JPH11299087A - Bus protecting system for spot network power receiving equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bus protecting system for high-resistance grounded high- voltage spot network power receiving equipment, which detects early a fault point for preventing the all power failure, and ensures higher degree of reliability in power supply. SOLUTION: This bus protecting system comprises protector breakers 41, 42, 43 connected with the secondary side of network transformers 31, 32, 33 connected with power receiving lines 14, 15, 16, bus interlinked breakers 44, 45 46 connected with network buses 17, 18, 19, grounding transformers 51, 52, 53 and ground current detectors 81, 82, 83 connected between the network buses, and controllers 91, 92, 93 which detect bus ground fault through the ground current detectors and open the protector breakers. A first specified time after the detection of a bus ground fault by the ground current detectors 81, 82, 83, the controllers 91, 92, 93 open the bus interlinked breakers 44, 45, 46. When the ground fault is not longer detected, the controllers 91, 92, 93 reset the bus interlinked breakers, and, after a second specified time longer than the first specified time, open the protector breakers 41, 42, 43.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bus protection system for a spot network power receiving facility, and more particularly to a bus for a spot network power receiving facility suitable for detecting a ground fault in a spot network bus provided with a bus communication circuit breaker. Regarding protection system.

[0002]

2. Description of the Related Art In general, spot network power receiving equipment is roughly classified into 1) high voltage spot network power receiving equipment and 2) low voltage spot network power receiving equipment. Also,
1) The grounding method in the high voltage spot network power receiving equipment is roughly classified into 1-1) non-grounding method and 1-2) high resistance grounding method.

[0003] 1-1) As a ground fault protection method in a non-grounding type high voltage spot network power receiving equipment, for example, a grounding type instrument transformer is provided between each bus of a network bus having a bus connection circuit breaker. A ground fault voltage is detected via a grounding type instrument transformer, a ground fault in a network bus or a ground fault in a system is detected from the detected value, and an alarm is issued via a protection relay.

[0004] 1-2) As a ground fault protection method in a high-resistance spot-type high-voltage spot network power receiving equipment, for example, a grounding transformer is provided between buses, and one of the grounding transformers is used.
A high resistance and a current transformer are provided at the neutral point of the secondary winding, and a ground fault current is detected via the current transformer.A ground fault in the network bus and a ground fault in the system are detected from the detected value. After a certain period of time, it is determined that a ground fault has occurred in the network bus, and then the protective circuit breakers on the secondary side of each network transformer installed in the substation equipment will be opened simultaneously via a protection relay. That is common.

[0005] 2) The grounding system in the low-voltage spot network power receiving equipment is a direct grounding system. In a commonly used ground fault protection method, one neutral point of each secondary winding of each network transformer is provided. , Equipped with a current transformer,
A ground fault current is detected through this current transformer, a ground fault in the network bus or a ground fault in the system is detected from the detected value, and after a certain time period, after a ground fault in the network bus is determined,
Usually, the protector breakers on the secondary side of each network transformer are opened at the same time. Therefore,
Since the secondary side protector breakers are opened all at once, there is a risk that the power receiving and substation equipment will be completely out of power.

On the other hand, for example, Japanese Patent Application Laid-Open No. 58-19 / 1983
As described in Japanese Patent No. 2435, 2) In a low-voltage spot network power receiving facility, a current transformer is directly provided between each bus, and a ground fault current is detected through the current transformer. There is known a device that detects a ground fault in a bus or a ground fault in a system and sequentially opens a circuit breaker and a protector circuit breaker in a network bus.

[0007]

When a ground fault occurs in a spot network bus having a bus connection circuit breaker, the bus connection circuit breakers are all closed and all the ground fault protection relays operate. become. Therefore, in the ground fault protection method of the high-voltage spot network power receiving equipment of 1-2) high resistance grounding method, all the power receiving and transforming equipment will be blacked out because the protector breakers on the secondary side of each network transformer will be opened at the same time. There was the first problem. In addition, in the case of the ground fault protection method of the non-grounded high-voltage spot network power receiving equipment, there is a second problem that there is a possibility that the short-circuit accident may be caused because only a warning is issued. Further, it is described in JP-A-58-192435.
2) In the low-voltage spot network power receiving equipment, current transformers are provided directly between the buses.However, each bus is generally coated with insulation, and current transformers should be installed on the buses. Is practically difficult, and there is a third problem that this method cannot be practically used.

