JPH03195321A - Bus protection relay unit - Google Patents

Abstract

PURPOSE:To prevent time delay of trip command for bridged circuit breakers even if a fault occurs during switching operation of disconnector by detecting open/close state of normal open and normal close auxiliary contacts in the disconnector with respect to a bridge detection circuit. CONSTITUTION:When a disconnector 2B is operating with a timing of T1+T2, disconnector auxiliary contact 2A2 is closed and disconnector auxiliary contact 2B3 is opened. Consequently, only integral protection of bus is executed. Upon elapse of a time T1+T2, the auxiliary contact 2B2 closes while the auxiliary contact 2B3 opens and bridge detection is kept as it is. When the disconnector 2A is opened to release the bridged state upon throw-in of the disconnector 2B, outputs from split differential relays 87A1, 87B1 are bypassed thus enabling trip of buses A, B based only on an output from an integral differential relay 87C1.

Description

[Detailed Description of the Invention] "Objective of the Invention" (Industrial Application Field) The present invention detects the bridge condition of double back wires based on the disconnector conditions, and issues a trip command only with the bus protection switch. Configure to output 1. In the multi-bus protection relay device,
The present invention relates to a busbar protection relay device that can reliably detect small accidents on the JD line during disconnector switching and can handle high-speed operations.

(Prior art) As for the protection method for frame busbars, accidents have occurred17 due to the combination of a split protection relay that protects only each busbar and a collective protection relay that protects the entire multiple busbars at once. Generally, only the stamens and disconnectors connected to the line are left unused.

In this case, operate the tweeter disconnector connected to the busbar.
For example, when switching from A bus to Otsu bus operation, A44 Nos. is temporarily bridged. If an accident occurs in this bridge state, the fault current may flow into the divided protection range of the busbar of A or B, and the split protection relay may become inoperable. To prevent this problem, the first step is to take in the disconnector conditions of each tweeter, configure a bridge detection circuit for the A and B bus lines, and while the bridge condition is being detected, the split protection relay output is bypassed, and only the - group protection relay is used. The stamens and disconnectors of all tweeters will be removed at the same time.

The disconnector condition used in this bridge detection circuit is introduced in the form of an auxiliary contact, but if there is a significant time discrepancy with the operation of the main contact, for example, the main contact will close and a bridge state will occur. If the operation of the auxiliary contact is slow despite the fact that the auxiliary contact is
Since the control that bypasses the output of the 1@ unit is delayed, the bus fault removal is delayed by a large amount of time, and the impact on system stability cannot be ignored.

An example of conventional busbar bridge detection will be described below with reference to FIGS. 2 and 3.

Figure 2 shows an example of an AC circuit of a double bus protection relay device, where IA and 1B are A and B busbars, 2A and 2B, respectively.

3^, 3B is a disconnector, 41.42 is a tweeter breaker, 43 is a bus tie breaker, 518, 51B,
528, 52B.

53A, 53B are current transformers <CT), 61.62.
63A and 63B are input converters for current differential relays for split protection, 71 and 72 are feeders, 87A and 87B are current differential relays for split protection for A-bus and O-bus, respectively.
C is a high impedance differential relay for bulk protection, 2^1.
, 2B1, 3A13B1 are disconnectors 2A, 2B, respectively.
3^, shows the normally open auxiliary contact of 3B. Next, Fig. 3 shows a trip circuit corresponding to Fig. 2, 87C1,
87^1.87B1 is the output of the differential relay mentioned above, 282
, 282, 3 to 2, and 3B2 are respectively disconnectors 2A,
2B, 3A, 3B normally open auxiliary contact, 10a, 1
0b, 10c, 10d are AND logic, 11a
, 11b, and 11c indicate the logical logic.

In FIG. 2, the disconnector 2^ of the feeder 71 is closed to the circuit 2B.
Consider the case where the breakers 41, 42, and 43 are all closed, and an accident occurs on the bus 1A.

In this case, the fault current flows from each feeder 1.72, but the fault current of the feeder 71 flows through the current transformer 51, the input converter 61, and the disconnector auxiliary contact 2^1 to the differential relay 87A, and Whether the fault current that has flowed from the foot bus 2 via the disconnector 3B and the bus tie breaker 43 flows into the foot bus, or whether this fault current is also connected to the current transformer 53A and the input converter 6
A differential current is applied to the differential relay 87A through 3^, and the differential relay 878 is activated.

Next, for the differential relay 87B, the fault current flowing from the feeder 72 flows into the differential relay 87B via the current transformer 52^, the input converter 62, and the disconnector auxiliary contact 3B1. Since the current flows in the outflow direction through the current transformer 53B on the bus tie and the input converter 63B, no differential current flows through the differential relay 87B and it is inoperative. In addition, for the negative protection differential relay 87C, the foot tough is 1.72.
The fault current becomes a difference current as it is, and the high impedance relay 87C is activated.

