KR100419261B1 - apparatus for protecting ground fault of low voltage bus in spot network system - Google Patents

Abstract

The present invention relates to a low voltage bus ground fault protection device of a spot network system, which is connected to first to fourth units (# 1 to # 4 units) each composed of a network transformer, a network protector, a network fuse, and a main circuit breaker. A low voltage bus ground fault protection device of a spot network system having a low voltage bus bar, the first ground over current relay unit performing a relay operation when a ground overcurrent caused by a ground fault generated at a certain point of the low voltage bus bar exceeds a predetermined reference value. And a first blocking / lock-out relay for outputting a signal for dividing and disconnecting the low voltage bus to determine the ground point of the relay operation and the low voltage bus according to the relay operation of the first ground overcurrent relay. First and second blocking and lockout contact portions, which are turned on and off according to a signal output from the first blocking and lockout relay, and the first blocking and lockout relay. Relaying operation when the ground overcurrent exceeds a predetermined reference value according to the operation of the first breaker for dividing the low voltage bus bar between the second unit and the third unit according to the signal output from the unit, and the first breaker / lockout contact unit. A ground fault point of the second ground fault overcurrent relay and the first unit and the second unit side low voltage bus divided by the relay operation and the first breaker according to the relay operation of the second ground overcurrent relay; A second blocking / lockout relay section for outputting a signal for dividing and blocking the low voltage busbar for discrimination, and third and fourth blocking / turning on / off according to a signal output from the second blocking / lockout relay section; A lockout contact portion, a second breaker for dividing and blocking a low voltage busbar between the first unit and the second unit according to a signal output from the second shutoff / lockout relay unit, and the third and fourth shutoff / Third and fourth ground over-current relays for outputting signals for blocking the network protectors and the main circuit breakers of the first and second units, respectively, according to on / off of the cutout contact portion, and the second blocking / lockout contact point; When the ground overcurrent exceeds a predetermined reference value according to the negative operation, the ground fault current is divided by the relay operation and the first interrupter according to the relay operation of the fifth ground overcurrent relay and the relay operation of the fifth ground overcurrent relay. A third cut-off / lock-out relay for outputting a signal for dividing and disconnecting the low-voltage bus to determine the ground fault of the third unit and the fourth unit-side low voltage bus; and an output from the third cut-off / lock-out relay Between the fifth and sixth blocking / lockout contact portions, which are turned on / off in accordance with the received signal, and the third and fourth units according to signals output from the third blocking and lockout relay portions. Outputs a signal for blocking the network protector and the main circuit breaker of the third and fourth units, respectively, according to the third cut-off part for dividing the low-voltage busbar and the on / off of the fifth and sixth cut-off / lock-out contact parts. It consists of sixth and seventh ground overcurrent relays, and the low voltage bus network is divided into units in the low voltage spot network system employed to secure high electricity supply reliability. Minimize, prevent and minimize property loss due to burnout of equipment caused by the continuation of ground faults, and has the effect of preventing the safety accidents of electric fire and life.

Description

Apparatus for protecting ground fault of low voltage bus in spot network system

The present invention relates to a spot network system, and in particular, a low voltage bus ground fault protection of a spot network system for minimizing the power outage section of a low voltage busbar when a low voltage bus ground fault occurs in a low voltage spot network system that is employed to secure high electricity supply reliability. Relates to a device.

Hereinafter, a spot network system according to the prior art will be described.

1 is a view illustrating an example of a spot network system according to the related art, and includes first to fourth units (# 1 to # 4 units), each of which comprises a switch 1 and a network transformer 2. Ground fault overcurrent relay (3), overcurrent relay (4), circuit breaker (5), transformer (6), voltage relay (7), transformer (8), phase relay (9), electric power The direction relay 10, the fuse 11, the low voltage bus | wire 12, the fuse 13, the overcurrent relay 14, the ground overcurrent relay 15, and the circuit breaker 16 are comprised.

The circuit breaker 5, transformer 6, voltage relay 7, transformer 8, phase relay 9, and power direction relay 10 of each unit are connected to a network protector. Will be constructed.

The fuse 13, the overcurrent relay 14, the ground overcurrent relay 15, and the breaker 16 constitute a takeoff device, and power is supplied to each load through the takeoff device.

The operation of the spot network system according to the related art configured as described above will be described in detail with reference to the accompanying drawings.

Spot network system (spot network system) is configured as shown in Figure 1, in the event of a ground fault, the network protector as the main protection, the network fuse or substation-side primary switch back protection, but actually the network protector (network The protector has no fault current blocking function, and blocking the forward current will place it in the protector's own function.

Network fuse or substation side switchgear can't distinguish ground faults, so all network fuses of all units must be blown out and all of the substation side breakers must be cut off, which can lead to power outages to other customers. The purpose of a spot network system, which is a facility, cannot be achieved.

In addition, in this process, the ground fault failure flow of the large current that completely melts the equipment in case of ground fault is sustained, resulting in irreparable fatal damage, and the entire circuit power failure when replacing the blown network fuse or repairing the trouble spot. This is inevitable.

Therefore, the present invention has been made in order to solve the above problems, in the low-voltage spot network system that is adopted to secure a high electricity supply reliability by dividing the low-voltage busbar unit by unit to reduce the power failure section of the low-voltage busbar when the ground fault failure occurs It is an object of the present invention to provide a low voltage bus ground fault protection device of a spot network system for minimization.

