JPH0767236B2 - Distribution line protection device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a distribution line protection device, and more specifically, a section including a distribution line accident such as a ground fault accident or a short circuit accident and including the accident point. The present invention relates to a distribution line protection device that separates (accident section) to eliminate a distribution line accident.

[Conventional technology]

Conventionally, a "division switch for automatic detection of a faulty section" has been used to quickly separate a healthy section from an accidental section when an accident occurs on a distribution line (Example: "Electrical Engineering" issued by the Institute of Electrical Engineers, February 1988). Handbook "p. 1264). According to this, after all the division switches have been opened due to the occurrence of an accident, the division switches are automatically re-closed at a preset time interval, and the distribution line of the substation is pulled. When an accident is detected by the protective relay installed at the exit, the circuit breaker at the outlet of the distribution line should be immediately opened, and the circle switch that was re-closed immediately before that should identify the section where the accident occurred. It is the one. This method is generally called a time-limited progressive power supply method.

[Problems to be Solved by the Invention]

Therefore, according to the conventional time-sequential progressive charging / discharging method, although the power distribution to the end of the distribution line is completed, (the number of switches having the time-sequential progressive function) x (progressive time) It will take a minute. As a result, there is a problem that the power outage time becomes longer toward the end. Further, if the power outage time is shortened, there is a limit to the number of switches having the time-sequential forwarding function, and the protection section (blackout section) becomes long.

Further, in the above-mentioned conventional method, when the time of the first accident detection and the time of the accident section detection are combined, there is a problem that the power failure of the sound section occurs twice.

An object of the present invention is to provide a distribution line protection device capable of minimizing a power failure section of a sound section for detecting and disconnecting an accident section of the distribution line.

Another object of the present invention is to provide a distribution line protection device that can shorten the time required for progressive power supply and shorten the power failure time.

[Means for Solving the Problems]

In order to achieve the above object, in the present invention, a switch for opening and closing the first and second distribution lines, and a power detection means for detecting the power state of the first or second distribution line, the first or The second distribution line is characterized in that a disconnecting device for opening the distribution line is connected to the second distribution line after the occurrence of the power abnormality in the distribution line and after the distribution line closing holding period for maintaining the closed state of the distribution line has elapsed. In the distribution line protection device, the first or second distribution line accident state detecting means for detecting an accident state of the distribution line,
The distribution line opening means for opening the switch in response to the signal from the distribution line accident state detection means, and the switch within the distribution line closed holding period after the switch is opened and according to the power detection signal from the power detection means. It is designed to be closed.

Further, in order to achieve another object, in the present invention, a switch that opens and closes the first and second distribution lines, and a power detection unit that detects a power state of the first or second distribution line, To the first or second distribution line, after power is supplied to this distribution line, a disconnecting device that closes the distribution line is connected after the distribution line opening holding period for maintaining the open state of the distribution line has elapsed. In the distribution line protection device characterized by the above, a distribution line accident state detecting means for detecting an accident state of the first or second distribution line, and a switch according to the accident state detection from the distribution line accident state detecting means. After opening the switch, the distribution line opening / closing means for closing this switch, and after the switch is closed by the distribution line opening / closing means, the distribution line accident state detection means does not detect an accident state during the distribution line opening retention period. If the switch is closed It is obtained by the.

Further, in order to achieve another object, in the present invention, in a distribution line protection device, which is connected to another switch through a distribution line to form a switch group, the distribution line protection device is It is provided with the operation function of the transmission switch and the operation function of the switch for connecting points between groups, and these functions can be arbitrarily selected and switched.

[Action]

With this configuration, the object of the present invention is achieved by the following actions.

First, the distribution line protection device is provided with distribution line accident state detection means to open the switch. At this time, the breaker has a fixed time (for example, about 1.5 seconds) even if the voltage on both sides is no power.
Since the closed state is maintained, it is possible to recharge a healthy section at once by closing the distribution line protection device closest to the distribution line to which power is being supplied immediately (for example, within 1 second). Become. Thereby, in case of a recoverable accident, the recovery operation is completed immediately.

In addition, the distribution line protection device is provided with distribution line accident state detection means to open and close the switch, and at this time the breaker maintains the open state of the distribution line for the distribution line open holding period. If a distribution line fault condition is not detected during the line open circuit holding period, the switch is kept closed, so that at least the charging of the distribution section between the breaker and the distribution line protection device can be ensured. become.

