JP3156999B2 - Distribution line protection system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distribution line protection system suitable for protection and recovery in the event of an accident in a distribution line drawn from a distribution substation bus.

[Related Art] When an accident such as a short circuit or a ground fault occurs in a distribution line, conventionally, an accident section is detected and separated by a reclosing timed progressive system. This will be described below with reference to FIG.

 FIG. 2 shows the configuration of a conventional distribution line.

In the figure, 1 is a bus of a distribution substation, 2 is one of a plurality of distribution lines drawn out from the bus, 31 is a disconnecting device installed at a distribution line outlet at the distribution substation, and 41 to 45 are a plurality of sections of the distribution line. , A reference numeral 52 denotes a normally open connection point switch installed at a connection point with another distribution line, and 61 denotes a protection relay device installed at a distribution substation.

The protective relay 61 detects a ground fault of the distribution line 2 from the zero-phase voltage of the substation bus 1 and the zero-phase current of the distribution line 2 and trips the circuit breaker 31. It consists of an overcurrent relay that trips the breaker 31 by detecting a short circuit accident of the distribution line 2 from the line current. The shutoff device 31 has a reclosing and reclosing control device.

Although not shown in FIG. 2, the automatic assembly switches 41 to
The switch 45 and the interconnection point switch 52 have a device that detects distribution line voltage and controls switching.

Next, a method of detecting and separating an accident section by a conventional reclosing time-sequential forwarding method will be described. As an example, it is assumed that a ground fault has occurred in a section between the automatic segment switches 42 and 43 as shown in FIG.

(1) The protective relay 61 of the distribution substation detects a ground fault in the distribution line 2 and opens the cutoff device 31 after a predetermined time has elapsed.

(2) When the shut-off device 31 is opened, the automatic section switches 41-
Since no voltage is applied to the switch 45, it is automatically released after a predetermined no-voltage release time limit.

(3) The shut-off device 31 is opened for a predetermined time (about 1 minute)
Reclose later.

(4) When the shutoff device 31 is reclosed, a voltage is applied to the automatic section switch 41. The automatic section switch 41 is automatically turned on after a predetermined closing time (X time, about 9 seconds) elapses after the voltage is applied. When the automatic section switch 41 is turned on, a voltage is applied to the automatic section switch 42, so that the switch is automatically turned on in the same manner as described above. In this way, time-sequential forwarding proceeds.

(5) When the automatic section switch 42 is turned on, if no accident remains, the reclosing is successful, the time-sequential forwarding is continued, and the recovery is completed. If an accident remains, the protection relay device 61 of the substation detects the accident again, opens the shutoff device 31, and fails to reclose.

(6) When the shut-off device 31 is opened, the automatic sorting switches 41, 42
Is automatically released again after a predetermined no-voltage release time limit. At this time, the automatic sorting switch 42
With regard to, since there is no voltage during a predetermined detection time period (Y time period, about 6 seconds) after being turned on, it has a function of detecting contact with an accident point and holding the state after opening.

(7) The breaking device 31 is opened and closed again after a predetermined time period. Thereafter, the automatic sorting switch 41 is turned on by timed sequential feeding, but the automatic sorting switch 42 remains open even if a voltage is applied, and is not turned on.

With the above procedure, the detection and separation of the fault section on the upper side which is the power supply side from the fault point is completed, and the power failure in the healthy section is restored.

On the other hand, the lower section, which is on the load side from the accident point, is still out of power, so after the restoration of the upper healthy section by time-sequential forwarding as described above, other power distribution via the interconnection point switch 52 is performed. Electricity will be received from the track.

The outline of the conventional method for restoration below the accident point is shown below.

(1) The switch 52 for the interconnection point is automatically turned on manually or by remote control. In the case of timed automatic closing, the switchgear 52 for the interconnection point
The time limit is set in advance so as to be turned on after a sufficient time required for the recovery of the upper side from the fault point due to the reclosing time-sequential feeding has been detected after detecting that the one-sided no-voltage has been reached.

(2) When the interconnection point switch 52 is turned on, a voltage is applied to the automatic segment switch 45, so that the switch is turned on after a predetermined turn-on time. Recover.

(3) In the case where the automatic segment switches 41 to 45 also have a time-return function similar to the time sequential function, when the interconnection point switch 52 is turned on, a voltage is applied to the automatic segment switch 44. , After a predetermined time limit.

(4) When the automatic segment switch 44 is turned on, a voltage is applied to the automatic segment switch 43, but it is not turned on because it is in contact with the accident point. The method is, for example, when the automatic segment switch 42 is turned on at the time of re-closing timed forward on the upper side of the accident point, the automatic segment switch 43 changes from a no-voltage state to a one-side voltage state, Since the substation shut-off device 31 is opened before the time limit elapses and the substation shutoff device 31 is opened, a voltage-free state is established again. From this, it is determined that the vehicle is in contact with the accident point, and the open state is maintained.

[Problem to be Solved by the Invention] The above-described conventional technology has the following problems.

(1) A healthy section higher than the accident point
Power failure and recovery takes time.

(2) The power outage time of a healthy section below the accident point is long, and it takes time to recover.

(3) If a power failure occurs due to a higher power supply system during timed sequential transmission, the same situation as when the automatic segment switch is in contact with the accident point may occur, and the automatic segment switch becomes unnecessary. Maintaining the open state increases power outage time and range.
For example, there are the following cases.

(I) If voltage is applied to the automatic segment switch during the time-sequential transmission and then a power failure occurs during a predetermined closing time (X period), the automatic segment switch will be on the lower side of the accident point and They mistakenly recognize that they are in contact with a point and keep the open state.

(Ii) If the power is interrupted during the predetermined detection time period (Y time period) after the automatic section switch is turned on during the time-sequential forwarding, the automatic section switch will be on the upper side of the accident point and touch the accident point. The lock is locked after opening.

On the other hand, in order to solve the problem (1), a breaker and a ground fault directional relay are installed at a plurality of points on the distribution line, and when the ground fault directional relay detects a ground fault, the operation of the upper ground fault directional relay is prohibited. A method has been proposed in which a signal is transmitted to open only the shutoff device closest to the accident point (Japanese Patent Application No. 58-139629). However, this method has a problem that if the shut-off device cannot be opened for any reason, there is a concern that an accident may spread and spread due to a delay in the protection operation.

A first object of the present invention is to enable uninterrupted power supply in a sound section higher than the accident point and, when the opening operation of the shutoff device is disabled, open the upper cutoff device to prevent the protection operation. An object of the present invention is to provide a distribution line protection system capable of improving reliability and minimizing a power failure range.

