KR19990083046A - Bus protection system for spot network type electric power receiving in stallation - Google Patents

Abstract

It is a first object of the present invention to provide a bus protection system of a high resistance grounding type network receiving equipment having a high resistance grounding system by preventing an overall power failure by early detection of an accident point, thereby improving reliability of power supply.

For this purpose, the protector circuit breakers 41, 42, 43 connected to the secondary side of the network transformers 3l, 32, 33 connected to the power receiving circuits 14, 15, 16, and the network bus lines l7, l8, 19 are connected. Connected ground bus breakers 44, 45, 46, ground transformers 51, 52, 53, ground fault current detectors 81, 82, 83 connected between respective bus bars of the network bus, and ground fault current detectors. The control unit 91, 92, 93 which detects a bus fault and opens a protector breaker is comprised. The control devices 9l, 92 and 93 detect the ground fault by the ground fault current detectors 81, 82 and 83, and open the bus contact breakers 44, 45 and 46 after the first predetermined time to detect the ground fault. If not, the bus bar breaker is returned and the protector breakers 41, 42, 43 are opened after the second predetermined time longer than the first predetermined time.

Description

BUS PROTECTION SYSTEM FOR SPOT NETWORK TYPE ELECTRIC POWER RECEIVING IN STALLATION}

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

The spot network power receiving equipment is generally divided into l) high voltage spot network power receiving equipment and 2) low voltage spot network power receiving equipment. In addition, 1) the grounding method in the high-voltage spot network power receiving equipment is largely divided into 1-1) a non-grounding method and 1-2) a high resistance grounding method.

1-1) As a ground fault protection method in a non-grounded high voltage spot network power receiving facility, for example, a grounding type transformer is provided between each busbar of a network bus provided with a busbar circuit breaker. A ground fault voltage is detected via an instrument transformer, and a ground fault in the network bus or a ground fault in the grid is detected from the detected value, and an alarm is issued via a protective relay.

1-2) As a ground fault protection method in a high-voltage spot network power receiving facility of a high resistance grounding system, for example, a ground transformer is provided between each bus bar, and a high resistance and a current transformer are disposed at the neutral point of the primary winding of the ground transformer. After detecting the ground fault current through the current transformer and detecting the ground fault in the network bus or the ground fault in the system from the detected value, it is determined that the ground fault is in the network bus. It is common to open the protector circuit breakers on the secondary side of each network transformer installed at the same time.

2) The grounding method in the low-voltage spot network power receiving equipment is a direct grounding system. In the ground fault protection method generally employed, the neutral point of the secondary windings of each network transformer is collected at one point and provided with a current transformer. After detecting the ground fault in the network bus or the ground fault in the system from the detected value, it is judged to be the ground fault in the network bus, and then the protector circuit breaker on the secondary side of each network transformer is unified. It is common to have it open. Therefore, since the protector circuit breakers of the secondary side are opened simultaneously, there is a fear that all of the water substation facilities will be outaged.

On the other hand, as described, for example, in Japanese Patent Application Laid-Open No. 58-l92435, 2) in a low voltage spot network power receiving facility, a current transformer is provided directly between each bus bar, and a ground fault current is passed through the current transformer. It is known to detect the ground fault in a network bus and the ground fault in a system from this detection value, and to open a circuit breaker in a network bus, and a protector circuit breaker in order.

In the event of a ground fault in a spot network bus with a busbar circuit breaker, the busbar circuit breakers are all closed so that the ground fault protection relays all operate. Therefore, in the ground protection method of the high-voltage spot network power receiving equipment of the high resistance grounding method, since the protector circuit breakers on the secondary side of each network transformer are opened at the same time, the first problem that all the water substation equipments are blackout is lost. there was.

In addition, in 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 of expanding to a short-circuit accident because it is only an alarm.

2) Low voltage spot network power receiving facilities described in Japanese Patent Application Laid-Open No. 58-192435 have a structure in which current transformers are directly installed between each busbar, but each busbar is generally insulated and coated. There is a third problem that it is practically difficult to install a current transformer in the system, and this method is practically unacceptable.