A first object of the present invention is to provide a bus protection system for a high-resistance spot-type high-voltage spot network power receiving equipment in which a total power failure is prevented by early detection of an accident point to improve the reliability of power supply. Is to provide. A second object of the present invention is to provide a bus protection system for a non-grounding type high-voltage spot network power receiving equipment with improved reliability of power supply by preventing an accident from occurring due to a bus ground fault. . A third object of the present invention is to provide a bus protection system for a low-voltage spot network power receiving equipment of a direct grounding system capable of detecting an accident point, preventing a total power failure, and improving power supply reliability. is there.

[0009]

(1) In order to achieve the first object, the present invention provides a protector circuit breaker connected to a secondary side of a network transformer connected to a power receiving line, and a network bus. A busbar circuit breaker connected to the
A high resistance having a grounding transformer and a ground fault current detector connected between each bus of the network bus, and a control device for detecting a bus ground fault by the ground fault current detector and opening the protector breaker. In the bus protection system of the grounding type spot network power receiving equipment, the control device may detect the first ground after detecting the bus ground fault by the ground fault current detector.
After the predetermined time, the bus communication circuit breaker is opened, and when the ground fault is no longer detected, the bus communication circuit breaker is returned, and the protector is restored after a second predetermined time longer than the first predetermined time. The circuit breaker is opened. With this configuration, by detecting an accident point early and disconnecting only the network bus in which the ground fault has occurred, it is possible to prevent a total power outage and improve the reliability of power supply.

(2) In order to achieve the second object,
The present invention relates to a network transformer connected to a power receiving line.
A protector circuit breaker connected to the next side, a bus communication breaker connected to the network bus, a transformer for a grounded type instrument and a ground fault voltage detector connected between each bus of the network bus, A bus protection system for a non-grounding type spot network power receiving equipment having a control device for detecting a bus ground fault with a ground voltage detector and opening the protector circuit breaker, wherein the control device includes a ground fault voltage detector. After the detection of the bus ground fault, after a first predetermined time,
If the bus fault is not detected anymore, the bus breaker is opened and the protector breaker is opened after a second predetermined time longer than the first predetermined time. It is like that. With this configuration, the buses are separated, so that it is possible to prevent the accidents from expanding due to the occurrence of the bus ground fault, and to improve the reliability of the power supply.

(3) In order to achieve the third object,
The present invention relates to a network transformer connected to a power receiving line.
In a bus protection system of a direct grounding type spot network power receiving equipment having a protector circuit breaker connected to a secondary side and a bus connection circuit breaker connected to a network bus, the neutral of the secondary winding of the network transformer is neutralized. A current transformer and a ground fault current detector connected to a point, and a control device that detects a bus ground fault with the ground fault current detector and opens the protector breaker. After the detection of the bus ground fault by the ground fault current detector, after the first predetermined time, the bus communication breaker is opened, and when the ground fault is no longer detected, the bus communication breaker is returned,
The protector circuit breaker is opened after a second predetermined time longer than the first predetermined time. With this configuration, by detecting an accident point early and disconnecting only the network bus in which the ground fault has occurred, it is possible to prevent a total power outage and improve the reliability of power supply.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of a high-resistance ground-type high-voltage spot network power receiving facility according to an embodiment of the present invention will be described below with reference to FIGS. FIG.
FIG. 2 is a system circuit diagram showing an entire configuration of a high-resistance grounding type high-voltage spot network power receiving facility according to an embodiment of the present invention, and FIG. 2 is used for a high-resistance grounding type high-voltage spot network power receiving facility according to the present embodiment. It is a circuit diagram of a control device.

In FIG. 1, the 3 connected to the power substation
Three-phase spot network lines 11, 12, 13
Are connected to power receiving lines 14, 15, and 16, respectively. Each power receiving line 14, 15, 16 is connected to network buses 17, 18, 19 via a three-line spot network power receiving device. As each spot network power receiving device, each power receiving disconnecting switch 21, 22, 22
23, each network transformer 31, 32, 33 and each protector breaker 41, 42, 43 are connected in series for each line.

The network buses 17, 18, and 19 include:
Bus bar circuit breakers 44, 45 and 46 are provided. In recent years, the bus bar circuit breakers 44, 45, and 46 have been provided as bus bar splitting opening / closing devices for maintenance. In the present embodiment, when a ground fault occurs in the network bus, the bus communication circuit breakers 44 and 4
5, 46, each network bus 17, 18, 1
By opening the space between the protector breakers 41 and 4
This is to prevent a total power outage of the power receiving and transforming equipment due to the simultaneous opening of 2, 43, the details of which will be described later.

