JPH0412615A - Method and apparatus for minimizing power interruption of power system - Google Patents

Abstract

PURPOSE:To shorten recovering time by opening only zone opening/ closing means of a zone to be monitored under the conditions that power supply is interrupted and a fault occurs at a load side from own monitoring zone, and then sequentially reclosing only the means of an open state. CONSTITUTION:A zero-phase current Io, a zero-phase voltage Vo are detected at zone units D1, D2, and a circuit breaker CB is tripped. In this case, the fact that a ground-fault accident is located at a load side from the monitoring zone of the fault in the units D1, D2 is detected. When power supply is interrupted and the output of a rectifier REC is reduced, a zone switch DM is opened. In this case, the switch DM is held in a closed state in the units D3-D6. Thereafter, when the breaker CB is reclosed after predetermined time, the units D1, D2 are sequentially energized. In this case, since data indicating a fault is stored in a memory, the switch DM is reclosed in the designated order according to a time limit sequential energization system.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method and device for minimizing power outages in a power system, and is particularly concerned with recovery accidents such as ground faults on distribution lines connecting substations and loads. The present invention relates to a power system power outage minimization method and device suitable for shortening power outage time during restoration when a power system occurs.

[Conventional technology]

Conventionally, when a ground fault or short circuit accident occurs on a distribution line connecting a substation and a load, "divider switches for automatic failure section detection" are used to quickly distinguish between healthy sections and faulty sections.
As described in (Published by the Institute of Electrical Engineers of Japan, February 1986 [Electrical Engineering Handbook J, p. 1264), a time-based power transmission charging system is adopted. According to this method, after all the sectional switches are opened due to an accident, each sectional switch is automatically re-closed in sequence at preset time intervals, and when the sectional switches are re-closed, the substation is If an accident is detected again by the protective relay installed at the power line outlet, the circuit breaker at the power line outlet will be opened immediately, and
It is possible to detect the sectional switch that was re-opened immediately before the breaker was opened, and from this detection result it can be determined in which section the accident occurred.

[Problem to be solved by the invention]

However, in the above-mentioned conventional technology, sufficient consideration is not given to recoverable accidents that occur on the power distribution line, and there is a problem in that it takes a long time to restore the entire section of the power distribution line. In other words, according to the conventional timed sequential charging system, it takes (number of switches with timed sequential transfer function) x (progressive transfer time) minutes to complete charging to the end of the distribution line. The more an accident occurs at the terminal, the longer the power outage will be.

Therefore, in order to shorten the power outage time, it is necessary to limit the number of switches having a timed progressive function to be installed, and even if the number of switches to be installed is limited, the protection zone (power outage zone) becomes long.

An object of the present invention is to provide a method and device for minimizing power outages in an electric power system that can shorten recovery time from a recoverable accident.

[Means to solve the problem]

In order to achieve the above object, the present invention, as a first method, divides a distribution line connecting a power source and a load into a plurality of monitoring sections, and provides a section opening/closing means for opening and closing the distribution line in each monitoring section, In a power system in which the main switching means is installed at the power supply side end of the distribution line, the occurrence and direction of an accident are monitored from the electrical quantity of the distribution line in each monitoring section, and the main switching means is opened due to an accident on the distribution line. Occasionally, on the condition that the power supply is cut off due to opening of this main switching means and an accident occurs on the load side from the own monitoring section, only the sectional switching means of the monitoring section is opened, This method employs a method for minimizing power outages in an electric power system, which is characterized in that when the main switching means is turned on again, only the section switching means that are in the open state are sequentially turned on again.

The second method is to divide the distribution line that connects the power supply and the load into multiple monitoring sections, provide segmental switching means for opening and closing the distribution line in each monitoring section, and provide main switching means at the power supply side end of the distribution line. In an electric power system consisting of a large number of people, the occurrence and direction of accidents are monitored from the amount of electricity in the distribution lines in each monitored section, and when the main switching means is opened due to an accident on the distribution line, the main switching means is opened. Each section switching means was opened on the condition that the power supply was cut off, and when the main switching means was then turned on again, it was detected that the accident occurred on the load side from the self-monitored section before opening. This method employs a power system power outage minimization method characterized by sequentially re-energizing only the segmental switching means in the monitored section and simultaneously re-energizing the other segmental switching means.