It is a first object of the present invention to provide a bus protection system for a high resistance grounded network power receiving facility of a high resistance grounding system in which a power failure is improved by early detection of an accident point, thereby preventing a total power failure.

It is a second object of the present invention to provide a bus protection system of a non-grounded high voltage spot network power receiving facility having improved reliability of power supply by preventing an expansion of an accident caused by a bus fault.

It is a third object of the present invention to provide a bus protection system for a low voltage spot network power receiving facility of a direct grounding method which enables detection of an accident point, prevents total power failure, and improves reliability of power supply.

1 is a system circuit diagram showing an overall configuration of a high resistance ground network power receiving facility of a high resistance grounding system according to a first embodiment of the present invention;

Fig. 2 is a circuit diagram of a control device used in the high-voltage spot network power receiving facility of the high resistance grounding system according to the present embodiment.

3 is a system circuit diagram showing an overall configuration of a non-grounding high voltage spot network power receiving facility according to a second embodiment of the present invention;

4 is a system circuit diagram showing an overall configuration of a low voltage spot network power receiving facility of a direct grounding system according to a third embodiment of the present invention.

※ Explanation of symbols for main parts of drawing

11, 12, 13: spot network circuit 14, 15, 16: power circuit

17, 18, 19: network bus 21, 22, 23: power breaker

31, 32, 33: network transformer 41, 42, 43: protector circuit breaker

44, 45, 46: busbar breaker 47: breaker

47A: Load 47B: Ground Protection Device

51, 52, 53: ground transformers 61, 62, 63: high resistance

71, 72, 73: Current transformers 81, 82, 83: Ground fault current detector

91, 92, 93: controller

101, 102, 103: grounding instrument transformer

111, 112, 113: Ground fault voltage detector 201, 202, 203: Protector fuse

(1) In order to achieve the first object, the present invention relates to a protector circuit breaker connected to a secondary side of a network transformer connected to a power receiving circuit, a bus circuit breaker connected to a network bus, and each bus of the network bus. A bus resistance system of a high resistance grounding spot network power receiving equipment having a ground transformer connected to a ground fault and a ground fault current detector, and a control device for detecting a bus fault by the ground fault current detector and opening the protector breaker. After the detection of the bus ground by the ground current detector, the control device opens the bus circuit breaker after the first predetermined time, and when the ground fault is not detected, returns the bus circuit breaker and at the same time the first predetermined circuit The protector breaker is opened after a second predetermined time longer than the time.

With such a configuration, by early detection of the accident point and removing only the network busbar where a ground fault has occurred, total power failure can be prevented and the power supply reliability can be improved.

(2) In order to achieve the above second object, the present invention provides a protector circuit breaker connected to a secondary side of a network transformer connected to a power receiving circuit, a bus circuit breaker connected to a network bus, and each bus of the network bus. In a bus protection system of a non-grounded spot network receiving equipment having a grounding type transformer and a ground voltage detector connected to each other, and a control device for detecting a bus fault by the ground voltage detector and opening the protector breaker. In the control apparatus, after the bus ground fault is detected by the ground voltage detector, the bus circuit breaker is opened after the first predetermined time, and when the ground fault is not detected, the bus circuit breaker is returned. The protector circuit breaker may be opened after a second predetermined time longer than the first predetermined time.

With such a configuration, since the bus bar is separated, it is possible to prevent the expansion of an accident due to the bus ground fault and to improve the reliability of the power supply.

(3) In order to achieve the third object, the present invention provides a direct grounding spot network having a protector circuit breaker connected to a secondary side of a network transformer connected to a power receiving line, and a bus circuit breaker connected to a network bus. A bus protection system of a power receiving equipment, comprising: a current transformer and a ground fault current detector connected to a neutral point of a secondary winding of the network transformer, and a control device for detecting a bus fault by the ground fault current detector to open the protector breaker. The control device opens the bus circuit breaker after the first predetermined time after detecting the bus ground by the ground current detector, and if the ground fault is not detected, the bus circuit breaker is returned. The protector circuit breaker may be opened after a second predetermined time longer than the first predetermined time.

With such a configuration, early detection of an accident point and removal of only the network busbar where a ground fault has occurred can prevent an overall power failure and improve the reliability of power supply.

