JP7199340B2 - Distribution line protection system - Google Patents

Description

The present application relates to distribution line protection systems.

In the distribution system of conventional electric power equipment, when a ground fault occurs, the circuit breaker is shut off or multiple sectional switches arranged on the distribution line are opened, and after the healthy section upstream from the abnormal section is restored in sequence, the downstream An interconnection switch connected to another distribution system provided in the power distribution system is turned on to supply power to the healthy section downstream from the abnormal section. Here, the upstream side indicates the power supply side, and the downstream side indicates the load side.

In the method described above, all the circuit breakers and section switches are opened when an abnormal ground fault occurs, so it takes a long time to restore power after a power failure in a healthy section. Therefore, conventionally, a protective relay having a detection unit that detects the ground fault on the distribution line and the ground fault direction transmits the detected fault information to the adjacent protective relay, detects the faulty section, and detects the faulty section. There is a distribution line protection system that cuts off a circuit breaker or opens a section switch (see, for example, Patent Document 1).

Japanese Patent No. 5381415

Conventional distribution line protection systems send and receive ground fault information to and from adjacent protective relays. There was a problem that the section could not be separated, and the interruption of the circuit breaker connected to the busbar would cause power failure in all sound sections and adversely affect it.

In addition, it is only intended for ground faults, and in the event of a short circuit, the circuit breaker connected to the conventional bus is cut off, and the healthy sections upstream of the abnormal section are sequentially restored, which takes time to restore and has an adverse effect. There was a problem.

The present application discloses a technique for solving the above problems, and an object of the present application is to obtain a distribution line protection system capable of reducing adverse effects when a ground fault or short circuit occurs.

The distribution line protection system disclosed in the present application comprises:
A distribution line connected to a bus via a circuit breaker and having a plurality of section switches, and a normally open interconnection switch provided at an interconnection point between the distribution line and another distribution line, In a distribution line protection system that disconnects a ground fault section by opening the circuit breaker or the section switch when a ground fault abnormality occurs in the distribution line and supplies power to a healthy section,
The protection relay installed in each of the circuit breaker, each of the section switches and the interconnection switch,
a ground fault detector that detects a ground fault on the distribution line;
a ground fault direction detection unit that detects the ground fault direction of the ground fault;
a transmission unit that transmits the ground fault direction of the ground fault to another protection relay adjacent to the upstream side;
a receiver that receives the ground fault direction of another protection relay adjacent to the downstream side;
When the ground fault direction determined by the ground fault direction detector is not upstream and the ground fault direction received by the receiver is different from the ground fault direction transmitted by the transmitter , determining that the circuit breaker, the dividing switch, or the interconnection switch installed in the protective relay is to be controlled when the ground fault occurs;
Further, another protective relay in which the ground fault direction transmitted by the transmission unit is downstream and the reception unit is adjacent to the downstream side within a predetermined time until the circuit breaker connected to the bus is opened. When the information on the ground fault direction cannot be received from a determination unit that determines that
a control unit that transmits and controls a cut -off or opening signal to the circuit breaker, the sectional switch, or the interconnection switch on which the protection relay determined to be controlled by the determination unit is installed; is provided.
In addition, the distribution line protection system disclosed in the present application includes:
A distribution line connected to a bus via a circuit breaker and having a plurality of section switches, and a normally open interconnection switch provided at an interconnection point between the distribution line and another distribution line, A distribution line protection system that disconnects the short-circuit abnormal section by opening the circuit breaker or the section switch when a short-circuit abnormality occurs in the distribution line, and supplies power to a normal section,
The protection relay installed in each of the circuit breaker, each of the division switches and the interconnection switch,
a short circuit detection unit that detects a short circuit on the distribution line;
a transmitter that transmits the short-circuit information to another protection relay adjacent to the upstream side;
a receiver that receives short-circuit information of another protective relay adjacent downstream;
A case where the receiving unit cannot receive short-circuit information from another protective relay adjacent downstream within a predetermined time until the circuit breaker connected to the bus is opened, and when the short-circuit abnormality occurs a determination unit that determines that the circuit breaker, the divisional switch, or the interconnection switch installed in the protection relay is to be controlled, and stores the fact that the switch is to be controlled in a memory unit;
The control unit of the protection relay in which the division switch is installed,
When the power is restored by the circuit breaker, if the information to be controlled is stored in the memory unit, the compartmental switch in which the protection relay is installed is controlled while maintaining the open state. .

According to the distribution line protection system disclosed in the present application,
Adverse effects in the event of a ground fault or short circuit can be reduced.