A circuit breaker 47 is connected to the network bus 17 and further connected to a load 4 via a ground fault protection device 47B.
7A is connected. When a ground fault occurs on the load 47A side, the ground fault protection device 47B of the load 47A operates to open the circuit breaker 47. Each network bus 1
Similarly, a circuit breaker, a ground fault protection device, and a load are connected to 8, 19, respectively.

Each of the network buses 17, 18, 19 is provided with a grounding transformer 51, 52, 53. In order to detect a ground fault in the secondary system of the network transformers 31, 32, 33, one of the grounding transformers 51, 52, 53 is used.
High resistances 61, 62, and 63 are connected to the neutral point of the secondary winding, and a ground fault current flows to the ground fault point. High resistance 61,6
Current transformers 71, 72, 73 are provided on the secondary side of the transformers 2, 63, and detect a current flowing to the neutral point of the primary winding of the ground transformers 51, 52, 53.

The ground fault current detectors 81, 82, 83 are connected to secondary terminals of the current transformers 71, 72, 73. The ground fault current detectors 81, 82, and 83 include current transformers 71, 72,
A current output from the secondary terminal 73 is detected to detect a ground fault that has occurred in the system. When the ground fault current is detected, the contact 81 in the ground fault current detectors 81, 82, 83
A, 82A, and 83A operate respectively.

The control devices 91, 92, and 93 are respectively
They are connected to ground fault current detectors 81, 82, 83. The control devices 91, 92, 93 are connected to ground fault current detectors 81, 8
When the contacts 81A, 82A, 83A of the 2,83 operate,
The respective internal contacts S1A, S2A, S3A operate to send the opening commands 91A, 92A, 93A to the bus communication breakers 44, 45, 46. Also, the control devices 91 and 9
2, 93 are contact points 8 of the ground fault current detectors 81, 82, 83.
When 1A, 82A, and 83A operate, internal contacts S1B, S2B, and S3B operate, respectively, and an opening command 91 is issued.
B, 92B, 93B to protector breakers 41, 42, 4
3 Here, the contacts S1A, S2A, S3A
Is provided with a timer inside the control devices 91, 92, 93 so as to operate at a timing earlier than the contacts S1B, S2B, S3B.

Here, the internal configuration of the control device 91 will be described with reference to FIG. Note that the control devices 92 and 93
Has the same configuration as the control device 91.

The control device 91 includes delay timers TA and TB connected to the contact 81A of the ground fault current detector 81, and contacts T1A and T2A that are operated after being delayed by a predetermined time by the delay timers TA and TB. . Delay timer T
A and TB are time-adjustable timers. The set time of the timer TA is set longer than the time during which the ground fault protection device 47B operates and the circuit breaker 47 opens when a ground fault occurs on the load 47A side. The set time of the delay timer TB is longer than the set time of the delay timer TA. The set time of the delay timer TA is, for example, 2 seconds, and the set time of the delay timer TB is, for example, 4 seconds.

As shown in FIG. 1, one of the grounding transformers 51
The current flowing to the neutral point of the next winding is detected by the ground fault current detector 81, and when its contact 81A operates, the timers TA and TB are started, and after a predetermined time, the contacts T1A and T2
A operates, and release commands 91A and 91B are transmitted, respectively.

That is, in the present embodiment, the control device 9
1, 92, 93 are protector breakers 41, 42, 43
It is characterized in that the opening commands 91A, 92A, 93A are sent to the bus connection circuit breakers 44, 45, 46 at a timing earlier than when the opening commands 91B, 92B, 93B are sent.

Next, the operation of the bus protection system for the spot network power receiving equipment according to the present embodiment will be described with reference to FIG. First, a case where a ground fault has occurred on the load 47A side will be described. When a ground fault occurs on the load 47A side, the ground fault protection device 47B operates to open the circuit breaker 47. The time until the ground fault protection device 47B operates is, for example, about 0.5 seconds.

In the event of a ground fault on the side of the load 47A, the contacts 81A, 82A, 83 of the
A operates. However, since the timers TA and TB of the control device 91 are set longer than the operation time of the ground fault protection device 47B, the control devices 91, 92 and 93 control the release commands 91A, 92A, 93A, 91B, 92B and 93.
Do not send B. Therefore, the bus barriers 44, 45,
46 and the protector breakers 41, 42, 43 do not operate, and no total power outage of the system occurs.