(Example)

1 and 2, the configuration of the high-voltage spot network power receiving equipment of the high resistance grounding system according to the first embodiment of the present invention will be described.

Fig. 1 is a system circuit diagram showing the overall configuration of a high resistance grounding network receiving apparatus of the high resistance grounding system according to the first embodiment of the present invention, and Fig. 2 is a high resistance grounding network of the high resistance grounding system according to the present embodiment. It is a circuit diagram of the control apparatus used for a power receiving facility.

In Fig. 1, power receiving lines 14, l5, and 16 are connected to three-phase, three-line, spot network circuits 11, 12, and 13 connected to a power substation, respectively. Each of the power receiving lines 14, 15, and 16 is connected to the network bus lines 17, 18, 19 via a three-line spot network receiving device. As the spot network receivers, each of the power receiver breakers 21, 22, 23, each of the network transformers 31, 32, 33, and the protector breakers 41, 42, 43 are connected in series for each line. have.

The bus bar breakers 44, 45, 46 are provided in the network buses l7, 18, l9. The busbar circuit breakers 44, 45 and 46 have recently begun to be installed as switchboards for busbars for repair. In the present embodiment, at the time of a ground fault in the network bus, the circuit breakers 44, 45, 46 are used to open the network breakers 17, 18, 19 to protect the circuit breakers 41, 42, The total power failure of the water substation facility is prevented due to the simultaneous opening of 43). Details thereof will be described later.

A circuit breaker 47 is connected to the network bus 17, and a load 47A is connected via a ground fault protection device 47B. If a ground fault occurs on the load 47A side, the ground fault protection device 47B of the load 47A is operated to open the breaker 47. Similarly, a circuit breaker, a ground fault protection device and a load are connected to each of the network buses 18 and 19, respectively.

Each of the network buses 17, 18, 19 is provided with ground transformers 51, 52, 53. In order to detect a ground fault in the secondary system of the network transformers 31, 32 and 33, high resistances 61, 62 and 63 are connected to the neutral point of the primary winding of the ground transformers 51, 52 and 53. A ground fault current is flowing into the ground fault point. Current transformers 71, 72, and 73 are provided on the secondary side of the high resistances 61, 62, and 63, and currents flowing to the neutral point of the primary winding of the ground transformers 51, 52, and 53 are detected.

Ground fault current detectors 81, 82, and 83 are connected to the secondary terminals of the current transformers 71, 72, and 73. The ground current detectors 81, 82, and 83 detect currents output from the secondary terminals of the current transformers 71, 72, and 73, and detect ground faults occurring in the system. When the ground current is detected, the contacts 81A, 82A, 83A in the ground current detectors 81, 82, 83 operate, respectively.

The control devices 91, 92, 93 are connected to the ground fault current detectors 81, 82, 83, respectively. When the control devices 91, 92, 93 operate the contacts 81A, 82A, 83A of the ground fault current detectors 81, 82, 83, the internal contacts S1A, S2A, S3A operate, respectively, and the open command ( 91A, 92A, and 93A are sent to bus bar breakers 44, 45, and 46. In addition, when the contacts 81A, 82A, 83A of the ground fault current detectors 81, 82, 83 operate, the control devices 91, 92, 93 operate to open the respective contacts SlB, S2B, and S3B. Commands 91B, 92B and 93B are sent to the protector breakers 41, 42 and 43. Here, the contacts S1A, S2A, S3A are provided with timers inside the control devices 91, 92, 93 so as to operate at a timing earlier than the contacts S1B, S2B, S3B.

Here, the internal structure of the control apparatus 9l is demonstrated using FIG.

In addition, the control apparatuses 92 and 93 also have the same structure as the control apparatus 9l.

The control device 9l is configured to operate the contacts TlA and T2A which are operated after a predetermined time delay by the delay timers TA and TB connected to the contacts 8lA of the ground current detector 81 and the delay timers TA and TB. Equipped. Delay timers TA and TB are time-adjustable timers. The setting time of the timer TA is corrected longer than the time when the ground fault protection device 47B operates and the breaker 47 opens at the time of a ground fault 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 setting time of the delay timer TA is 2 seconds, for example, and the setting time of the delay timer TB is 4 seconds, for example.