1 is a view showing an example of a spot network system according to the prior art;

Figure 2 is a view showing an embodiment of a low voltage bus ground fault protection device of the spot network system according to the present invention

3 is a view showing another embodiment of a low voltage bus ground fault protection device of a spot network system according to the present invention;

4 is a view showing another embodiment of a low voltage bus ground fault protection device of a spot network system according to the present invention;

Explanation of symbols for main points in the drawings

101: network transformer 102: network protector

103: network fuse 104: main circuit breaker

111: first ground over-current relay section 112: first cut-off / lockout relay section

113, 114: 1st and 2nd blocking / lockout contact part

115: first breaker 116: second ground over-current relay

117: 2nd blocking / lockout relay

118, 119: third and fourth blocking / lockout contacts

120: second blocking unit

121, 122: 3rd and 4th ground overcurrent relay

123: fifth ground over-current relay section 124: third blocking / lockout relay section

125, 126: fifth and sixth blocking / lockout contact points

127: third block

128, 129: 6th and 7th ground overcurrent relay

Features of the low voltage bus ground fault protection device of the spot network system according to the present invention for achieving the above object, the first and second units each consisting of a network transformer, a network protector, a network fuse, and a main circuit breaker ( In the low voltage bus ground fault protection device of a spot network system having a low voltage bus bar connected to # 1, # 2 Unit), if the ground overcurrent according to the ground fault generated at a certain point of the low voltage bus exceeds a predetermined reference value A first ground over-current relay unit for performing the operation, and the cut-off / lock outputting a signal for dividing the low voltage bus bar to determine the grounding point of the relay operation and the low-voltage busbar according to the relay operation of the first ground over-current relay unit An out relay section, first and second blocking / lockout contact sections that are turned on / off according to a signal output from the blocking / lockout relay section, and A breaker for dividing and blocking the low voltage busbar between the first unit (# 1 unit) and the second unit (# 2 unit) according to the signal output from the breaker / lockout relay unit; and the first and second shutoff / locks. Including a second and a third ground over-current relay for outputting a signal for blocking the network protector and the main circuit breaker of the first and second units (# 1, # 2 Unit) according to the on / off of the contact point It is composed.

Each of the first to third ground over-current relays and the break / lock-out relays is either a mechanical or electronic relay, and the breaker includes a low voltage bus bar in which a three-pole circuit breaker or a ground fault does not occur and a ground fault occurs. Another feature is that it is either a 4-pole breaker for continuing operation with 2 units (3 units) or 3 units (3 units), the minimum combination of spot network systems.

Another feature of the low-voltage bus ground fault protection device of the spot network system according to the present invention for achieving the above object is, the first to third respectively composed of a network transformer, a network protector, a network fuse, and a main circuit breaker In a low voltage bus ground fault protection device of a spot network system having a low voltage bus bus connected to a unit (# 1 to # 3 unit), when the ground overcurrent caused by a ground fault generated at a certain point of the low voltage bus exceeds a predetermined reference value. A first ground over-current relay for performing the relay operation, and the first ground over-current relay unit for outputting a signal for dividing the low voltage bus bar to determine the ground fault of the relay operation and the low voltage bus according to the relay operation A first blocking / lockout relay section and first and second blocking / ropping on / off according to a signal output from the first blocking / lockout relay section; A first breaker for dividing and disconnecting the low voltage bus bar between the second contact unit and the third unit according to the signal output from the first contact / lockout relay unit; Relay operation and the second ground overcurrent relay for performing the relay operation if the ground overcurrent exceeds a predetermined reference value according to the operation of the first blocking / lockout contact portion; A second cut-off which outputs a signal for dividing the low-voltage busbar to discriminate the ground points of the low-voltage busbars of the first unit (# 1 Unit) and the second unit (# 2 Unit) divided by the first breaker; / Lock-out relay, the third and fourth blocking / lockout contact portion on / off in accordance with the signal output from the second blocking / lockout relay, and output from the second blocking / lockout relay The first unit (# 1 Unit) and the second unit according to the received signal A second blocking portion for dividing and blocking the low voltage busbar between the nits and the first and second units according to on / off of the third and fourth blocking / lockout contacts; Relay operation when the ground overcurrent exceeds a predetermined reference value according to the operation of the third and fourth ground overcurrent relays for outputting a signal to block the network protector and the main circuit breaker, respectively, and the second blocking / lockout contact portion. A fifth ground overcurrent relay configured to perform a third ground / over current relay; a third blocking / lockout relay performing a relay operation according to a relay operation of the fifth ground overcurrent relay; Blocking the fifth blocker / lockout contact unit turned on / off in response to a signal, and the network protector and the main circuit breaker of the third unit (# 3 Unit) according to on / off of the fifth blocker / lockout contact unit. Outputting signal for It consists of 6 ground overcurrent relays.

Each of the first to sixth ground overcurrent relays is either a mechanical or electronic relay, and each of the first and third blocking / lockout relays is either a mechanical or electronic relay.

The first breaker separates the low voltage bus without the ground fault and the low voltage bus with the ground fault so as to continue operation with 2 units or 3 units, which is a minimum combination of spot network systems. It is a pole breaker, and the second breaker is characterized by another one of the three-pole breaker or four-pole breaker.

Another feature of the low-voltage bus ground fault protection device of the spot network system according to the present invention for achieving the above object is the first to fourth configured with a network transformer, a network protector, a network fuse, and a main circuit breaker, respectively. In a low voltage bus ground fault protection device of a spot network system having a low voltage bus bus connected to a unit (# 1 to # 4 unit), when the ground overcurrent caused by a ground fault generated at a certain point of the low voltage bus exceeds a predetermined reference value. A first ground over-current relay for performing the relay operation, and the first ground over-current relay unit for outputting a signal for dividing the low voltage bus bar to determine the ground fault of the relay operation and the low voltage bus according to the relay operation A first blocking / lockout relay section and first and second blocking / ropping on / off according to a signal output from the first blocking / lockout relay section; A first breaker for dividing and disconnecting the low voltage bus bar between the second contact unit and the third unit according to the signal output from the first contact / lockout relay unit; Relay operation and the second ground overcurrent relay for performing the relay operation if the ground overcurrent exceeds a predetermined reference value according to the operation of the first blocking / lockout contact portion; A second cut-off which outputs a signal for dividing the low-voltage busbar to discriminate the ground points of the low-voltage busbars of the first unit (# 1 Unit) and the second unit (# 2 Unit) divided by the first breaker; / Lock-out relay, the third and fourth blocking / lockout contact portion on / off in accordance with the signal output from the second blocking / lockout relay, and output from the second blocking / lockout relay The first unit (# 1 Unit) and the second unit according to the received signal A second blocking portion for dividing and blocking the low voltage busbar between the nits and the first and second units according to on / off of the third and fourth blocking / lockout contacts; Relay operation when the ground overcurrent exceeds a predetermined reference value according to the operation of the third and fourth ground overcurrent relays for outputting a signal to block the network protector and the main circuit breaker, respectively, and the second blocking / lockout contact portion. The fifth ground overcurrent relay unit for performing the operation, and the third unit (# 3 Unit) and the fourth unit (# 3 unit) divided by the relay operation and the first blocking unit in accordance with the relay operation of the fifth ground overcurrent relay unit A third cut-off / lock-out relay for outputting a signal for dividing and cutting off the low-voltage bus to determine the ground fault of the low-voltage bus on the 4 unit side; and according to the signal output from the third cut-off / lock-out relay 5th and 6th blocking / locks on / off A third breaker for dividing and blocking the low voltage busbar between the third unit (# 3 Unit) and the fourth unit (# 4 Unit) according to the upper contact portion and the signal output from the third shutoff and lockout relay unit; And a sixth signal outputting a signal for shutting off the network protector and the main circuit breaker of the third and fourth units (# 3, # 4 Unit) according to the on / off of the fifth and sixth blocking / lockout contacts. And a seventh ground overcurrent relay.