Next, the network buses 17, 18, 19
A case where a ground fault has occurred will be described. For example, if it is determined that a ground fault has occurred on the network bus 17, the contact 8 of the ground fault current detectors 81, 82, 83
1A, 82A and 83A operate simultaneously. Then, the timer TA of the control device 91, 92, 93 operates, and after the set time of this timer, the control device 91, 92, 93
Operates the contacts S1A, S2A, S3A to send the opening commands 91A, 92A, 93A, and
4, 45, 46 are released all at once.

The network bus breakers 44, 45, 46 are simultaneously opened to divide the respective network buses 17, 18, 19, so that the primary of the ground transformers 52, 53 connected to the sound network buses 18, 19 are separated. No current flows to the neutral point of the winding. Therefore, the ground fault current detectors 82 and 83
Contacts 82A and 83A return, and release commands 92A and 93
Since A stops, the bus communication circuit breaker 46 returns. However, the grounding transformer 5 connected to the network bus 17
Since the current continuously flows at the neutral point of the secondary winding No. 1, the timer TB of the control device 91 operates, and after the set time of the timer, the control device 91 operates the contact S1B. Then, the release command 91B is transmitted to open the protector circuit breaker 47. Therefore, power transmission from the healthy lines 15 and 16 is continued, and unnecessary power failure can be prevented.

As described above, in the present embodiment, the bus protection system for a ground fault in the network bus includes the bus connection circuit breakers 44, 45, 46, the ground fault current detectors 81, 82, 83, Control devices 91, 92 and 93 are provided. Among these configurations, the bus-barrier circuit breakers 44, 45, and 46 have recently been used for the purpose of dividing the buses 17, 18, and 19 for maintenance of each bus. Uses existing circuit breakers. In addition, the ground fault current detectors 81, 82, 83
Is provided for protection in the event of a ground fault in each system. Therefore, in this embodiment,
A part of the configuration of the control devices 91, 92, 93 is added, that is,
When a bus ground fault occurs, a delay timer TA that distinguishes the load 47A from a ground fault, and contacts S1A, S2A, S
Since it is only necessary to provide 3A, it can be realized only by easy improvement of the existing circuit.

In the conventional bus protection system for spot network power receiving equipment, the control devices 91 and 9 are used.
2 and 93 have only the contacts S1B, S2B and S3B, so that the ground fault point is
18 and 19, the ground fault current detectors 81 and 8
The contact points 81A, 82A and 83A of the power supply units 2 and 83 operate at the same time, and the ground fault protection device of the load 47A does not operate even if a time limit is given by the control devices 91, 92 and 93. Judgment, protector breaker 4
In some cases, the power-off commands 91B, 92B, and 93B are transmitted to 1, 42, and 43 to cause a total power failure.

On the other hand, according to the present embodiment, it is possible to easily prevent a total power failure only by improving the control device as described above. Therefore, it is possible to improve the reliability of power supply in the bus protection system of the direct grounding type low voltage spot network power receiving equipment.

Next, the configuration of a non-grounded high-voltage spot network power receiving facility according to a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a system circuit diagram illustrating an entire configuration of a non-grounded high-voltage spot network power receiving facility according to a second embodiment of the present invention. The same reference numerals as those in FIG. 1 indicate the same parts.

Power receiving lines 14, 15, 16 are connected to the three-phase, three-point spot network lines 11, 12, 13 connected to the power substation, respectively. Each power receiving line 14, 15, 16 is connected to a network bus 17, 1 via a three-line spot network power receiving device.
8 and 19 are connected. As each spot network power receiving device, each power receiving disconnecting switch 21, 22, 23, each network transformer 31, 32, 33, and each protector breaker 41, 42, 43 are connected in series for each line. It is configured.

The network buses 17, 18, and 19 have
Bus bar circuit breakers 44, 45 and 46 are provided. In recent years, the bus bar circuit breakers 44, 45, and 46 have been provided as bus bar splitting opening / closing devices for maintenance. In the present embodiment, when a ground fault occurs in the network bus, the bus communication circuit breakers 44 and 4
5, 46, each network bus 17, 18, 1
By opening the space between the protector breakers 41 and 4
The total power failure of the power receiving and transforming equipment due to the simultaneous opening of 2,43 is prevented.

