JPS6350935B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bus bar protection relay device for protecting bus bars of a power system.

As a conventional bus protection relay device of this kind, a circuit configuration as shown in FIG. 1 is known. That is, in the figure, 1 and 2 are busbars to be protected, and between the two busbars is a busbar selection disconnector (hereinafter referred to as LS);
3-1...3-n and 4-1...4-n are connected as shown. In addition, 3-1a...3-na and 4-1a...4-na close their contacts when the above-mentioned LS3-1...3-n and 4-1...4-n are closed. Auxiliary relay contacts (hereinafter referred to as LS
(referred to as auxiliary relay contact). Next, 5-1 to 5-n are lines such as power transmission lines and transformers, and are power supply lines which are arbitrarily switched to bus line 1 or 2 by the above-mentioned LS. In addition, 6 is a bus bar connection connecting bus bars 1 and 2, 7-1...7-n and 8-1...8-n, 9-1
...9-2 is a current transformer (hereinafter referred to as
The signals obtained from each CT are transmitted to bus bar protection devices 10 and 20 which protect bus bar 1 and bus bar 2, respectively.The equipment configuration of the protection devices is as follows. First, reference numerals 11 and 21 are collective protection bus relays (hereinafter referred to as collective relays) for detecting faults on bus 1 or 2, and 12 and 22 are split protection bus relays (hereinafter referred to as collective relays) for detecting faults on bus 1 and 2, respectively. (referred to as split relay), and 13-1...
13-n and 14 are respectively the above-mentioned CT8-1...8-
Input devices 23-1...23-n and 24 are respectively connected to the CT8-1...8 for deriving an appropriate output proportional to the secondary current of CT8-1 and applying it to the split relay 12. -n, and an input device for deriving an appropriate output proportional to the secondary current of 9-2 and applying a signal to the split relay 22;
is a differential output circuit built into the input device 13-1, and is connected to the operation input circuit of the division relay 12. Similarly, 15-2 is the input device 13-1.
It is connected to the suppression circuit of the split relay 12 with a built-in suppression output circuit. Although not shown, the input devices 13-1...13-n and 23-1
...23-n, 14, 24 are all input devices 13-1
It has the same configuration as . 15 is a differential circuit, 16
is a suppression circuit and the input device 13-1...13-n
The output of the LS auxiliary relay contact 3-1a...3-
After all of these are connected in parallel via na, they are input to the split relay 12 along with the output of the suppression circuit 14, which is connected as is without using a contact.

Next, the operation of the conventional busbar protection relay device shown in FIG. 1 will be described below. First, bulk relay 11
and 21 connect the secondary sides of CT7-1...7-n of all lines except for busbar communication CT9-1, 9-2 in parallel, and operate if the combined electricity amount is above a certain value. For example, a voltage differential type relay is used. These collective relays 11 and 21 are
It detects a failure on the inside of the bus bar from CT7-1 and CT7-n, and does not have the ability to determine whether bus bar 1 or bus bar 2 has failed. Therefore,
It is necessary to separately provide a relay for selecting a faulty bus, and this is called a split relay. That is, as will be described later, this divided relay malfunctions due to an external fault in a special bus configuration, so as a countermeasure, a collective relay is provided. And split relay 1
2 and 22 are constructed so that failures in the buses 1 and 2 can be selectively detected separately. That is, only the line connected to the bus 1 is selected as the input to the split relay 12, and only the line connected to the bus 2 is selected as the input to the split relay 22. For example, line 5-1
When is connected to bus 1, LS3-1 is closed.
Since LS4-1 is open, LS auxiliary relay contact 3-1a is also closed, 4-1a
It will also be open. Then, the output of CT8-1 is introduced to the split relay 12 via the input device 13-1, and the detection signal of the CT8-1 is input to the split relay 22 because the LS4-1 is in the opening operation. become. In this way, the CT current of each line is
It is selectively introduced into the split relay 12 or 22 depending on the LS conditions. Furthermore, since the busbar connections 6 are fixed to the busbars 1 and 2, the secondary outputs of CT9-1 and 9-2 are directly introduced to the split relays 12 and 22 via the input devices 14 and 24, respectively, regardless of the LS conditions. Therefore, differential protection is provided for each bus bar 1 or bus bar 2. In the case of the conventional circuit example shown in FIG. 1, ratio differential relays are used for the split relays 12 and 22, and the input devices for each line include a differential output circuit 15-1 and a suppression output circuit 15-2. are provided for each.