1 is a diagram showing a configuration of a distribution line protection system according to Embodiment 1; FIG. 2 is a block diagram showing the configuration of a protection relay in FIG. 1; FIG. 3 is a flow chart showing the operation of the protection relay in FIG. 2; 3 is a flow chart showing the operation of the protection relay in FIG. 2; 3 is a flow chart showing the operation of the protection relay in FIG. 2; 3 is a flow chart showing the operation of the protection relay in FIG. 2; 3 is a flow chart showing the operation of the protection relay in FIG. 2; FIG. 10 is a diagram showing the configuration of a distribution line protection system according to Embodiment 2; 9 is a flow chart showing the operation of the protection relay of the distribution line protection system in FIG. 8; 9 is a flow chart showing the operation of the protection relay of the distribution line protection system in FIG. 8; 9 is a flow chart showing the operation of the protection relay of the distribution line protection system in FIG. 8; 9 is a flow chart showing the operation of the protection relay of the distribution line protection system in FIG. 8; 9 is a flow chart showing the operation of the protection relay of the distribution line protection system in FIG. 8; 9 is a flow chart showing the operation of the protection relay of the distribution line protection system in FIG. 8; 9 is a flow chart showing the operation of the protection relay of the distribution line protection system in FIG. 8;

Embodiment 1.
FIG. 1 is a diagram showing the configuration of a distribution line protection system according to Embodiment 1. As shown in FIG. FIG. 2 is a block diagram showing the configuration of the protection relay of the distribution line protection system shown in FIG. 3 and 4 are flow charts showing the operation of the protection relay shown in FIG. 2 when a ground fault occurs. 5 and 6 are flow charts showing the operation of the protection relay shown in FIG. 2 when a short circuit occurs. FIG. 7 is a flow chart showing the operation of the protection relay shown in FIG. Here, the upstream side refers to the power supply side, and the downstream side refers to the load side.

1, the distribution line protection system 100 includes a circuit breaker 2 connected to a bus 5 via a transformer 1, a distribution line 6 connected via the circuit breaker 2, and a plurality of switches arranged on the distribution line 6. section switches 3A, 3B, 3C, 3D, 3E, 3F, and 3G, and a normally open interconnection switch 4 provided at an interconnection point between this distribution line 6 and another distribution line 60. The other distribution line 60 connected by the interconnection switch 4 may belong to the same distribution system or may belong to another distribution system, for example, in the form of a ring.

Furthermore, in the circuit breaker 2, the section switches 3A to 3G and the interconnection switch 4, protective relays 8A, 8B, 8C, 8D, 8E, 8F, 8G, 8H, and 8I are connected to communication lines 7 for information transmission. connected to each other via A server 11 that monitors and manages the distribution lines 6 and 60 and a master station 10 that transmits and receives management information of the server 11 is provided. The server 11, master station 10, and protection relays 8A-8I are connected via a communication line 9 and can communicate with each other. As a matter of course, each information of the protection relays 8A to 8I is transmitted to the server 11 via the master station 10. FIG.

As shown in FIG. 2, the protective relays 8A to 8I include a measurement unit 102, a control unit 110, a ground fault detection unit 103, a ground fault direction detection unit 104, a short circuit detection unit 105, a determination unit 108, a memory unit 109, a transmission unit 106 and a receiver 107 . Measuring unit 102 measures voltage and current connected to measuring devices 101A and 101B for measuring voltage and current including zero-phase voltage and zero-phase current installed on distribution lines 6 and 60 and bus line 5, respectively. The control unit 110 transmits a control command to the circuit breaker 2, the section switches 3A to 3G, or the interconnection switch 4 connected to the protection relays 8A to 8I via the communication line 7. FIG.

A ground fault detection unit 103 detects a ground fault from the voltage measured by the measurement unit 102 . The ground fault direction detection unit 104 detects the ground fault direction from the phase difference between the voltage and the current measured by the measurement unit 102 . A short circuit detection unit 105 detects a short circuit from the current measured by the measurement unit 102 . The transmitter 106 transmits ground fault information, ground fault direction, and short circuit information to other adjacent protection relays via the communication line 9 . The receiving unit 107 receives ground fault information, ground fault direction, and short circuit information from other adjacent protection relays via the communication line 9 .

Judging section 108 selects circuit breaker 2, sectioning switch 3A to It is determined whether or not the 3G or interconnection switch 4 is to be controlled. Further, when the determination unit 108 determines that the object is to be controlled, the determination unit 108 transmits the content of the control to the control unit 110, or stores the short-circuit information in the memory unit 109 of a nonvolatile storage medium, for example. Each function of the protective relays 8A to 8I can be performed similarly whether configured by software or configured by hardware.

Next, the operation of the distribution line protection system 100 of Embodiment 1 configured as described above will be described. First, the operation when a ground fault occurs will be described with reference to FIGS. 3 and 4. FIG. First, protective relays 8A to 8I determine whether or not ground fault detection section 103 has detected a ground fault based on the magnitude and duration of the zero-phase voltage from the measurement results of measurement section 102 (step ST101 in FIG. 3). . If not detected (NO), the process returns to step ST101 and repeats the operation. If a ground fault is detected (YES), the ground fault direction detection unit 104 determines the ground fault direction from the phase difference between the zero-phase voltage and the zero-phase current from the measurement result of the measurement unit 102, and determines the direction of the ground fault. The transmitter 106 transmits the direction of the ground fault to other protection relays adjacent to the downstream side (step ST102 in FIG. 3).

Next, determination section 108 determines whether or not the ground fault direction determined by ground fault direction detection section 104 is upstream (step ST103 in FIG. 3). If the direction of the ground fault is upstream (YES), the ground fault information is cleared and nothing is done (step ST109 in FIG. 4). If the ground fault direction is downstream (NO), determination section 108 determines whether receiving section 107 has received the ground fault direction from another protection relay adjacent to the downstream side (see FIG. 3). step ST104). When the direction of the ground fault is not received from the other protection relay adjacent to the downstream side (NO), a predetermined time, for example 100 ms, elapses until the circuit breaker 2 connected to the bus 5 is opened. It is determined whether or not (step ST105 in FIG. 3).