A circuit breaker 47 is connected to the network bus 17 and further connected to a load 4 via a ground fault protection device 47B.
7A is connected. When a ground fault occurs on the load 47A side, the ground fault protection device 47B of the load 47A operates to open the circuit breaker 47. Each network bus 1
Similarly, a circuit breaker, a ground fault protection device, and a load are connected to 8, 19, respectively.

Each of the network buses 17, 18, and 19 is provided with a ground-type instrument transformer 101, 102, or 103, and further, a ground fault voltage detector 111, 112, or 113.
Is connected. When the ground fault voltage is detected, the contacts 111A, 1 in the ground fault voltage detectors 111, 112, 113 are connected.
12A and 113A operate respectively.

The control devices 91, 92 and 93 are respectively
It is connected to ground fault voltage detectors 111, 112, 113. The control devices 91, 92, and 93 are connected to the ground fault voltage detector 11
1, 112, 113 contact points 111A, 112A, 113
When A operates, the internal contacts S1A, S2 respectively
A, S3A operate and release commands 91A, 92A, 93
A is sent out to the bus connection circuit breakers 44, 45, 46. Further, the control devices 91, 92, and 93 are connected to the ground fault voltage detector 11
1, 112, 113 contact points 111A, 112A, 113
When A operates, the internal contacts S1B, S2 respectively
B and S3B operate, and release commands 91B, 92B and 93 are issued.
B is sent to the protector breakers 41, 42, 43. Here, the contacts S1A, S2A, S3A are connected to the contacts S1B, S
In order to operate earlier than 2B and S3B,
A timer is provided inside each of the control devices 91, 92, and 93.

Each timer and each contact S1A, S2A, S3A and each contact S1 inside the control devices 91, 92, 93
The configurations of B, S2B, and S3B are the same as those described in FIG. The set time of the delay timer TA connected to the contact point 111A of the ground fault voltage detector 111 is:
In the event of a ground fault on the load 47A side, the ground fault protection device 47B is activated, and the breaker 47 is set longer than the open time. The set time of the delay timer TB is longer than the set time of the delay timer TA. The set time of the delay timer TA is, for example, 2 seconds, and the set time of the delay timer TB is, for example, 4 seconds.

Next, the operation of the bus protection system for spot network power receiving equipment according to the present embodiment will be described. First, a case where a ground fault has occurred on the load 47A side will be described. When a ground fault occurs on the load 47A side, the ground fault protection device 47B operates to open the circuit breaker 47. The time until the ground fault protection device 47B operates is, for example, about 0.5 seconds.

In the event of a ground fault on the side of the load 47A, the contacts 11 of the ground fault voltage detectors 111, 112, 113 connected to the tertiary side of the grounding type transformers 101, 102, 103 are also used.
1A, 112A and 113A operate. However,
The timers TA and TB of the control device 91 are connected to the ground fault protection device 4.
Since the operation time is set longer than the operation time of 7B, the control devices 91, 92, 93 issue the opening commands 91A, 92A, 93.
A, 91B, 92B and 93B are not transmitted. Therefore, the busbar circuit breakers 44, 45, 46 and the protector circuit breaker 4
1, 42, and 43 do not operate, and no total power failure occurs in the system.

Next, the network buses 17, 18, 19
A case where a ground fault has occurred will be described. For example, when it is determined that a ground fault has occurred in the network bus 17, the contacts 111A, 112A, 113A of the ground fault voltage detectors 111, 112, 113 operate simultaneously.
Then, the timer TA of the control device 91, 92, 93 is operated, and after the set time of this timer, the control device 9
1, 92 and 93 operate the contacts S1A, S2A and S3A to send the release commands 91A, 92A and 93A, and open the bus communication breakers 44, 45 and 46 all at once.

Since the network buses 17, 18, and 19 are divided by the simultaneous opening of the bus connection circuit breakers 44, 45, and 46, the transformers 102 and 103 for grounded instruments connected to the sound network buses 18 and 19 are connected. No voltage is applied to the tertiary side. Therefore, the ground fault voltage detectors 112 and 113
Contacts 112A and 113A return, and the release command 92A,
Since 93A stops, the bus bar circuit breaker 46 returns. However, since a voltage is continuously generated on the tertiary side of the grounded-type instrument transformers 102 and 103 connected to the network bus 17, the timer TB of the control device 91 operates and after the set time of this timer. The control device 91
By operating the contact S1B, an open command 91B is transmitted, and the protector breaker 47 is opened. Therefore, power transmission from the healthy lines 15 and 16 is continued, and unnecessary power failure can be prevented.

