JPS5837964B2 - Pressure relay operation test method for oil-filled electrical equipment - Google Patents

Description

[Detailed Description of the Invention] This invention relates to the operation of a pressure relay for detecting failures in electrical equipment installed in a connecting pipe between an expansion chamber and an outer case housing electrical equipment such as a transformer or tap changer. The present invention relates to test methods, and in particular to an operation test method in which an oil flow is generated in a connecting pipe while a pressure relay is still installed in an electrical device.

Press-fit relays, which are one of the protection devices for oil-filled electrical equipment, undergo operation tests at regular intervals to confirm the reliability of their operation.

For example, as shown in FIGS. 1 and 2, a test of a pressure relay 4 installed in a connecting pipe 3 between an outer case 1 containing oil-filled electrical equipment and an expansion chamber 2 is performed using a pressure relay 4 installed in the relay itself. A method of injecting gas from the cylinder 6 through the operation test valve 5 which has been set up to operate the pressure receiving plate or float γ for detecting the flow rate of the pressure relay, or a method of operating the pressure receiving plate or float with a connecting rod connected and pulled out from the outside of the relay. Methods such as forcing the system to operate were used.

In the figure, reference numeral 8 indicates a switch, 9 indicates a connecting valve, and 10 indicates a pressure relief pipe.

However, the above method does not create a state of oil flow in the connecting pipe 3 due to the rise in oil pressure in the outer case 1 when an electrical device breaks down, but simply creates a mechanical flow between the pressure receiving plate or float in the relay and the switch 8. The disadvantage was that it could only confirm the physical connection and could not confirm the characteristics originally expected of a relay.

That is, even with the method shown in FIGS. 1 and 2, the gas introduced into the pressure relay 4 through the operation test valve 5 is not directed to the pressure receiving plate or the float 1 as shown in FIG. It is sprayed directly and does not create an oil flow on the inner metal body of the pressure relay 4.

This invention creates a predetermined high pressure inside the outer box by injecting gas into the expansion chamber of oil-filled electrical equipment, closes the connecting valve to bring the expansion chamber to atmospheric pressure, and then opens the connecting valve to increase the pressure inside the connecting pipe. It is an object of the present invention to provide a method for testing the operation of a pressure relay by which the original performance of the pressure relay can be confirmed by forming an oil flow having the operating flow velocity of the relay.

The test method of the present invention will be explained below with reference to the drawings.

FIG. 3 is a piping diagram showing oil-filled electrical equipment for carrying out the method for testing the operation of a pressure relay according to the present invention.

As shown in the figure, the expansion chamber 2 is communicated with or shut off from the atmosphere by a valve 11, and the cylinder 6 is connected to the expansion chamber 2 via the valve 12.
is a pressure gauge that indicates the pressure in the expansion chamber 2.

The test procedure is as follows: First, gas is injected from the cylinder 6 through the valve 12 at the top of the expansion chamber 2, and when the expansion chamber 2 is brought to atmospheric pressure, the oil flow rate in the connecting pipe 3 reaches the operating flow rate of the pressure relay 4. The inside of the outer box 1 is pressurized to a pressure P so that

Due to this pressure, each part of the outer case is slightly deformed as shown by the dotted line in the figure, the gas in the pressure relief pipe 10 contracts, and the oil level in the expansion chamber 2 decreases.

In order to accumulate this pressure P in the outer case 1, the connecting valve 9 provided in the connecting pipe 3 is closed, and then the pressure P in the expansion chamber 2 is returned to atmospheric pressure by opening the valve 11.

When the connecting valve 9 is opened rapidly from this state, an oil flow velocity ■ is generated from the outer case 1 toward the expansion chamber 2, so the operation test of the pressure relay 4 is performed using this oil flow. As shown in FIG. 4, when the test method according to the invention is applied to electrical equipment such as a tap changer 14 where the storage container is small and rigid and sufficient oil flow cannot be obtained, a gas-filled auxiliary If the tank 15 is temporarily connected and pressurized from the expansion chamber 2, the oil in the expansion chamber 2 will move to the auxiliary tank 15, so that the oil flow necessary for the operation test can be obtained.

As described above, the present invention is a pressure relay operation test method for oil-filled electrical equipment, in which gas is injected into the expansion chamber of the oil-filled electrical equipment to create a predetermined high pressure inside the outer box, and the connection valve is closed to open the expansion chamber. After the pressure is set to atmospheric pressure, the connecting valve is opened and an oil flow with the operating flow rate of the pressure relay is created in the connecting pipe, which improves the reliability of the test. This has excellent effects such as eliminating the need for a valve or mechanism.

[Brief explanation of the drawing]

Fig. 1 is a piping diagram showing a device for carrying out a conventional pressure relay operation test method, Fig. 2 is an enlarged cross-sectional view of the same main part, and Fig. 3 is a diagram for carrying out a test method according to the present invention. FIG. 4 is a piping diagram showing another device. In each figure, the same reference numerals indicate the same or corresponding parts, 1
is an outer box, 2 is an expansion chamber, 3 is a connecting pipe, 4 is a pressure relay, 9
indicates a connecting valve. Further, in the figure, P indicates the pressure necessary to generate an oil flow, and ■ indicates the oil flow velocity necessary for the test.

Claims (1)

[Claims] 1. An oil-filled device for checking the operation of a pressure relay installed in a connecting pipe that communicates the outer case of an oil-filled electrical device with an expansion chamber, which has a pressure-receiving part operated by an oil flow and a contact that closes due to the operation of the pressure-receiving part. In the method for testing the operation of a pressure relay for electrical equipment, the steps include: increasing the pressure inside the outer box to a predetermined high pressure by injecting gas into the expansion chamber; and closing the connecting valve to bring the inside of the expansion chamber to atmospheric pressure. A method for testing the operation of a pressure relay for oil-filled electrical equipment, comprising the step of: opening the connecting valve to form an oil flow having an operating flow rate of the pressure relay in the connecting pipe.