If 100 ms has not elapsed (NO), the process returns to step ST104 and repeats the operation. If 100 ms has passed (YES), the process proceeds to step ST106 in FIG. 4, which will be described later. Further, in the judgment of step ST104, when the ground fault direction is received from another protective relay adjacent downstream (YES), the self-detected ground fault direction transmitted by the transmitting unit 106 and the received It is determined whether or not the ground fault direction received by the section 107 is different from the direction of the ground fault detected by the other protection relay adjacent to the downstream side (step ST108 in FIG. 3). If the ground fault direction transmitted by the transmitter 106 and the ground fault direction received by the receiver 107 are the same (NO), the ground fault information is cleared and nothing is done (see FIG. 4). step ST109).

If it is determined in step ST108 that the ground fault direction transmitted by transmitting section 106 and the ground fault direction received by receiving section 107 are different (YES), the process proceeds to step ST106 in FIG. Next, when it is determined YES in steps ST105 and ST108 described above, it is determined whether or not the ground fault has been eliminated (step ST106 in FIG. 4). Then, if the ground fault has been eliminated, the ground fault information is cleared and nothing is done (step ST109 in FIG. 4).

Further, when the ground fault has not been resolved, that is, when the ground fault has occurred (NO), the determination unit 108 determines whether the circuit breaker 2, the sectional switches 3A to 3G, or It is determined that the interconnection switch 4 is to be controlled. When the control unit 110 determines that the protection relay is to be controlled, the control unit 110 transmits an open or cutoff signal to the circuit breaker 2, the sectional switches 3A to 3G, or the interconnection switch 4 to which the protection relay is connected. (step ST107 in FIG. 4). Then, the circuit breaker 2, the division switches 3A to 3G, or the interconnection switch 4 are opened or interrupted to disconnect the ground fault section.

Thus, the determination unit 108 determines that the ground fault direction determined by the ground fault direction detection unit 104 is the downstream side, and information about the ground fault direction is not received within 100 ms from another protection relay adjacent to the downstream side. If the ground fault is not cleared, it is determined that an abnormality has occurred in another protection relay adjacent to the downstream side of the ground fault section and the ground fault section cannot be isolated, and the upstream healthy section is protected. In order to prevent power outage, an open or cut command is output to the control unit 110, and the circuit breaker 2 or the section switches 3A to 3G or the interconnection switch 4 connected to the protection relay is opened or cut off. A control command is transmitted through the communication line 7 to disconnect the abnormal section.

In step ST105 of FIG. 3, the determination unit 108 waits for 100 ms for information on the direction of the ground fault from another protection relay adjacent to the downstream side. It suffices if it is possible to determine whether to shut off or open before the opening, and the predetermined time is appropriately set according to the actual system settings.

In step ST102 of FIG. 3, an example of transmitting the ground fault direction to other protection relays adjacent to the upstream side and the downstream side has been shown, but the present invention is not limited to this, and other protection relays adjacent to the upstream side have been described. Even if the ground fault information is transmitted only to the relay, the operation shown above can be implemented.

When the ground fault section is disconnected by the operation of the control unit 110, the sound section on the downstream side is in a power failure state. A closing signal is transmitted to the interconnection switch 4 via the master station 10 . Then, the interconnection switch 4 is turned on, and power is supplied from another distribution line 60 to the healthy section.

A specific example is shown here. When a ground fault exists between the sectional switches 3C and 3D and the sectional switch 3C is released, the server 11 detects that the ground fault is present in the sectional Since it can be determined that it is between 3C and the section switch 3D, the connection switch 4 is turned on according to the power load state of the interconnection system from the section switches 3G to 3E, and power is supplied from the other distribution line 60. supply and restore the sound section downstream from the ground fault section.

Further, when a ground fault exists between the sectioning switch 3C and the sectioning switch 3D and the sectioning switch 3C is released, the server 11 detects the ground fault if the protection relay 8E is in a state in which communication is impossible. Since it cannot be determined that it is between the division switch 3C and the division switch 3D, the server 11 judges the ground fault section according to the ground fault information of the protective relays 8F to 8I. For example, if the direction of the ground fault detected by the protective relay 8F is upstream, the server 11 determines that the ground fault is between the sectional switches 3C to 3E, and the server 11 detects the fault between the sectional switches 3G to 3F. The interconnection switch 4 is turned on according to the power load state of the interconnection system, power is supplied from another distribution line 60, and the sound section downstream of the ground fault section is restored. It should be noted that the location where the ground fault has occurred shown here is just an example, and the same operation can be carried out even if it occurs in another segmented switch section.

Next, the operation when a short-circuit abnormality occurs will be described with reference to the flow charts of FIGS. 5 to 7. FIG. First, protective relays 8A to 8I determine whether or not short circuit detection section 105 has detected a short circuit based on the magnitude and duration of the three-phase current from the measurement result of measurement section 102 (step ST201 in FIG. 5). And when it is not detected (NO), it returns to step ST201 and repeats the said operation|movement. If a short circuit is detected (YES), transmitting section 106 transmits short circuit information to another protective relay adjacent upstream (step ST202 in FIG. 5).