As shown in Fig. 1, the current flowing to the neutral point of the l-th winding of the ground transformer 51 is detected by the ground fault current detector 81, and when the contact 81A operates, the timers TA and TB start up. After a predetermined time, the contacts TlA and T2A operate to send the open commands 9lA and 91B, respectively.

In other words, in the present embodiment, the control devices 9l, 92, 93 have a bus circuit breaker 44, at a faster timing than the open commands 91B, 92B, 93B are sent to the protector breakers 4l, 42, 43. It is characterized in that the open commands 91A, 92A, 93A are sent to 45 and 46).

Next, with reference to FIG. 1, operation | movement of the bus | wire protection system of the spot network power receiving equipment by this embodiment is demonstrated.

First, a case where a ground fault has occurred on the load 47A side will be described.

If a ground fault occurs on the load 47A side, the ground fault protection device 47B operates to open the 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, 83A of the ground current detectors 8l, 82, 83 operate. However, since the timers TA, TB of the control device 91 are corrected longer than the operation time of the ground fault protection device 47B, the control devices 91, 92, 93 are set to the open commands 9lA, 92A, 93A, 91B, 92B, 93B) are not transmitted. Therefore, the bus bar breakers 44, 45, 46 and the protector breakers 4l, 42, 43 do not operate, and the entire power failure of the system does not occur.

Next, a case where a ground fault has occurred in the network buses 17, 18 and l9 will be described.

For example, when it is determined that a ground fault has occurred in the network bus 17, the contacts 8lA, 82A, 83A of the ground current detectors 81, 82, 83 operate simultaneously. The timers TA of the control devices 91, 92, and 93 operate, and after the set time of this timer, the control devices 9l, 92, and 93 operate the contacts SlA, S2A, and S3A to release the opening command. 91A, 92A, and 93A are sent out to simultaneously open the busbar breakers 44, 45, and 46.

Since each network bus 17, 18, 19 is divided by opening the bus contact breaker 44, 45, 46 at once, l of the ground transformers 52, 53 connected to the healthy network bus 18, 19. No current flows through the neutral point of the secondary winding. Therefore, since the contact instructions 82A, 83A of the ground fault current detectors 82, 83 return, and the open command 92A, 93A stops, the bus-bar breaker 46 returns. However, since the current continues to flow through the neutral point of the secondary winding of the ground transformer 51 connected to the network bus 17, the timer TB of the control device 91 operates and after the set time of the timer, the control device 91 operates the contact SlB to send the opening command 91B to open the protector breaker 47.

Therefore, power transmission from the power 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 of the network bus includes busbar breakers 44, 45, and 46, ground fault current detectors 81, 82, and 83, and control devices 91, 92, and 93. It is comprised by). Among these configurations, busbar circuit breakers 44, 45 and 46 have been recently used for the maintenance and management of busbars by dividing busbars 17, l8 and 19, and use the existing circuit breakers. . In addition, the ground current detectors 8l, 82 and 83 are conventionally provided for the protection of the ground fault of each system. Therefore, in the present embodiment, a part of the configuration of the control devices 91, 92, 93 is added, that is, the delay timer TA and the contact SlA which distinguish the ground fault from the load 47A side when a ground fault occurs in the bus. , S2A, S3A) is good just to provide a simple improvement of the existing circuit.

In addition, in the bus protection system of the conventional spot network power receiving facility, since the control devices 91, 92, and 93 have only the contacts S1B, S2B, and S3B, the ground fault point is the network bus 17, 18, 19. ), The ground fault current detectors 81, 82, and 83 of the contacts 8lA, 82A, and 83A operate simultaneously to protect the load 47A from the ground even if the control devices 91, 92, and 93 have a time limit. Since the device does not operate, it is determined that a ground fault has occurred in the network bus, and there are cases in which open commands 91B, 92B, and 93B are sent to the protector breakers 4l, 42, and 43, and all of them are out of power.

In contrast, according to the present embodiment, the entire power failure can be easily prevented only by the improvement of the control device as described above. Therefore, it is possible to improve the reliability of power supply in the bus protection system of the low-voltage spot network power receiving equipment of the direct grounding system.

