JPH0564354A - Accident section separating method for power distribution - Google Patents

Abstract

PURPOSE:To make it possible to have the minimum isolation of accident section and minimize the power interrupted section by attaching a superconducting current limiter to a section switch and by setting its operation value to the accident voltage value. CONSTITUTION:Two power distribution lines are connected in a loop form through a plurality of section switches 3 (3a to 3e), and a current limiter 4 (4a to 4e) for limiting the accident current and an overcurrent relay 15 for monitoring an accident current are connected to each point of said switch. A quench sensor 13 is attached to each end of a trigger coil 12 of said current limiter 4. Operation value of limiting value 4 is properly selected for the short-circuit current value during the accident at power distribution line; at the time of accident on the line, a superconducting current limiter 4 which is the closest to the accident point is operated and accident is eased, and the accident current after limiting is removed by the section switch for load current switching based on the operation output of the quench sensor 13. By doing this, accident isolation can be performed at a high speed at the same time with the accident occurrence, and power interruption time period can be reduced and power interruption range can be minimized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power distribution system in which two power distribution lines are looped in order to improve the reliability of power supply.
By combining a current limiting device and a division switch, sections other than the fault section can be separated without causing a voltage drop in the feeder when a fault occurs in the distribution line, so that the blackout time can be minimized at the same time. The present invention relates to an accident section separation method for power distribution.

[0002]

2. Description of the Related Art Distribution lines are stretched around like a mesh, but generally not in a loop form, but in a radial system configuration in which a switch at a normally open point is opened to operate.
This is because the accident segmentation device can only be used in a radial system, and each feeder has a division switch and an accident investigation device installed at the division point. FIG. 10 shows the configuration of a conventional accident isolation device in a distribution line, and FIG. 11 shows an example of the configuration of a timed type accident investigation device. In Figure 10, 1 is the breaker of the substation,
2 is the second section of the distribution line, 3 is the section switch for opening and closing the load current of the distribution line, 5 and 6 are the second section and the third section of the distribution line, respectively, and 21 is the judgment of the fault point. 20 is a timed type accident investigation device for controlling section separation, and 20 is a power supply transformer for stepping down the system voltage to give a low voltage.

In this case, if an accident occurs inside the second section 5 of the distribution line (point F in the figure), the overcurrent relay of the substation operates and the breaker provided under the feeder. 1 trips and cuts off the accident current. After that, the circuit breaker 1 is closed again, and power is sequentially transmitted from the first section 2 near the substation. When the feeder is restored, a voltage is applied to the timed type accident investigation device 21 through the power transformer 20, the built-in timed operation timer 24 starts counting time, and the division switch 3 is turned on after a fixed time. If the accident at point F is still continuing when the switch 3 is turned on, a large accident current flows again and the breaker 1 at the substation immediately trips. In this case, the timed accident investigation device 21 stores the fact that the closing operation has been performed in the time-return timer 23, and that the system voltage has been lost again within a certain time after the closing operation (= 2 of the power transformer).
Secondary side voltage has been lost)
A logical judgment is made at 24, 25 and 26, and it is judged that the adjacent section 5 is an accident occurrence section.

[0004]

As described above, in the method in which the accident investigation device 21 detects an accident point, a power failure occurs in the entire feeder line at the time of a distribution line accident, and a substation is required to search for the accident point. Since the circuit breaker 1 at the location trips twice and needs to be reclosed, the power supply failure time and the affected area extend to the entire feeder line. I can say. The present invention has been made in view of the above circumstances, and in order to improve the supply reliability, it is not used in the conventional radial system, but is also used in a loop system capable of improving the supply reliability. In addition, it is possible to effectively utilize the conventional segmented switch that has a load current switching efficiency, and install a fault current limiting device (for example, a superconducting fault current limiter) at the point where the switch is installed. If an accident occurs on a distribution line, the fault current limiter installed at the division point adjacent to the faulty section operates to limit the fault current, and then the fault current is controlled to open by the sectional switch. , It is possible to eliminate the accident that occurred in the distribution line without using the breaker of the substation, and it is possible to separate the section with the switch adjacent to the accident section. The arrangement that enables the minimum section together And its object is to provide a use fault section separation method.

[0005]

In order to achieve the above object, according to the present invention, two distribution lines are connected in a loop through a plurality of section switches, and a fault current is limited to each switch installation point. Equipped with a current limiter and an overcurrent relay for fault current monitoring, with a quench sensor at both ends of the trigger coil of the current limiter, and the operating value of the current limiter against the short-circuit current value at the time of a distribution line fault. Is properly selected, the superconducting fault current limiter at the division point closest to the fault point operates at the time of a distribution line fault to reduce the fault current, and at the same time, operates with the overcurrent relay and the quench sensor of the activated fault current limiter. The fault current after current limiting is removed by the load current switching section switch based on the output, and line voltage monitoring is performed when the current limiting quench sensor does not operate and the monitoring overcurrent relay operates. Line if the voltage relay for Residual voltage is configured to open the fault current in the section switch after a predetermined time under the following set level value.