A third method is to divide the distribution line connecting the power source and the load into multiple monitoring sections, provide a section switching means for opening and closing the distribution line in each monitoring section, and provide a main switching means at the power supply side end of the distribution line. In an electric power system consisting of a network, when the main switching means is opened due to an accident on the distribution line in each monitoring section, the power supply is cut off due to the opening of the main switching means, and the amount of electricity in the own monitoring section. Under the condition that the occurrence of an accident has been detected, only the segmental opening/closing means in the monitored section will be opened, and then when the main switching means is re-engaged, only the segmental switching means that are in the open state will be sequentially re-engaged. This method adopts a power system power outage minimization method characterized by the following.

As a fourth method, the distribution line connecting the power source and the load is divided into multiple monitoring sections, and each monitoring section is provided with a section switching means for opening and closing the distribution line, and the main switching means is provided at the power supply side end of the distribution line. In an electric power system consisting of a large area, the occurrence of an accident is monitored from the amount of electricity on the distribution line in each monitored section, and when the main switching means is opened due to an accident on the distribution line, power is supplied as the main switching means is opened. Each segment switching means is opened on the condition that the main switching means is turned on again, and the segment opening/closing of the monitored section where the occurrence of an accident was detected from the electrical quantity of the self-monitored section before opening. This method employs a method for minimizing power outages in an electric power system, which is characterized by sequentially re-energizing only the sectional opening/closing means and re-energizing five other sectional opening/closing means at the same time.

As a fifth method that includes the first or second method, zero-sequence current and zero-sequence voltage are detected as electrical quantities of the distribution line in each monitoring section, and the occurrence of an accident and the cause of an accident are determined from each detected current and voltage. This method employs a power system power outage minimization method that determines the direction of occurrence.

As a sixth method that includes the third or fourth method, zero-sequence current and zero-sequence voltage are detected as electrical quantities of the distribution line in each monitoring section, and the occurrence of an accident and the cause of an accident are determined from each detected current and voltage. This method employs a power system power outage minimization method that determines the direction of occurrence.

As a seventh method that includes the third or fourth method, zero-sequence current or line current is detected as the amount of electricity in the power distribution line in each monitoring section, and when either of the detected currents exceeds a set value, power is distributed. This method employs a power system power outage minimization method that determines when an accident has occurred on a railway line.

As a first device, the distribution line connecting the power source and the load is divided into multiple monitoring sections, and each monitoring section is provided with a section switching means for opening and closing the distribution line, and the main switching means is provided at the power supply side end of the distribution line. In a power system consisting of a power system, an accident detection means detects the occurrence of an accident from the amount of electricity on the distribution line, and a direction detection means detects from the amount of electricity on the distribution line that the direction in which the accident occurs is on the load side from the self-monitored section. and a power cutoff detection means for detecting that the power supply has been cut off; and an opening means for opening the sectional opening/closing means on the condition that each detection output of the accident detection means, the direction detection means, and the power cutoff detection means is generated.
A power outage minimization device for an electric power system, characterized in that each monitoring section is provided with a reinsertion means for reinserting the sectional switching means in an open state in a specified order when the main switching means is reintroduced. It is composed of

As a second device, the distribution line connecting the power supply and the load is divided into a plurality of monitoring sections, and each monitoring section is provided with a section switching means for opening and closing the distribution line, and the main switching means is provided at the power supply side end of the distribution line. In a power system consisting of a power system, an accident detection means detects the occurrence of an accident from the amount of electricity on the distribution line, and a direction detection means detects from the amount of electricity on the distribution line that the direction in which the accident occurs is on the load side from the self-monitored section. a power cutoff detection means for detecting that the power supply has been cut off; an opening means for opening the sectional opening/closing means according to the way the power cutoff detection means detects; and when the main opening/closing means is turned on again. On the condition that a detection output has been generated from the accident detection means and the direction detection means before this re-closing, the sectional opening/closing means will be re-closed in accordance with the specified order; otherwise, the categorization will be performed in accordance with the re-closing of the main opening/closing means. This invention constitutes a power outage minimization device for an electric power system, characterized in that a re-introduction means for re-introducing the opening/closing means is provided in each monitored section.