As described above, in the present embodiment, the bus protection system against a ground fault of the network bus includes the bus connection circuit breakers 44, 45, 46, the ground fault voltage detectors 111, 112, 113, Control devices 91, 92, 9
3. In these configurations, the bus bar circuit breakers 44, 45, 46
Has been recently used for the purpose of maintaining each bus by dividing the same, and existing circuit breakers are used. In addition, the ground fault voltage detectors 111, 11
2, 113 are conventionally provided for protection in the event of a ground fault in each system. Therefore, in the present embodiment, a part of the configuration of the control devices 91, 92, and 93 is added, that is, when a ground fault occurs on the bus, a delay timer TA for distinguishing the ground fault from the load 47A side, and the contact S1A ,
Since it is only necessary to provide S2A and S3A, it can be realized only by easy improvement of existing circuits.

In the conventional bus protection system for spot network power receiving equipment, the control devices 91, 9
2 and 93 have only the contacts S1B, S2B and S3B, so that the ground fault point is
18 and 19, the ground fault voltage detector 111,
The contacts 111A, 112A, 113A of 112, 113 operate simultaneously and only display an alarm. Since only an alarm was displayed, there was a risk that the situation would expand to a short circuit accident.

On the other hand, according to the present embodiment, it is possible to prevent the occurrence of a short circuit accident only by improving the control device as described above. Therefore, the reliability of power supply in the bus protection system of the non-grounded high-voltage spot network power receiving equipment can be improved.

Next, a configuration of a direct grounding type low voltage spot network power receiving equipment according to a third embodiment of the present invention will be described with reference to FIG. FIG. 4 shows a third embodiment of the present invention.
It is a system circuit diagram which shows the whole structure of the low voltage spot network power receiving equipment of a direct grounding system by embodiment of FIG. The same reference numerals as those in FIG. 1 indicate the same parts.

Power receiving lines 14, 15, 16 are connected to the three-phase, three-line spot network lines 11, 12, 13 connected to the power substation, respectively. Each power receiving line 14, 15, 16 is connected to a network bus 17, 1 via a three-line spot network power receiving device.
8 and 19 are connected. As each spot network power receiving device, each power receiving disconnecting switch 21, 22, 23, each network transformer 31, 32, 33, protector fuse 201, 202, 203, and each protector breaker 41, 42, 43. , And are connected in series for each line.

The network buses 17, 18, and 19 have
Bus bar circuit breakers 44, 45 and 46 are provided. In recent years, the bus bar circuit breakers 44, 45, and 46 have been provided as bus bar splitting opening / closing devices for maintenance. In the present embodiment, when a ground fault occurs in the network bus, the bus communication circuit breakers 44 and 4
5, 46, each network bus 17, 18, 1
By opening the space between the protector breakers 41 and 4
This is to prevent a total power failure of the power receiving and transforming equipment due to the simultaneous opening of 2,43.

A circuit breaker 47 is connected to the network bus 17 and further connected to a load 4 via a ground fault protection device 47B.
7A is connected. When a ground fault occurs on the load 47A side, the ground fault protection device 47B of the load 47A operates to open the circuit breaker 47. Each network bus 1
Similarly, a circuit breaker, a ground fault protection device, and a load are connected to 8, 19, respectively.

Current transformers 71, 72, 73 are provided at the neutral points of the secondary windings of the respective network transformers 31, 32, 33, and the secondary windings of the network transformers 31, 32, 33 are provided. The current flowing to the neutral point is detected.

The ground fault current detectors 81, 82, 83 are connected to the secondary terminals of the current transformers 71, 72, 73. The ground fault current detectors 81, 82, and 83 include current transformers 71, 72,
A current output from the secondary terminal 73 is detected to detect a ground fault that has occurred in the system. When the ground fault current is detected, the contact 81 in the ground fault current detectors 81, 82, 83
A, 82A, and 83A operate respectively.

The control devices 91, 92 and 93 are respectively
They are connected to ground fault current detectors 81, 82, 83. The control devices 91, 92, 93 are connected to ground fault current detectors 81, 8
When the contacts 81A, 82A, 83A of the 2,83 operate,
The respective internal contacts S1A, S2A, S3A operate to send the opening commands 91A, 92A, 93A to the bus communication breakers 44, 45, 46. Also, the control devices 91 and 9
2, 93 are contact points 8 of the ground fault current detectors 81, 82, 83.
When 1A, 82A, and 83A operate, internal contacts S1B, S2B, and S3B operate, respectively, and an opening command 91 is issued.
B, 92B, 93B to protector breakers 41, 42, 4
3 Here, the contacts S1A, S2A, S3A
Is provided with a timer inside the control devices 91, 92, 93 so as to operate at a timing earlier than the contacts S1B, S2B, S3B.

