JP3101736B2 - Distribution line protection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a distribution line protection device, and more particularly, to a distribution line protection device suitable for a power generation system that is installed in divided switches arranged in a distribution line and that uses a timed progressive system.

[0002]

[Prior art]

As described in Japanese Patent Application No. 61-162224, the conventional system detects the zero-sequence voltage or zero-sequence current when the segment switch is turned on, and exceeds the set value. Occasionally, an open command was given to the section switch to prevent a power outage again.

[0003]

[Problems to be solved by the invention]

In the above prior art, in the case of zero-sequence voltage control, when the switch is turned on, if a ground fault occurs in another feeder of the same bank, a zero-sequence voltage is generated and the switch is unnecessarily opened. In addition, even in the case of zero-phase current control, if a capacitive load such as a phase-adjustment capacitor or a cable system exists on the load side of the switch, a ground fault occurs in another feeder in the same bank as described above. Occurs, a ground fault current flows out of the ground capacity on the load side as shown in FIG.
No consideration is given to the unnecessary opening of the switch, and if such an unnecessary operation is performed, the originally healthy system (section) will be out of power and there is a problem in power supply. .

In order to prevent unnecessary operation due to a ground fault in the same bank and another feeder as described above (hereinafter, such a fault is referred to as an external fault), a directional ground fault detection relay is used. is there.

[0005] Generally, the distribution system is operated in the form of a tree, but as shown in FIG. Depending on the nature, it may be moved to another section switch and operated. At this time, the direction of the power source side is reversed for the segmented switches existing between the sections 2 to 4 shown in FIG. When operating in such a state, when a ground fault accident occurs and the reclosing operation is performed, the ground fault directional relay installed in the section switch between the sections 2 to 4 has a resin reverse direction. Therefore, even if a ground fault occurs in the next section of the segmented switch, it cannot be detected.

When a normally open section switch is turned on to operate different banks in a loop, an apparent zero-phase current may flow due to a voltage difference between the two banks. Unnecessary operation may cause the segment switch to open.

[0007] An object of the present invention is to provide an arrangement which can prevent the opening of a segment switch due to the imbalance of the voltages of both banks when the segment switch is turned on and a different bank is operated in a loop. An object of the present invention is to provide a wire protection device.

[0008]

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides a segmented switch that is distributed and arranged in a distribution line to open and close the distribution line,
A detection circuit for detecting each of the zero-phase voltage and the zero-phase current of the distribution line and outputting each detection value; and inputting each detection value by the detection of the detection circuit, and detecting a ground fault from each detection value at the time of a ground fault. A ground fault relay that determines a direction and outputs a ground fault direction signal based on the determination, a power distribution state detector that detects a power distribution state of a distribution line connected to both sides of the segmented switch, and the ground fault direction. A control circuit that opens the segmented switch in response to a ground fault direction signal from a relay, and only one of the distribution lines on both sides of the segmented switch is set to the charged state by the power distribution state detector. A polarity switching circuit that switches the input polarity of the ground fault directional relay according to the detection state when it is detected, and the distribution line on both sides of the segmented switch before closing by the power application state detector. In charge state And an open circuit stop circuit for stopping the open of the segmented switch by the control circuit regardless of the generation of the ground fault direction signal when it is detected, and maintaining an open circuit state. It was done.

According to the present invention, the polarity of one of the outputs of the detection circuit that detects the zero-phase voltage and the zero-phase current of the distribution line and outputs the values is switched and input to the ground fault direction relay. Even if the direction of the power supply side of the segmented switch is reversed, a ground fault in the load side can be detected to protect the distribution line.

[0010] Next, when a ground fault occurs during operation of the system by moving to the normally open point, and when the circuit is reclosed, when one of the sectional switches is charged, one of the power supply circuits is turned off. When the control power is output and the polarity of either output of the detection circuit is switched, the power application side is regarded as the power supply side and the ground fault direction relay is considered, and when the section switch is closed, a ground fault occurs in the next section This can be detected. On the other hand, when the other switch is energized, control power is output from the other power supply circuit, and the polarity of one output of the detection circuit is switched to connect the other power supply to the ground. Since the short-circuit relay is considered, the polarity of the short-circuit relay can be switched to the correct polarity in the power application direction before the closing of the segment switch. In this way, when the section switch is closed, if a ground fault occurs in the next section on the opposite side, this can be detected.

Further, two ground-fault directional relays are provided, and the output of one of the detection circuits is input to one ground-fault directional relay with a forward polarity, and the other ground-fault directional relay is supplied with a reverse direction. Input with a polarity of, and the specific direction of the segment switch is connected as the power side of one ground fault relay, and the opposite side of the specific direction of the segment switch is connected as the power side of the other ground fault direction relay. As described above, as described above, the power is supplied by the control power output from the power application direction before the switch is closed, and the ground fault direction relay with the power application direction as the power supply side is selected and output. Can be input to the control circuit of the segmented switch. In this way, when the section switch is closed, if a ground fault occurs in the next section on the opposite side, this can be detected.