Each of the first to seventh ground overcurrent relays and the first to third blocking / lockout relays is one of mechanical and electronic relays.

The first breaker separates the low voltage bus without the ground fault and the low voltage bus with the ground fault so as to continue operation with 2 units or 3 units, which is a minimum combination of spot network systems. It is a pole breaker, and each of the second and third breaker is characterized in another one of the three-pole breaker or four-pole breaker.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

Hereinafter, a preferred embodiment of the low voltage bus ground fault protection device of the spot network system according to the present invention will be described.

2 is a view showing an embodiment of a low voltage bus ground fault protection device of a spot network system according to the present invention, an embodiment of a low voltage bus ground fault protection device of a 2 unit (# 1, # 2 Unit) spot network system The network transformer 31, the network protector 32, the network fuse 33, the main circuit breaker 34, the first ground over-current relay 41, the shut-off / lock-out relay (42), the first and second blocking / lockout contact portions 43 and 44, the blocking portion 45, and the second and third ground overcurrent relay portions 46 and 47.

Each of the first to third ground overcurrent relays 41, 46, 47, and the blocking / lockout relay 42 is either a mechanical or electronic relay, and the blocking unit 45 is a three-pole circuit breaker or One of the four-pole breakers.

The network transformer 31, the network protector 32, the network fuse 33, and the main circuit breaker 34 constitute first and second units # 1 and # 2 units, respectively.

The network transformer 31 transforms power supplied through a substation (not shown) to a predetermined level.

The network protector 32 supplies an uninterrupted supply of power transformed from the network transformer 31.

The network fuse 33 cuts off the power supplied from the network protector 32 when overloaded.

The main circuit breaker 34 cuts off the power supplied through the network fuse 33.

The first ground overcurrent relay 41 performs a relay operation when the ground overcurrent according to the ground fault generated at a predetermined point of the low voltage bus exceeds a predetermined reference value.

The cutoff / lockout relay section 42 outputs a signal for dividing and cutting off the low voltage busbar to determine the grounding point of the relay operation and the low voltage busbar according to the relaying operation of the first ground overcurrent relay 41. do.

The first and second blocking / lockout contact parts 43 and 44 are turned on / off according to the signal output from the blocking / lockout relay part 43.

The blocking unit 45 cuts off the low-voltage busbar between the first unit (# 1 Unit) and the second unit (# 2 Unit) according to the signal output from the blocking / lockout relay unit 43.

The second and third ground overcurrent relays 46 and 47 are connected to the network of the first and second units # 1 and # 2 according to on / off of the first and second blocking / lockout contacts. Signals for blocking the protector 32 and the main circuit breaker 34, respectively.

3 is a view showing another embodiment of a low voltage bus ground fault protection device of a spot network system according to the present invention, one embodiment of a low voltage bus ground fault protection device of a three-unit (# 1 ~ # 3 Unit) spot network system The diagram shows the network transformer 71, the network protector 72, the network fuse 73, the main circuit breaker 74, the first ground overcurrent relay 81, and the first blocking / locking out. Relay portion 82, first and second blocking / lockout contact portions 83 and 84, first blocking portion 85, second ground overcurrent relay portion 86, and second blocking / locking The out relay section 87, the third and fourth blocking / lockout contact sections 88 and 89, the second blocking section 90, the third and fourth ground overcurrent relay sections 91 and 92, And a fifth ground overcurrent relay 93, a third blocking / lockout relay 94, a fifth blocking / lockout contact 95, and a sixth ground overcurrent relay 96 It is composed.

Each of the first to sixth ground overcurrent relays 81, 86, 91, 92, 93, and 96 is either a mechanical or electronic relay, and the first and third blocking / lockout relays 82, 87. 94 each is either a mechanical or electronic relay.

The first blocking unit 85 separates the low-voltage busbar from which the ground fault does not occur and the low-voltage busbar from the ground fault, and continues to operate with 2 units or 3 units, which is a minimum combination of spot network systems. It is a 4-pole breaker, and the second breaker 90 is either a 3-pole breaker or a 4-pole breaker.

The network transformer 71, the network protector 72, the network fuse 73, and the main circuit breaker (74) constitutes first to third units (# 1 to # 3 Unit), respectively.

The network transformer 71 transforms power supplied through a substation (not shown) to a predetermined level.

The network protector 72 supplies an uninterrupted supply of power transformed from the network transformer 71.

The network fuse 73 cuts off the power supplied from the network protector 72 when overloaded.

The main circuit breaker 74 cuts off the power supplied through the network fuse 73.

The first ground overcurrent relay 81 performs a relay operation when the ground overcurrent according to the ground fault generated at a predetermined point of the low voltage bus exceeds a predetermined reference value.

The first blocking / lock-out relay unit 82 may provide a signal for dividing and disconnecting the low voltage bus bar in order to determine the grounding point of the relay operation and the low voltage busbar according to the relay operation of the first ground overcurrent relay unit 81. Will print.

The first and second blocking / lockout contact parts 83 and 84 are turned on / off according to the signal output from the first blocking / lockout relay part 82.

The first blocking unit 85 divides and cuts the low voltage busbar between the second unit (# 2 Unit) and the third unit (# 3 Unit) according to the signal output from the first blocking / lockout relay unit 82. Done.

The second ground overcurrent relay 86 performs a relay operation when the ground overcurrent exceeds a predetermined reference value according to the operation of the first blocking / lockout contact portion 83.