In addition, the operation function of the progressive switch to the distribution line protection device,
Since there is an operation function of the switch for connecting points between groups and this function can be arbitrarily selected and switched, for example, the length of the group section of the distribution system can be arbitrarily set according to the situation. As a result, the response can be made uniform when an accident occurs.

〔Example〕

 Hereinafter, the present invention will be described based on examples.

FIG. 1 shows the system configuration of a 6.6 KV distribution line to which the present invention is applied. As shown in the figure, power is supplied from the transformer 1 of the substation to the distribution line 3 via the power bus 2 of 6.6 KV. An outlet breaker FCB having a breaking capability is provided at the substation drawing point of the distribution line 3. Switch DM1 to DM on distribution line 3
6 or distributed appropriately, and accident detection relay R in the middle of these
The cut-off switches PCB ₁ and PCB ₂ having y are arranged to define the distribution sections L _{1 to} L _9, etc.

Transformers FCT, CT ₁ and CT _{2 for} accident detection and accident detection relays FRY and R are used for the outlet breaker FCB and the break switch PCB ₁ and PCB _2.
Y ₁ and RY ₂ are provided respectively. As these transformers, a current transformer, a zero-phase current transformer, or a voltage transformer or a zero-phase voltage transformer is provided as necessary.

Further, the operating time of the short circuit accident detection relay may be variably set in proportion to the line voltage of the distribution line at the installation point of the breaking switch.

Power supply transformers T _{1 to} T ₆ are installed on the power supply side of the switches in the switches DM _{1 to} DM _6, and power supply transformers T ₁₁ and T ₂₁ are also installed in the disconnecting switches PCB ₁ and PCB _2. Has been done.

The switches DM _{1 to} DM ₆ are applied to one side for a time period X (eg 10
After a lapse of seconds), the switch DM is closed, and the circuit is maintained so as to be closed for a fixed time period (about 1.5 seconds) after the voltage disappears.

DMR ₁ to DMR ₆ are switch control devices that control the opening and closing of the switch DM.

Similarly, the interrupting switch control devices CBR ₁ and CBR ₂ open and close the interrupting switch PCB depending on the presence or absence of voltage when the accident detection relays Ry ₁ and Ry ₂ are not operating, similar to the switching device control device DMR. . When the accident detection relays Ry ₁ and Ry ₂ are activated, the break switch PCB is immediately opened, and when one side is under pressure (the power supply side is in a healthy state), the break switch PCB is immediately opened (approximately 1 second). Make a circuit. Furthermore, if the accident detection relay Ry does not operate within the Y time period (for example, 8 seconds ... somewhat shorter than the X time period) after closing the circuit breaker PCB, an accident occurs on the load side of the circuit breaker PCB. It is considered that there is no such thing, so even if the accident detection relay Ry operates again, the blocking switch PCB is locked so as not to open (however, the locking is automatically released after a predetermined time). When the accident detection relay Ry operates again during the Y period, it is determined that there is an accident on the load side, the disconnecting switch PCB is opened, and the next reclosing time is coordinated with the non-voltage release delay time of the disconnecting switch PCB. Is the time limit. Also, when there is no voltage on both sides after opening, the circuit breaker switch PCB is closed after X time has elapsed after voltage application, as in DMR.

The operation of the embodiment configured as described above will be described along with the operation timing chart of each unit shown in FIG.
This figure are those shown in the case of an accident at the point F of the distribution leg L _9, hatched portion at the L ₁ ~L ₉ in Zuzo the voltage application state, a blank portion is a power failure state Indicates.

The switches DM ₁ and DM ₂ not directly related to the description of the present invention are not shown.

Now, assuming that an accident occurs at point F at t ₁ , the accident detection relays FRy, Ry ₁ and Ry ₂ have approximately the same accident current, so
The operation starts almost at the same time. However, by previously timed set as towards the accident detection relay Ry _1, Ry ₂ of each cutoff switch is operated earlier than the accident detection relay FRy of outlets, for example substation, each at t ₂ time Break switch PCB ₁ and PC
The accident detection relays Ry ₁ and Ry _{2 of} B ₂ are activated, and the break switch
An open command is output to PCB ₁ and PCB ₂ almost at the same time, and the interrupting switches PCB ₁ and PCB ₂ are delayed by the open response time t _s and are turned on at time t _3.
Is opened.

At this time t _3, the outlet breaker FCB has not yet been opened, and the accident detection relay FRy at the outlet will be restored when the accident is removed. It does not lead to tripping. As a result, there is no voltage in L _{4 to} L ₉ including the section L ₉ having the accident point. However, since the outlet breaker FCB is not opened, the power failure does not occur in the sections L _{1 to} L ₃ . One feature of the present invention is that there is no power outage in the sections L _{1 to} L ₃ .