Next, the structure of the non-grounding high voltage spot network power receiving equipment according to the second embodiment of the present invention will be described with reference to FIG. 3.

Fig. 3 is a system circuit diagram showing the overall configuration of a non-grounding high voltage spot network power receiving equipment according to a second embodiment of the present invention. In addition, the same code | symbol as FIG. 1 has shown the same part.

The power receiving lines 14, l5, and 16 are connected to the spot network lines ll, l2, and 13 of the three-phase three lines connected to the power substation, respectively. Each of the power receiving lines 14, 15, 16 is connected to the network buses 17, l8, 19 via a three-line spot network receiving device. As the spot network receivers, each of the power receiver breakers 21, 22, 23, the network transformers 31, 32, 33, and the protector breakers 4l, 42, 43 are connected in series for each line. .

The bus bar breakers 44, 45 and 46 are provided in the network buses 17, 18 and 19. The busbar contact breakers 44, 45, and 46 are beginning to be installed as a busbar switchgear for repair in recent years. In the present embodiment, the protector circuit breakers 41, 42, 43 are opened by using the bus circuit breakers 44, 45, 46 to open the network buses l7, l8, 19 at the time of a ground fault in the network bus. It is to prevent the total power failure of the water substation equipment by the opening of Japan.

A circuit breaker 47 is connected to the network bus 17, and a load 47A is connected via a ground fault protection device 47B. If a ground fault occurs on the load 47A side, the ground fault protection device 47B of the load 47A operates to open the breaker 47. Similarly, a circuit breaker, a ground fault protection device and a load are connected to each of the network buses 18 and 19, respectively.

Each of the network buses l7, 18, and 19 is provided with grounding type transformers 101, 102, l03, and ground fault voltage detectors 111, l12, 113 are connected. When the ground voltage is detected, the contacts lllA, 112A, and 113A in the ground voltage detectors 11l, ll2, and l13 operate, respectively.

The control devices 91, 92 and 93 are connected to the ground fault voltage detectors 111, l12 and 113, respectively. In the control devices 91, 92, and 93, when the contacts 11lA, 1l2A, and 113A of the ground voltage detectors ll1, 112, and l13 operate, the internal contacts SlA, S2A, and S3A operate, respectively, and the open command ( 91A, 92A, and 93A are sent to bus bar breakers 44, 45, and 46. In addition, when the contacts 11lA, l12A, and 1l3A of the ground voltage detectors 1l1, 112, and 113 operate, the control devices 9l, 92, 93 operate to open the respective contacts SlB, S2B, and S3B. Commands 91B, 92B and 93B are sent to the protector breakers 41, 42 and 43. Here, the contacts S1A, S2A, S3A are provided with timers inside the control devices 91, 92, 93 so as to operate at a timing faster than the contacts S1B, S2B, S3B.

The structure of each timer, each contact S1A, S2A, S3A and each contact S1B, S2B, S3B in the control apparatus 91, 92, 93 is the same as that demonstrated in FIG. The setting time of the delay timer TA connected to the contact point 111A of the ground fault voltage detector 111 is larger than the time that the ground fault protection device 47B operates when the ground fault occurs on the load 47A side and the breaker 47 opens. It has been corrected for a long time. The set time of the delay timer TB is longer than the set time of the delay timer TA. The setting time of the delay timer TA is 2 seconds, for example, and the setting time of the delay timer TB is 4 seconds, for example.

Next, the operation of the busbar protection system of 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.

If a ground fault occurs on the load 47A side, the ground fault protection device 47B operates to open the breaker 47. The time until the ground fault protection device 47B operates is, for example, about 0.5 seconds.

Even in the event of a ground fault on the load 47A side, the contacts 11lA, 112A, 1l3A of the ground voltage detectors 111, 112, ll3 connected to the tertiary side of the ground-type instrument transformer 101, 102, 103 operate. However, since the timers TA, TB of the control device 91 are corrected longer than the operation time of the ground fault protection device 47B, the control devices 91, 92, 93 are open commands 91A, 92A, 93A, 9LB. , 92B, 93B). Therefore, the bus bar breakers 44, 45, 46 and the protector breakers 4l, 42, 43 do not operate, and the entire power failure of the system does not occur.