The second blocking / lockout relay unit 87 is a first unit (# 1) which is divided and blocked by the relay operation and the first blocking unit 85 according to the relay operation of the second ground overcurrent relay unit 86. In order to determine the ground fault point of the low voltage busbar of the unit and the second unit (# 2 Unit), a signal for dividing the low voltage busbar is outputted.

The third and fourth blocking / lockout contact portions 88 and 89 may be turned on / off according to a signal output from the second blocking / lockout relay portion 87.

The second blocking unit 90 blocks and cuts the low voltage busbar between the first unit (# 1 Unit) and the second unit (# 2 Unit) according to the signal output from the second blocking / lockout relay unit 87. Done.

The third and fourth ground overcurrent relays 91 and 92 are connected to the network of the first and second units # 1 and # 2 according to on / off of the third and fourth blocking / lockout contacts. Signals for blocking the protector 72 and the main circuit breaker 74, respectively.

The fifth ground overcurrent relay 93 performs a relay operation when the ground overcurrent exceeds a predetermined reference value according to the operation of the second blocking / lockout contact portion 84.

The third blocking / lockout relay unit 94 performs a relay operation according to the relay operation of the fifth ground overcurrent relay 93.

The fifth blocking / lockout contact unit 95 is turned on / off according to the signal output from the third blocking / lockout relay unit 94.

The sixth ground overcurrent relay 96 includes the network protector 72 and the main circuit breaker 74 of the third unit (# 3 Unit) according to the on / off of the fifth blocking / lockout contact portion 95. It will output a signal to block each.

Figure 4 is a view showing another embodiment of a low voltage bus ground fault protection device of a spot network system according to the present invention, one embodiment of a low voltage bus ground fault protection device of a four-unit (# 1 ~ # 4 Unit) spot network system As an example, the network transformer 101, the network protector 102, the network fuse 103, the main circuit breaker 104, the first ground over-current relay 111, and the first blocking / locking Out relay section 112, first and second blocking / lockout contact sections 113 and 114, first blocking section 115, second ground overcurrent relay section 116, and second blocking / Lockout relay section 117, third and fourth blocking / lockout contact sections 118 and 119, second blocking section 120, and third and fourth ground overcurrent relay sections 121 and 122 And the fifth ground overcurrent relay 123, the third blocking / lockout relay 124, the fifth and sixth blocking / lockout contact portions 125 and 126, and the third blocking portion 127 ), Sixth and seventh ground fault exhibitions It is configured to include a system part (128, 129).

Each of the first to seventh ground overcurrent relays 111, 116, 121, 122, 123, 128, and 129, and the first to third blocking / lockout relays 112, 117, and 127 may be mechanical or electronic. One of the relays.

The first breaker 115 separates the low voltage busbar from which the ground fault does not occur and the low voltage busbar from the ground fault, and operates the unit by 2 units or 3 units, which is a minimum combination of spot network systems. It is a 4-pole breaker for continuing, and each of the second and third breakers 120, 127 is either a 3-pole breaker or a 4-pole breaker.

The network transformer 101, the network protector 102, the network fuse 103, and the main circuit breaker 104 constitute first to fourth units (# 1 to # 4 units), respectively.

The network transformer 101 transforms power supplied through a substation (not shown) to a predetermined level.

The network protector 102 supplies an uninterrupted supply of power transformed from the network transformer 101.

The network fuse 103 cuts off the power supplied from the network protector 102 when overloaded.

The main circuit breaker 104 cuts off the power supplied through the network fuse 103.

The first ground overcurrent relay 111 performs a relay operation when the ground overcurrent according to the ground fault generated at a predetermined point of the low voltage bus exceeds a predetermined reference value.

The first blocking / lockout relay unit 112 divides and cuts a low voltage busbar signal to determine the grounding point of the relay operation and the low voltage busbar according to the relaying operation of the first ground overcurrent relay 111. Will print.

The first and second blocking / lockout contact parts 113 and 114 may be turned on / off according to a signal output from the first blocking / lockout relay part 112.

The first breaker 115 separates the low voltage busbar from which the ground fault does not occur and the low voltage busbar from the ground fault, and operates the unit by 2 units or 3 units, which is a minimum combination of spot network systems. A 4-pole breaker for continuing, to split the low-voltage busbar between the second unit (# 2 Unit) and the third unit (# 3 Unit) in accordance with the signal output from the first blocking / lockout relay 112 do.

The second ground overcurrent relay 116 performs the relay operation when the ground overcurrent exceeds a predetermined reference value according to the operation of the first blocking / lockout contact portion 113.

The second blocking / lockout relay unit 117 is a first unit (# 1) which is divided and blocked by the relay operation and the first blocking unit 115 according to the relay operation of the second ground overcurrent relay unit 116. In order to determine the ground fault point of the low voltage busbar of the unit and the second unit (# 2 Unit), a signal for dividing the low voltage busbar is outputted.

The third and fourth blocking / lockout contact parts 118 and 119 are turned on / off according to the signal output from the second blocking / lockout relay part 117.

The second blocking unit 120 is either a 3-pole breaker or a 4-pole breaker, and according to a signal output from the second blocking / lockout relay unit 117, the first unit (# 1 Unit) and the second unit Cut off the low voltage bus between (# 2 Unit).

The third and fourth ground over-current relays 121 and 122 are connected to the first and second units # 1, according to on / off of the third and fourth blocking / lockout contact portions 118 and 119. # 2 Unit outputs a signal for blocking the network protector 102 and the main circuit breaker 104, respectively.

The fifth ground overcurrent relay 123 performs the relay operation when the ground overcurrent exceeds a predetermined reference value according to the operation of the second blocking / lockout contact portion 114.

The third blocking / locking out relay unit 124 is divided by the relay operation and the first blocking unit 115 according to the relay operation of the fifth ground overcurrent relay unit 123 (# 3). In order to determine the ground fault point of the low voltage busbar of the unit and the fourth unit (# 4 unit), a signal for dividing the low voltage busbar is outputted.

The fifth and sixth blocking / lockout contact parts 125 and 126 may be turned on / off according to a signal output from the third blocking / lockout relay part 124.

The third breaker 127 is either a three-pole breaker or a four-pole breaker, and according to a signal output from the third shut-off and lock-out relay unit 124, the third unit (# 3 Unit) and the fourth Cut off the low voltage bus between the units (# 4 Unit).