As a third device, the distribution line connecting the power supply and the load is divided into a plurality of monitoring sections, and a section switching means for opening and closing the distribution line is provided in each monitoring section, and a main switching means is provided at the power supply side end of the distribution line. In an electric power system consisting of a The opening means opens the compartment opening/closing means on the condition that a detection output is generated, and the re-closing means re-opens the compartment opening/closing means in the open state in a specified order when the main opening/closing means is re-closed. This is a power system power outage minimization device characterized in that it is installed in a section.

As a fourth device, the distribution line connecting the power source and the load is divided into a plurality of monitoring sections, and a section switching means for opening and closing the distribution line is provided in each monitoring section, and a main switching means is provided at the power supply side end of the distribution line. In an electric power system consisting of an electric power system, there is an accident detection means that detects the occurrence of an accident from the amount of electricity in the distribution line, a power cutoff detection means that detects that the power supply is cut off, and a divided switching system based on the detection output of the power cutoff detection means. When the opening means for opening the means and the main opening/closing means are turned on again, the sectional opening/closing means are turned on again in a specified order on the condition that a detection has occurred from the accident detection means before this reinsertion. and, at other times, re-introduction means for re-introducing the sectional switching means in accordance with the re-introduction of the main switching means, are provided in each monitored section. It is something.

[Effect]

The occurrence and direction of an accident are monitored from the amount of electricity on the distribution line in each monitoring section, and when a recoverable accident occurs on the distribution line and the main opening means is opened and the power supply is cut off,
The section opening/closing means of only the monitoring section in which it is detected that an accident has occurred on the load side of the own monitoring section is opened, and the section opening/closing means of the other monitoring sections are kept closed. Thereafter, when the main opening means is re-closed, only the sectional opening/closing means which are in the open state are sequentially re-closed. In other words, the entire power distribution line can be placed in the energized state by simply re-energizing only the section switching means in the monitored section where the occurrence of an accident has been detected, making it possible to shorten the restoration time. Furthermore, even when monitoring the direction of occurrence in the event of a recoverable accident, if the main switching means is opened due to a recoverable accident and the power supply is cut off, and all segmented switching means are opened, the main switching means will be restarted after that. When the system is turned on, only the segment opening/closing means of the monitoring section in which it is detected that an accident has occurred on the load side from the own monitoring section are sequentially re-energized, and the other segment opening/closing means are simultaneously re-energized. According to this method, the power outage time is only the time required to sequentially re-energize the sectional opening/closing means of the monitored section where it is detected that the direction of the accident is on the load side rather than the self-monitored section, so the recovery time is shortened. becomes possible. Furthermore, even when only the occurrence of an accident is monitored from the amount of electricity on the distribution line, it is possible to shorten the restoration time using a similar method.

〔Example〕 An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, a distribution transformer T installed at a substation
A 6.6KV high-voltage distribution line BUS is connected to the output side of R, and this distribution line BUS includes distribution lines Ll, L2 .・・・・・・
・Ln is connected via the distribution line daily use switch (main switching means) CB.

The opening/closing state of each switch CB is controlled by a current transformer CT and a ground fault protection relay RY, and the distribution lines L1 to Ln between the switch CB outlet side and the load are each monitored by multiple monitors. It is divided into sections. For example, the power distribution line L1 is divided into seven monitoring sections 81 to S7. Sorting devices D1 to D6 are provided in each monitoring section 81 to S7. Each division device D1 to D6 has a power distribution line L
A sectional switch (sectional switching means) DM that opens and closes the distribution line L1, a current transformer FCT that detects the amount of electricity of the distribution line L1, and a voltage transformer PT are provided. A controller C0NT and the like that control the opening/closing state of the sectional switch DM from the output are provided.