Next, determination section 108 determines whether or not receiving section 107 has received short-circuit information from another protective relay adjacent downstream (step ST203 in FIG. 5). If short-circuit information is received from another protective relay adjacent downstream (YES), the short-circuit information is cleared and nothing is done (step ST207 in FIG. 6). Further, when short-circuit information is not received from another protective relay adjacent downstream (NO), a predetermined period of time, for example 100 ms, elapses until the circuit breaker 2 connected to the bus 5 is opened. (step ST204 in FIG. 5).

If 100 ms has not passed (NO), the process returns to step ST204 and repeats the operation. If 100 ms has passed (YES), it is determined whether or not the short circuit has been eliminated (step ST205 in FIG. 6). Then, when the short circuit is eliminated, the short circuit information is cleared and nothing is done (step ST207 in FIG. 6).

Further, when the short circuit has not been eliminated, that is, when a short circuit abnormality has occurred (NO), the determination unit 108 determines whether the circuit breaker 2 to which the protection relay is connected, the sectional switches 3A to 3G, or the interconnection It is determined that the switch 4 is to be controlled. Then, the control target is stored as short-circuit information in memory section 109, and the process ends (step ST206 in FIG. 6).

After that, all the distribution lines are put into a power outage state due to the interruption of the circuit breaker 2 connected to the bus line 5 . Power is then restored by automatic closing of circuit breaker 2, and protection relays 8B to 8H connected to division switches 3A to 3G are sequentially activated (step ST301 in FIG. 7). Next, when the protective relays 8B to 8H are activated, they determine whether or not there is short-circuit information in the memory section 109 (step ST302 in FIG. 7). If there is no short-circuit information in the memory unit 109 (NO), the automatic input is immediately executed, the power is restored at high speed, and the process ends.

Also, if there is short-circuit information in the memory section 109, it locks the automatic closing of the sectional switch connected to itself, limits the closing, and maintains the open state (step ST303 in FIG. 7). Then, the short-circuit information in the memory section 109 is cleared and the process ends (step ST304 in FIG. 7).

In step ST204 of FIG. 5, the time for which the determination unit 108 waits for short-circuit information from another protection relay adjacent to the downstream side was set to 100 ms. It is only necessary to be able to determine whether to shut off or open, and the predetermined time is appropriately set according to the actual system settings.

In step ST202 of FIG. 5, an example of transmitting the short-circuit information to other protection relays adjacent to the upstream side has been shown, but the present invention is not limited to this, and other protection relays adjacent to the upstream side and the downstream side are shown. , the operation shown above can be performed even if the short-circuit information is transmitted to each of the .

When the short-circuited section is disconnected by the operation of the control unit 110, the healthy section on the downstream side is in a power failure state. A closing signal is transmitted to the system switch 4 via the master station 10 . Then, the interconnection switch 4 is turned on, and power is supplied from another distribution line 60 to the healthy section.

A specific example is shown here. When there is a short circuit between the sectional switch 3C and the sectional switch 3D, and the automatic closing of the sectional switch 3C is locked, the server 11 closes the sectional switch if the protective relay 8E is in a communicable state. From 3G to 3E, the interconnection switch 4 is turned on according to the power load state of the interconnection system, power is supplied from another distribution line 60, and the healthy section downstream of the short-circuited section is restored.

Further, when a short circuit exists between the sectional switch 3C and the sectional switch 3D, and the automatic closing of the sectional switch 3C is locked, the server 11, if the protection relay 8E is in a state in which communication is impossible, Since it cannot be determined that there is a short circuit between the section switches 3C and 3D, the server 11 determines the short circuit section according to the ground fault information of the protective relays 8F to 8I. For example, if the protective relay 8F does not detect short-circuit information, the server 11 determines that the ground fault section is between the sectional switches 3C to 3E, and the server 11 connects the sectional switches 3G to 3F to the interconnection system. The interconnection switch 4 is turned on according to the power load state of , power is supplied from another distribution line 60, and the sound section downstream of the short-circuit section is restored.

In addition, although there is a short circuit between the sectional switch 3E and the sectional switch 3F, the protective relay 8D connected to the sectional switch 3C cannot communicate, and the sectional switch 3B is automatically closed by the above-described processing. is locked, there is a possibility that power will not be restored in the normal sections of the section switches 3B to 3E. However, if the protection relay 8F can communicate, the server 11 determines that the short-circuit fault section is between the section switch 3E and the section switch 3F based on the short-circuit information from the protection relay 8F. Release the automatic input lock of Since the protection relay 8F detects a short circuit here, it locks the automatic closing of the division switch 3E, so that the short circuit section is not restored.

In addition, although there is a short circuit between the sectional switch 3E and the sectional switch 3F, the protective relay 8F connected to the sectional switch 3E cannot communicate, and the sectional switch 3D is automatically closed by the above-described processing. is locked, there is a possibility that power will not be restored in the normal sections of the section switches 3D to 3E. Since the protection relay 8F cannot communicate with the protection relay 8F and cannot acquire the short-circuit information from the protection relay 8F, the server 11 determines that the short-circuit section is between the section switches 3D and 3F. Note that the location where the short-circuit has occurred shown here is an example, and the same operation can be carried out even if it occurs in the section of another segmented switch.