Therefore, in FIG. 3, the outputs 87C1 and 87AI of the differential relays 87C and 87A are 1", so the AND
The output of the logic 10c becomes 1'', which is the output of the high-speed bus strip. Although this bus strip output is not shown in the figure, it is applied to the circuit breaker 41 and the bus tie breaker 43 connected to the circuit bus via the disconnector conditions of each feeder, and tripping is performed.

Next, during the above-mentioned operation, when the disconnector 2B is closed and the feeder 71 is switched to the Oto bus 1B, the A and O bus become bridges by the disconnectors 2A and 2B, and the A and O bus are connected to the A bus IAJ-. Let's discuss an example where an accident occurs.

The fault current flowing from the feeder 71 due to the closing operation of the disconnector 2B flows into the upper bus 1A via the disconnector 2^, the disconnector 2B, and the bus tie breaker 43. Also, regarding the fault current flowing from the feeder 72, the disconnect switch 3B
Flows into the Otobus via the Otsubus, and further from the Otsubus
, 2 or via the bus tie breaker 43 to the bus 1A.

Now, if we look at the split protection of the Otobus, the current flowing from the Feetuff 1 is the current transformer 51^ input converter 6.
1 to the disconnector auxiliary contacts 281 and 281, but in the direction of inflow to both the differential relays 87^ and 87B. Further, the current flowing from the feeder 72 is in the direction of flowing into the differential relay 87B via the current transformer 52A, the input converter 62, and the disconnector auxiliary contact 3B1. However, the current flowing into the bus tie breaker 43 flows into the differential relay 87B via the current transformer 53B and the input converter 63B. Therefore, depending on the operating current sensitivity or ratio characteristics of the Otobus divisional protection relay 87B, there is a risk that 87B will not operate, and the feeder breaker 42 will not be tripped, causing the disconnectors 3B, 2B, 2A
The accident continues due to this. In order to prevent this, a bridge detection circuit as shown in FIG. 3 is provided.

Both disconnectors 28 and 2B are closed, that is, A and B (when the 3 wires are bridged, their normally open auxiliary contacts 282 and 2B2 are closed, and the latter 8Ml) Logic 10a
Is the output ゛1゛° and is the output of OR logic 11a?”]”
Since the OR logics 11b and 11c at the subsequent stage become "1" regardless of the presence or absence of the output of the divided differential relays 87A and 87B, the AND logics 10c and 10d output depends only on the operation of the collective differential relay 87C. become. In this case, the negative differential relay 87C detects an internal fault and is activated, and the circuit breakers 41 and 42 and the bus tie circuit breaker connected to the first and second buses are instantly tripped.

Next, consider a case where there is a non-negligible difference in the operation of each contact of the disconnector, as shown in FIG.

At the same gate as in the above case, the main contact of the disconnector 2B is closed as shown in FIG. 4, and its normally open auxiliary contact 2B2 is closed.
If an accident occurs on the bus at the timing of T2 when the circuit is not closed, the bridge is not detected during this T2 time even though the main contact is closed, and the auxiliary Although the contact 2A2 is closed, the output of the static 0 logic 10a is 0", and the OR logic 11a also remains 0", so it does not become a 1~rip of only the negative differential relay 87C. In the worst case scenario, the Otob strip would be delayed by T2 hours, and there is a risk of an accident spreading.

Similarly, when the disconnector 2B is closed and the disconnector 2A is opened, even though the main contact to the disconnector 2 is still closed and in the bridge state at time T3 in FIG. The normally open auxiliary contact 2A2 becomes open circuit and releases the bridge detection circuit, so if this time T3
If an accident occurs on the first bus during this period, the first bus split differential relay 878 and the collective differential relay 87C operate, and the bus tie breaker 43 is opened to cut off the current flowing from the second bus. The Otsu bus split differential relay 87B cannot operate and can only trip the circuit breakers 41 and 42, which may lead to a serious situation where an accident spreads.

(Problems to be Solved by the Invention) The present invention has been made to solve the above problems, and even if an accident occurs during switching of a disconnector, the closing or opening time of the main contact of the 111 switch and its auxiliary contact It is an object of the present invention to provide a busbar protection relay device that performs bridge detection without being affected by the difference in the voltage and does not cause a time delay in issuing a disconnection command for a breaker in a bridge.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a bridge detection circuit for detecting that the bus bar is bridged and outputting an l-rip command using only a handle wire protection relay. It is configured to include a circuit that detects the open/closed state of the normally closed contact and the normally open contact of the disconnector auxiliary contact.

(Function) When the bus bar is in the bridge state, the normally open contact of the disconnector auxiliary contact that was in the connected state is closed, and the normally closed contact is open.