Therefore, when the conventional divided relay circuit has a special busbar configuration as described below, it malfunctions due to an external failure, so as a countermeasure, it is necessary to separately provide a collective relay or the like as described above. In other words, split relay 12
An example of malfunction of the busbars 1 and 22 occurs when the busbars 1 and 2 are bridged by a disconnector (referring to a bridge state) as shown in FIG. In Figure 2, now, LS
Consider a case where lines 3-2 and 4-2 are closed and a failure occurs outside line 5-3. That is,
The current I ₁ +I ₂ flowing from the power supply line 5-1 is divided into the current I 1 via LS3-2 and LS 4-2 and the current I ₂ via the bus connection 6 as shown in the figure, and then the current I 1 +I ₂ flows into the LS4-
3, and I ₁ +I ₂ flows out to the fault point. At this time, the current passing through each CT is CT8-1 in the inflow direction of I ₁ +I ₂ , CT8-3 in the outflow direction of I ₁ +I 2 , and CT9-1 in the outflow direction of I 1 +I ₂
is the outflow direction of I ₂ and CT9-2 is the inflow direction of I _2. Therefore, if the current inflow direction and outflow direction are expressed _as
i ₂ ), CT8-3 is (i ₁ + i ₂ ), CT9-1 is i ₂ ,
CT9-2 becomes _i2 . On the other hand, the auxiliary relay contacts 3-1a...3-na and 4-1a... of each LS
Since the state of 4-na is the same as the LS state of the grid, line 5-1 is LS, 3-1 closed, 4-1 open, and LS auxiliary relay contact 3-1a is closed and 4-1a is open. So, line 5-2 is LS, 3-2 closed, 4-2
is closed and LS auxiliary relay contact 3-2a is closed, 4-2
a is closed, and line 5-3 is LS3-3 open,
LS auxiliary relay contact 3-3a for closing LS4-3
is open, and 4-3a is closed. Therefore, the differential output circuits 15-1...15-3 and 25 of each line
The secondary outputs of -1...25-3, 14, and 24 are proportional to the CT secondary current, and the polarity is derived in the same direction as the secondary current. 22, the output i ₁ ' will be introduced. That is, this output i ₁ ' is LS3-2,
It is proportional to the current I ₁ passing through 4-2,
This problem occurred because the busbars 1 and 2 were in a bridged state.

As described above, the conventional split protection system has the disadvantage of causing malfunctions when a bus bridge condition occurs, and as a countermeasure to this, a separate relay is installed and a complicated control configuration is required to put this in a disconnection condition. was taken.

