JPS5915251B2 - Inspection method of protective relay device - Google Patents

Description

[Detailed description of the invention] The present invention relates to an inspection method for a protective relay device.

In recent years, protective relay devices have been installed on most lines and equipment to protect power systems, and ensuring the reliability of these protective relay devices is directly the mission of the electric power industry. This will lead to improved services.

On the other hand, as power systems become more complex and diversified, the requirements for the performance of protective relay devices are also becoming stricter.
It's becoming commonplace.

FIG. 1 shows a differential protection relay as an example of a protective relay device, which can be inspected using conventional inspection methods.

In the figure, 1 is the device to be protected, 21.22 is the power supply in the power system, 31°32 is the CT, 411.42 is the input quadrature transformer of the differential protection relay 100, and 10.20 is the inspection wound around the input quadrature transformer. Input application winding, 51.52 is a suppression coil for applying suppression force to the protective relay, 6 is an operating coil for applying operating force, 81.82 is a voltage source for inspection, 7
1.72 is a resistor for converting the respective outputs of the inspection voltage sources 81 and 82 into currents, and T3tT4 are inspection contacts that are closed during inspection to provide an inspection input.

The inspection method shown in Fig. 1 can be said to be a method that can sufficiently check the function of the differential protection relay 100 as long as no current flows through the protected device at all times. If current is flowing, the current is supplied from the CTs 31 and 32 to the input quadrature transformer 41.42, and the current is combined with the inspection current applied from the inspection input application winding 10.20 to the suppression coil 51, 52. The input will be input to the differential coil 6, and the magnitude of the power flow and the voltage source for inspection 81.8
Depending on the phase relationship with No. 2, it is conceivable that the quality of the inspection will be greatly disturbed.

In order to avoid this, it is necessary to carry out inspections by giving an input that can ignore the magnitude of the current, and as a result, the performance confirmation of the protective relay becomes cursory, and even delicate Changes in characteristics cannot be ascertained.

On the other hand, Fig. 2 shows a system in which the input from CT31 is short-circuited at the inspection contact T1 during inspection, opened at T2, and then given the inspection input at T. Although it is certainly effective in the sense of eliminating the influence of
Contacts T1 and T2 that are operated during inspection will directly enter the secondary circuit of CT31, so they must have the ability to close the CT secondary current that flows if an actual system fault occurs during inspection. be.

This is considerably inferior to the inspection method shown in Figure 1 in terms of cost and space.

Furthermore, if the contacts T1 and T2 are defective, the secondary circuit of the CT 31 becomes open, leading to dielectric breakdown of the CT 31, so the advantages and disadvantages balance each other out.

The present invention has been made to eliminate the drawbacks of the conventional systems shown in FIGS. 1 and 2.

Next, FIG. 3 shows its configuration.

In the figure, 44 is an auxiliary transformer, and 9 is a resistor that converts the input of the auxiliary transformer 44 into a voltage.

The primary current of the auxiliary transformer 44 is the secondary current of the CT31,
Since the current is supplied as is, a voltage proportional to the magnitude of the CT secondary current is generated across the resistor 9.

Therefore, this generated voltage is passed through the resistor 71 to the inspection winding 1.
The influence of the current can be removed by setting the current applied to 0 to cancel out the input due to the current supplied from the CT side of the input quadrature 41 for the relay.

Therefore, when the inspection contact T3 is closed during inspection, the inspection winding 10 receives the voltage generated in the resistor 9 and the inspection voltage source 8.
1 is converted into a current by the resistor 71 and supplied, so that an inspection method that is not affected by power current, which was the intended purpose, is realized.

According to this method, compared to the conventional method (the one in Fig. 1), inspection can be performed by simply adding an auxiliary transformer 44 and a resistor 9, and compared to the one in Fig. 2, the secondary oven of CT31 can be inspected. There is no need to worry, and it is quite advantageous in terms of space and cost.

In summary, with the present invention, by simply using a simple auxiliary transformer and a voltage conversion resistor, it is now possible to carry out inspections that eliminate the effects of constant power flow, and it is now possible to check the performance of protective relays in detail. It has the following characteristics.

In the explanation, a differential protection relay was explained for the sake of convenience, but this method can be applied to any general current relay in which it is necessary to remove the influence of power flow and inspect it.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of a conventional inspection method in which the influence of tidal currents cannot be ignored. Figure 2 is a conventional inspection method in which inspection is performed by opening and closing the CT secondary, and the influence of tidal currents can be ignored. FIG. 3 is a circuit diagram of an inspection method according to the present invention, and is a circuit diagram of an inspection method in which the influence of tidal current can be ignored. 1...Equipment to be protected, 21.22...Power system power supply, 31.32...CT, 41.42...Relay quadrence, 100...Differential protection relay, 51.52...
... Suppression coil, 6... Differential coil, 10, 20...
・Inspection windings, Ti, T2, T3. T4
, Tis...Inspection contact, 71, 72, 9...
・Resistance, 81.82... Voltage source for inspection, 44... Auxiliary transformer, 43... Relay man cadence.

Claims (1)

[Claims] 1 Using a voltage source for inspection and a current conversion resistor that converts this voltage source into a current, the quality of the protective relay device can be checked by passing a current for inspection through the inspection winding wound around the quadrance of the protective relay device. In the inspection method of the protective relay device, the current transformer input signal for detecting the load current of the protected device is connected in series with the primary winding of the protective relay device-type cadence and the primary winding of the auxiliary transformer. A voltage conversion resistor for converting the current output of the secondary winding of the auxiliary transformer into a voltage is inserted in series with the inspection voltage source and the current conversion resistor to form a series circuit. An inspection method for a protective relay device, characterized in that a series circuit is connected to the single inspection winding through an inspection contact.