The sixth and seventh ground overcurrent relays 128 and 129 may be connected to the third and fourth units # 3 and 3 according to on / off of the fifth and sixth blocking / lockout contact portions 125 and 126. # 4 Unit) outputs a signal for blocking the network protector 102 and the main circuit breaker 104, respectively.

The operation of the low voltage bus ground fault protection device of the spot network system according to the present invention configured as described above will be described in detail with reference to FIGS. 1 to 4.

As shown in FIG. 2, each of the first and second units # 1 and # 2 units includes a network transformer 31, a network protector 32, a network fuse 33, and a main circuit breaker 34. It is configured to, and since the same operation as shown in Figure 1 will be performed, a description thereof will be omitted.

First, when a ground fault occurs at the “F1” point of the low voltage busbar, the first ground overcurrent relay 41 may cause the ground overcurrent according to the ground fault generated at the “F1” point of the low voltage bus to exceed a predetermined reference value. When the relay operation is performed.

Then, the first blocking / lockout relay section 42 turns off the first and second blocking / lockout contact sections 43 and 44, respectively, in accordance with the relay operation of the first ground overcurrent relay section 41, The breaker 45, which is either a 3-pole breaker or a 4-pole breaker, is shut off to block an overcurrent caused by a ground fault from flowing into the low voltage busbar divided into the second unit (# 2 Unit). Normalizes the low pressure bus on the unit side.

Accordingly, in the third ground overcurrent relay 47, the circuit breaker 45, which is either a 3-pole breaker or a 4-pole breaker, is the first unit despite the turning off of the second break / lock-out contact 44. Since the low-voltage busbar between the # 1 unit and the second unit (# 2 Unit) is cut off, the overcurrent caused by the ground fault does not flow, so that the relay operation cannot be performed. Therefore, power is supplied to the (B) point through the second unit (# 2 Unit), so that power is supplied to the load stage regardless of the occurrence of ground fault at the "F1" point.

On the other hand, the second ground overcurrent relay 46 is connected to the network protector 32 and the main circuit breaker 34 of the first unit (# 1 Unit) in response to the first blocking / lockout contact portion 43 is off. It will cut off the power supply to (A) point.

In addition, when a ground fault occurs at the "F2" point of the low voltage busbar, the first ground overcurrent relay 41 may cause the ground overcurrent according to the ground fault generated at the "F2" point of the low voltage bus to exceed a predetermined reference value. When the relay operation is performed.

Then, the first blocking / lockout relay section 42 turns off the first and second blocking / lockout contact sections 43 and 44, respectively, in accordance with the relay operation of the first ground overcurrent relay section 41, The breaker 45, which is either a 3-pole breaker or a 4-pole breaker, is cut off to block an overcurrent caused by a ground fault from flowing into the low voltage busbar divided to the first unit (# 1 Unit). Normalizes the low pressure bus on the unit side.

Accordingly, in the second ground overcurrent relay 46, the circuit breaker 45, which is either a 3-pole breaker or a 4-pole breaker, is the first unit despite the turning-off of the first blocking / lock-out contact portion 43. Since the low-voltage busbar between the # 1 unit and the second unit (# 2 Unit) is cut off, the overcurrent caused by the ground fault does not flow, so that the relay operation cannot be performed. Therefore, power is supplied to the point (A) through the first unit (# 1 Unit) so that power is supplied to the load stage regardless of the ground fault of the "F2" point.

Meanwhile, the third ground overcurrent relay 47 disconnects the network protector 32 and the main circuit breaker 34 of the second unit (# 2 Unit) in response to the second blocking / lockout contact portion 44 being turned off. It cuts off the power supply to (B) point.

As described above, according to the present invention, a breaker is provided so that a spot network system having a plurality of units can be divided for each unit, so that a ground fault occurs at the "F1 or F2" point. By minimizing the blackout period only in the unit where the ground fault occurs, other units that do not have a ground fault can supply power normally.

As shown in FIG. 3, each of the first to third units # 1 to # 3 units includes a network transformer 71, a network protector 72, a network fuse 73, and a main circuit breaker 74. It is configured to, and since the same operation as shown in Figure 1 will be performed, a description thereof will be omitted.

First, when a ground fault occurs at the "F1" point of the low voltage busbar, the first ground overcurrent relay unit 81 causes the ground overcurrent according to the ground fault generated at the "F1" point of the low voltage bus to exceed a predetermined reference value. When the relay operation is performed.

Then, the first blocking / lockout relay unit 82 turns off the first and second blocking / lockout contact units 83 and 84, respectively, according to the relay operation of the first ground overcurrent relay unit 81, The first pole is a 4-pole circuit breaker that separates the low voltage bus without the ground fault and the low voltage bus with the ground fault to continue operation with 2 units or 3 units, which is the minimum combination of the spot network system. By blocking the blocking unit 85, the overcurrent according to the ground fault is prevented from flowing into the low pressure bus divided into the third unit (# 3 Unit), thereby normalizing the low pressure bus of the third unit (# 3 Unit).

Accordingly, in the fifth ground overcurrent relay 93, the first circuit breaker 85, which is a 4-pole circuit breaker, is the second unit (# 2 Unit) in spite of the second blocking / lock-out contact portion 84 being turned off. Since the low-voltage busbar between the and the third unit (# 3 Unit) is cut off, the overcurrent caused by the ground fault does not flow, so that the relay operation cannot be performed.

In addition, the fifth blocking / lockout relay unit 94, the fifth blocking / lockout contact unit 95, and the sixth ground overcurrent relay unit 96 also perform an operation because no overcurrent occurs due to a ground fault. You will not. Accordingly, power is supplied to the point (C) through the third unit (# 3 Unit) so that power is supplied to the load stage regardless of the occurrence of a ground fault at the "F1" point.

On the other hand, the second ground over-current relay unit 86 performs the relay operation when the ground over-current exceeds a predetermined reference value according to the off of the first blocking / lockout contact portion 83.

Then, the second blocking / lockout relay section 87 turns off the third and fourth blocking / lockout contact sections 88 and 89, respectively, according to the relaying operation of the second ground overcurrent relay section 86. The second blocking unit 90, which is one of the three-pole circuit breaker and the four-pole circuit breaker, is cut off to block the overcurrent caused by the ground fault from being supplied to the low voltage busbar on the side of the second unit (# 2 Unit).