Specifically, as shown in FIG. 2, the division devices D1 to D6 include a voltage transformer PD, a zero-phase current transformer zCT, a division switch DM, a control power transformer Tr, a rectifier REC, a controller C0NT, It consists of an auxiliary relay CX, a relay contact CX-a, etc.

The sectional switch DM connects the distribution line Al that constitutes the distribution line L1.
, A2. A3 and distribution line Bl, B2. It is inserted into the line of B3 and is composed of main contacts 11a, 11b, lie, closing coil cc, and auxiliary contact 12. The circuit-closing coil CC is connected to the relay contact CX-a, and the auxiliary contact 12 is connected to the controller C0NT. Then, when the relay contact CX-a closes and the excitation coil C is excited, the main contacts 11 a, 1 l b, 11 c
are the distribution lines Al, A2., respectively. A3 and distribution line Bl, B2
゜B3 is connected. That is, the section switch DM is closed by the excitation of the closing coil CC, and when the section switch DM is closed, the auxiliary contact 12 is closed, and information on this closed state is sent to the controller C0NT. It has become. On the other hand, when the relay contact CX-a is opened, the circuit closing coil CC
is in a de-energized state, the main contacts 11a, llb, and llc are opened, and the one-section switch DM is in an open state.

In addition, distribution lines Al, A2. A3 has capacitors C1 and C
A voltage transformer PD composed of components 2, C3, and C4 is provided, and a zero-phase current transformer ZCT is also provided. The voltage transformer PD detects the zero-sequence voltage as an amount of electricity on the distribution line L1, and converts this zero-sequence voltage v0 to the controller C'O.
It is designed to output to NT. Zero phase current transformer ZCT
detects zero-phase current 0 as the amount of electricity on the distribution line L1,
The detected zero-sequence current Io is output to the controller C0NT. In addition, distribution line AI.

A control power transformer Tr is connected to A3, and this transformer Tr converts a voltage of 6.6 kV to 100 V, and supplies the converted voltage to a rectifier REC. The output of the rectifier REC is supplied to the controller C0NT and the relay contact CX-a.

The controller C0NT receives power from the rectifier REC, inputs a signal related to the open/closed state of the sectional switch DM from the auxiliary contact 12, and outputs zero-sequence current 0 and zero-sequence voltage ■ as the electrical quantity of the distribution line L1. are input, and the operation of the auxiliary relay CX is controlled based on these input signals.

In order to control the operation of this auxiliary relay CX, the controller C0NT operates as an accident detection circuit that detects that a ground fault has occurred on the distribution line L1 when the zero-phase current generator 0 exceeds a set value. , a direction detection circuit that detects from the phase of zero-sequence current worker 0 and zero-sequence voltage vO that the direction in which a ground fault occurs is on the load side from the self-monitored section, and a no-voltage state because no voltage is supplied from the rectifier REC. a power cutoff detection circuit that detects when a fault has occurred, a memory that stores the output of the accident detection circuit as nonvolatile accident history data, and a memory that stores the outputs of the accident detection circuit, direction detection circuit, and power cutoff detection circuit. Consists of an open command circuit that generates an open command signal according to the conditions, and a re-close command circuit that outputs a re-close command according to the timed sequential power transmission method when the switch CB is re-closed after a recoverable accident occurs. has been done. That is,
Controller C0NT constitutes fault detection means and direction detection means together with zero-phase current transformer ZCT and voltage transformer PD, constitutes power cutoff detection means together with control power transformer Tr and rectifier REC, and further includes auxiliary relay CX, Relay contact C
Together with X-a and the closing coil CC, it constitutes an opening means and a reinsertion means.

In the above configuration, if a ground fault accident occurs in the monitoring section S3, which is a recoverable accident (an accident in which the accident returns to a normal state in a short time) due to contact with a tree, etc., the 1-category device DI
, D2, zero-sequence current ■0 and zero-sequence voltage vO are detected, and switch CB is tripped by relay RY. At this time, it is detected that the ground fault is on the load side of the accident monitoring section only in the dividing devices Di and D2. Then, when the power supply is cut off due to tripping of the switch CB and the output of the rectifier REC decreases, the dividing device DI,
The section switch DM of D2 is opened. At this time, the zero-sequence current Io and zero-sequence voltage vO cannot be detected in the dividing devices D3 to D6, and the dividing switches DM of these devices cannot be detected.
is maintained in a closed circuit state.