The break switches PCB ₁ and PCB ₂ are the accident detection relays Ry ₁ and y ₂
Immediately after opening by the action of, the circuit breaker PCB _1, which is in a pressurized state on one side, is immediately closed (Δt ₁ = approximately 1 second later) from the control device CBR ₁ . Switch DM ₃ at this time
~ DM ₆ is still closed, but the break switch P
It is opened after the no-voltage open delay time Delta] t ₂ (and 1.5 seconds) switches DM ₅ to dm ₆ of non-power side than cutoff switch PCB ₂ for CB ₂ is opened by the detection relay Ry ₂ operation accident . D
Since M ₃ and DM ₄ have Δt ₁ <Δt ₂ , the open circuit state is still maintained, and the sections L _{4 to} L ₆ are energized at the same time as the interruption switch PCB ₁ is turned on.

In this state, since the fault section L ₉ is disconnected, after interrupting switch PCB _1-on accident detection relay Ry ₁ is not a fault detection in Y timed (e.g. 8 seconds), determines that試充electrostatic success To do. After that, even if the accident detection relay Ry ₁ operates for an appropriate time, the trip signal to the break switch PCB ₁ is locked.

The cut-off switch PCB ₂ is closed after X time (for example, 10 seconds) has elapsed after pressurization on one side. As a result, the section L ₇ is energized and the switch DM ₅ is in a one-sided pressurization state, so that the circuit is closed after the X time limit. As a result, the section L ₈ is energized, the switch DM ₆ is closed after the X time period (this is referred to as a progressive energization method), and the section L ₉ is pressurized.

And again, if it is erased accident interval L _9, anyway, will enter into operation, if not removed, as in the second figure, the accident reoccurrence and makes fault detection relay FRy, Ry _1, Ry ₂ Start to work together. However, in this case, as in the case of the first accident, the accident detection relays Ry ₁ and Ry ₂ operate faster than the accident detection relay FRy. Therefore, the outlet breaker FCB does not open until the same reason as described above. Absent. Then, looking at the accident detection relay Ry _1, which is the fact that shut off switch PCB ₁ has passed over reclosing after Y timed (<X timed), as opening command to shut off switch PCB ₁ is not given It is locked. Therefore, the open command to only interrupting switch PCB ₂ is given (time t _8), interrupting switch PCB
After the response time (time ts), interrupting switch PCB ₂ is opened (time point t _9). As described above, according to the present invention, the sections L _{1 to} L ₆ do not have a power failure due to a re-occurrence accident, and only the section L _{4 to} L ₆ initially has a power failure for a short time (about Δt ₁ ≈ 1 second). Just do it.

After the disconnecting switch PCB ₂ is opened, the operation of the progressive power-on / off method in the opening / closing switch DM is started, the X-time after-breaking switch PCB ₂ is closed again, the L ₇ section is pressurized, and the X-time after-break switch DM ₅ closed, it completes its operation and charging in order of L ₈ sections pressurized to L ₈ sections. What happens is that the switch DM ₆ becomes unpressurized within the Y time limit after the circuit closed due to the reoccurrence of the accident, so the subsequent progressive power is locked according to the rules of the progressive power supply system. From
The switch DM ₆ does not close due to the pressurization of the L ₈ section.

The time chart in Fig. 3 shows that after the interrupting switch PCB ₂ recloses and the X time period or more has passed (the time when the switch DM ₅ advances),
And the next again and again closing operation as no accident factor is at reopening the next section L ₇ interval interruption switch PCB ₂ faster than X timed, the time switch is no voltage open (Delta] t ₃ ≒ e.g. 2 seconds)
Is shown.

According to this, since the switches DM ₅ and DM ₆ after the interrupting switch PCB ₂ are once opened at Δt ₂ (<Δt ₃ ), the interrupting switch PC
Even if B ₂ is reclosed at high speed, the subsequent operation time chart of the progressive power-supply method using the switch DM shows that it is performed at the same time, and that length, sections L ₇ and L ₈ will recover faster. Shows.