Accordingly, the fourth ground overcurrent relay 92 has a second breaker 90 which is either a three-pole breaker or a four-pole breaker despite the turn-off of the fourth shut-off / lock-out contact portion 89. Since the low-voltage busbar between the first unit (# 1 Unit) and the second unit (# 2 Unit) is cut off, the overcurrent caused by the ground fault does not flow, so that the relay operation cannot be performed. Therefore, power is supplied to the point (B) through the second unit (# 2 Unit) so that power is supplied to the load terminal regardless of the occurrence of a ground fault at the "F1" point.

On the other hand, the third ground overcurrent relay 91 is connected to the network protector 72 and the main circuit breaker 74 of the first unit (# 1 Unit) in accordance with the off of the third blocking / lockout contact portion (88). It will cut off the power supply to (A) point.

On the other hand, when a ground fault occurs at the "F2" point of the low-voltage busbar, the first ground overcurrent relay unit 81 causes the ground overcurrent according to the ground fault generated at the "F2" point of the low-voltage busbar to exceed a predetermined reference value. When the relay operation is performed.

Then, the first blocking / lockout relay unit 82 turns off the first and second blocking / lockout contact units 83 and 84, respectively, according to the relay operation of the first ground overcurrent relay unit 81, The first pole is a 4-pole circuit breaker that separates the low voltage bus without the ground fault and the low voltage bus with the ground fault to continue operation with 2 units or 3 units, which is the minimum combination of the spot network system. The blocking unit 85 is blocked to prevent the overcurrent caused by the ground fault from flowing into the low voltage busbar divided into the first and second units # 1 and # 2 units, thereby preventing the first and second units # 1 and #. Normalizes the low pressure bus on the 2 unit side.

Accordingly, in the second ground overcurrent relay unit 86, the first circuit breaker 85, which is a four-pole circuit breaker, is the first and second units despite the turn-off of the first blocking / lock-out contact portion 83. Since the low-voltage busbar between 1, # 2 Unit and # 3 Unit is cut off, the overcurrent caused by the ground fault does not flow and thus relay operation is not performed.

In addition, the second blocking unit 90, which is any one of the second blocking / lockout relay unit 87, the third and fourth blocking / locking contact units 88 and 89, and a three-pole breaker or a four-pole breaker. ) And the third and fourth ground overcurrent relays 91 and 92 also do not perform an overcurrent due to a ground fault.

Accordingly, power is supplied to (a) and (b) points through the first and second units # 1 and # 2 units so that power is supplied to the load stage regardless of a ground fault at the "F2" point.

On the other hand, the fifth ground overcurrent relay 93 performs a relay operation when the ground overcurrent exceeds a predetermined reference value according to the turning off of the second blocking / lockout contact portion 84.

Then, the third blocking / lockout relay unit 94 turns off the fifth blocking / lockout contact unit 95 according to the relaying operation of the fifth ground overcurrent relay 93.

Accordingly, the sixth ground overcurrent relay 96 disconnects the network protector 72 and the main circuit breaker 74 of the third unit (# 3 Unit) in response to the fifth blocking / lockout contact 95 being turned off. It cuts off the power supply to the branch (C).

As described above, according to the present invention, by installing a plurality of breakers to divide a spot network system having a plurality of units for each unit, when a ground fault occurs at the "F1 or F2" point, By minimizing the blackout period only in the unit where the ground fault occurs in the unit, other units that do not have a ground fault can supply power normally.

As shown in FIG. 4, each of the first to fourth units # 1 to # 4 units includes a network transformer 101, a network protector 102, a network fuse 103, and a main circuit breaker 104. It is configured to, and since the same operation as shown in Figure 1 will be performed, a description thereof will be omitted.

First, when a ground fault occurs at the “F1” point of the low voltage busbar, the first ground overcurrent relay 111 may cause the ground overcurrent according to the ground fault generated at the “F1” point of the low voltage bus to exceed a predetermined reference value. When the relay operation is performed.

Then, the first blocking / lockout relay unit 112 turns off the first and second blocking / lockout contact units 113 and 114, respectively, according to the relay operation of the first ground overcurrent relay unit 111, The first pole is a 4-pole circuit breaker that separates the low voltage bus without the ground fault and the low voltage bus with the ground fault to continue operation with 2 units or 3 units, which is the minimum combination of the spot network system. The blocking unit 115 is blocked to prevent the overcurrent caused by the ground fault from flowing into the low voltage busbar divided into the third and fourth units (# 3, # 4 Unit), thereby preventing the third and fourth units (# 3, #). Normalizes the low pressure bus on the 3 unit side.

Accordingly, in the fifth ground over-current relay unit 123, the first circuit breaker 115, which is a four-pole circuit breaker, is the first and second units despite the turn-off of the second blocking / lock-out contact portion 114. Since the low-voltage busbar between the 1, # 2 Unit and the third and the fourth unit (# 3, # 4 Unit) is cut off, the overcurrent caused by the ground fault does not flow, so that the relay operation cannot be performed.

In addition, the third blocking / lockout relay unit 124, the fifth and sixth blocking / lockout contact portions 125 and 126, and the third blocking unit 127 which is any one of a three-pole breaker and a four-pole breaker. ) And the sixth and seventh ground overcurrent relays 128 and 129 also do not perform the overcurrent due to the ground fault.

Accordingly, power is supplied to the points (C) and (D) through the third and fourth units (# 3, # 4 Unit) so that the power is supplied to the load stage regardless of the ground fault of the "F1" point.

On the other hand, the second ground overcurrent relay 116 performs the relay operation when the ground overcurrent exceeds a predetermined reference value according to the turn-off of the first blocking / lockout contact portion 113.

Then, the second blocking / lockout relay unit 117 turns off the third and fourth blocking / lockout contact units 118 and 119 according to the relay operation of the second ground overcurrent relay unit 116, respectively. The second blocking unit 120, which is one of the three-pole breaker and the four-pole breaker, is blocked to block the overcurrent caused by the ground fault from being supplied to the low voltage busbar of the second unit (# 2 Unit).