A second object of the present invention is to accurately determine an accident section, to keep the upper and lower section switchgears or breakers of the accident section open, and to determine the cause of the higher power system side. It is an object of the present invention to provide a distribution line protection system that does not needlessly maintain the sectional switchgear and the shutoff device even in the event of a power outage due to power failure.

A third object of the present invention is to provide a distribution line protection system capable of properly controlling a plurality of interconnection point switches to restore a healthy section on the load side from an accident point in a short time. Is to do.

Means for Solving the Problems In order to achieve the above object, the present invention relates to the above-described conventional substation shutoff device, automatic section switch, interconnection point switch, and substation protection relay device. In addition to the above, install breakers, protection relays, signal control devices, and signal transmission paths between adjacent signal control devices at multiple locations on distribution lines, and detect accidents between adjacent protection relay devices. Information is transmitted and received via a signal control device and a signal transmission path.

That is, in order to achieve the first object, the present invention is installed at one or more segmented switches for dividing a distribution line into a plurality of sections, and at a connection point between the distribution line and another distribution line. With respect to a distribution line having a switch for interconnection point, distribution line breakers are installed at a plurality of locations on the distribution line, and the occurrence of an accident in the distribution line is determined based on the voltage and current of the distribution line to open and close the breaker. A protective relay for controlling the
A signal control device for transmitting and receiving a signal between the protection relay device and an adjacent protection relay device, and a signal transmission line for transmitting a signal between the adjacent signal control devices; A trip timer capable of extending the time of the protection relay during operation, a means for activating the trip timer when an accident is detected, and receiving accident detection information from a lower side via the signal control device. Means for setting a time extension of the trip timer.

Further, the present invention provides the distribution line, in which a plurality of distribution line interruption devices are installed at a plurality of positions of the distribution line, and the protection relay device is provided for each interruption device, and the divided switch and the protection interconnection are provided. For each of the electrical devices, a signal control device for transmitting and receiving a signal between an adjacent protective relay device or a section switch is provided, and a signal transmission path for transmitting a signal between adjacent signal control devices is provided. It can be provided and configured.

In order to achieve the second object, in the present invention, at least one of the segmented switches and the breaker detects that a voltage application state of a distribution line has changed in a shorter time than a predetermined time limit. Means, and on condition that the corresponding signal control device has received an accident detection signal from a higher-order side, it is detected from the detection result that it is in contact with the accident point, and the open state is maintained. It is preferable to provide a setting unit.

In the present invention, the signal control device receives an accident detection signal from a lower signal control device, and outputs a signal for setting a time extension of a trip timer to a corresponding protection relay device; And a means for transmitting the detected fault detection signal and the fault detection signal from the corresponding protection relay device to a higher-level signal control device on the power supply side.

Further, in the present invention, when the signal control device receives the accident detection signal from the upper side, if it has already received the accident detection signal from the lower side, it ignores this, and from the lower side, Means for transmitting the accident detection signal from the upper side to the lower side when no accident detection signal is received, means for storing the accident detection signal from the upper side, and detection of an accident from the lower side. It is preferable that the apparatus further comprises means for preventing the storage when a signal has already been received, and canceling the storage when the signal has been received after the storage.

Further, in order to achieve the third object, according to the present invention, a signal control device having a function of receiving at least an accident detection signal from an adjacent signal control device corresponding to the interconnection point switch is provided by the adjacent control device. A signal transmission path for transmitting signals between the signal control devices to be provided, and the switch for interconnection point is changed from an open state in which voltage is applied to both sides to a state of one-side voltage, and the signal control device is It is preferable to provide a means for activating a closing timer of the connection point switch when the accident detection signal is received.

The interconnecting point switch is preferably a single-sided voltage while the step-up timer is in progress, the two-sided voltage is maintained for a shorter time than a predetermined time limit, and when the single-sided voltage is reached again, the connection timer is turned on. Means are provided for stopping the stepping and holding the interconnection point switch in an open state.

[Operation] The operation of each device described above will be described below.

Opening and closing devices installed at multiple points in the distribution line are controlled by the protective relays, as well as the re-closing and re-closing functions similar to those of conventional substations, and the same as those of conventional automatic section switches. It has a no-voltage release function and a timed sequential forwarding function. Also, a timed reverse transmission function can be added.

As with the conventional protective relays installed in the above-mentioned substations, the protective relay installed for each circuit breaker of the distribution line detects the voltage and current of the distribution line and detects a ground fault in the distribution line. The direction of the fault or the direction of the short-circuit fault is determined, and when it is determined that there is a fault on the lower side, a trip timer of the shut-off device for outputting a trip command of the shut-off device is activated after a predetermined time period. Further, an accident detection signal is transmitted to an upper side or both an upper side and a lower side via a signal control device and a signal transmission path.

Each protective relay is either in contact with the fault point or higher than the fault point, depending on its own fault detection status and the fault detection status of the adjacent protective relay obtained as described above. Side, or lower than the accident point. From the determination result, for example, the following control can be performed.

(1) The time limit of the shut-off device trip timer is set longer on the upper side of the accident point. As a result, a healthy section higher than the accident point can be uninterrupted, and the reliability of the protection operation can be improved.

(2) Keep the shut-off devices or automatic section switches on the upper and lower sides of the accident point in contact with the accident point in an open state. As a result, even in the event of a power failure due to a higher-level power supply system, the shut-off device and the automatic section switch can be prevented from being kept unnecessarily open.

(3) The closing timer of the interconnecting point switch lower than the fault point is appropriately set, and the closing timer is started. Thus, a healthy section on the load side from the accident point can be restored in a short time.

Embodiment An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, reference numeral 1 denotes a bus of a distribution substation, reference numeral 2 denotes one of a plurality of distribution lines extending from the bus, and reference numeral 31 denotes a shutoff device installed at a distribution line extraction point in the distribution substation.

Further, 32 to 35 are shut-off devices arranged at a plurality of locations on the distribution line, 41 to 45 are automatic segment switches for dividing the distribution line, 51
Reference numerals 53 denote normally open interconnection point switches installed at interconnection points with other power generation lines.

Reference numeral 61 denotes a protective relay device installed in the distribution substation, and 62 to 65 denote protective relay devices for each of the interrupting devices arranged at the plurality of locations.

71 to 75 are signal control devices for transmitting and receiving accident detection information by the respective protective relays, and 81 to 88 are installed for the automatic section switches 41 to 45 and interconnecting point switches 51 to 53, respectively. It is a signal control device.