Thereafter, when the switch CB is turned on again after a certain period of time, power is sequentially supplied to the one-category bags [Dl and D2. At this time, since the memories of the sorting devices Di and D2 store data indicating the occurrence of an accident as accident history data, the sorting devices iD1. The sectional switches DM of D2 are re-closed in the specified order according to the time-sequential power transmission charging system. At this time, sorting device D
Since the section switches DM of sections 3 to D6 are maintained in the closed state, the entire distribution line L1 can be restored to the energized state by simply turning on the section switches DM of the section devices Di and D2. The time can be significantly reduced.

In addition, the controller C0NT is provided with an open command circuit that outputs an open command to the sectional switch DM based on the detection output of the power cutoff detection circuit, and when the switch CB is turned on again, the fault detection circuit is activated before the power cutoff detection circuit is turned on again. Under the condition that a detection output is generated from the direction detection circuit, the sectional switch DM is re-closed using the timed sequential power transmission system, and in other cases, the sectional switch DM is instantaneously closed in accordance with the re-close of the switch CB. It is also possible to provide a re-input command circuit for re-inputting the power.

In this case, if a ground fault occurs in the monitoring section S3, when the switch CB is re-closed, the division switches DM of the division devices Di and D2 are sequentially re-closed by the timed sequential power transmission charging method, The compartment switches DM for the compartment bags [D3 to D6 are instantly re-inserted. Therefore, even in the case of this method, the entire distribution line L1 can be restored to the energized state by only the time required to re-energize the division switches DM of the division devices Di and D2, thereby shortening the restoration time. be able to.

In the above embodiment, a case has been described in which the direction of occurrence of an accident is detected from the zero-sequence current Io and the zero-sequence voltage ■0, but a line current detector for detecting the line current and a line voltage for each distribution line are used. A line voltage detector or phase voltage detector is installed to detect the occurrence of an accident when the line current exceeds a set value, and to detect an accident when the line voltage or phase voltage falls below the set value. Even if the occurrence is detected, the same effect as in the above embodiment can be obtained.

In this case, as a first method, the controller C0NT is provided with an open command circuit that outputs an open command to the sectional switch DM on the condition that each detection output of the accident detection circuit and the power cutoff detection circuit is generated, and the switch CB A re-closing command circuit is provided which commands the sectional switch DM, which is in an open state, to be re-closing according to a time-sequential power transmission charging system when the sectional switch DM is re-closing.

The second method includes an open command circuit that instructs the controller C0NT to open the sectional switch DM based on the detection output of the power cutoff detection circuit, and when the switch CB is turned on again, before it is turned on again. On the condition that a detection output is generated from the fault detection circuit, the section switch DM is commanded to re-close according to the timed sequential power transmission method, and in other cases, the section switch DM is instructed to close in accordance with the re-close of the switch CB. A possible method is to provide a re-input command circuit that outputs a re-input command for instantaneously re-introducing the power.

Further, in the above embodiment, only a ground fault accident was explained as a recoverable accident, but the above embodiment can be applied to a recoverable accident even if it is a short circuit accident. That is, in case of a short circuit accident.

The short circuit current flowing due to the fault point is determined by the distribution line impedance. Therefore, each sorting device! This can be handled by setting the magnitude of the short circuit current detected by Di to D6 in each of the dividing devices D1 to D6.

Furthermore, if the method according to the above embodiment is adopted, not only a recovery accident on the distribution line but also an accident on the primary side of the distribution transformer TR or the power transmission system causes a power outage on the distribution lines L1 to Ln, and after this power outage, each distribution line Even when L1 to Ln are brought into the restored state, each distribution line L1 to Ln can be restored in a short time, contributing to shortening the restoration time.

As described above, according to this embodiment, only the section switches DM of the section devices D1 and D2 need to be turned on again using the timed sequential power transmission method, and the other section switches DM may be kept in the closed state or Alternatively, since the power is turned on again instantaneously, as shown in FIG. 3, the recovery time can be significantly shortened compared to the conventional system that employs only the time-limited power transmission charging system.