In the above embodiment, the upstream power supply side is set to the circuit breaker 2 side until power is supplied from the other distribution line 60 by the interconnection switch 4 after a ground fault or short circuit occurs. , the load side on the downstream side is shown as an example of the side of the interconnection switch 4, but after the interconnection switch 4 is turned on by the server 11, the power is supplied from the other distribution line 60 by the interconnection switch 4. supplied. Therefore, in this case, the division switch to which power is supplied from the other distribution line 60 via the interconnection switch 4 and the protection relay connected to the interconnection switch are supplied with power by the interconnection switch 4. One side is the upstream side, and the other side is the load side and the downstream side. Further, in this way, when the upstream side and the downstream side are reversed, for example, when the server 11 transmits the closing signal to the interconnection switch 4, the information should be transmitted to the target protection relay at the same time. can be handled easily. Moreover, since this also applies to the following embodiments, the description thereof will be omitted as appropriate.

In the above first embodiment, the case where a single protective relay is used to handle a short circuit and a ground fault is shown, but the present invention is not limited to this, and separate protective relays are used to handle a short circuit and a ground fault. It is also possible to correspond, and a similar effect can be obtained. Moreover, since this also applies to the following embodiments, the description thereof will be omitted as appropriate.

In the first embodiment, an example is shown in which each device communicates using the communication line 7 or the communication line 9. However, the present invention is not limited to this. It can be performed in the same way regardless of whether it is wired or wireless, and the same effect can be obtained. Moreover, since this also applies to the following embodiments, the description thereof will be omitted as appropriate.

According to the distribution line protection system of Embodiment 1 configured as described above,
A distribution line connected to a bus via a circuit breaker and having a plurality of section switches, and a normally open interconnection switch provided at an interconnection point between the distribution line and another distribution line, In a distribution line protection system that disconnects a ground fault section by opening the circuit breaker or the section switch when a ground fault abnormality occurs in the distribution line and supplies power to a healthy section,
The protection relay installed in each of the circuit breaker, each of the division switches and the interconnection switch,
a ground fault detector that detects a ground fault on the distribution line;
a ground fault direction detection unit that detects the ground fault direction of the ground fault;
a transmission unit that transmits the ground fault direction of the ground fault to another protection relay adjacent to the upstream side;
a receiver that receives the ground fault direction of another protection relay adjacent to the downstream side;
When the ground fault direction received by the receiving unit and the ground fault direction transmitted by the transmitting unit are different, and when the ground fault abnormality occurs, determining that the ground fault is to be controlled;
Further, another protective relay in which the ground fault direction transmitted by the transmission unit is downstream and the reception unit is adjacent to the downstream side within a predetermined time until the circuit breaker connected to the bus is opened. a determination unit that determines that the ground fault is to be controlled when the ground fault abnormality occurs when information on the direction of the ground fault cannot be received from the
and a control unit that transmits and controls an interruption or opening signal to the circuit breaker or the sectional switch in which the protective relay that is determined to be controlled by the determination unit is installed,
In the event of an abnormal ground fault, even if other protective relays on the adjacent downstream side cannot communicate, the healthy section on the upstream side of the ground fault section can be protected, reducing the adverse effects of a ground fault or short circuit. can.

Further, when the ground fault direction transmitted by the transmission unit is upstream, or when the ground fault direction received by the reception unit and the ground fault direction transmitted by the transmission unit are different. If it is the same, it is determined that it is not a control target,
Since the control unit clears the ground fault information and does not control anything,
Unnecessary ground fault information can be cleared.

Further, the control unit is provided with a server that transmits an closing signal to the interconnection switch when the control unit transmits an interruption or opening signal to the circuit breaker or the sectional switch according to the ground fault information to control the circuit breaker or the sectional switch.
Since the interconnection switch allows power to be interchanged from the interconnection system and restored to the healthy section on the downstream side, a highly reliable distribution line protection system can be obtained.

In addition, the distribution line is connected to the bus via a circuit breaker and has a plurality of section switches, and a normally open interconnection switch provided at the interconnection point between the distribution line and another distribution line. and, when a short-circuit abnormality occurs in the distribution line, the circuit breaker or the section switch is opened to isolate the short-circuit abnormal section and supply power to the healthy section,
The protection relay installed in each of the circuit breaker, each of the division switches and the interconnection switch,
a short circuit detection unit that detects a short circuit on the distribution line;
a transmitter that transmits the short-circuit information to another protection relay adjacent to the upstream side;
a receiver that receives short-circuit information of another protective relay adjacent downstream;
When short-circuit information cannot be received from another protection relay adjacent downstream by the receiving unit within a predetermined time until the circuit breaker connected to the bus is opened, and when the short-circuit abnormality occurs, control is performed. a determination unit that determines that it is a target and stores that it is a control target in a memory unit;
a control unit that maintains and controls the open state of the compartmental switch in which the protection relay is installed when the information to be controlled is stored in the memory unit when power is restored by the circuit breaker; because it provides
When a short circuit occurs, after the circuit breaker connected to the bus is shut off and turned on, power can be quickly restored in the healthy section on the upstream side, so that adverse effects when a ground fault or short circuit occurs can be reduced.