 9 is a signal transmission path between adjacent signal control devices.

The distribution line to which the present embodiment is applied is, for example, from 66 kV.
It is connected to the bus 1 of the distribution substation that drops down to 6.6 kV, and as described above, the shutoff device 31 and the protection relay device 61
And the signal control device 71 is installed in a distribution substation.

Also, the protection relay devices 62 to 65 and the signal control devices 72 to 75
Each of the blocking devices 32 to 35 constitutes a group, such as the blocking device 32, the protection relay device 62, and the signal control device 72.

Similarly, each of the automatic sorting switches 41 to 45 also forms a group with the corresponding signal control device 81 to 85.

Similarly, each of the interconnection point switches 51, 52, 53 also forms a group with the corresponding signal control device 86, 87, 88.

These groups, for example, the division of these devices in the units of the shutoff device 32, the protection relay device 62, and the signal control device 72 are for convenience only as long as the function of each of these devices is exhibited. Therefore, the present invention is not limited to the name, division, and the like of the device. For example, as described below,
It is also conceivable to combine devices having similar signal levels into one device.

Further, the signal control devices 71 to 75, 81 to 85, and 86 to 88
Are connected by the signal transmission line 9 to construct an accident information transfer system. In this system, basically, a signal is serially transferred from an accident detection point to an upper side and a lower side. In addition, the signal is transferred via each signal control device 9.

It is preferable to install these communication control devices for all of the shutoff device, the automatic section switch, and the switch for interconnection point as in the present embodiment, but some of them may be omitted.

The configuration of FIG. 1 differs from that of FIG. 2 described as a conventional example in that, in addition to the conventional devices, a shutoff device and a protection relay device are installed at a plurality of locations, a signal control device and a signal control device. The installation of a transmission line, the presence of a plurality of normally connected points with other distribution lines, the installation of a signal control device also in the automatic section switch and the switch for the connection point, and the like.

Next, the operation of the distribution line protection system of the present embodiment will be described.

For specific examples of the shutoff device, the protective relay device, the signal control device, the automatic section switch and the switch for interconnection point,
It will be described later.

In Fig. 1, it is assumed that a ground fault occurs in the section between the automatic segment switches 42 and 43. First, it is explained that most of the upper healthy section on the power supply side from the accident point can be uninterrupted. I do.

FIG. 3 shows an accident detection situation of each protection relay device, an operation situation of each breaker and a switch, and an energization situation of each distribution line section.

(1) Protective relays 61, 62 and 6 above the accident point
3 detects an accident of the lower side from the voltage and current of the distribution line, activates the blocking device trip timer for outputting a trip command of the relevant shut-off device 31, 32 and 33 after a predetermined time period (time period T _1). Further, an accident detection signal is transmitted to the upper side through each signal control device 71, 72, 73 and the signal transmission line 9.

(2) Each time the signal control devices 71, 72 and 81 receive the accident detection signal from the lower side, they take over the signal and transmit the accident detection signal to the upper side. The protective relays 61 and 62 that are detecting the accident are signal controllers 71 and 72.
There each time it receives the fault detection signal from the lower side, timed the predetermined time period of the shut-off device trip timer, for example, extend T ₁ TU. Thus, for example, trip timer timed shutoff device 33,32,31 is a T _1, 2T _1, 3T ₁ respectively.

(3) Since the signal control device 73 does not receive the accident detection signal from the lower side, the trip timer for the shutoff device 33 expires earliest and the shutoff device 33 is opened.
When the shut-off device 33 opens, the protective relay devices 61 and 62
Since no accident is detected, the stop of the tripping timer of the shutoff device is stopped, and the time limit of the timer is restored.
For some reason, if the shutoff device 33 is not opened, the trip timer interrupt device 32 of the trip timer timed 2T ₁ becomes expired, shut-off device 32 is opened. If the shut-off device 32 was not opened, the trip timer timed out 3T ₁
Will be opened.

(4) When the shut-off device 33 is opened, which from the lower blocking device 34, 35 and the automatic sectionalizing switches 42-45 since the no-voltage, the predetermined voltage-free opening time period (T ₂ units of instruction) is opened after .

(5) After the first opening, the shut-off device 33 operates for a predetermined time (T ₃
Reclose after the expiration of the time limit.

(6) Each of the automatic segment switches 42 to 45 and the shut-off devices 34 and 35 is turned on after a predetermined turn-on time (X time-out) has been applied by applying a voltage. As a result, the blackout sections are sequentially restored.

(7) If an accident remains during the re-closing timed sequential operation, the accident will occur again when the automatic section switch 42 is turned on, so that the shut-off devices 33 and The automatic section switch 42 is opened for the second time.

(8) Since the automatic segment switch 42 is closed during the predetermined detection time period (Y time period) after being turned on in the reclosing time period sequential feeding, it is determined that it is in contact with the accident point, and the open state is maintained. I do.

(9) After the second opening, the shut-off device 33 operates for a predetermined time (T ₄
After the expiration of the period, the circuit is closed again. The automatic section switch 42 maintains the open state even when a voltage is applied.

Thus, the operation of restoring the healthy section higher than the accident point is completed.

As a result, the section higher than the shutoff device 33 is uninterrupted. The section between the shut-off device 33 and the automatic section switch 42 is
Although there is a power outage twice, the power outage time is greatly reduced as compared with the conventional method of re-closing and re-closing by the above-described substation shutoff device 31. Further, even in the event that the shut-off device cannot operate, sufficient backup can be performed by the higher-order shut-off device. Each protective relay has a longest time limit of the tripping device trip timer, and even when extending the time limit of the timer, by not exceeding this longest time limit, the tripping of the tripping device is delayed more than necessary. Can be prevented.

In FIG. 1, when an accident occurs in a section between the shutoff device 33 and the automatic section switch 42, the accident occurs again when the shutoff device 33 is closed again. In such a case, the shut-off device
After re-closing 33, during the predetermined detection time limit, the protective relay 63 detects the accident again and opens the shut-off device 33, so it is determined that the contact point is in contact with the accident point, and the open state is maintained thereafter. And do not re-close.

On the other hand, as is clear from the above description, the signal transmission amount at the time of the accident is only a result of the judgment of the accident state by the protective relay, and is small. Since necessary information can be transmitted, not only a communication path dedicated to signal transmission but also a distribution line itself can be used as a signal transmission path.

Further, since the transmission amount is small, transmission and reception of all signals can be completed before an accident occurs and the shut-off device 33 is opened. Therefore, since the voltage of the distribution line can be used as a power supply for transmitting and receiving signals, the signal control device and the like do not require a special power supply device.

