JPS6074931A - Bus protecting and relaying device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a state line protection relay device, particularly a state line protection 8φ relay that uses the same relay to deal with ground faults and short circuit faults. It relates to electrical equipment.

[Technical background of the invention]

FIG. 1 shows a conventional bus protection relay device in a resistance grounding system. In the figure, 1 is the side line to be preserved, 21°22.23 is the breaker, 31, 32.33 is the current transformer installed in each feeder, 41, 42, 43 is the feeder connected to the preserved bus line, 5 is a voltage converter, 6 is a short-circuit fault protection relay, 7 is a ground fault detection relay, 8 is a short-circuit fault detection relay, and 9 is a ground fault detection relay.・- FIG. 2 is a block diagram of the breaker tripping circuit of the busbar protection relay device shown in FIG. 1. In the figure, 6a+7a+8a
, 9a are the respective output signals of the relays 6, 7, 8.9 shown in FIG. 1, and 10 are the circuit breaker tripping signals. As shown in FIGS. 1 and 2, the conventional resistance connection j1. b.

Describes the single-bus protection relay device applied to the system.Z)
. , Now, if a short circuit fault occurs at point F1 in the maintenance interval shown in Fig. 1, the short circuit fault relays 6 and 4 connected to the differential circuit constituted by current transformers 31, 32, and 33. .1j By the logical product with the fault detection relay 8, υ, the breaker limit is 1°22
．． 23. Similarly, if a ground fault occurs at point F1, the ground fault relay 8 and the ground fault precipitation relay 9
Toni, l:LLya disconnection 2L22,2349;:Evening("i
.

In general, the relay 6 for short-circuit failure is outside the protection zone shown in Figure 1.
The sensitivity is set to be low in order to prevent malfunction due to saturation of the current transformers 31, 32, 33, etc. in case of a failure at two points. On the other hand, since the ground fault current in the resistance grounding system is suppressed by the main transformer's neutral point grounding resistance (NCR), the ground fault relay 7 is set to be highly sensitive. When a fault occurs in two or more phases, such as a two-phase ground fault, the ground fault relay 7, which has been set to high sensitivity due to CT errors, may respond unnecessarily. The output cuff a is locked at the output 8a of the short-circuit failure detection relay 8. In addition, an undervoltage relay is often used as the short-circuit fault relay 8, and a zero-phase over-1α voltage relay is often used as the ground fault relay 9.

[Problems with background technology]

As explained above, the conventional edge protection device applied to a resistance grounding system requires protective relays for short circuit failures and for ground fault failures.

[Purpose of the invention]

The present invention has been made in view of the above problems, and provides a busbar that has the same function as a conventional busbar protection relay device without separately installing protective relays for short circuit failure and ground fault failure. The purpose is to provide a protective relay device.

[Summary of the invention]

In the present invention, a high-sensitivity detection circuit and a low-sensitivity detection circuit are provided in the protective relay to distinguish between short circuit faults and ground faults.
i Connect to the differential circuit of the current transformer through the contacts of the onboard electric equipment, and in the event of a short-circuit failure, the low-sensitivity detection circuit will be activated, and in the event of a ground-fault failure, the high-sensitivity detection circuit will be activated, and the circuit breaker will be activated. It is an attempt to remove the

[Embodiments of the invention]

Examples will be described below with reference to the drawings. FIG. 3 is a block diagram of an embodiment of the busbar protection relay device and a circuit breaker tripping circuit according to the present invention. In FIG. 3, the same reference numerals as in FIGS. 1 and 2 have the same functions as in each of the above figures.

(The numeral 61 is a new protective appliance, which consists of a high-sensitivity detection circuit 62 and a low-sensitivity detection circuit 63.

11 is an auxiliary relay for discriminating short circuit failure or ground fault, and 11a is a normally open connection Ak% 1 of the auxiliary relay 11.
1b is a normally closed contact. 61a is the output signal of the protective relay 6], and the rest is the same as in FIGS. 1 and 2 [N1].