Further, when the receiving unit receives the short-circuit information of another protection relay adjacent downstream, the determination unit clears the short-circuit information.
Unnecessary short circuit information can be cleared.

Further, when the power is restored by the circuit breaker, the control unit controls the divisional switch in which the protection relay is installed to the closed state if the information on the control target is not stored in the memory unit. so
When a short-circuit abnormality occurs, power can be quickly restored in the healthy section on the upstream side after the circuit breaker connected to the bus is shut off and turned on.

Further, when the power is restored by the circuit breaker according to the short-circuit information of the control unit, the server is provided for transmitting a closing signal to the interconnection switch.
Since the interconnection switch allows power to be interchanged from the interconnection system and restored to the healthy section on the downstream side, a highly reliable distribution line protection system can be obtained.

In addition, the distribution line is connected to the bus via a circuit breaker and has a plurality of section switches, and a normally open interconnection switch provided at the interconnection point between the distribution line and another distribution line. Then, when a short circuit or ground fault occurs in the distribution line, the circuit breaker or section switch is opened to isolate the short circuit or ground fault section, and power is supplied to the healthy section. Because you can
In the event of an abnormal ground fault, the healthy section upstream of the ground fault section can be protected even if other adjacent downstream protection relays cannot communicate, and
When an abnormal short circuit occurs, after the circuit breaker connected to the bus is shut off and turned on, power can be quickly restored in the healthy section on the upstream side, so that adverse effects when a ground fault or short circuit occurs can be further reduced.

Embodiment 2.
In the first embodiment, an example in which the distribution line 6 is not branched is shown, but the present invention is not limited to this. For example, as shown in FIG. will be described. The branched side is provided with a normally open interconnection switch 4A provided at an interconnection point with the distribution line 6 and another distribution line 61 . The other distribution line 61 connected by the interconnection switch 4A may belong to the same distribution system or may belong to another distribution system, for example, in the form of a ring. A protection relay 8J is connected to the interconnection switch 4A via a communication line 7. As shown in FIG. As with other protection relays, protection relay 8J is connected to server 11, master station 10, and protection relays 8A to 8I via communication line 9 so that they can communicate with each other. The protective relays 8A to 8I are constructed in the same manner as in the first embodiment.

However, in this case, the determination unit 108 of the protection relay 8D connected to the division switch 3C on the upstream side of the branch point 12 is connected to the other two adjacent protection relays 8E and 8G downstream of itself. and the number of other protection relays 8E and 8G installed downstream of the branch point 12 is determined in the same manner as in the first embodiment.

Next, the operation of the protection relay 8D on the downstream side of the branch point 12 in the distribution line protection system 100 of Embodiment 2 configured as described above will be described. First, the operation of the protection relay 8D when a ground fault occurs will be described with reference to FIGS. 2 and 9 to 12. FIG. First, steps ST101 to ST103 in FIG. 9 are performed in the same manner as in the first embodiment. If the direction of the ground fault is upstream (YES) in step ST103, the ground fault information is cleared, No (step ST109 in FIG. 12).

In step ST103, if the ground fault direction is downstream (NO), determination section 108 determines that reception section 107 is grounded from first or second protection relay 8E or 8G adjacent to the downstream side. It is determined whether or not the connection direction has been received (step ST401 in FIG. 10, step ST402 in FIG. 11). When the direction of the ground fault is not received from the other protection relay adjacent to the downstream side (NO), a predetermined time, for example 100 ms, elapses until the circuit breaker 2 connected to the bus 5 is opened. (step ST105A in FIG. 10, step ST105B in FIG. 11).

If 100 ms has not passed (NO), the process returns to steps ST401 and ST402 to repeat the operation. If 100 ms has passed (YES), the process proceeds to step ST403 in FIG. 12, which will be described later. In addition, in the determination of steps ST401 and ST402, when the ground fault direction is received from another protection relay adjacent downstream (YES), the self-detected ground fault direction transmitted by transmission section 106 and , determines whether or not the ground fault direction received by the receiving unit 107 is different from that detected by another protection relay adjacent downstream (step ST108A in FIG. 10, step ST108B in FIG. 11). If the ground fault direction transmitted by transmitting section 106 and the ground fault direction received by receiving section 107 are the same (NO), the process proceeds to step ST404 in FIG. 12 described later.

If it is determined in steps ST108A and ST108B that the ground fault direction transmitted by transmitting section 106 and the ground fault direction received by receiving section 107 are different (YES), the process proceeds to step ST403 in FIG. move. Next, if YES is determined in steps ST105A and ST105B and steps ST108A and ST108B described above, it is determined whether determination of all protection relays adjacent to the downstream side has been completed (step of FIG. 12). ST403). Then, if the determination of all the protective relays adjacent to the downstream side has not been completed (NO), the operation of step ST403 is repeated. Further, when the determination of all protective relays adjacent to the downstream side has been completed (YES), the same operation as in the first embodiment is performed.