Next, referring to FIG. 1, a description will be given of how the shutoff device and the automatic segment switch can be kept from being unnecessarily held open even in the event of a power failure due to a higher power supply system. Similarly to the above, it is assumed that an accident occurs in a section between the automatic segment switches 42 and 43.

(1) The protective relay devices 61, 62, 63 that have detected the accident activate the trip timers for the corresponding shutoff devices 31, 32, 33, respectively, and the signal control devices 71, 72, 73, and the signals, respectively. An accident detection signal is transmitted to the lower side as well as the upper side via the transmission line 9.

(2) When each signal control device receives an accident detection signal from the lower side and receives an accident detection signal from the upper side, it is provided with a function of ignoring the signal. , 73, 81 and 82 ignore the accident detection signal from the upper side even if they are received. The function will be described later.

(3) When the signal control device does not receive the accident detection signal from the lower side and receives the accident detection signal from the upper side, the signal control device takes over the accident detection signal and transmits the accident detection signal to the lower side, and The fact that this signal has been received is stored. However, after that, when the accident detection signal is received from the lower side, the storage of the reception of the accident detection signal from the upper side is canceled. As a result, the signal control devices 82, 83, 74, etc., which are on the lower side of the shut-off device 33 on the upper side of the accident point and closest to the accident point, memorize the fact that the accident detection signal from the upper side has been received.

(4) According to the procedure described above, the opening and re-closing of the shut-off device 33, the second opening, and the re-closing are performed. After the automatic section switch 42 is turned on in the reclosing cycle time-sequential feeding, a predetermined detection time period (Y
No voltage during the time period) and the signal control device 82
Has stored the fact that it has received the fault detection signal from the upper side, it is determined that it is in contact with the fault point, and after the no-voltage release, the open state is maintained.

(5) The automatic segment switch 43 is turned on and the voltage is applied by the automatic closing switch 42 in the reclosing time-sequential order, and becomes a voltage-free state during a predetermined closing time (X period); and Since the signal control device 83 stores that the accident detection signal has been received from the upper side, it is determined that the vehicle is in contact with the accident point, and the open state is maintained.

As described above, the open / hold operation of the automatic segment switch in contact with the fault points on the upper side and the lower side of the fault point is completed.
The release of the open state of the automatic section switch is released manually or by a command from a central control unit (not shown) via a signal control unit.

According to the above method, the open holding of the automatic segment switch is
It is necessary to memorize the reception of the accident detection signal from the upper side, so even in the event of a power failure or retransmission due to the cause of the upper power supply system, the automatic segment switch is kept open unnecessarily. Never do.

The open-holding operation described above with the automatic segment switch as an example is exactly the same even when the protective joint device is a shut-off device in which no accident is detected. Depending on the capacitance to the ground of the distribution line and the situation of the accident, the protection relay device may not detect the accident even if it is installed on the higher side than the accident point. Protective relays below the fault point do not normally detect the fault.

Next, referring to FIG. 1, a description will be given of a method of appropriately controlling the plurality of interconnection point switches to restore a healthy section on the load side from the accident point in a short time.

Similarly to the above, it is assumed that an accident occurs in a section between the automatic segment switches 42 and 43. FIG. 4 shows the operation status of each breaker and switch and the current distribution status of each distribution line section below the accident point.

(1) According to the above-described procedure, the protection relay device 63 that has detected an accident transmits an accident detection signal to the lower side via the signal control device 73. This signal is sent to the signal control devices 8 for the switches 51, 52, 53 for connection points via the signal control devices 82, 83, 74, etc.
Reach 6,87,88.

(2) The signal control devices 86, 87, and 88 of the interconnection point switch receiving the accident detection signal memorize the reception of this signal.

(3) According to the above-described procedure, the opening and re-closing of the shut-off device 33, the second opening, and the re-closing are performed. Interconnection point switches 51, 52, 53, on the condition that the signal control device stores that the accident detection signal has been received when the shut-off device 33 is opened and the voltage on one side becomes zero. Activate an input timer for inputting after a predetermined time period. The time limit of the closing timer is set not to be shorter than the time limit for completing the open-holding operation of the automatic segment switches 42 and 43 that are in contact with the accident point described above,
It is set in advance for each interconnection point switch in consideration of the input priority.

(4) When the automatic segment switch 42 is turned on by the reclosing time period sequential feeding, the switch 51 for the interconnection point has a voltage on both sides, but during the predetermined time period (X time period), the state of the one-sided voltage is restored. Therefore, it is determined that the vehicle is in contact with the accident point, and the stepping-in timer is stopped.

(5) For example, if the priority of the interconnection point switch 52 is higher than that of the interconnection point switch 53, the closing timer of the interconnection point switch 52 ( _T52 period) expires first. , Will be thrown.
If the connection point switch 52 is not turned on for some reason, the connection timer of the connection point switch 53 is then turned on (timed
T ₅₃ ) expires and is re-entered.

(6) When the interconnection point switch 52 is turned on, the shutoff device 35 and the automatic section switch 45 are sequentially turned on by the timed sequential function. Since the interconnection point switch 53 is in a state of voltage on both sides,
Stop the advance of the injection timer.

(7) Similarly, the automatic sorting switch 44,
The shutoff devices 34 are sequentially turned on. Since the automatic section switch 43 is in contact with the accident point, it is kept open according to the procedure described above.

As described above, the restoration operation of the healthy section lower than the accident point is completed.

In realizing such an operation, in this embodiment, since the amount of signal transmission is small, high-speed transmission can be performed on a small-capacity signal transmission line, and all signal transmission and reception are performed before the cutoff device 33 opens the first time. Can be completed. Therefore, since the voltage of the distribution line can be used as a power source for transmitting and receiving signals, the signal control device or the like does not require a special power supply device.

In the conventional method of performing the re-closing operation by using the cutoff device of the substation, it takes a longer time to keep the automatic segment switch in contact with the fault point open as the fault point is closer to the load side end.
On the other hand, according to the present system in which the re-closing operation is performed by the breaking devices installed at a plurality of locations on the distribution line, the automatic section switch in contact with the accident point can be opened and held in a relatively short time. Therefore, since the time limit of the closing timer of the interconnection point switch can be set relatively short, a healthy section on the load side from the accident point can be restored in a short time.