When the switch is closed to operate the normally open point in a loop, power is applied to both sides of the switch. Therefore, the switch is energized by control power output from both sides of the switch. In order to disconnect the ground fault direction signal output from the ground fault direction relay and block the input to the control circuit, the ground fault opens the sectional switch even if an apparent zero-phase current flows when the switch is closed. The direction signal is not input to the control circuit, thereby preventing unnecessary opening of the sectional switch.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, an embodiment of the present invention will be described.

FIG. 1 shows a circuit diagram of a control system for detecting a ground fault and protecting a distribution line. The zero-phase voltage of the system at the point where the segment switch 1 is installed is detected by a zero-phase capacitor voltage divider (hereinafter referred to as ZPD) 2, and the zero-phase current is detected by a zero-phase current transformer (hereinafter referred to as ZCT) 3. To detect. The zero-sequence voltage and zero-sequence current detected by the ZPD and ZCT are input to a ground fault directional relay (DG) 6A. The DG6A has a polarity that performs a phase comparison between the zero-sequence voltage and the zero-sequence current and operates only when there is a ground fault in a certain direction. The operation principle of DG6A in this embodiment is a known DG
The operation direction is determined by the input phase relationship between ZPD and ZCT.

On the other hand, when the closing command 5 is closed, the closing switch
Turned on when CC4 is excited. Here, the power supply 7 is an operation power supply for the closing coil 4 and may be supplied in any form, either DC or AC, and is not limited in the present invention. When the section switch 1 is closed, if there is a ground fault in the next section, the DG 6A operates, the contact 8 is opened, and the section switch 1 is opened. As a result, the ground fault current disappears, so that the ground fault relay at the substation at the starting point of the line does not operate, thereby preventing the entire section of the line from power failure. Also, by adding a circuit that blocks the output of DG6A if there is no operation of DG6A in the time period before the next section switch 1 is turned on, and there is no ground fault in the section following that section switch 1, If there is a ground fault after the next section, it is possible to avoid opening the switchgear 1 by the DG6A. The above operation and specific method are described in
Since it is disclosed in Japanese Patent No. 162224, it is not shown in FIG.

Immediately after the switch 1 is turned on, a ground fault occurs in another feeder in the same bank, and the switch 1 is turned on.
Even if a fault current flows due to a capacitive load or the like in the next section, the DG 6A does not operate because the input is in the reverse direction, and the sectional switch 1 does not open. In addition, even if a multiple accident such as a lightning strike causes the switching operation of the sectional switch 1 and the ground fault accident of the same bank and other feeder simultaneously occur, unnecessary opening of the sectional switch 1 of a sound line can be prevented, and supply failure can be prevented. Can be prevented.

The first embodiment will be described with reference to FIG. Control power is taken out from the distribution lines on both sides of the segmented switch 1 via transformers 10 and 11, and the coils 12 and 13 are energized, respectively. That is, when the coil 12 is operated, it means that power is applied from the direction of FIG. 2A, and when the coil 13 is operated, it means that power is applied from the B side.

The contacts of the coils 12 and 13, for example as shown in FIG.
Switches the DG6A PT input polarity. With the coil 12 operating,
When the coil 13 is in the reset state, and immediately when power is applied from the A side,
ZPD secondary terminal 1 to DG6A P1 terminal, ZPD secondary terminal 2
Is connected to the P2 terminal of DG6A. At this time, if the polarity of DG6A is determined so that the A side is regarded as the power supply side, power is applied from the A side, and when the switch 1 is closed, there is a ground fault in the next section. If this is the case, this can be detected.
On the other hand, when the segment switch 1 is closed, if there is a ground fault in the other feeder of the same bank, that is, in the direction A, the DG6A will not operate even if a fault current flows out from the next section. In addition, the sectional switch 1 is not unnecessarily opened.

On the other hand, when power is applied from the B side, the coil 13 operates, and the coil 12 is in the return state. Therefore, the connection of the secondary circuit of the ZPD 2 1 is P2 of DG6A
Terminal and the terminal 2 of the ZPD are connected to the P1 terminal of the DG6A.
Therefore, the DG 6A has a polarity in which the power supply side is in the direction B opposite to the above, and when the switch 1 is turned on, it is possible to detect a ground fault accident in the next section, that is, the A side. As described above, the polarity of DG6A is automatically switched in the power application direction before switching on the section switch, so even if the power supply side is reversed due to a change in system operation, etc., DG6A will not This has the effect that the correct polarity can be obtained automatically.

In the present embodiment, the switching of the polarity is realized by switching the polarity of the PT circuit. However, if protection measures are taken when the CT is opened, the switching of the polarity of the ZCT 3 can also be realized. Furthermore, in the case of a digital relay using an electronic circuit in the DG6A or a microprocessor, switching by a program is also possible. Here, it is not necessary to limit the specific means of switching, and the invention is to switch the polarity of DG6A by detecting the direction of power application.