First, on one power supply side (A side), since the current value of the fault current ifa to the fault point is between the operating values of the fault current limiters installed at the positions sandwiching the fault point, the power source (A
Side) current limiter shuts off at high speed and opens the switch on the power supply side. Further, since the current limiter at the loop point is set to operate at the lowest level for the inflow current from the other side (B side), the switch is opened at the loop point.

[0006]

Embodiments will be described below with reference to the drawings. Figure 1
FIG. 3 is an overall structural diagram for explaining a distribution fault segmentation method according to the present invention. In FIG. 1, 10a and 10b are power supplies A and B of the distribution system, 1 is a breaker of the substation, 2 is the first section of the distribution line, and 3n (n is a to e) are installed at division points. 4n is a section switch for load current switching, 4n is a superconducting fault current limiter installed at the same place, and 5, 6, 7, 8 and 9 are the second, third, fourth, fifth and sixth sections of the distribution line. Is shown. The superconducting fault current limiter used here has the circuit configuration shown in Fig. 2, where 11 is a current limiting coil, 12 is a trigger coil, 13 is a quench detection sensor, 14 is a current transformer (CT), and 15 is an accident. An overcurrent relay for monitoring, 16 is a voltage transformer (PT), 17 is a voltage detection relay (VD), 18 is a timer for timed operation, and 19 is a trip command unit.

Further, the current limiting device is provided with operating current characteristics at the time of quenching as shown in FIG. 4 in order to properly separate the faulty section, and a device having a high operating current value is installed at a point near the power source. .. Also, the one that operates with the lowest current shall be installed at the loop point, and in the case of an accident on the adjacent feeder, the switch shall be opened under the condition of the voltage relay. Fig.5 and Fig.6 show the response of the device in case of a distribution line accident.
Shown in. In the system configuration shown in the figure, the device response on the power supply A side and the power supply B side with the loop point as a boundary is a target operation. That is, the sixth section has the same operation as the first section, the fifth section and the second section have the same operation, and the fourth section has the same operation as the third section. Two cases will be explained.

First, an FA accident in the third section 6 will be described with reference to FIG. Speaking of the response on the power supply A (10a) side, the current value of the fault current ifa flowing from the power source 10a to the fault point is between the operating values of the fault current limiters 4b and 4c, as shown in Fig. 4. In addition, the current limiter 4b operates at high speed, and the switch 3b is immediately opened to prevent inflow of a fault current from the power source 10a and perform fault isolation. That is, cLa ＞ ifa ＞ cLb → 4b operation →
Separated at 3b. As for the response on the power supply 10b side, the fault current ifb flows from the power supply 10b via the loop point. In this case, as shown in FIG. 3, the current limiter 4c at the loop point is set to operate at the lowest level, so that the inflowing fault current ifb is quickly limited. Then, the switching switch 3c is opened under the operating conditions of the quench sensor of 4c, and the accident point is separated from the power supply 10b at high speed. That is, cLd>ifb>
cLc → 4c operation → 3c separates. Note that Za is the impedance of the power source A, Zb is the impedance of the power source B, and has a relationship of Za> Zb. As the operation level cooperation, cLa>cLb> cLc <
cLd <cLe.

Second as another typical accident case
The FB accident in section 5 will be described with reference to FIG. this
In the case, the fault current limiter 4a is the same as in the case of the FA accident described above.
Only the fault current limiter 4a at the division point close to the power supply A operates and high-speed current limiting
Along with the operation, the quench sensor detects and classifies
It issues a circuit opening command to the switch 3a. This allows power from 10a
It enables high-speed interruption of fault current and high-speed segmentation. Immediately
After that, cLa> ifa → 4a operation → 3a. On the other hand, power source B
The response on the side is a bit different from the previous case.
It For the fault current from power supply B, the lowest operating
The current limiter 4c at the loop point with the bell operates at high speed to limit the current.
Shed. In other words, the current limiter 4b adjacent to the
Yes. In the present invention, in order to monitor the system condition, the voltage detection relay is
System with electric current (VD) and overcurrent relay installed after current limiting operation
Separation of sections based on two judgment conditions: general voltage and current
To By the voltage detection relay 17 attached to the fault current limiter 4b
Determine the residual voltage on the line and it is lower than the set level
In case of overcurrent for fault current monitoring via time relay 18.
When the AND condition with the operating condition of relay 15
An order shall be issued. In the system configuration of FIG. 6, the power source A side is
Since it consists of three sections, the level of system voltage monitoring
Is the voltage value obtained by dividing the power supply voltage by the number of sections (3 here)
Basic value (K), K, KX (division
Interval-1) (twice the value of K) is used as the judgment value
It In other words, E / 3 for the division switch 3b, E / for 4a
3x2  