Fig. 4 shows the switch DM for shortening the X time limit during re-closing operation.
It is also applied to the circuit breaker PCB at time t ₁₀ ′.
_{After 2} is closed, switch DM ₅ is Δt ₄ (for example, 1 second), and in this case, interrupting switch PCB ₂ has Δt ₃ > Δt ₂ and switch DM ₆
Is closed, so it is closed immediately. In this way, in FIG. 2, it takes 20 seconds (when X = 10 seconds) from time t ₉ for the section L ₈ to recover power.
It is 12 seconds, and in the method of Fig. 4, it is greatly shortened to 3 seconds, showing that the practical effect is extremely large.

Fig. 5 shows the time chart when the accident in section L ₉ is recoverable and does not reoccur when the break switch PCB ₁ is opened. Conventionally, in such a case, it is opened by the outlet breaker FCB of the substation,
Although L ₉ section for sequentially voltage application all the region after reclosing the X timed chronic had took 80 seconds + FCB reclosing time to complete voltage application, it suffices only 31 seconds according to the present method Becomes (X =
When 10 seconds. ) Fig. 6 is a time chart when a permanent accident occurs in the section L ₆ between the break switch PCB ₁ and the break switch PCB ₂ and the reclosed time of the break switch PCB ₁ is the same as in Fig. 3. Similarly, it shows the case of shortening to Δt ₃ .

Fig. 7 shows a switchgear similar to Fig. 4 in the event of an accident similar to Fig. 6.
The DM also shows the case where the closing time is shortened again. Figure 8 is eventually switches DM ₃ ~ switchgear DM ₆ at a time chart when an accident of the section L ₆ is instantaneously removed by the recovery sub connexion without being opened, the interval L ₄ ~L ₉ Also, a one second power failure will suffice.

The present invention relates to a progressive power supply system that has been widely used in the past, and the existing switch DM equipment based on the progressive system is used as it is, and accident detection equipment (accident detection relay Ry +
It aims to reduce the power failure time and its range as much as possible by providing a break switch PCB having a break switch controller CBR). Therefore, the content of the control method for the circuit breaker PCB should be taken into consideration when installing a new device, for example, as shown in Fig. 2,
FIGS. 3, 5, 6, and 8 show a method that can be carried out with a length in which a new interrupting switch PCB is newly inserted while leaving the existing switch DM as it is.

The method of shortening the X time limit when the switch DM is reclosed in FIGS. 4 and 7 requires improvement of the switch control device DMR (control part of the switch DM). Of course, it is obvious that the existing switches and switch groups can be implemented even if they are modified according to the present invention.

Further, in the conventional switch DM system, the number of switch DMs has a limit because the repeated control for a long time is required until the accident section is separated when the number is large, but the present invention has been described above. Since the switch DM group is divided into several groups and the break switch PCBs are provided at the connection points of these groups, the control for the fault section determination as a whole is greatly shortened compared to the conventional method. It will be a thing.

Although the embodiment of the present invention has been described with reference to the system of FIG. 1, as is apparent from the above description, the interrupting switch PCBs are arbitrarily inserted in the scattered switch DMs and the interrupting switch within 2 lines in series from the power source end. It is only necessary to arrange so that the container PCB is inserted.

Fig. 9 shows a circuit breaker PCB at the branch point of one feeder
In the application example that shows the case where the
The individual break switch PCBs are connected in series, and the same operation as in the case of Fig. 1 is expected in any accident section. Also, even if two or more disconnecting switch PCBs are installed in series, if they can be operated in the same way as other switch DMs, they can be arbitrarily switched (two in series). Good things are obvious. In particular, the distribution line has an extension pipe or the like for accommodating the load and the like, and this has a great effect.

Next, in the above-mentioned embodiment, the breaking switch PCB does not have to be a circuit breaker for breaking a short-circuit current, but may be a switch having a desired operation responsibility when only a ground fault is targeted. The following is a case in which only the ground fault accident is targeted and the case of the circuit breaker system that also targets short circuit.
Detailed description will be given of each of the breaker switch parts such as B, the breaker switch controller CBR, and the accident detection relay Ry. A specific configuration of the device when the above embodiment is applied to a ground fault accident protection relay device will be described below.

FIG. 10 shows the overall structure around a pole break switch according to an embodiment of the present invention. In the figure the break switch PCB
When the closing coil CC is excited by the pole break switch, the main contact 11 (11a, 11b, 11c) is closed against the spring 12 and the stopper 14 is hooked on the hook 13 to maintain the closed state. I'm running. On the other hand, when the opening coil TC is excited, the stopper 14 is disengaged and the main contact 11 is pulled back by the spring 12 to open.