Further, when the above-mentioned steps ST108A and ST108B are determined as NO, it is determined whether determination of all protection relays adjacent to the downstream side has been completed (step ST404 in FIG. 12). Then, if the determination of all the protective relays adjacent to the downstream side has not been completed (NO), the operation of step ST404 is repeated. Further, when the determination of all protective relays adjacent to the downstream side has been completed (YES), the same operation as in the first embodiment is performed. Note that step ST403 and step ST404 are mutually determined, and if each protective relay adjacent downstream is determined in any flow, it is determined that the process has ended.

Next, the operation of the protection relay 8D when a short circuit occurs will be described with reference to FIGS. 2 and 13 to 15. FIG. First, steps ST201 to ST202 in FIG. 13 are performed in the same manner as in the first embodiment, and transmitting section 106 transmits short-circuit information to other protection relays adjacent to the upstream side (step ST202 in FIG. 13). ).

Next, determination section 108 determines whether or not receiving section 107 has received short-circuit information from first and second protection relays 8E and 8G adjacent downstream (steps ST501 and ST502 in FIG. 14). ). When short-circuit information is received from other protection relays adjacent to the downstream side (YES), it is determined whether determination of all protection relays adjacent to the downstream side has been completed (step of FIG. 12). ST503). Then, if the determination of all the protection relays adjacent to the downstream side has not been completed (NO), the operation of step ST500 is repeated. Further, when the determination of all protective relays adjacent to the downstream side has been completed (YES), the same operation as in the first embodiment is performed.

Further, in steps ST501 and ST502, if short-circuit information is not received from other protective relays adjacent to the downstream side (NO), the circuit breaker 2 connected to the bus 5 is opened within a predetermined time. , for example, 100 ms has elapsed (steps ST204A and ST204B in FIG. 14). If 100 ms has not elapsed (NO), the process returns to steps ST501 and ST502 to repeat the operation.

If 100 ms has passed (YES), it is determined whether or not determination of all protective relays adjacent to the downstream side has been completed (step ST504 in FIG. 15). Then, if the determination of all the protection relays adjacent to the downstream side has not been completed (NO), the operation of step ST504 is repeated. Further, when the determination of all protective relays adjacent to the downstream side has been completed (YES), the same operation as in the first embodiment is performed. Note that step ST503 and step ST504 are determined mutually, and if each protection relay adjacent to the downstream side is determined in any flow, it is determined that the process has ended.

In the second embodiment, the radial distribution system branched into two at the branch point 12 has been described, but the present invention is not limited to this, and a plurality of branches of two or more can be similarly carried out. can be done.

According to the distribution line protection system of Embodiment 2 configured as described above, the same effects as those of Embodiment 1 are obtained,
When the distribution line is branched at a branch point,
Since the determination unit of the protection relay installed upstream of the branch point determines the number of other protection relays installed downstream of the branch point,
Even if the distribution line is branched, in the event of an abnormal ground fault, even if other protective relays on the adjacent downstream side cannot communicate, the healthy section on the upstream side of the ground fault section can be protected, and
When a short circuit occurs, after the circuit breaker connected to the bus is shut off and turned on, power can be quickly restored in the healthy section on the upstream side, so that adverse effects when a ground fault or short circuit occurs can be reduced.

While this disclosure describes various exemplary embodiments and examples, various features, aspects, and functions described in one or more of the embodiments may vary from particular embodiment to embodiment. The embodiments are applicable singly or in various combinations without being limited to the application.
Accordingly, numerous variations not illustrated are envisioned within the scope of the technology disclosed herein. For example, modification, addition or omission of at least one component, extraction of at least one component, and combination with components of other embodiments shall be included.

1 transformer, 101A measuring instrument, 101B measuring instrument, 102 measuring unit,
103 ground fault detector, 104 ground fault direction detector, 105 short circuit detector, 106 transmitter, 107 receiver, 108 determination unit, 109 memory unit, 110 controller, 2 circuit breaker,
3A segmented switch, 3B segmented switch, 3C segmented switch, 3D segmented switch,
3E section switch, 3F section switch, 3G section switch, 4 interconnected switch,
4A grid switch, 5 busbar, 6 distribution line, 60 other distribution line, 61 other distribution line,
7 communication line, 8A protection relay, 8B protection relay, 8C protection relay,
8D protection relay, 8E protection relay, 8F protection relay, 8G protection relay,
8H protection relay, 8I protection relay, 8J protection relay, 9 communication line, 10 master station,
11 servers, 12 branch points.

Claims (11)