In the embodiment of the present invention, in FIG.
Although the case where only the connection point switches 52 are turned on has been described, a plurality of connection point switches may be turned on due to the time limit of the turning-on timer. In this case, in order to prevent the distribution line from forming a loop configuration, the automatic section switch or the cutoff device that is open and has a double-sided voltage during timed forward or timed reverse feed is not turned on.

In addition, in order to cope with the case where another accident occurs in the temporary distribution line state at the time of the accident when power is supplied from another distribution line via the switch for interconnection point, each protection relay The device may be configured such that, when the shutoff device detects and applies the one-sided voltage, the side to which the voltage is applied is set as the upper side and the subsequent accident detection is performed.

In the above-described embodiment, the shutoff device has the forward and backward functions. The present invention preferably has these functions, but depending on the use mode, the forward / backward function of the shut-off device may be omitted. The difference between a case without the forward / backward function and a case with the forward / backward function will be described below.

Regarding the first object of the present invention, that is, the uninterruptible power supply in the healthy section higher than the accident point and the minimization of the power outage range, the forward / reverse transmission function is irrelevant and is omitted. can do.

If the forward / backward function is not provided, no voltage is released even if the circuit breaker is in contact with the fault point on the load side of the fault point. When restoration is performed by transmission, the range where restoration from power failure does not occur may be widened.

Also, when the forward / backward function is not provided, the breaker does not open at no load on the load side than the fault point and keeps the closed state. The feature is that the recovery by sending is fast.

On the other hand, when the blocking device has a forward / reverse function, there are the following merits.

(1) Even if an accident is not detected on the load side from the accident point, if it is in contact with the accident point, it can be closed in the open state as in the case of a segmented switch. Can be minimized.

(2) In the event of a failure of the protective relay, signal control device, etc., the same protective function as in the past can be ensured.

Next, an embodiment of each device used in the configuration of the present embodiment will be described. Here, one of a plurality of components provided will be described.

FIG. 5 shows a shut-off device 33 suitably used in this embodiment,
An outline of an embodiment of a protection relay device 63 and a signal control device 73 is shown. These are grouped for each shutoff device, and constitute a shutoff control group. The reference numerals correspond to those shown in FIG.

The breaking device 33 is connected to the distribution line 2 and
Receiving a signal from the upper voltage transformer VT1, the lower voltage transformer VT2, the protective relay 63 and the signal controller 73 of the distribution line 2, and interrupting the breaking operation of the interrupter 331. It has a control unit 332 for controlling.

The protection control device 63 includes upper and lower voltage transformers.
VT1 and VT2, and current transformer CT that detects the current of distribution line 2
And an accident detection unit 63 that detects the state of the distribution line 2 and outputs an accident detection signal and a trip timer start signal
1 and a trip timer that can be extended during operation
Trip timer start signal or signal control device 73 described later
And a control section 632 for outputting a timing trip command determined by the timer time extension command from the control section 332 to the control section 332.

The signal control device 73 transmits the accident detection signal from the accident detection unit 631 or the accident detection signal from another device to the transmission device 731 and the accident detection signal from the other device. When receiving the detection signal of the receiving unit 732 that outputs a timer time extension command, storage of the signal received by the receiving unit 732, deletion, management of transmission, and a control unit 733 that manages a signal transmitted by the transmission unit 731, While storing the signal from the control unit 733, the open hold command
And a storage unit 734 for outputting to the control unit 332.

The signal transmission path 9 includes a receiving unit 73 from the upper side and the lower side.
2 and is drawn out from the transmitting unit 731 toward the lower side and the upper side. That is, the signal control device 73 relays a two-minute transmission line from the upper side to the lower side and from the lower side to the upper side.

Next, an example of the shutoff device 33 will be described in detail with reference to FIG.

The breaking section 331 is configured to include a contact A1, a closing coil A2, and a trip coil A3. When the contact A1 is in the open state, the shut-off unit 331 controls the closing coil A2 by a command from the control unit 332.
Is excited, and the contact A1 is turned on. When the contact A1 is in the closed state, the trip coil A3 is excited by a command from the control unit 332, and the contact A1 is opened.

The control unit 332 is configured by circuits indicated by reference numerals B1 to B13 in FIG. The configuration and function of each of the circuits B1 to B13 are as follows.

B1 and B2 are voltage detection units, and the voltage transformer V
Via T1 and VT2, the voltage on both sides of the cutoff section 331 is detected, converted to a signal level that can be processed by the subsequent circuits B3 and B4, and output.

The circuit B3 is a one-sided voltage detection circuit, which includes an inhibit circuit IH and an OR circuit OR, and detects whether a voltage is applied to only one side. The circuit B4 is a double-sided non-voltage detection circuit, which includes an OR circuit OR and an inverter circuit INV, and detects whether both sides have no voltage.

The circuit B5 is a closing command circuit and an inhibit circuit.
It is composed of IH and a timer having a closing time X, provided that the reclosing timer in the circuit B12 described below is not being activated.
When the circuit B3 detects the one-sided voltage, it activates a closing timer and outputs a closing command for forward or backward feeding after X time period. The circuit B6 is a closing coil drive circuit, and is configured by an OR circuit OR and an inhibit circuit IH. Outputs a closing command to excite the closing coil A2.

The circuit B7 is a no-voltage detection circuit including an inverter circuit INV and an AND circuit AND. This circuit B7 detects that there is no voltage during the X time period, determines that the circuit is in contact with the fault point on the lower side of the fault point, and outputs an open hold command for the shutoff unit 331. The circuit B8 is a non-voltage detection circuit including a timer having a detection time limit Y, an inverter circuit INV, and an AND circuit AND. This circuit B8
After the power supply is turned on, it is detected that no voltage is applied during the Y time period, and it is determined that the vehicle is in contact with the fault point on the higher side than the fault point, and an open hold command for the shut-off unit 331 is output.

The circuit B9 is a closing prohibition signal output circuit including an OR circuit OR, an AND circuit AND, and a memory. This circuit B9 is
When an open hold command is input from the circuit B7 or B8, and an open hold command is input from the signal control device 63,
Alternatively, when an open hold command is input from a circuit B13 described later, the fact that the open hold command is input is stored in the memory, and a closing prohibition signal is output. The memory is reset by a reset command or a closing command by manual or remote control.

The circuit B10 is a trip command circuit constituted by a timer, and outputs a trip command for the cutoff unit 331 after a predetermined time when both sides are in a no-voltage state. The circuit B11 is a trip coil drive circuit composed of an OR circuit OR, and a trip command from the circuit B10 or a protection relay device 6
The trip coil A3 is excited by the trip command from 3, and the contact A1 is opened.