The contact 15 is an auxiliary contact that opens and closes with the main contact. Tr is a power supply transformer for control, which is connected to the A-side distribution lines A1 and A3 of the cut-off switch and the cut-off switch PCB from the distribution potential of 6.6KV.
It has a 100V control power supply. REC is a rectifying device that supplies control power to the control device CONT, the closing coil CC, and the opening coil TC. Voltage transformer PD inserted between distribution line and ground
Obtains the zero-phase voltage Vo of the distribution system by dividing the voltage on the capacitor.

ZCT is a zero-phase current transformer that extracts the zero-phase current Io flowing in the distribution line. The outputs Vo and Io of the voltage transformer PD and the zero-phase transformer ZCT are guided to the control device CONT, where they are used to determine the presence / absence of a ground fault. CX and TX are auxiliary relays for closing and opening command output of the breaking switch PCB, and the breaking switch is controlled to open and close by the respective contacts CX-1 and TX-a.

Fig. 11 shows a functional block diagram of the control unit CONT. In Fig. 11, the ground fault direction relay DG with Vo and Io as inputs operates in the direction where the ground fault occurred on the distribution line is on the side opposite to the power source side than ZCT, and not on the power source side. It is a ground fault accident detection relay that has characteristics. The cooperation timer TL outputs an operation signal after the settling time T after the DG operates.

LOC and 1NH ₁ do not have the ability of the switch to block excessive current, and when the fault current exceeds a certain level, FCB at the substation exit
Although not shown in Fig. 10, it is attached to the circuit breaker switch PCB, which is a necessary part when the disconnection is given, and I is used as a sensor for the current transformer that transforms the current flowing through it. It outputs an output signal when the magnitude of the current exceeds a certain value, and locks the operation signal from the DG relay with 1NH ₁ . In this case, the substation's FCB operation will be entrusted.

To judge whether or not the break switch PCB should be opened, the open command TX is output to the TX relay for opening the break switch PCB via 1NHz on condition that there is no lock signal LOCK from the GEQ section. As a result, when the circuit breaker PCB opens, auxiliary contact 1
5 opens.

Also, in the embodiment of FIG. 10, only PD, ZCT, and
Although the PT is provided, it may be provided on the B side or both sides. Also, a DG relay with directional characteristics was used as the ground fault detection relay, but it is only
OCG relay operating at I ₁ size (ground fault overcurrent relay)
But it's okay. In addition, when the power supply end side viewed from the break switch PCB is either A side or B side (that is, when power is transmitted from the adjacent power supply to the section beyond the accident point), the ground fault direction relays are respectively It should be provided for the direction of.
Therefore, the application of the present invention can be applied to a switch having a large breaking capacity as it is even for a progress accident from a ground fault accident to a short-circuit accident, and the power outage time can be greatly shortened.

In the above examples, only the ground fault accident was explained,
It can be applied to a short circuit accident as it is. Next, the case where a circuit breaker capable of breaking short circuit current is applied to the circuit breaker PCB will be described below.

FIG. 12 is a diagram showing an overall configuration around a pole breaker to which this embodiment is applied. FIG. 10 has substantially the same configuration as that of the embodiment, except that a short-circuit accident detection is provided side by side, and a transformer CT for line current detection is installed. Further, the control unit CONT 'has a configuration different from that of FIG. 10, and its detailed block diagram is shown in FIG.

As shown in FIG. 13, the line current I detected by the transformer CT is input to the overcurrent relay OC. This overcurrent relay OC
Is designed to output an operation signal when the line current has a value larger than a preset current value. TL
R is a variable timer whose time limit changes according to the magnitude of voltage V. When an operating signal from an overcurrent relay is input, it is instantaneous when voltage V is zero volt, and proportional to it when voltage V is large. The output signal has a delay time.

Further, the accident detection relay including the overcurrent relay OC and the variable timer TLR may be a relay having the following operational characteristics as a whole.

That is, the line current and voltage V are input, and the impedance May be an impedance relay in which the output time limit of the operation signal is variable depending on the magnitude of the value.

This is focused on the fact that the distribution line becomes thinner as it goes to the end. If a short-circuit accident occurs at the end far from the substation, the voltage at the accident point will drop to almost 0 volt. , The voltage increases as it approaches the substation. However, since the magnitude of the fault current is the same, each breaking switch
If the relay operating time at the PCB installation point is changed in proportion to the residual voltage, the relay closer to the accident point will operate faster.

The impedance relay ZRy attempts to vary the operation time in proportion to the impedance from the relay installation point to the accident point.

