessary.

[0032] 〔summary〕 A first aspect of the present disclosure is a method for testing electric power equipment connected to gas-insulated equipment, comprising: connecting an adapter having a metal container for enclosing an insulating medium and a lead for applying a test voltage to the main circuit outlet of the electric power equipment in place of the gas-insulated equipment; grounding the housing of the electric power equipment through a first grounding wire; arranging a first ammeter on the first grounding wire; grounding the metal container of the adapter through a second grounding wire; arranging a second ammeter on the second grounding wire; applying a predetermined test voltage to the main circuit of the electric power equipment through the lead of the adapter to perform a voltage resistance test of the electric power equipment; and, if a discharge is detected during application of the test voltage, determining whether the discharge occurred in the electric power equipment or the adapter based on the current detected by the first ammeter and the current detected by the second ammeter.

[0033] The method for testing an electric power device according to the second aspect of the present disclosure may be configured in the first aspect above, wherein an insulating paint is applied to an outer surface of the metal container.

[0034] The method for testing power equipment of aspect 3 of the present disclosure may be configured in such a way that, in aspect 1 or 2 above, the resistance value of the resistor provided in the first ground wire and the resistance value of the resistor provided in the second ground wire are the same, and the judgment is made based on the magnitude relationship between the current detected by the first ammeter and the current detected by the second ammeter.

[0035] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in the embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0036] 10 Transformers (electrical equipment) 11. Housing 11S Housing internal space 12 cores 13 windings 14 Main circuit outlet 141 Partition 142 connection terminal 20 Adapter 21 Metal containers 21S Container internal space 22 Lead 241 Partition 30 Test voltage application device 31 Loading bushing 32 Power Cable 100 1st ground wire 200 2nd ground wire

Claims

1. A test method for electric power equipment connected to gas-insulated equipment, comprising: an adapter including a metal container for enclosing an insulating medium and a lead for applying a test voltage is connected to the main circuit outlet of the electric power equipment in place of the gas-insulated equipment; a housing of the power device is grounded through a first grounding wire, and a first ammeter is disposed on the first grounding wire; The metal container of the adapter is grounded through a second ground wire, and a second ammeter is disposed on the second ground wire; A predetermined test voltage is applied to a main circuit of the power device through the lead of the adapter to perform a withstand voltage test of the power device; A method for testing electric power equipment, in which, when a discharge is detected during application of the test voltage, a determination is made as to whether the discharge occurred in the electric power equipment or the adapter based on the current detected by the first ammeter and the current detected by the second ammeter.

2. 2. The method for testing an electric power device according to claim 1, wherein an outer surface of the metal container is coated with an insulating paint.

3. 3. A method for testing electric power equipment as described in claim 1 or 2, wherein the resistance value of the resistor provided in the first ground wire and the resistance value of the resistor provided in the second ground wire are the same, and the judgment is performed based on the magnitude relationship between the current detected by the first ammeter and the current detected by the second ammeter.

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