〔Effect of the invention〕

As explained above, according to the present invention, when a recoverable fault occurs on a distribution line, only the segmental switching means located on the load side from the fault point or the segmental switching means in the monitored section where the accident was detected is kept open. , the other section opening/closing means are held in a closed state, and when the main switching means is turned on again, only the section opening/closing means in the open state are sequentially reinserted, so that the recovery time can be shortened.

In addition, when a recoverable accident occurs on the distribution line, all segmental switching means are opened when the main switching means is opened, and when the main switching means is re-energized, the segmental switching means located on the load side from the fault point Alternatively, only the section opening/closing means in the monitored section where the accident was detected are re-engaged in sequence, and the other section opening/closing means are re-engaged at the same time as the main opening/closing means, which contributes to shortening the recovery time. can.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention, FIG. 2 is a specific configuration diagram of a sorting device, and FIG. 3 is a diagram for explaining the difference in recovery time between the present invention and a conventional example. be. TR...Distribution transformer, CB...Distribution line pull-out daily switch, Ll, L2
・・Ln・・・・Distribution line, Sl, S2・・S7・
...Monitoring section. DI, D2...D6...--Dividing device, DM...
...Division switch, ZCT...Zero-phase current transformer, PD...Voltage transformer, C0NT...Controller, CX...Auxiliary relay Fig. 2

Claims (1)