A second embodiment will be described with reference to FIG. In the present embodiment, it is assumed that DG6A and DG6B are connected in reverse to each other in advance, and that DG6A is connected to the power supply side in direction A and DG6B is connected to the power supply side in direction B. now,
When power is applied from the A side, the coil 12 operates, and after the switch 1 is closed, a ground fault occurs in the next section on the B side.
6A operates, the contact 8 closes, the relay 14 operates, and the switchgear 1 is opened, so that the ground fault can be eliminated. On the other hand, when an external failure occurs at the same time when the sectional switch 1 is closed, and a ground fault current flows due to a capacitive load in the B-side section, the DG 6B operates, but the coil 13 is in the return state. , And the switch 1 is not opened. Conversely, when power is applied from the B side, the coil 13 operates, that is, the DG 6B connected with the polarity such that the B side becomes the power supply side is selected. As described above, according to the present embodiment, similarly to the first embodiment, the DG with the correct polarity is automatically selected when the sectional switch is turned on.

A third embodiment will be described with reference to FIG. In this example, DG
A relay 17 receiving an output of 6 A is provided, and as a condition for operating the relay 17, a condition that at least one of the coils 12 or 13 is restored is entered as a logical product. That is, when both A and B are in the power-on state from the beginning (when the sectional switch 1 is open at the meeting point).
Coil 12 and coil 13 are both in operation and relay
Since the switch 16 is operated and turned off, the relay 17 is not energized and the switch 1 is not opened even when the DG 6A operates. Conversely, only one of A and B is charged, and the other is
In the power failure state, the relay 16 does not operate, and if the DG 6A operates, the relay 17 operates, the sectional switch closing coil 4 returns, and the sectional switch 1 is opened. According to the present embodiment, the segmented switch 1 which is generated when the segmented switch in the open state of the contact point is turned on and a different bank loop is turned on.
Even if an apparent zero-phase current flows due to voltage imbalance on both sides of the DG6A and the DG6A operates, it is possible to prevent the sectional switch 1 from being unnecessarily opened.

According to the present embodiment, there is provided a ground fault direction relay for automatically switching the polarity depending on the power application direction, and its output can be locked when the loop is turned on. Has a significant effect. 1. It is possible to prevent unnecessary opening of a sectional switch due to an external failure that occurs when the switch is turned on. 2.The DG power supply direction is automatically switched when an accident occurs and reclose operation is performed even if the normally open point is moved and the power supply direction is changed due to system operation. Therefore, there is no restriction on system operation in applying DG. 3. It is possible to prevent unnecessary opening of the segment switch in the DG operation due to the apparent zero-phase current generated when the loop is turned on.

[0024]

【The invention's effect】

According to the present invention, when the partitioning switch is turned on, when the distribution lines on both sides of the partitioning switch are both in the power-on state, the opening of the partitioning switch by the control circuit is stopped. Even if the voltages on both sides of the segment switch become unbalanced with the turning on and an apparent zero-phase current flows, the segment switch can be prevented from being unnecessarily opened.

[0025]

[Brief description of the drawings]

FIGS. 1 to 4 are circuit diagrams of an embodiment of the present invention, and FIG. 5 is a circuit in which a capacitive load or a cable system exists on the load side, and a fault current flows when an external fault occurs. FIG. FIG. 6 is a system diagram illustrating an example in which the power supply direction is reversed by system switching.

[Explanation of symbols]

 1… Segmented switch, 2… Zero-phase voltage detector (ZPD), 3… Zero-phase current detector (ZCT), 4… Segmented switch closing coil, 5… Segmented switch closing command contact, 6A… Ground fault directional relay A, 6B… Ground fault directional relay B, 7… Sectional switch drive power, 8… Control circuit control power.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-316646 (JP, A) JP-A-60-133616 (JP, A) Japanese Utility Model Showa 57-36735 (JP, U) Japanese Utility Model Showa 51- 31945 (JP, Y1) (58) Field surveyed (Int. Cl. ⁷ , DB name) H02H 7/26

Claims (1)

(57) [Claims] 1. A divisional switch that is distributed and arranged in a distribution line to open and close the distribution line, a detection circuit that detects a zero-phase voltage and a zero-phase current of the distribution line and outputs each detection value, A ground fault direction relay that inputs each detection value by the detection of the detection circuit and determines a direction of a ground fault from each detection value at the time of a ground fault and outputs a ground fault direction signal based on the determination,
An applied state detector that detects an applied state of a distribution line connected to both sides of the section switch; and a control circuit that opens the section switch in response to a ground fault direction signal from the ground fault direction relay. When it is detected by the power distribution state detector that only one of the distribution lines on both sides of the segmented switch is in the power distribution state, the ground fault direction relay is operated in accordance with the detected state. A polarity switching circuit for switching the input polarity, and when the power distribution state detector detects that both distribution lines on both sides of the segmented switch are in a power distribution state before closing, the generation of the ground fault direction signal is performed. An open circuit stop circuit for stopping the open circuit of the sectional switch by the control circuit and maintaining the closed circuit state.