On the other hand, since both the normally open contact and the normally closed contact of the auxiliary contact on the disconnector side that enters the bridge state are open, the bridge state can be detected by detecting this condition.

(Example) Examples will be described below with reference to the drawings.

FIG. 1 shows a 1-rip circuit of a busbar protection relay device according to the present invention, and the same parts as in FIG. 3 are given the same reference numerals and their explanation will be omitted, and only the different parts will be described here. In Fig. 1, 2A3°2B3, 3A3,
383 are disconnectors 2^ and 2B in FIG. 2, respectively.

3A, 3B normally closed auxiliary contacts, 12a, 12b,
12c, 12d are NOT logic, 11e, 11
f, 11g, and 11h indicate the logic logic.

First, in Fig. 2, disconnector 2 is operated to connect Feetuff 1 to Otsubus from the state where disconnector 3B is closed and circuit breakers 41, 42, and 43 are closed.
Consider the case where B is closed. When the state of the disconnector 2B is at timing T+10T2 in the disconnector opening/closing time chart in Figure 4, the disconnector auxiliary contact 2A2 is closed before the disconnector 2B is operated in Figure 1, and 2B3 is open. ing. Therefore, NOT logic 12a
is “1”, and since 2A2 is a closed circuit, OR logic 11e is “1”
″, Next, both 2B2 and 283 are open circuits, but 2^
3 is open circuit, and since the auxiliary contact 282NOT logic 12b of the disconnector 2B is "1", the OR logic 11f at the subsequent stage is also
1'', so AND logic 10a ``1'')
::, resulting in bridge detection. Therefore, OR logic 11
Since a11b and 11c are set to 1'', bus protection is performed only by collective protection.

Next, in the time chart, T1 + 'r', time has passed and the normally open contact of the disconnector is closed. In Figure 1, 2B2 becomes closed, 2B3 opens, and NOT logic 12b becomes °1'. Therefore, OR logic 11f is still 1
′, and bridge detection remains unchanged.

When the disconnector 2^ is opened after the disconnector 2B is closed and the bridge state is canceled, time T3+74 in the time chart of FIG. 4 can be considered.

In this case, in Figure 1, disconnector auxiliary contact 2B2 closed, 2
Since both 82 and 283 are open circuits, the logic 11f is "
1'', the NOT logic 12a is '1'', so the subsequent stage 11e is '1''. Therefore, AND logic 10
a or “i” and OR logic 11a, 11b,
11c are both set to "1", the divided differential relay output 87^1.87B1 is bypassed, and A and B strips can be performed only by the negative differential relay output 87C1.

The bridge detection of Feetuff 2 will also be explained in the same manner as above.

As mentioned above, when closing a disconnect switch, the bridge is detected before the main contact closes, and the split differential relay is bypassed. Also, when the disconnect switch is opened, the bridge is detected after the main contact opens. Since the detection is canceled, in the event of an accident during operation of the disconnector, the breaker can be tripped at high speed by operating only the collective differential relay, and the tripping due to the mismatch in operating time of the disconnector's main contact and auxiliary contact can be prevented. This will prevent delays in removal.

[Effects of the Invention] As explained above, according to the present invention, bridge detection is performed by incorporating the disconnector condition, and during bridge detection, a tripping command is output using only collective protection. In a bus protection relay device, if there is a difference in operating time between the disconnector auxiliary contact and the disconnector main contact for detecting the disconnector status, it is assumed that the normally closed contact of the disconnector auxiliary contact is open during disconnector switching. Alternatively, since the normally open contact is detected to be closed and used for bridge detection, there is no trip delay even in the event of a busbar accident during bridge operation during disconnector switching operation, and it is used only for -finger protection. Therefore, it is possible to provide a bus protection relay device that can trip a circuit breaker.

[Brief explanation of drawings]

Fig. 1 is a breaker tripping block diagram of the busbar protection relay device according to the present invention, Fig. 2 is an AC circuit of the busbar protection relay device applied to a double busbar, and Fig. 3 is a conventional breaker tripping block diagram. FIG. 4 is a time chart diagram of the disconnector contacts. 87^1.87B1... Differential relay for split protection 87C
...-Differential relay for bulk protection

Claims (1)

[Claims] In a busbar protection relay device that is configured to protect multiple buses under the logical product condition of a collective busbar protection relay and a split busbar protection relay, it detects that the busbars are bridged and issues a trip command using only the collective busbar protection relay. The bridge detection circuit for output is equipped with a circuit that detects the open/closed state of the normally closed contact and the normally open contact of the disconnector auxiliary contact, and the bridge is detected using the conditions that the normally open contact is closed or the normally closed contact is open. A busbar protection relay device characterized by detecting.