FIG. 7 is an overall structural view of another embodiment. This embodiment is an example applied to a radial distribution line. 7, the same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. This embodiment shows one end from one power supply A to the loop point, and as is clear from the configuration shown in FIG. 8, the operating value of each fault current limiter with respect to the short circuit current at the time of a distribution line fault. Is properly selected and is as shown in FIG. FIG. 9 is a characteristic diagram of the current limiting device in the case of quenching in the case of the present embodiment. In the present embodiment, in the F1 accident, only 4a operates to perform the current limiting operation. That is, the quenched fault current limiter detects its state by the quench sensor 13,
An opening command is output to 3a via the opening command unit 19. Even if the operating time of the overcurrent relay at the substation is fast,
It is about 50 milliseconds, whereas the current limiting device operates in several milliseconds and can judge an accident, so that sufficient operation time can be emphasized for the existing overcurrent relay.

[0011]

As described above, according to the present invention, since the superconducting fault current limiter is provided side by side with the switchgear and the operating value thereof is set in consideration of the fault voltage value of the system, For distribution lines that require reliable power supply,
Even if the system is configured in a loop, the current limiting device at the section point adjacent to the fault section can perform high-speed current limiting at the time of the accident. It becomes possible to limit the current from the wave,
By opening a low fault current with the load switching switch, it is possible to immediately perform a reliable fault segment determination and optimal system separation. As a result, although the circuit has been reclosed twice or more in the past, the accident can be separated at a high speed at the same time as the occurrence of the accident, and the power outage time can be reduced and the power outage range can be minimized.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram for explaining a power distribution accident section separation method according to the present invention.

FIG. 2 is a structural example diagram of a superconducting fault current limiter.

FIG. 3 is a diagram showing an example of installation conditions of a superconducting fault current limiter.

FIG. 4 is a characteristic example diagram of an operating current value of a superconducting fault current limiter.

FIG. 5 is a diagram showing an accident separation method at the time of an FA accident in the third section of the distribution line.

FIG. 6 is a diagram showing an accident separation method at the time of an FB accident in the second section of the distribution line.

FIG. 7 is an overall configuration diagram illustrating another embodiment.

FIG. 8 is a structural example view of a superconducting fault current limiter applied in another embodiment.

FIG. 9 is a characteristic example diagram of an operating current value of a superconducting fault current limiter applied in another embodiment.

FIG. 10 is a structural diagram of a conventional accident isolation device for a distribution line.

FIG. 11 is a structural diagram of a timed accident investigation device.

[Explanation of symbols]

 1 Distribution breaker 2, 5, 6, 7, 8, 9 Each section 3a to 3e Sectional switch 4a to 4e Superconducting fault current limiter 10a, 10b Power supply 11 Current limiting coil 12 Trigger coil 13 Quench sensor 14 Current transformer 15 Overcurrent relay 16 Voltage transformer 17 Voltage detection relay 18 Time delay relay 19 Tripping command section

Front page continuation (72) Inventor Takamitsu Tada 1-1-1, Shibaura, Minato-ku, Tokyo Inside Toshiba Headquarters Office (72) Inventor Hiroyuki Okumura 1st Toshiba Town, Fuchu-shi, Tokyo Inside Toshiba Fuchu Factory

Claims (2)

[Claims] 1. Two current distribution lines are connected in a loop through a plurality of section switches, and a fault current limiter for limiting a fault current and an overcurrent relay for fault current monitoring are installed at each switch installation point. A quench sensor is provided at both ends of the trigger coil of the fault current limiter, and the operating value of the fault current limiter is properly selected for the short-circuit current value at the time of a fault in the distribution line. The superconducting fault current limiter at the nearest division point operates to reduce the fault current, and the operation output of the overcurrent relay and the quench sensor of the activated current limiter are both limited by the division switch for switching the load current. When the overcurrent relay for monitoring operates by removing the fault current after the flow and the quench sensor of the fault current limiter does not operate, the residual voltage of the line is set when the voltage relay for monitoring the line voltage operates. After a certain amount of time when the level value is below A fault section separation method for power distribution, which is characterized by opening a fault current with a division switch. 2. A plurality of section switches for separating fault sections on a distribution line and a plurality of fault current limiters for limiting fault current at the switch installation points, and both ends of a trigger coil of the fault current limiter. Equipped with a quench sensor, the operating value of each fault current limiter is properly selected for the short-circuit current value at the time of a distribution line accident,
In the event of a distribution line accident, the superconducting fault current limiter at the division point closest to the accident point operates at high speed to reduce the fault current, and after the current is cut off by the division switch for switching the load current based on the output of the quench sensor. A fault segment separation method for power distribution, which is characterized by opening the fault current of.