In addition, the high-sensitivity detection circuit 62 is set to 11 so that the protective relay 61 can sufficiently operate in response to a short circuit outside the protection zone. In response to a failure, the current transformers 31, 32, 33, etc. are adjusted to prevent the protective relay 61 from malfunctioning.

Next, the operation will be explained. Now, short 1 at F1 point within the protected area.・
(If a failure occurs, the short-circuit failure detection relay 8 will
+M"l/, since the auxiliary relay 11 is inoperative, the pressure generated in the differential circuit composed of the variable te [Input to the low sensitivity detection circuit 63 of the protective relay 6j, and the output 8 of the short circuit failure detection relay 8
The breaker tripping signal 10 is output by ANDing & with the output 61g of the protective relay 61.

On the other hand, if a ground fault occurs at 11 points within the protection zone, the ground fault detection relay 9 operates and the auxiliary relay 11 also operates, so the differential voltage is protected via the normally closed contact 11a of the auxiliary relay 11. It is input to the high-sensitivity detection circuit 62 of the relay 61, and is connected to the output 9a of the ground fault detection relay 9 and the protection relay 6.
1 and the output 61a, a breaker trip signal 10 is output.

FIG. 4 is a block diagram of another embodiment of switching the operating sensitivity of a protective relay. In the figure, 71 is a protective relay, 72 is an operating coil, R4yR2 is an operating control resistor, 73 is a transformer, and the other parts are the same as in FIGS. 1, 2, and 3.

Here, in the example shown in FIG. 4(a), in the event of a short circuit failure with a large fault current, the current is shunted at the normally closed contact 11b of the auxiliary relay 11, and in the event of a ground fault with a small fault current, the current is shunted through the normally closed contact 11b. By opening the circuit and making the total voltage applied to the operating coil 72 higher than when the normally closed contact 11b is closed,
It detects ground faults with high sensitivity.

In the example shown in FIG. 4(b), the operating sensitivity is set using a transformer 73. In the case of a ground fault with a small fault current, the normally open contact 11a is used, and in the case of a short circuit fault with a large fault current, the normally open contact 11a is used. In this case, the normally closed contact 11b is used to switch the secondary tap of each transformer to change the sensitivity.

〔Effect of the invention〕

As explained above, according to the present invention, a protective relay is provided with a high-sensitivity detection circuit and a low-sensitivity detection circuit, and the switching is detected by the auxiliary relay contacts that discriminate between short-circuit failures and ground-fault failures. It is possible to provide a small-sized busbar protection relay device that has conventional functions without separately installing protective relays for failures and ground faults.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a busbar protection relay device applied to a conventional resistance grounding system, Figure 2 is a diagram of a conventional circuit breaker tripping circuit, and Figure 3 is a diagram of a busbar protection relay device according to the present invention. FIG. 4 is a block diagram of one embodiment of the device, a block diagram of a circuit breaker trip, and a block diagram of another embodiment of switching the operating sensitivity of a protective relay. 1... Bus bar 21, 22. 23... Breaker 31.
32. -33...Current transformer 41,42.43...Feeder 5...Transformer 6...Protective relay for short circuit failure 7...Protective relay for earth fault 8...Short circuit failure detection relay 9... Earth fault detection relay 10... Breaker tripping signal 11... Auxiliary relay 61.71... Protective relay 6
2...High sensitivity detection circuit 63...Low sensitivity detection circuit 7
2... Operating coil 73... Transformer patent applicant Tokyo Shibaura Electric Co., Ltd. Agent Patent attorney Norio Ishii

Claims (1)

[Claims] In busbar protection relay devices applied to resistance grounding systems,
A first circuit that detects a ground fault, a second circuit that detects a short circuit fault, and a third circuit that has a plurality of detection sensitivities and operates when a fault is within a protection range, When only the first circuit operates, the detection sensitivity of the third circuit is controlled to high sensitivity, and when the second circuit operates or when both the first and second circuits are inoperative, the third detection sensitivity is controlled to be high. A busbar protection relay device characterized by low-sensitivity control.