[Claims] 1. The distribution line connecting the power source and the load is divided into a plurality of monitoring sections, and each monitoring section is provided with a section switching means for opening and closing the distribution line, and the main switching means is provided at the power supply side end of the distribution line. In a power system that is equipped with On the condition that the power supply is suddenly cut off and an accident occurs on the load side of the monitoring section, only the segmental switching means of the monitoring section will be opened, and then the main switching means will be turned on again. 1. A method for minimizing power outages in an electric power system, characterized by sequentially re-energizing only the section opening/closing means that are in an open state when a power failure occurs. 2. A power system in which a distribution line connecting a power source and a load is divided into a plurality of monitoring sections, a section switching means for opening and closing the distribution line is provided in each monitoring section, and a main switching means is provided at the power supply side end of the distribution line. In each monitored section, the occurrence and direction of an accident are monitored from the amount of electricity on the distribution line, and when the main switching means is opened due to an accident on the distribution line, the power supply is stopped due to the opening of the main switching means. When each section switching means is opened on the condition that the main switching means has been disconnected, and the main switching means is then re-opened, the corresponding monitoring section that detects that the accident has occurred on the load side from the self-monitored section before opening. A method for minimizing power outages in an electric power system, characterized by sequentially re-energizing only the segmental opening/closing means of a section, and simultaneously re-energizing other segmental opening/closing means. 3. A power system in which a distribution line connecting a power source and a load is divided into a plurality of monitoring sections, a section switching means for opening and closing the distribution line is provided in each monitoring section, and a main switching means is provided at the power supply side end of the distribution line. , when the main switching means was opened due to an accident on the distribution line in each monitoring section, the accident was caused by the fact that the power supply was cut off due to the opening of the main switching means and the amount of electricity in the own monitoring section. It is characterized by opening only the segmental opening/closing means of the monitoring section on the condition that the occurrence of is detected, and then sequentially reinserting only the segmental opening/closing means that are in the open state when the main switching means is turned on again. A method for minimizing power outages in power systems. 4. A power system in which a distribution line connecting a power source and a load is divided into a plurality of monitoring sections, a section switching means for opening and closing the distribution line is provided in each monitoring section, and a main switching means is provided at the power supply side end of the distribution line. In this system, the occurrence of an accident is monitored from the amount of electricity on the distribution line in each monitored section, and when the main switching means is opened due to an accident on the distribution line, the power supply is interrupted or interrupted due to the opening of the main switching means. When the main switching means is turned on again, only the section opening/closing means of the monitored section in which the occurrence of an accident was detected from the electrical quantity of the monitored section before opening is opened. A method for minimizing power outages in an electric power system, characterized by sequentially re-energizing other divisional switching means and simultaneously re-energizing other divisional opening/closing means. 5. The electric power according to claim 1 or 2, wherein zero-sequence current and zero-sequence voltage are detected as electric quantities of the distribution line in each monitored section, and the occurrence of an accident and the direction of occurrence of the accident are determined from each detected current and detected voltage. Method for minimizing grid power outages. 6. Claim 3, wherein zero-sequence current or line current is detected as the electrical quantity of the distribution line in each monitored section, and it is determined that an accident has occurred on the distribution line when either of the detected currents exceeds a set value. Or the method for minimizing power outages in an electric power system according to 4. 7. Claim 3, wherein line voltage or phase voltage is detected as the amount of electricity on the distribution line in each monitored section, and when either detected voltage falls below a set value, it is determined that an accident has occurred on the distribution line. Or the method for minimizing power outages in an electric power system according to 4. 8. A power system in which a distribution line connecting a power source and a load is divided into a plurality of monitoring sections, a section switching means for opening and closing the distribution line is provided in each monitoring section, and a main switching means is provided at the power supply side end of the distribution line. , an accident detection means for detecting the occurrence of an accident from the amount of electricity on the distribution line; a direction detection means for detecting from the amount of electricity on the distribution line that the direction in which the accident has occurred is on the load side from the self-monitored section; power interruption detection means for detecting that the supply has been cut off; and opening means for opening the section opening/closing means on the condition that each detection output of the accident detection means, the direction detection means, and the power interruption detection means is generated. and a reinsertion means for reinserting the segmental switching means in an open state in a specified order when the main switching means is reinserted, in each monitored section. conversion device. 9. A power system in which a distribution line connecting a power source and a load is divided into a plurality of monitoring sections, a section switching means for opening and closing the distribution line is provided in each monitoring section, and a main switching means is provided at the power supply side end of the distribution line. , an accident detection means for detecting the occurrence of an accident from the amount of electricity on the distribution line; a direction detection means for detecting from the amount of electricity on the distribution line that the direction in which the accident has occurred is on the load side from the self-monitored section; A power failure detection means for detecting that the supply has been cut off; a release means for opening the sectional opening/closing means based on the detection output of the power failure detection means; , on the condition that a detection output has been generated from the accident detection means and the direction detection means before this re-closing, the sectional opening/closing means are re-closed in accordance with the specified order; otherwise, in accordance with the re-closing of the main opening/closing means. A power outage minimization device for an electric power system, characterized in that a re-input means for re-introducing a section opening/closing means is provided in each monitored section. 10. A power system in which a distribution line connecting a power source and a load is divided into a plurality of monitoring sections, a section switching means for opening and closing the distribution line is provided in each monitoring section, and a main switching means is provided at the power supply side end of the distribution line. , an accident detection means for detecting the occurrence of an accident from the amount of electricity on a distribution line, a power failure detection means for detecting that the supply of power is interrupted, an accident detection means and a power failure detection means. opening means for opening the segmental opening/closing means on the condition that each of the detection outputs is generated, and a reinsertion means for reintroducing the segmental switching means in the open state in a specified order when the main switching means is re-energized. A power system power outage minimization device characterized by being provided in each monitored section. 11. A power system in which a distribution line connecting a power source and a load is divided into a plurality of monitoring sections, a section switching means for opening and closing the distribution line is provided in each monitoring section, and a main switching means is provided at the power supply side end of the distribution line. According to the detection output of the power failure detection means, there is an accident detection means for detecting the occurrence of an accident from the amount of electricity on the distribution line, a power failure detection means for detecting the sudden interruption of the power supply, and a detection output of the power failure detection means. When the opening means for opening the compartment opening/closing means and the main opening/closing means are turned on again, the compartment opening/closing means is restarted in a specified order on the condition that a detection output has been generated from the accident detection means before this reinsertion. A power outage minimization device for an electric power system, characterized in that each monitoring section is provided with a re-closing means for re-closing the sectional switching means in accordance with the re-closing of the main switching means.