Next, a case where a ground fault has occurred in the network bus lines l7, 18 and l9 will be described.

For example, when it is determined that a ground fault has occurred in the network bus 17, the contacts 11lA, l12A, ll3A of the ground voltage detectors 1111, 112, l13 operate simultaneously. Then, the timers TA of the control devices 91, 92, 93 operate, and after the set time of the timers, the control devices 91, 92, 93 operate the contacts SlA, S2A, S3A to open command. (9lA, 92A, 93A) were sent to open the busbar circuit breakers 44, 45, 46 at once.

Since each network bus 17, l8, 19 is divided by the open of bus bus circuit breaker 44, 45, 46 at once, the ground type instrument transformer 102, 103 connected to the healthy network bus 18, 19. The voltage does not go to the tertiary side of). Therefore, since the contacts 1112A and 113A of the ground voltage detectors ll2 and 113 return, and the open commands 92A and 93A stop, the bus contact breaker 46 returns. However, since the voltage is continuously generated on the tertiary side of the ground-type instrument transformers 102 and l03 connected to the network bus 107, the timer TB of the control device 91 operates and after the set time of this timer. The control unit 91 operates the contact S1B to send the opening command 91B to open the protector breaker 47.

Therefore, power transmission from the power 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 of the network bus includes the bus contact breakers 44, 45, 46, the ground voltage detectors 11, 112, 113, and the control devices 9l, 92, 93). Among these configurations, busbar contact breakers 44, 45 and 46 have recently been used for the purpose of maintaining and managing the busbars by dividing busbars l7, 18 and 19. Doing. In addition, the ground voltage detectors 111, 12, and 1l3 are conventionally provided for the protection of the ground fault of each system. Therefore, in this embodiment, a part of the control apparatus 91, 92, 93 is added, ie, the delay time TA which distinguishes from the ground fault of the load 47A at the time of the ground fault of a bus, and a contact point, Since it is only necessary to provide (S1A, S2A, S3A), it can be achieved only by easy improvement of the existing circuit.

In addition, in the bus protection system of the conventional spot network power receiving facility, since the control devices 91, 92, and 93 have only the contacts SlB, S2B, and S3B, the ground fault point is the network bus 17, l8. , 19), the contacts lllA, 1l2A and 113A of the ground voltage detectors 1111, 112 and 113 simultaneously operated and displayed an alarm. Since it was only an alarm display, there was a fear that the short circuit accident would expand.

In contrast, according to the present embodiment, the expansion of the short circuit accident can be prevented only by the improvement of the control device as described above. Therefore, it is possible to improve the reliability of power supply in the bus protection system of the non-grounding high voltage spot network power receiving equipment.

Next, with reference to FIG. 4, the structure of the low voltage | voltage spot network power receiving equipment of the direct grounding system by 3rd Embodiment of this invention is demonstrated.

4 is a system circuit diagram showing the overall configuration of a low-voltage spot network power receiving facility of the direct grounding system according to the third embodiment of the present invention. In addition, the same code | symbol as FIG. 1 has shown the same part.

The power receiving lines 14, l5, and 16 are connected to the spot network lines 11, l2, and 13 of the three-phase three lines connected to the power substation, respectively. Each power receiving line 14, 15, 16 is connected to the network bus lines 17, 18, 19 via a three-line spot network receiving device. As the spot network receivers, the power receiver breakers 21, 22, 23, the network transformers 31, 32, 33, the protector fuses 201, 202, 203, and the protector breakers 41, 42, 43, respectively. Each line is connected in series.

The bus bar breakers 44, 45, and 46 are provided in the network buses 7, 18, and 19. The busbar circuit breakers 44, 45 and 46 have recently started to be installed as switchboards for busbars for repair. In the present embodiment, the protector breakers 41, 42, 43 are opened between the network buses 17, 18, l9 by using these bus contactors 44, 45, 46 at the time of a ground fault in the network bus. This is to prevent the total power outage of the water substation equipment by opening in Japan.