Each timer and each contact S1A, S2A, S3A and each contact S1 inside the control devices 91, 92, 93
The configurations of B, S2B, and S3B are the same as those described in FIG. Contact 8 of ground fault current detector 81
The set time of the delay timer TA connected to 1A is set longer than the time during which the ground fault protection device 47B operates and the circuit breaker 47 opens when a ground fault occurs on the load 47A side. The set time of the delay timer TB is longer than the set time of the delay timer TA. The set time of the delay timer TA is, for example, 2 seconds, and the set time of the delay timer TB is, for example, 4 seconds.

Next, the operation of the bus protection system for the spot network power receiving equipment according to the present embodiment will be described. First, a case where a ground fault has occurred on the load 47A side will be described. When a ground fault occurs on the load 47A side, the ground fault protection device 47B operates to open the circuit breaker 47. The time until the ground fault protection device 47B operates is, for example, about 0.5 seconds.

In the event of a ground fault on the load 47A side, the contacts 81A, 82A, 83 of the
A operates. However, since the timers TA and TB of the control device 91 are set longer than the operation time of the ground fault protection device 47B, the control devices 91, 92 and 93 control the release commands 91A, 92A, 93A, 91B, 92B and 93.
Do not send B. Therefore, the bus barriers 44, 45,
46 and the protector breakers 41, 42, 43 do not operate, and no total power outage of the system occurs.

Next, the network buses 17, 18, 19
A case where a ground fault has occurred will be described. For example, if it is determined that a ground fault has occurred on the network bus 17, the contact 8 of the ground fault current detectors 81, 82, 83
1A, 82A and 83A operate simultaneously. Then, the timer TA of the control device 91, 92, 93 operates, and after the set time of this timer, the control device 91, 92, 93
Operates the contacts S1A, S2A, S3A to send the opening commands 91A, 92A, 93A, and
4, 45, 46 are released all at once.

Since the network buses 17, 18, and 19 are divided by the simultaneous opening of the bus communication circuit breakers 44, 45, and 46, the primary of the grounding transformers 52 and 53 connected to the sound network buses 18, 19 are separated. No current flows to the neutral point of the winding. Therefore, the ground fault current detectors 82 and 83
Contacts 82A and 83A return, and release commands 92A and 93
Since A stops, the bus communication circuit breaker 46 returns. However, the grounding transformer 5 connected to the network bus 17
Since the current continuously flows at the neutral point of the primary winding of No. 1, the timer TB of the control device 91 operates, and after the set time of the timer, the control device 91 operates the contact S1B. Then, the release command 91B is transmitted to open the protector circuit breaker 47. Therefore, power transmission from the healthy lines 15 and 16 is continued, and unnecessary power failure can be prevented.

As described above, in the present embodiment, the bus protection system against a ground fault in the network bus includes the bus connection circuit breakers 44, 45, 46, the ground fault current detectors 81, 82, 83, Control devices 91, 92 and 93 are provided. Among these configurations, the bus-barrier circuit breakers 44, 45, and 46 are recently used for the purpose of dividing the buses 17, 18, and 1 and performing maintenance on each bus. Uses existing circuit breakers. In addition, the ground fault current detectors 81, 82, 83
Is provided for protection in the event of a ground fault in each system. Therefore, in this embodiment,
A part of the configuration of the control devices 91, 92, 93 is added, that is,
When a bus ground fault occurs, a delay timer TA that distinguishes the load 47A from a ground fault, and contacts S1A, S2A, S
Since it is only necessary to provide 3A, it can be realized only by easy improvement of the existing circuit.

In the conventional bus protection system for the low-voltage spot network power receiving equipment, the control device 91,
Since 92 and 93 only have the contacts S1B, S2B and S3B, the ground fault point is
7, 18, 19, the ground fault current detector 8
1, 82 and 83, the contacts 81A, 82A, and 83A operate simultaneously, and even if the control devices 91, 92, and 93 give time limits, the ground fault protection device of the load 47A does not operate. It is determined that an accident has occurred, and the protector breakers 41, 42, and 43 are issued opening commands 91B, 92B, and 93.
There is a case where B is transmitted and all power outages occur.