The circuit B12 is a reclose circuit closing command circuit including a memory and a timer. This circuit B12 outputs a closing command for re-closing or re-closing after a predetermined period of time, with the fear that a trip has occurred due to a command from the protective relay device 63. circuit
The memory of B12 is reset by detecting that the input command is output from the circuit B6.

The circuit B13 is formed by an AND circuit AND, detects that a trip command is output from the protective relay 63 during the Y time period after being turned on, outputs an open hold command when it is determined that it is in contact with an accident point. .

The non-voltage release operation by the circuit B10 may not be performed. By doing so, there is an effect that timed sequential transmission and timed reverse transmission can be performed in a short time when recovering the lower side from the accident point. Although not shown, the closing command and the trip command can be configured to be externally given by remote control or manually.

Next, an example of the protection relay device 63 will be described in detail with reference to FIG.

The fault detection unit 631 includes protection relay elements (44S) C1, (UV) C2, and (6
7) AND circuit C5, which ANDs C3 and (OVG) C4, protection relay elements C1 and C2, and protection relay elements C3 and C4
AND circuit C6 that takes the logical product of AND circuit C5
And an OR circuit C7 for calculating the logical sum of C6 and C6.

The protection relay element (44S) C1 is a short-circuit fault detection direction comparison element, and detects a short-circuit fault on the lower side from the line voltage and line current of the distribution line. The protection relay element (UV) C2 is an undervoltage detection element that detects a drop in line voltage of the distribution line. The protection relay element (67) C3 is a ground fault detection direction comparison element, and detects a lower-side ground fault from the zero-phase voltage and zero-phase current of the distribution line. The protection relay element (OVG) C4 is a zero-phase overvoltage detection element that detects an increase in the zero-phase voltage of the distribution line.

The AND circuit C5 takes the logical product of the output of the protection relay element (UV) C2 and the output of the protection relay element (UV) C2 to prevent detection after a short circuit accident due to a failure of the protection relay element (44S) C1. When the condition is satisfied, an accident detection signal is output. The AND circuit C6 performs a logical AND operation on the outputs of the protection relay element (67) C3 and the protection relay element (OVG) C4 in order to prevent false detection of a ground fault due to a failure of the protection relay element (67) C3. And outputs an accident detection signal when the AND condition is satisfied. Further, the OR circuit C7 outputs these accident detection signals to the control unit 63.
2 and sent to the signal controller 73.

The control unit 632 includes a trip timer D1, a memory D2, and an inverter D3.

Trip timer D1 is a variable timer having an initial timed T _1, is activated by accident detection signal from the fault detection unit. The memory D2 includes, for example, a counter, and stores the number of times that the timer time extension command has been received from the signal control device 73.

The trip timer D1 selects an extension time limit according to the number of times stored in the memory D2. For example, once
_1, the t ₂ when the two, the t ₃ when the three, when n times t _n
Is selected. After all, the time limit of the trip timer D1 is T ₁ + t _n
When this time limit expires, a trip command is output. _If the value of tn is set to be larger as the number of times stored in the memory D2 is larger, the time limit of the trip timer D1 can be set longer on the higher side than the accident point.

When the accident detection unit 631 stops detecting the accident, the stepping of the trip timer D1 stops, and the memory D2 stores the inverter
Reset via D3.

In general, the time limit of the trip timer D1 is set to be different between a short circuit accident and a ground fault accident. Although the example of FIG. 7 shows only the principle configuration of the protection control device of the embodiment, it is not possible to configure the time limit of the trip timer to be different between a short circuit accident and a ground fault accident. Easy.

The shutoff device 33, the protective relay device 63, and the signal control device 73 described above can be provided as individual devices, but may be configured as appropriate or in combination.

Next, an example of the signal control device 73 will be described in detail with reference to FIG.

The transmitting unit 731 includes a carrier oscillator for transmission E1, switches E2 and E3 for carrier modulation, amplifiers E4 and E5, isolation transformers E6 and E7, and OR circuits E8 and E9.

Switch E2, amplifier E4 and isolation transformer E6 are connected in series, and switch E3, amplifier E5 and isolation transformer
E7 is connected in series and each series circuit has a carrier oscillator E1
Is supplied from the carrier. Switch E2
And E3 are on / off controlled by corresponding OR circuits E8 and E9 to modulate the carrier.

The receiving unit 732 includes an isolation transformer F1 and a level detection circuit F3.
Are connected in series, and a lower receiving circuit is formed by connecting the insulating transformer F2 and the level detection circuit F4 in series. The former receiving circuit receives a signal from the upper side and outputs it to a control unit 733 described later. The latter receiving circuit receives a signal from the lower side and issues a timer time delay command to the protection controller 63 shown in FIG.
To the transmitting unit 731 and a control unit 733 described later.

The control unit 733 stores the memory G1 that stores the reception from the lower side and a signal indicating that the memory G1 has the reception storage from the lower side, and transmits the reception signal from the upper side to the transmission unit 731. An inhibit circuit G2 for suppressing transmission to the storage unit 734, and an OR circuit G3 for transmitting a signal indicating that the memory G1 has a reception storage from the lower side or an external reset signal to the storage unit 734 as a reset signal. And Note that the memory G1 can be configured by, for example, a flip-flop circuit.

The storage unit 734 stores the fact that there is a reception from the upper side sent via the inhibit circuit G2, and is reset by a reset signal from the OR circuit G3.
It has H1. The memory H1 is configured by, for example, a flip-flop circuit.

In the signal control device 73, when the accident detection signal is input from the protection relay device 63, the transmission unit 731 modulates the carrier with the switches E2 and E3 and transmits the modulated carrier to the upper side and the lower side. In addition, the signal from the lower side received by the receiving unit 732 is modulated by the switch E2, while the signal from the upper side is modulated by the switch E3, and the carrier from the lower side is modulated by the switch E3. Those from the upper side are transmitted to the lower side.

When detecting signals from the lower side or the upper side, receiving section 732 outputs to control section 733 that these signals have been received. When a signal from the lower side is received, a trip timer time extension command is output to the protection relay device 63.

When detecting the signal reception from the upper side, the control unit 733 does not perform the suppression by the inhibit circuit G2, and does not perform the suppression by the inhibit circuit G2, and transmits the transmission instruction to the lower side to the transmission unit 731 if there is no reception storage from the lower side in the memory G1. At the same time, it outputs a signal to the memory H1 of the storage unit 734 so as to store that the signal has been received from the upper side. Further, when detecting the reception of a signal from the lower side, the controller 733 further outputs a transmission command to the upper side to the transmitter 731 and stores the fact that the signal from the lower side has been received in the memory G1. .