The operation signal of the impedance relay ZRy is adapted to immediately output an opening command via an OR gate which takes the logical sum of the operation signal of the impedance relay ZRy and the operation signal of the ground fault direction relay DG. 1NH is the P
The SEQ section determines whether or not the CB should be released, and outputs the release command TX on condition that there is no lock signal LOCK.

In the above description, it is assumed that no more than two circuit breaker PCBs are provided in series from the power supply side, but the following consideration may be taken even if the number of circuit breaker PCBs is three or more. That is, if the operation time of the accident detection relay is gradually shortened as the non-power source end is approached to the power source end, the cut-off switch PCB closest to the accident point opens first, but the chasing switch closes to the accident point second Container pcb
It may or may not be opened.

According to the present invention, even if two chasing switch PCBs are opened in series if chasing after the second switch described in the system diagram of FIG.
It is clear that the same operation as in FIGS. 8 to 8 is performed and three or more units may be arranged in series.

〔The invention's effect〕

As described above, according to the present invention, the switch DM having the protection relay element is installed on the way while leaving the switch DM by the existing time-sequential power-supplying system as it is, so that the section from the power source side to the power source side when the accident occurs In addition to minimizing power outages in sections, it has the effect of requiring only a very short power outage over the entire system in the event of a recoverable instantaneous accident.

Another major feature is that the effect can be exhibited without providing any communication means such as a pilot wire.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a distribution line device of an embodiment to which the present invention is applied, FIGS. 2 to 8 are time charts showing the operation of the present invention, and FIG. 9 is an application of the present invention. The other execution system diagram is shown. 10 to 13 show a concrete configuration of the control device. L _{1 to} L ₉ …… Distribution section, FCB …… Outlet and breaker, PCB ₁ , PC
B ₂ ...... Breaking switch, CBR ...... Control device for breaking switch, Ry ₁ , Ry ₂ ...... Accident detection relay.

Claims (7)

[Claims] 1. A switch for opening and closing first and second distribution lines,
And a power detection means for detecting the power state of the first or second distribution line, the closed state of the distribution line in the first or second distribution line after the occurrence of power abnormality of the distribution line. In a distribution line protection device, which is characterized in that a breaker for opening the distribution line is connected after a maintenance period for maintaining the distribution line closed, a fault condition of the first or second distribution line is detected. Distribution line accident state detection means, distribution line circuit means for opening the switch according to an accident signal from the distribution line accident state detection means, and power detection from the power detection means after the switch is opened. A distribution line protection device, characterized in that the switch is closed within the distribution line closing holding period according to a signal. 2. The distribution line protection device according to claim 1,
A disconnecting device that closes the distribution line is supplied to the first or second distribution line after the power is supplied to the distribution line, and after a distribution line opening holding period for maintaining the open state of the distribution line has elapsed. The distribution line, which is connected, maintains the circuit closed state of the switch when the distribution line accident state detection means does not detect an accident state during the distribution line open circuit holding period after the switch is closed. Protective device. 3. The distribution line protection device according to claim 2,
A distribution line protection device, characterized in that, when the distribution line accident state detecting means detects an accident state during the distribution line open circuit holding period, the switch is closed after the distribution line circuit closing holding period has elapsed. 4. The distribution line protection device according to claim 2,
A distribution line protection device, which maintains the closed state even when an accident state is detected by the distribution line accident state detection means after the passage of the distribution line open circuit holding period. 5. The distribution line protection device according to claim 1,
A distribution line protection device which closes the switch when electric power is not supplied to the first or second distribution line after a specific period has elapsed. 6. A switch for opening and closing the first and second distribution lines,
An electric power detection means for detecting the electric power state of the first or second distribution line, and after the electric power is supplied to the first or second distribution line, the open state of the distribution line In a distribution line protection device, a disconnecting device that closes the distribution line is connected after the distribution line opening holding period for maintaining the above is detected, and an accident state of the first or second distribution line is detected. The distribution line accident state detecting means, the distribution line opening / closing means for closing the switch after the switch is opened in response to the accident state detection from the distribution line accident state detecting means, and the distribution line opening / closing means. After the switch has been closed, during the holding period of the distribution line opening, the closed state of the switch is maintained when the distribution line accident state detecting means does not detect an accident state. apparatus. 7. A distribution line protection device, which is connected to another switch via a distribution line to form a switch group, wherein the distribution line protection device has an operation function of a progressive switch. A distribution line protection device having an operation function of a switch for connecting points between groups and capable of arbitrarily selecting and switching the function.