A circuit breaker 47 is connected to the network bus 17, and a load 47A is connected via a ground fault protection device 47B. If a ground fault occurs on the load 47A side, the ground fault protection device 47B of the load 47A is operated to open the breaker 47. In addition, circuit breakers, ground fault protection devices, and loads are similarly connected to the respective network buses 18 and 19.

Current transformers 71, 72, and 73 are provided at the neutral points of the secondary windings of the network transformers 31, 32, and 33, and currents flowing through the neutral points of the secondary windings of the network transformers 3l, 32, and 33 are detected. do.

Ground fault current detectors 81, 82, and 83 are connected to the secondary terminals of the current transformers 7l, 72, and 73. The ground current detectors 81, 82, and 83 detect a current output from the secondary terminal of the current transformers 71, 72, and 73 to detect a ground fault occurring in the system. When the ground current is detected, the contacts 81A, 82A, 83A in the ground current detectors 8l, 82, 83 operate, respectively.

The control devices 91, 92 and 93 are connected to the ground fault current detectors 81, 82 and 83, respectively. When the contacts 81A, 82A, 83A of the ground fault current detectors 8l, 82, 83 operate, the control devices 9l, 92, 93 operate to open the respective contacts S1A, S2A, S3A. The commands 9lA, 92A, 93A are sent to the bus bar breakers 44, 45, and 46. In addition, when the contacts 81A, 82A, 83A of the ground fault current detectors 81, 82, 83 operate, the control devices 9l, 92, 93 operate to open the respective contacts SlB, S2B, and S3B. The commands 91B, 92B and 93B are sent to the protector breakers 4l, 42 and 43. Here, the contacts S1A, S2A, S3A are provided with timers inside the control devices 91, 92, 93 so as to operate at a timing earlier than the contacts S1B, S2B, S3B.

The structure of each timer, each contact S1A, S2A, S3A and each contact S1B, S2B, S3B in the control apparatus 91, 92, 93 is the same as that demonstrated in FIG. The setting time of the delay timer TA connected to the contact 8lA of the ground fault current detector 81 is the time at which the ground fault protection device 47B operates when the ground fault of the load 47A causes the breaker 47 to open. The correction is longer than. The set time of the delay timer TB is longer than the set time of the delay timer TA. The setting time of the delay timer TA is 2 seconds, for example, and the setting time of the delay timer TB is 4 seconds, for example.

Next, the operation of the busbar protection system of 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.

If a ground fault occurs on the load 47A side, the ground fault protection device 47B operates to open the breaker 47. The time until the ground fault protection device 47B operates is, for example, about 0.5 seconds.

Even in the event of a ground fault on the load 47A side, the contacts 81A, 82A, 83A of the ground current detectors 8l, 82, 83 operate. However, since the timers TA, TB of the control device 91 are corrected longer than the operation time of the ground fault protection device 47B, the control devices 91, 92, and 93 are open commands 91A, 92A, and 93A. , 91B, 92B, 93B) are not sent. Therefore, the bus bar breakers 44, 45, 46 and the protector breakers 41, 42, 43 do not operate, and no system power failure occurs.

Next, a case where a ground fault has occurred in the network buses 17, 18 and l9 will be described.

For example, when it is determined that a ground fault has occurred in the network bus 107, the contacts 81A, 82A, 83A of the ground fault current detectors 81, 82, 83 operate simultaneously. Then, the timers TA of the control devices 9l, 92, 93 operate, and after the set time of this timer, the control devices 9l, 92, 93 operate the contacts SlA, S2A, S3A, and open command. (9lA, 92A, 93A) were sent to open the busbar circuit breakers 44, 45, 46 at once.

Since each network bus 1, 18, 19 is divided by opening the bus contact breakers 44, 45, and 46 simultaneously, one of the ground transformers 52, 53 connected to the healthy network buses 18, 19 is divided. No current flows through the neutral point of the secondary winding. Thus, the contact points 82A, 83A of the ground fault current detectors 82, 83 return, and the open command 92A, 93A stops, so that the bus bar breaker 46 returns. However, since the current continuously flows to the neutral point of the primary winding of the ground transformer 51 connected to the network bus 107, the timer TB of the control device 91 operates to operate after the set time of this timer. The control device 9l operates the contact S1B to send the open command 9lB to open the protector breaker 47.