The control unit 733 outputs a signal for resetting the signal reception storage from the upper side to the memory H1 of the storage unit 734 when the memory G1 has the reception storage from the lower side, and the following control is performed by the inhibit circuit G2. Causes signal detection from the upper side to be ignored.

The storage unit 734 stores the signal reception from the upper side in the memory H1 as described above.
Outputs an open hold command to

The memories G1 and H1 of the control unit 733 and the storage unit 734
Is reset command by manual or remote control, or
It is reset by a closing command of the shut-off unit 33.

Next, FIG. 9 shows an outline of an embodiment of the automatic section switch 42 and the signal control device 82 suitably used in the configuration of this embodiment. The reference numerals correspond to those shown in FIG.

The automatic section switch 42 is connected to the distribution line 2 to open and close the line 2, an upper voltage transformer VT 1, a lower voltage transformer VT 2 of the distribution line 2, and a signal control device 82 described later. And a control unit 422 for controlling the opening / closing operation of the opening / closing unit 421 in response to a signal from the control unit 422.

The signal control device 82 includes a transmission unit 821 that transmits an accident detection signal from another device to another device, a reception unit 822 that receives an accident detection signal from another device, and storage and deletion of the signal received by the reception unit 822. And a storage unit 824 that stores a signal from the control unit 823 and sends an open hold command to the automatic sorting switch 42.

The signal transmission line 9 is connected to the signal control device described above.
Same as 72.

FIG. 10 shows an example of a specific configuration of the automatic segment switch 42 in FIG.

The opening / closing section 421 includes a contact A1 and a closing coil A2. The closing coil A2 is excited by a command from the control unit 422, and the contact A1 is closed. When the closing coil A2 is de-energized, the contact
A1 cannot be maintained in the closed state and is opened.

The control unit 422 is configured by circuits indicated by reference numerals B1 to B9 in FIG. Each circuit has almost the same configuration and the same function as the circuit of the same reference numeral of the shut-off device 33 shown in FIG.

B1 and B2 are voltage detection units, B3 is a one-sided voltage detection circuit, and B4 is a non-voltage detection circuit on both sides, which are the same as those having the same reference numerals in FIG.

B5 is a predetermined closing time (X time) after detecting one side voltage
This is a closing command circuit which outputs a closing command for forward or backward feeding after the lapse of time.
There is no difference.

B6 is a closing coil drive circuit for outputting a closing command, which is different from that of FIG. 6 in that there is no OR circuit OR.

B7 is a no-voltage detection circuit during the X time period, and B8 is
A no-voltage detection circuit during a predetermined detection time period (Y time period) after being turned on, and is the same as that in FIG.

B9 is a closing prohibition signal that outputs a closing prohibition signal on condition that an open hold command from the signal control device 82 is input when no voltage during the X time period or no voltage during the Y time period is detected. The output circuit differs from that of FIG. 6 in that the OR circuit OR is smaller by one.

The automatic segment switch 42 shown in FIG. 10 is different from the conventional automatic segment switch having forward and backward functions,
The fact that the open hold command is input from the signal control device 82 is added to the closing prohibition condition. In this way, when compared with the conventional method in which no voltage is detected during the X time period or no voltage during the Y time period and only the voltage is prohibited, a power failure due to a higher-level system during time-sequential transmission causes an error. Judgment that the vehicle is in contact with the accident point is not prohibited.

FIG. 11 shows an example of a specific configuration of the signal control device 82 in FIG.

The transmitting unit 821 includes a switch E2, an amplifier E4, and an isolation transformer E6 connected in series, a switch E3, an amplifier E5, and an isolation transformer E7 connected in series, and a carrier wave from the carrier oscillator E1 to each series circuit. It is configured to be supplied.

The control unit 823 transmits a received signal from the upper side to the memory G1 that stores the reception from the lower side, and a signal indicating that the memory G1 has the reception storage from the lower side. An inhibit circuit G2 for suppressing transmission to the storage unit 824; and an OR circuit G3 for transmitting a signal indicating that the memory G1 has a reception storage from the lower side or a reset signal from the outside to the storage unit 824 as a reset signal. And

The receiving unit 822 includes an isolation transformer F1 and a level detection circuit F3.
Are connected in series, and a lower receiving circuit is formed by connecting the insulating transformer F2 and the level detection circuit F4 in series.

The storage unit 824 stores the fact that there has been reception from the upper side sent via the inhibit circuit G2, and is reset by a reset signal from the OR circuit G3.
It has H1.

The circuit of each of the parts 821 to 824 of FIG. 11 configured as described above differs from the circuit of each of the parts 731 to 734 of FIG. 8 in that there is no input of an accident detection signal and the timer time extension command is issued. It is not output. For other components,
Since there is no difference between them, the same reference numerals are given and duplicate explanations are omitted.

Next, FIG. 12 shows an outline of an embodiment of the interconnection point switch 52 and the signal control device 87 suitably used in the configuration of the present embodiment. The reference numerals correspond to those shown in FIG.

The interconnection point switch 52 includes a switch 521 and a controller 522.

The signal control device 87 includes a transmission unit 871, a reception unit 872, a control unit 87
3. It has a storage unit 874. The function of the present invention is achieved without using transmitting section 871. Therefore, it may be omitted.

FIG. 13 shows a specific configuration example of each device shown in FIG. Hereinafter, description will be made based on this.

Note that the same components as those described so far are denoted by the same reference numerals, and the description thereof will be simplified or omitted in order to avoid duplication.

The switching unit 521 of the interconnection point switch 52 shown in FIG.
1 and a closing coil A2.
This is the same as the opening / closing section 421 of the automatic sorting switch 42 shown in FIG.

In the control unit 522, the circuits B1 and B2 are a voltage detection unit, a circuit B3
Denotes a one-sided voltage detection circuit, each having the same reference numeral as that in FIG.

The circuit B4 is constituted by an AND circuit and has no inverter, and thus, unlike the above-described circuit, constitutes a double-sided voltage detection circuit that detects the presence of a voltage on both sides.

Circuit B5 is a closing command circuit, and a timer with an AND circuit and a predetermined charged timed T _52. This circuit B
5 is turned timer start request signal from the signal control device 87 is inputted, and, when the one-side voltage detecting signal from circuit B3 is inputted, start-up timer, it outputs a closing command after a predetermined charged time period T ₅₂ I do.