On the other hand, according to the present embodiment, it is possible to easily prevent a total power failure only by improving the control device as described above. Therefore, it is possible to improve the reliability of power supply in the bus protection system of the high-resistance spot-type high-voltage spot network power receiving equipment.

Further, since the ground fault current detector is provided at the neutral point of the secondary winding of the network transformer, it can be easily installed.

[0060]

As described above, in the bus protection system of the high-resistance spot network power receiving equipment of the high-resistance grounding system, it is possible to early detect an accident point, prevent a total power failure, and improve the reliability of power supply. can do. Also,
In a bus protection system of a non-grounding type high-voltage spot network power receiving equipment, it is possible to prevent the spread of an accident due to the occurrence of a bus ground fault and improve the reliability of power supply. Furthermore, in the bus protection system of the low-voltage spot network power receiving equipment of the direct grounding system, an accident point can be detected, a total power failure can be prevented, and the reliability of power supply can be improved.

[Brief description of the drawings]

FIG. 1 is a system circuit diagram showing an entire configuration of a high-resistance spot-type high-voltage spot network power receiving facility according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a control device used for a high-resistance spot-type high-voltage spot network power receiving facility according to the present embodiment.

FIG. 3 is a system circuit diagram showing an entire configuration of a non-grounded high-voltage spot network power receiving facility according to a second embodiment of the present invention.

FIG. 4 is a system circuit diagram showing an entire configuration of a low-voltage spot network power receiving equipment of a direct grounding type according to a third embodiment of the present invention.

[Explanation of symbols]

 11, 12, 13 ... spot network lines 14, 15, 16 ... power receiving lines 17, 18, 19 ... network buses 21, 22, 23 ... power receiving disconnectors 31, 32, 33 ... network transformers 41, 42, 43 ... Protector circuit breakers 44, 45, 46 ... busbar communication circuit breakers 47 ... circuit breakers 47A ... loads 47B ... ground fault protection devices 51, 52, 53 ... grounding transformers 61, 62, 63 ... high resistance 71, 72, 73 ... Current transformers 81, 82, 83 ... ground fault current detectors 91, 92, 93 ... control devices 101, 102, 103 ... transformers for grounded instruments 111, 112, 113 ... ground fault voltage detectors 201, 202, 203 ... Protector fuse

Claims (3)

[Claims] 1. A protector circuit breaker connected to a secondary side of a network transformer connected to a power receiving line, a bus connecting circuit breaker connected to a network bus, and a ground connected between each bus of the network bus. A transformer and a ground fault current detector, and a bus ground fault is detected by the ground fault current detector,
A bus protection system for a high resistance grounding type spot network power receiving equipment having a control device for opening the protector breaker, wherein the control device detects a bus ground fault by the ground fault current detector and performs a first predetermined process. After a time, the bus communication circuit breaker is opened, and when the ground fault is no longer detected, the bus communication circuit breaker is restored, and after a second predetermined time longer than the first predetermined time, the protector circuit breaker is opened. A bus protection system for a high-resistance grounding type spot network power receiving equipment, characterized by opening up the power. 2. A protector circuit breaker connected to a secondary side of a network transformer connected to a power receiving line, a bus connection circuit breaker connected to a network bus, and a connection connected between respective buses of the network bus. Bus protection for non-grounded spot network power receiving equipment, including a transformer for a terrain instrument and a ground fault voltage detector, and a control device for detecting a bus ground fault by the ground fault voltage detector and opening the protector breaker In the system, the control device opens the bus communication breaker after a first predetermined time after the detection of the bus ground fault by the ground fault voltage detector. And turning off the protector circuit breaker after a second predetermined time longer than the first predetermined time. Bus protection system for network power receiving equipment. 3. The bus protection of a direct grounding type spot network power receiving equipment having a protector circuit breaker connected to a secondary side of a network transformer connected to a power receiving line and a bus connecting circuit breaker connected to a network bus. In the system, a current transformer and a ground fault current detector connected to a neutral point of a secondary winding of the network transformer, a bus ground fault is detected by the ground fault current detector, and the protector circuit breaker is A control device for opening the bus connection breaker after a first predetermined time after the detection of the bus ground fault by the ground fault current detector. Resetting the busbar circuit breaker and opening the protector circuit breaker after a second predetermined time longer than the first predetermined time. Busbar protection system of pot network power receiving equipment.