Therefore, the present invention has been made in order to eliminate the above-mentioned drawbacks, and has a circuit configuration that prevents the divided relay from malfunctioning even in the state of bus bridge, and also provides a separate collective relay other than the divided relay, and the like. The purpose of the present invention is to provide a simplified bus protection relay device that does not require any CT required for detection operation.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In Fig. 3, the same parts as in Fig. 1 are shown with the same reference numerals, and 7 and 27 are for all lines.
CT8-1...8-n and 9-1, 9-2 are combined and connected to introduce a current, and an input device that introduces an operation (differential output) proportional to this current, 18a,
28a is an a contact that closes when busbars 1 and 2 enter the bridge state, and 18b and 28b are busbars 1 and 2.
This is a b contact that opens when the is in a bridge state. (Relays 18 and 28 are not shown) Next, the operation of the present invention will be explained with reference to FIG.
Although not shown, the differential outputs of the input devices 17 and 27 are determined by the conditions of the relays 18 and 28, which operate when both LS3-1 and 4-1 are closed, or when both LS3-n and 4-n are closed. Conventional input device 13-
1...13-n, 23-1...23-n, and 14,
The differential output derived from 24 is switched and introduced into split relays 12 and 22. In other words, if it is not a bus bridge, contacts 18b and 2
8b is closed, and contacts 18a and 28a are open, which is exactly the same state as the conventional one. Next, when a bus bridge occurs, contacts 18a and 28a are closed, and contacts 18a and 28b are opened, so that the above-mentioned differential (operation) input signal, that is, input Device 1
7 and 27 outputs will be introduced, respectively. As shown in the figure, the input signals to the input devices 17 and 27 include the busbar communication CTs 9-1 and 9-2, but the CTs 9-1 and 9-2 are connected so that their polarities are opposite. , the output phases of CT9-1 and CT9-2 are in an antiphase relationship of 180 degrees. Therefore,
CT8-1 to 8-n, and CT9-1, 9-2
If all the ratios are the same, CT9-1 and 9-2
The output sum of is zero. In the end, CT8-1 to 8
-n current sum becomes input to input devices 17 and 27.
In the case of an external failure of the CT8-1...8-n, zero current is applied, and in the case of an internal failure, a current proportional to the failure current is applied. Therefore, even if the busbar is in a bridge state,
When an external failure occurs in the CTs 8-1...8-n, no error current is applied to the input devices 17 and 27, and the divided relays 12 and 22 do not malfunction.
Note that there is no problem even if the suppression output circuits 16 and 26 are not switched especially when the bus bridge condition occurs, but there is no problem even if only the suppression output of the bus communication input devices 14 and 24 is disconnected using contacts 18b and 28b, etc. .

In the above embodiment, the differential output is switched under the bus bridge condition, but as shown in FIG. The differential outputs of the input devices 17 and 27 are introduced into this relay, and the suppression output is configured to be shared with the split relays 12 and 22,
Even if the suppression output is configured to be shared with the divided relays 12 and 22, and the relays 12' and 22' are used in the same role as the conventional collective relays 11 and 21, the operational function of the present invention changes. isn't it.

As described above, according to the present invention, a divided relay is installed between two sets of protected buses to prevent the protective relay from malfunctioning even when a bus bridge occurs.
It is equipped with an input device that introduces and activates a composite current, and the circuit is configured so that each divided relay is selectively operated by a signal from another relay that operates when the LS malfunctions, so it is a special integrated relay for bus bridge prevention. There is no need to provide a CT or the like for this purpose, which simplifies the configuration, making the device less expensive.It is also extremely significant that even in internal failure conditions during bus bridges, there is no shunting of differential current, making operation more reliable. It has a great effect.

[Brief explanation of drawings]

Fig. 1 is a principle circuit diagram showing the circuit configuration of a conventional busbar protection device, Fig. 2 is an explanatory diagram of an example of malfunction of a split relay in the conventional method, and Fig. 3 is a diagram of a busbar protection device showing an embodiment of the present invention. Principle circuit diagram showing a circuit example, No. 4
The figure is a principle circuit diagram showing another embodiment of the present invention. 13-1...13-n, 14, 24, 23-1...
23-n; Input device, 12, 22; Bus bar protection relay, 17, 27; Input device for all current transformer composite secondary current, 3-1a...3-na, 4-1a...4-na; Auxiliary relay contact , 18a, 28a, 18b, 28
b; Busbar switching disconnector contact. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1 Busbar relays provided for each of the plurality of busbars,
The input signal is a line connected to the plurality of busbars and arbitrarily switched to the busbars by a disconnector, and a secondary current of a current transformer that interconnects the line and the plurality of busbars and is provided in the busbar connection. an input device for each bus relay, an auxiliary relay contact that controls on/off the secondary output of the input device according to the status of the bus switching disconnector, and an output proportional to the secondary current of all the current transformers. A busbar protection relay device comprising: an input device for deriving a signal, and when the busbars are short-circuited to each other by a busbar switching disconnector, the operation input of the input device is disconnected and the operation input is switched to the operation input of the latter input device.