Accordingly, the fourth ground overcurrent relay 122 has a second breaker 120 which is either a three-pole breaker or a four-pole breaker despite the turn-off of the fourth blocking / lock-out contact portion 122. Since the low-voltage busbar between the first unit (# 1 Unit) and the second unit (# 2 Unit) is cut off, the overcurrent caused by the ground fault does not flow, so that the relay operation cannot be performed. Therefore, power is supplied to the point (B) through the second unit (# 2 Unit) so that power is supplied to the load terminal regardless of the occurrence of a ground fault at the "F1" point.

On the other hand, the third ground over-current relay 121 is connected to the network protector 102 and the main circuit breaker 104 of the first unit (# 1 Unit) in accordance with the off of the third blocking / lockout contact portion 118. It will cut off the power supply to (A) point.

On the other hand, when a ground fault occurs at the "F2" point of the low-voltage busbar, the first ground overcurrent relay 111 is such that the ground overcurrent according to the ground fault generated at the "F2" point of the low-voltage busbar exceeds a predetermined reference value. When the relay operation is performed.

Then, the first blocking / lockout relay unit 112 turns off the first and second blocking / lockout contact units 113 and 114, respectively, according to the relay operation of the first ground overcurrent relay unit 111, The first pole is a 4-pole circuit breaker that separates the low voltage bus without the ground fault and the low voltage bus with the ground fault to continue operation with 2 units or 3 units, which is the minimum combination of the spot network system. The blocking unit 115 is blocked to prevent the overcurrent caused by the ground fault from flowing into the low voltage busbar divided into the first and second units # 1 and # 2 units, thereby preventing the first and second units # 1 and #. Normalizes the low pressure bus on the 2 unit side.

Accordingly, in the second ground over-current relay unit 116, the first circuit breaker 115, which is a 4-pole circuit breaker, is the second unit (# 2 Unit) despite the turn-off of the first blocking / lock-out contact portion 113. Since the low-voltage busbar between the and the third unit (# 3 Unit) is cut off, the overcurrent caused by the ground fault does not flow, so that the relay operation cannot be performed.

In addition, the second blocking unit 120, which is any one of the second blocking / lockout relay unit 117, the third and fourth blocking / lockout contact units 118 and 119, and a three-pole breaker or a four-pole breaker. ), And the third and fourth ground overcurrent relays 121 and 122 also do not perform the overcurrent due to the ground fault.

Accordingly, power is supplied to (a) and (b) points through the first and second units # 1 and # 2 units so that power is supplied to the load stage regardless of the occurrence of a ground fault at the "F" point.

On the other hand, the fifth ground overcurrent relay 123 performs the relay operation when the ground overcurrent exceeds a predetermined reference value according to the turning off of the second blocking / lockout contact portion 114.

Then, the third blocking / lockout relay unit 124 turns off the fifth and sixth blocking / lockout contact units 125 and 126 according to the relay operation of the fifth ground overcurrent relay unit 123, respectively. The third blocking unit 127, which is one of the three-pole circuit breaker and the four-pole circuit breaker, is cut off to block the overcurrent caused by the ground fault from being supplied to the low voltage busbar on the third unit (# 3 Unit) side.

Accordingly, the sixth ground overcurrent relay 128 has a third breaker 127 which is either a three-pole breaker or a four-pole breaker in spite of the fifth blocking / lock-out contact portion 125 being off. Since the low-voltage busbar between the third unit (# 3 Unit) and the fourth unit (# 4 Unit) is cut off, the overcurrent caused by the ground fault does not flow, thereby preventing the relay operation. Therefore, power is supplied to the point (C) through the third unit (# 3 Unit), so that power is supplied to the load stage regardless of the occurrence of a ground fault at the "F" point.

Meanwhile, the seventh ground overcurrent relay 129 disconnects the network protector 102 and the main circuit breaker 104 of the fourth unit (# 4 Unit) in response to the sixth blocking / lockout contact unit 126 being turned off. It cuts off the power supply to the branch (D).

As described above, according to the present invention, a spot network system having a plurality of units is provided so that a plurality of breakers can be divided for each unit, so that a ground fault occurs at the “F” point. By minimizing the blackout period only in the unit where the ground fault occurs, other units that do not have a ground fault can supply power normally.

As described above, the low voltage bus ground fault protection device of the spot network system according to the present invention divides the low voltage bus bus by unit in the low voltage spot network system which is adopted to ensure high reliability of electricity supply. Minimize the power outage, prevent and minimize the property loss caused by equipment damage caused by the continuation of the ground fault, and can prevent the safety accidents of electric fire and life.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims and their equivalents.

Claims (14)

