JPS6032426B2 - Busbar protection ground fault relay device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a busbar protection ground fault relay system layer that protects ground faults in equipment to be protected by a ratio differential relay,
In particular, the operating force is the vector sum of the currents introduced from each terminal installed for the device to be protected on the busbar, and the suppressing force is the maximum sorting suppression using a value proportional to the maximum value of the terminal currents. This relates to a busbar protection ground fault relay system layer that employs this method.

First, a conventional device will be explained.

In Fig. 1, 1 is the suppression input transformer, 2 is the differential input transformer, 3 is the primary winding of the suppression input transformer, 4 is the secondary winding (suppression output section), and 5 is the same-point differential input transformer. Next winding, 6 is the primary winding of the differential input transformer, 7 is the secondary winding (differential output part), 8 is the resistor, 9 is the rectifier circuit, 10al, 10a2, 10a3 are always connected, inspect 11 and 12 are inspection power transformers, 13 is a ratio differential relay, and 14 is an inspection power supply.

For simplicity, only one terminal of the suppression input transformer 1 and the differential input transformer 2 are shown. In FIG. 1, the switching contacts 10al, 10a2, and 10a3 are normally open, and no inspection input is received.

On the other hand, the input is the residual current that enters from each terminal CT installed for the equipment to be protected on the busbar, so if no ground fault has occurred, each terminal CT input is in a three-phase balanced state and suppressed. There is also no input from input transformer 1 and differential input transformer 2. During inspection, switch contact 10
A suppression input is applied by al, a high differential input is applied by the switching contact 10a2, and a low differential input is applied by the switching contact 10a3 in order, and the health of the ratio characteristic of the ratio differential relay 13 is confirmed.

FIG. 2 is a diagram showing the checkpoints of ratio characteristics. Point 100 indicates when switching contacts 10al and 10a2 in FIG. 1 are closed, and point 200 indicates when switching contacts 10al and 10a3 are closed. The former is a healthy state when the relay operates, and the latter is when the ratio differential relay 13 is inoperative.

According to this method, the secondary windings 4 and 2 of the suppression input transformer 1
Disconnection of the next circuits B and C, disconnection of the resistor 8 or rectifier circuit 9, tertiary winding 5 or tertiary circuit D for inspection of the suppression input transformer 1,
If E disconnection occurs, check input (suppression plus low differential,
When the suppression brass (high differential) is applied, the ratio differential relay 13 becomes inoperable, and an abnormality can be detected.

Since the conventional busbar protection ground fault relay system with inspection circuit is configured as described above, even if the secondary winding of the differential input transformer 2 is disconnected A, the ratio differential relay 13 will not be affected. Since both the suppression output and the differential output are applied and the ratio differential relay 13 operates normally, there is a problem in that it is not possible to detect a disconnection abnormality.

This invention was made in order to solve the above-mentioned conventional problems, and it makes it possible to detect disconnection abnormalities in the secondary circuit of a differential input transformer, and also reduces the number of parts used and improves the configuration. The purpose is to simplify.

An embodiment of the present invention will be described below with reference to FIG. 3, in which the same parts as those in FIG. 1 are denoted by the same reference numerals.

In Fig. 3, reference numeral 15 indicates an inspection 3 installed in the insert transformer 2.
It is a secondary winding, one end of which is connected to one end of the inspection tertiary winding 5 provided in the suppression input transformer 1, and the other end is used for inspection via the first inspection command cutout contact 10a2. It is connected to the branch end of the tertiary winding 5 and to the other end of the inspection tertiary winding 5 via the second inspection command switching contact 10a3.

And inspection power supply transformer 11, inspection power supply 14, switching contact 1
0al constitutes a check input supply V supply circuit that supplies a check input to the secondary winding of the reed input transformer 2. In FIG. 3, the secondary winding 4 of the suppression input transformer 1, the secondary circuits B, C,
Disconnections in the inspection tertiary winding 5, tertiary circuits D and E, resistor 8, and rectifier circuit 9 can be detected on the same machine as in the case of FIG. Regarding the disconnection in the secondary circuit A of the differential input transformer 2, which could not be detected by the conventional circuit shown in FIG. This can be detected by connecting the inspection tertiary winding 15 with the switching contacts 1082 and 10a3.

In other words, normally, as in FIG. 1, the switching contacts 10al,
10a2 and 10a3 are opened, the inspection input is removed, and no current flows. Therefore, if the circuit and the ratio differential relay 13 are normal, the ratio difference relay 13 will not respond.

During inspection, when switching contacts 10al and 10a2 are closed, a low suppression plus differential input is given to the ratio differential relay 13, and the ratio differential relay 13 is operated, and when 10al and 10a3 are opened, a high suppression plus differential input is given. When the input is applied and the ratio differential relay 13 becomes inoperable, it can be confirmed that the ratio differential relay 13 is healthy.

In FIG. 2, point 300 corresponds to the former, and point 400 corresponds to the latter. On the other hand, the secondary windings 7, 2 of the differential input transformer 2
Next, if the circuit A is disconnected, the ratio differential relay 13 is activated by applying the inspection input (high suppression plus differential) because the suppression input is removed, and a disconnection abnormality can be detected.

As described above, according to the present invention, only one power transformer is required for inspection, which makes it possible to easily and reliably detect disconnection abnormalities in the secondary circuit of the differential input transformer, which is a component of the ground input device. This makes it possible to discover abnormalities in the busbar protection ground fault relay system layer.

[Brief explanation of drawings]

Fig. 1 is a connection diagram showing a conventional busbar protection ground fault relay fin device, Fig. 2 is a ratio characteristic diagram, and Fig. 3 is a connection diagram showing an embodiment of the busbar protection ground fault relay system layer of the present invention. . 1 is a suppression input transformer, 2 is a differential input transformer, 5 is a tertiary winding for inspection of the suppression input transformer, and 15 is a tertiary winding for inspection of the differential input transformer. Note that the same reference numerals in each figure indicate the same or corresponding parts. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A suppression input transformer that introduces current from each terminal installed for the bus protection target equipment into the primary winding and has a secondary winding as a suppression output section and a tertiary winding for inspection, and each of the above terminals. a differential input transformer that introduces a current of 200 to a primary winding and has a secondary winding as a differential output section and a tertiary winding for inspection;
A ratio differential relay that inputs the suppression output of the suppression input transformer via a rectifier circuit and also inputs the differential output of the differential input transformer, and a check input to the secondary winding of the differential input transformer. and a test input supply circuit that directly connects one end of the test tertiary winding of the differential input transformer to one end of the test tertiary winding of the suppression input transformer, and connects the other end to the test tertiary winding of the suppression input transformer. The first inspection command switching contact provided on the connection path connected to the branch end of the inspection tertiary winding of the input transformer and the other end of the inspection tertiary winding of the differential input transformer are suppressed. For inspection of input transformer 3
A busbar protection ground fault relay device comprising a second inspection command switching contact provided in a connection path connected to the other end of the next winding.