Therefore, power transmission from the power lines l5 and l6 is continued, and unnecessary power failure can be prevented.

As described above, in the present embodiment, the bus protection system for the ground fault of the network bus includes the bus contact breakers 44, 45, 46, the ground current detectors 8l, 82, 83, and the control devices 9l, 92, 93. It consists of). Among these configurations, busbar circuit breakers 44, 45, and 46 have been recently used for the purpose of maintaining and managing buses by dividing buses 17, 18, and 19, and use existing circuit breakers. . In addition, the ground current detectors 81, 82, and 83 are conventionally provided for the protection of the ground fault of each system. Therefore, in the present embodiment, the delay timer TA and the contact SlA which add a part of the configuration of the control apparatus 91, 92, 93, that is, to distinguish the ground fault from the load 47A side when a ground fault occurs in the bus bar. , S2A, S3A) is good, so that it can be realized by easy improvement of the existing circuit.

In addition, in the bus protection system of the conventional low voltage spot network power receiving facility, since the control devices 91, 92, and 93 have only the contacts S1B, S2B, and S3B, the ground fault point is the network bus (1). If they occur within l8, 19, the contacts 47A, 82A, 83A of the ground fault current detectors 81, 82, 83 operate simultaneously to allow the control devices 91, 92, 93 to time the load 47A. Since the ground fault protection device does not operate, there is a case where it is determined that a ground fault has occurred in the network bus.

In contrast, according to the present embodiment, the entire power failure can be easily prevented only by the improvement of the control device as described above. Therefore, the reliability of the power supply in the bus protection system of the high-voltage spot network power receiving equipment of the high resistance grounding system can be improved.

In addition, 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.

As described above, in the bus protection system of the high-voltage spot network power receiving facility of the high-resistance grounding system, early detection of an accident point can be performed, and overall power failure can be prevented to improve the reliability of power supply.

In addition, in the bus protection system of the non-grounded high voltage spot network power receiving facility, it is possible to prevent the expansion of an accident caused by a bus ground fault and to improve the reliability of power supply.

In addition, in the bus protection system of the low-voltage spot network power receiving facility of the direct grounding system, it is possible to detect an accident point, prevent a total power failure, and improve the reliability of power supply.

Claims (3)

A protector circuit breaker connected to the secondary side of the network transformer connected to the power receiving circuit, a bus circuit breaker connected to the network bus, a ground transformer and a ground current detector connected between each bus of the network bus, and the ground current detector In a bus protection system of a spot network power receiving facility having a control device for detecting a bus fault and opening the protector breaker, The control device opens the bus circuit breaker after the first predetermined time after detecting the bus ground by the ground current detector, and if the ground fault is not detected, returns the bus circuit breaker and at the same time, And said protector circuit breaker is opened after a second predetermined time longer than a first predetermined time. A protector circuit breaker connected to the secondary side of the network transformer connected to the power receiving circuit, a bus circuit breaker connected to the network bus, a grounding type instrument transformer and ground voltage detector connected between each bus of the network bus, and the ground fault In a bus protection system of a spot network power receiving facility having a control device which detects a bus fault with a voltage detector and opens the protector breaker, The control device, after detecting the ground fault by the ground voltage detector, opens the bus contact breaker after the first predetermined time and returns the bus contact breaker when the ground fault is not detected. And said protector circuit breaker is opened after a second predetermined time longer than one predetermined time. In a bus protection system of a spot network power receiving facility having a protector circuit breaker connected to a secondary side of a network transformer connected to a power receiving circuit, and a bus circuit breaker connected to a network bus, A current transformer and a ground fault current detector connected to the neutral point of the secondary winding of the network transformer, and a control device for detecting a bus fault by the ground fault current detector to open the protector breaker, The control device, after detecting the bus ground fault by the ground current detector, after the first predetermined time, opens the bus circuit breaker and returns the bus circuit breaker when the ground fault is not detected. And the protector circuit breaker is opened after a second predetermined time longer than the predetermined time of the network.