A low voltage bus ground fault protection device of a spot network system having a low voltage bus bus connected to a first unit and a second unit including a network transformer, a network protector, a network fuse, and a main breaker, respectively. A first ground overcurrent relay for detecting a ground overcurrent generated at a predetermined point of the low voltage bus bar by a ground fault and performing a relay operation when the detected ground overcurrent exceeds a predetermined reference value; A blocking / locking out relay unit performing a relay operation according to a relay operation of the first ground overcurrent relay; A blocking unit connected to the low voltage bus bar between the first and second units to divide and block the low voltage bus bar between the first and second units according to a relay operation of the blocking / lock-out relay unit; First and second blocking / locking out contact parts which are turned on / off according to the relaying operation of the blocking / locking out relay part; And According to the on / off operation of the first and second cut-off / lock-out contact parts, the ground over-current of any one of the first and second unit-side low voltage buses divided by the cut-off part is detected, and the detected ground Low voltage of the spot network system including second and third ground overcurrent relays which relay when the overcurrent exceeds a predetermined reference value to control the operation of each network protector and the main circuit breaker included in the first and second units, respectively. Bus ground fault protection device. The method of claim 1, Each of the first to third ground overcurrent relays is a low voltage bus ground fault protection device of a spot network system. The method of claim 1, Low voltage bus ground fault protection device of the spot network system wherein the cut-off / lock out relay is either mechanical or electronic relay. The method of claim 1, The breaker separates the low voltage busbar from the three-pole circuit breaker or ground fault and the low voltage busbar from the ground fault to continue operation with 2 units or 3 units, the minimum combination of spot network systems. Low voltage bus ground fault protection device in spot network system, which is one of the four pole breakers. A low voltage bus ground fault protection device of a spot network system having a low voltage bus bus connected to first to third units including a network transformer, a network protector, a network fuse, and a main breaker, respectively. A first ground overcurrent relay for detecting a ground overcurrent generated at a predetermined point of the low voltage bus bar by a ground fault and performing a relay operation when the detected ground overcurrent exceeds a predetermined reference value; A first blocking / locking out relay unit performing a relay operation according to a relay operation of the first ground overcurrent relay; A first blocking unit connected to the low voltage bus bar between the second and third units to divide and block the low voltage bus bar between the second and third units according to a relay operation of the first blocking / lock-out relay unit; First and second blocking / locking-out contact parts which are turned on / off according to a relaying operation of the first blocking / locking-out relay part; And According to the on / off operation of the first and second cut-off / lock-out contact parts, the ground over-currents of the first and second unit-side low voltage buses and the third unit-side low voltage buses are detected, and the detected ground over-current Second and third ground overcurrent relays which perform a relay operation when a predetermined reference value is exceeded; Second and third blocking / locking-out relays respectively performing relay operations in accordance with relay operations of the second and third ground overcurrent relays; A second blocking unit connected to the low voltage bus bar between the first and second units to divide and block the low voltage bus bar between the first and second units according to a relay operation of the second blocking / lock-out relay unit; Third and fourth blocking / locking-out contact parts which are turned on / off in accordance with a relay operation of the second blocking / lockout relay part; A fifth blocking / locking-out contact unit which is turned on / off according to the relaying operation of the third blocking / locking-out relay unit; Detects and detects ground fault currents of any one of the first and second unit-side low voltage busbars that are divided and cut off by the second blocking unit, respectively, according to the on / off operation of the third and fourth blocking / lockout contact portions. Fourth and fifth ground overcurrent relays configured to perform relay operation when the ground fault overcurrent exceeds a predetermined reference value to control the operation of each network protector and the main circuit breaker included in the first and second units, respectively; And When the ground overcurrent of the third unit-side low voltage bus line is divided by the first blocking unit according to the on / off operation of the fifth blocking / lock-out contact unit, and the detected ground overcurrent exceeds a predetermined reference value. Low voltage bus ground fault protection device of a spot network system including a sixth ground over-current relay for controlling the operation of the network protector and the main circuit breaker included in the third unit by the relay operation. The method of claim 5, Each of the first to sixth ground overcurrent relays is any one of a mechanical and an electronic relay. The method of claim 5, Each of the first and third blocking / lock-out relays is either a mechanical or electronic relay, and a low voltage bus ground fault protection device of a spot network system. The method of claim 5, The first breaker separates the low voltage bus without the ground fault and the low voltage bus with the ground fault so as to continue operation with 2 units or 3 units, which is a minimum combination of spot network systems. Low voltage bus ground fault protection device in spot network system as pole breaker. The method of claim 5, The second breaker is a low voltage bus ground fault protection device of the spot network system which is either a three-pole breaker or a four-pole breaker. A low voltage bus ground fault protection device of a spot network system having a low voltage bus bus connected to the first to fourth units including a network transformer, a network protector, a network fuse, and a main breaker, respectively. A first ground overcurrent relay for detecting a ground overcurrent generated at a predetermined point of the low voltage bus bar by a ground fault and performing a relay operation when the detected ground overcurrent exceeds a predetermined reference value; A first blocking / locking out relay unit performing a relay operation according to a relay operation of the first ground overcurrent relay; A first blocking unit connected to the low voltage bus bar between the second and third units to divide and block the low voltage bus bar between the second and third units according to a relay operation of the first blocking / lock-out relay unit; First and second blocking / locking-out contact parts which are turned on / off according to a relaying operation of the first blocking / locking-out relay part; And According to the on / off operation of the first and second cut-off / lock-out contact parts, the ground overcurrents of the first and second unit side low voltage buses and the third and fourth unit side low voltage buses are detected and detected. Second and third ground overcurrent relays that perform relay operation when the ground overcurrent exceeds a predetermined reference value; Second and third blocking / locking-out relays respectively performing relay operations in accordance with relay operations of the second and third ground overcurrent relays; A second blocking unit connected to the low voltage bus bar between the first and second units to divide and block the low voltage bus bar between the first and second units according to a relay operation of the second blocking / lock-out relay unit; A third breaker connected to the low voltage busbar between the third and fourth units to divide and block the low voltage busbar between the third and fourth units according to a relay operation of the third blocking / lock-out relay unit; Third and fourth blocking / locking-out contact parts which are turned on / off in accordance with a relay operation of the second blocking / lockout relay part; Fifth and sixth blocking / locking out contact parts which are turned on / off in accordance with a relaying operation of the third blocking / locking out relay part; Detects and detects ground fault currents of any one of the first and second unit-side low voltage busbars that are divided and cut off by the second blocking unit, respectively, according to the on / off operation of the third and fourth blocking / lockout contact portions. Fourth and fifth ground overcurrent relays configured to perform relay operation when the ground fault overcurrent exceeds a predetermined reference value to control the operation of each network protector and the main circuit breaker included in the first and second units, respectively; And According to the on / off operation of the fifth and sixth cut-off / lock-out contact parts, the ground overcurrent of the third and fourth unit side low voltage buses divided by the third cut-off part is detected, respectively, and the detected ground overcurrent Is a low voltage bus of the spot network system including a sixth and seventh ground over-current relay for controlling the operation of each network protector and the main circuit breaker included in the third and fourth units, respectively, when the value exceeds a predetermined reference value Ground fault protection device. The method of claim 10, Each of the first to seventh ground overcurrent relays is either a mechanical or electronic relay, and a low voltage bus ground fault protection device of a spot network system. The method of claim 10, Each of the first to third blocking / lock-out relays is either a mechanical or electronic relay, and the low voltage bus ground fault protection device of the spot network system. The method of claim 10, The first breaker separates the low voltage bus without the ground fault and the low voltage bus with the ground fault so as to continue operation with 2 units or 3 units, which is a minimum combination of spot network systems. Low voltage bus ground fault protection device in spot network system as pole breaker. The method of claim 10, Each of the second and third breakers is a low voltage bus ground fault protection device of a spot network system, which is either a 3-pole breaker or a 4-pole breaker.