A distribution line connected to a bus via a circuit breaker and having a plurality of section switches, and a normally open interconnection switch provided at an interconnection point between the distribution line and another distribution line, In a distribution line protection system that disconnects a ground fault section by opening the circuit breaker or the section switch when a ground fault abnormality occurs in the distribution line and supplies power to a healthy section,
The protection relay installed in each of the circuit breaker, each of the section switches and the interconnection switch,
a ground fault detector that detects a ground fault on the distribution line;
a ground fault direction detection unit that detects the ground fault direction of the ground fault;
a transmission unit that transmits the ground fault direction of the ground fault to another protection relay adjacent to the upstream side;
a receiver that receives the ground fault direction of another protection relay adjacent to the downstream side;
When the ground fault direction determined by the ground fault direction detector is not upstream and the ground fault direction received by the receiver is different from the ground fault direction transmitted by the transmitter , determining that the circuit breaker, the dividing switch, or the interconnection switch installed in the protective relay is to be controlled when the ground fault occurs;
Further, another protective relay in which the ground fault direction transmitted by the transmission unit is downstream and the reception unit is adjacent to the downstream side within a predetermined time until the circuit breaker connected to the bus is opened. When the information on the ground fault direction cannot be received from a determination unit that determines that
a control unit that transmits and controls a cut -off or opening signal to the circuit breaker, the sectional switch, or the interconnection switch on which the protection relay determined to be controlled by the determination unit is installed; distribution line protection system. When the ground fault direction transmitted by the transmitter is the upstream side, or when the ground fault direction received by the receiver is the same as the ground fault direction transmitted by the transmitter. In this case, determining that the circuit breaker, the division switch, or the interconnection switch installed in the protection relay is not a control target when the ground fault occurs ,
2. The distribution line protection system according to claim 1, wherein the control unit clears the ground fault information and controls nothing. 3. The server according to claim 1 or 2, further comprising a server for transmitting an closing signal to the interconnection switch when the control unit transmits an interruption or opening signal to the circuit breaker or the sectional switch according to ground fault information to control the switch. Distribution line protection system as described. A distribution line connected to a bus via a circuit breaker and having a plurality of section switches, and a normally open interconnection switch provided at an interconnection point between the distribution line and another distribution line, A distribution line protection system that disconnects the short-circuit abnormal section by opening the circuit breaker or the section switch when a short-circuit abnormality occurs in the distribution line, and supplies power to a normal section,
The protection relay installed in each of the circuit breaker, each of the section switches and the interconnection switch,
a short circuit detection unit that detects a short circuit on the distribution line;
a transmitter that transmits the short-circuit information to another protection relay adjacent to the upstream side;
a receiver that receives short-circuit information of another protective relay adjacent downstream;
A case where the receiving unit cannot receive short-circuit information from another protective relay adjacent downstream within a predetermined time until the circuit breaker connected to the bus is opened, and when the short-circuit abnormality occurs a determination unit that determines that the circuit breaker, the divisional switch, or the interconnection switch installed in the protection relay is to be controlled, and stores the fact that the switch is to be controlled in a memory unit;
The control unit of the protection relay in which the division switch is installed,
When power is restored by the circuit breaker, if information to be controlled is stored in the memory unit, distribution line protection that maintains and controls the open state of the compartmental switch in which the protection relay is installed. system. 5. The distribution line protection system according to claim 4, wherein the determination unit clears the short-circuit information when the reception unit receives the short-circuit information of another protective relay adjacent downstream. When the power is restored by the circuit breaker, the control unit closes the sectional switch in which the protection relay is installed if the information to be controlled is not stored in the memory unit. The distribution line protection system according to claim 4 or 5. 7. The distribution line protection according to any one of claims 4 to 6, further comprising a server that transmits a closing signal to the interconnection switch when power is restored by the circuit breaker according to short-circuit information from the control unit. system. 8. The distribution line protection system according to any one of claims 4 to 7, wherein the circuit breaker or the section switch is opened when a short circuit or ground fault occurs in the distribution line, and the short circuit section is closed. Alternatively, the ground fault abnormal section is separated and power is supplied to the normal section,
The protective relay is
a ground fault detector that detects a ground fault on the distribution line;
A ground fault direction detection unit that detects the ground fault direction of the ground fault,
The transmission unit transmits the ground fault direction of the ground fault to another protection relay adjacent to the upstream side,
The receiving unit receives the ground fault direction of another protection relay adjacent downstream,
The determination unit determines that the ground fault direction determined by the ground fault direction detection unit is not upstream, and the ground fault direction received by the reception unit is different from the ground fault direction transmitted by the transmission unit. If different, determine that the circuit breaker, the division switch, or the interconnection switch installed in the protection relay is to be controlled when the ground fault occurs ;
Further, the ground fault direction transmitted by the transmitting unit is the downstream side, and the receiving unit is adjacent to the downstream side within a predetermined time until the circuit breaker connected to the bus is opened. When the ground fault direction information cannot be received from the protection relay, the circuit breaker, the section switch, or the interconnection switch installed in the protection relay is determined to be the control target when the ground fault occurs . judge,
The control unit transmits a cut -off or open signal to the circuit breaker, the sectional switch, or the interconnection switch in which the protective relay determined by the determination unit to be controlled is installed. Distribution line protection system to control. When the ground fault direction transmitted by the transmitter is the upstream side, or when the ground fault direction received by the receiver is the same as the ground fault direction transmitted by the transmitter. In this case, it is determined that the circuit breaker, the division switch, or the interconnection switch installed in the protection relay is not a control target,
9. The distribution line protection system according to claim 8, wherein the control unit clears the ground fault information and controls nothing. 10. The server according to claim 8 or 9, further comprising a server for transmitting an closing signal to the interconnection switch when the control unit transmits an interruption or opening signal to the circuit breaker or the sectional switch according to ground fault information to control the switch. Distribution line protection system as described. When the distribution line is branched at a branch point,
11. The judging unit of the protective relay installed upstream of the branch point makes judgments as many as the number of other protective relays installed downstream of the branch point. 2. The distribution line protection system of claim 1.

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