The circuit B6 is a closing coil drive circuit including an OR circuit, an inhibit circuit, and a memory. This circuit B6 is
When a closing prohibition command from a circuit B7 described later is not output, the closing coil A2 is excited by a closing command from the circuit B5 or a closing command by remote control, manual operation, or the like.
The memory is reset by remote control or manual release command.

The circuit B7 is a two-sided voltage detection circuit which is configured by a timer having a predetermined time limit X, an inverter circuit, an AND circuit, a memory, and the like, while the input timer is advancing. The circuit B7 determines that it is in contact with an accident point and outputs a closing prohibition signal when the voltage on both sides becomes shorter than a predetermined time period X during the advance of the closing timer of the circuit B5. The memory is reset by remote control or a manual input command.

In the signal control device 87 shown in FIG. 13, the reception unit 872 is configured to include the isolation transformers F1 and F2 and the level detection circuits F3 and F4, and when the input signal is detected, the control unit 87 Output to 873.

The control unit 873 includes an OR circuit, and when receiving a signal from the receiving unit 872, outputs a signal to the storage unit 874 to store that the signal has been received.

The storage unit 874 is made up of a memory, stores the reception of the signal from the control unit 873, and outputs a closing timer start command to the interconnection point switch. The memory is reset by remote control or a manual input command.

By changing the time limit of the closing timer of the interconnection point switch 52 depending on the location of the accident, and appropriately selecting the closing priority of multiple interconnection point switches, it is necessary to restore the lower side from the accident point. This is effective in reducing time and optimizing load distribution. As described above, the storage unit 734 of the signal control unit 73 in FIG. 5 and the storage unit 824 of the signal control unit 82 in FIG. 9 indicate whether the shutoff device or the automatic segment switch is in contact with the accident point. Whether the information is stored. Therefore, the signal control device of the shut-off device or the automatic segment switch in contact with the accident point,
The accident location information is transmitted to the lower interconnection point switch. The signal control device of each interconnection point switch can know the position of the accident by receiving the position information. The accident location information may be determined for each signal control device, or may be determined for each appropriate region in order to reduce the amount of transmission.

The above-mentioned shutoff device 33, protective relay device 63 and signal control device 73, and automatic section switching device 42 and signal control device 82
And, in the switch 52 for the interconnection point and the signal control device 87, a part configured by a logic circuit or the like, for example, the control unit 332,
The 632, 733, 422, 522, 823, 873, the storage units 734, 824, 874, etc., can each be constituted by a semiconductor IC or the like.

When these are configured as ICs, it is preferable to provide a general-purpose component including all of the components, and to selectively use elements required by the circuit at the time of mounting. For example, the above-described control units 332422 and 522 are configured assuming such a situation. In each description, although not shown for simplicity, some elements not used in the control unit are included. That is, as shown in FIG. 6, a circuit including all the circuits B1 to B13 and having a different configuration, for example, B5 has an inverter, an AND circuit, and a timer in common, and in the example of FIG. All of them are used, and only the timer is used in the example shown in FIG. 10, and the example shown in FIG. 13 is implemented using only the AND circuit and the timer.

Not limited to this, the communication control devices 71 to 75 and 81 to 88 are also configured assuming a similar mode.

Note that all or a part of the control units 332 to 873 described above can be configured using a microcomputer. In this case, each control unit or the like is configured by a program that defines a procedure for executing the various control operations described above, and hardware that executes the program. The hardware is configured to include a ROM for storing programs and the like, a CP for executing the programs, a working RAM, and various interfaces.

When a microcomputer is used, for example, for the unit of the shutoff device 33, the opening / closing control of the shutoff unit, the protection relay operation control of the protection relay device 63, and the signal control device 73 are performed.
Can be performed collectively or all in a distributed manner.

[Effects of the Invention] As described above in detail, according to the present invention, (1) a healthy section higher than an accident point can be uninterrupted, and when the shut-off device cannot be opened, the higher-order shut-off device backs up. And the reliability of the protection operation can be improved.

(2) The switch and the breaker in contact with the accident point can be reliably maintained in the open state, and can be prevented from being unnecessarily maintained in the open state in the event of a power failure due to a higher power system side. .

(3) A healthy section on the load side from the accident point can be restored in a short time by appropriately controlling the switches for the interconnection points at a plurality of locations.

And so on.

[Brief description of the drawings]

1 is a schematic diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a schematic diagram showing the configuration of a conventional method, FIGS. 3 and 4 are time charts showing the protection operation of the present invention, Figures 5 to 13
FIG. 1 is a block diagram showing a configuration example of each device in the present invention. 2 ... distribution line, 31-35 ... shut-off device, 41-45 ... automatic section switch, 51-53 ... interconnection point switch, 61-65 ... protective relay device, 71-75, 81-88 ... signal control device, 9 ...
Signal transmission path.

Continuation of the front page (72) Inventor Eisaburo Sakami 1-1-1, Kokubuncho, Hitachi City, Ibaraki Prefecture Inside the Hitachi, Ltd. Kokubu Plant (56) References JP-A-55-141921 (JP, A) JP-A Sho 64-64525 (JP, A) Japanese Utility Model Showa 50-103136 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02H 7/26

Claims (1)

(57) [Claims] 1. A protection system for a distribution line connected to another distribution line via a plurality of normally-operated interlocking switches, comprising: a disconnection device disposed at a plurality of locations on the distribution line; A protective relay device for detecting an accident on a track and opening a corresponding breaking device; a segmented switch arranged at a plurality of locations on a distribution line to divide the distribution line into a plurality of sections in the event of an accident; A plurality of signal control devices that are provided corresponding to the relay device, the segmented switch and the link point switch, and that are connected via a signal transmission path, wherein the signal control device is provided from an upstream side. When an accident detection signal is sent, it is sent downstream from its own device, and
When an accident detection signal is sent from the downstream side, means for sending it to the upstream side from itself, and means for storing and holding the accident detection signal sent from the upstream side, and the signal control device, If it corresponds to a protective relay, when the corresponding protective relay detects an accident, it transmits an accident detection signal to other signal control devices upstream and downstream thereof. When the voltage is reapplied after a fault in a section closer to the power supply than the position of the device, and the fault is detected again within a predetermined time, the storage means outputs a fault detection signal. A means for maintaining the segmented switch in an open state on condition that the information is memorized, and the interlocking point switch is configured such that when one of the connected distribution lines is in a no-voltage state, an accident occurs. Judge whether it is in contact with the point When not in contact with each other, provided that the corresponding signal control device stores an accident detection signal from the upstream side, the device has means for closing itself. A distribution line protection system, which is performed after opening of a segment switch.