CN107561408A - A kind of method for improving low-current ground fault line selection accuracy rate - Google Patents
A kind of method for improving low-current ground fault line selection accuracy rate Download PDFInfo
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- CN107561408A CN107561408A CN201710751482.8A CN201710751482A CN107561408A CN 107561408 A CN107561408 A CN 107561408A CN 201710751482 A CN201710751482 A CN 201710751482A CN 107561408 A CN107561408 A CN 107561408A
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Abstract
The invention discloses a kind of method for improving low-current ground fault line selection accuracy rate.It, which solves the problems, such as that stable state selection method electric fault amount currently with failure steady-state quantity is small, causes route selection accuracy rate low; with after singlephase earth fault occurs for small current neutral grounding system; fault current steady-state component is set to be significantly increased when bus section breaker closes; so as to improve the sensitivity of route selection and positioning protection based on failure steady-state quantity; reach reliable route selection and positioning purpose, its structure is：It is included by the bus of protection distribution system, and the bus is sectionalized single busbar connection system, and busbar sectional izing switch uses breaker, and breaker is connected with measure and control device, and measure and control device is connected with voltage transformer, and voltage transformer is then connected with bus；Whether measure and control device detection small current neutral grounding system occurs singlephase earth fault, and earth current is carried out to help increasing by the connection of two sections of buses of breaker control.
Description
Technical field
The present invention relates to Earth Fault Detection technology in a kind of power system, more particularly to a kind of raising small current neutral grounding event
Hinder the method for route selection accuracy rate.
Background technology
In power system, the conventional earthing mode of neutral point mainly has：Isolated neutral mode, neutral point are through arc blowout wire
It is small current neutral grounding mode to enclose earthing mode and neutral-point solid ground mode, first two earthing mode.
China 6-35kV power distribution network mainly uses small current neutral grounding mode, single-phase in low current neutral grounding system fault
Earth fault odds highest, more than 80% failure is singlephase earth fault in distribution according to statistics.When single-phase earthing event
When barrier occurs, electric power system still ensures that line voltage is symmetrical, because it does not form fault loop, electric current very little, does not influence to negative
The continuous power supply of lotus, the 1-2h that operates with failure can be continued according to code regulation.But as power network becomes increasingly complex, circuit is more next
More, if can not fix a breakdown in time, last longer operates with failure, and easily deteriorates failure and expands, causes more
Serious short trouble, so as to cause system trip, and the overvoltage that can cause whole power network is also possible under certain conditions, it is right
Equipment is unfavorable, influences the normal operation of power system.Therefore, when singlephase earth fault occurs, although not influenceed in the short time
Power supply to user, but must also find faulty line as early as possible, to prevent adverse effect that failure is brought to power network.
At present, single-phase grounded malfunction in grounded system of low current route selection technology is broadly divided into following four classes：First, it is based on failure
The stable state selection method of steady-state quantity；Second, the transient line selection based on fault transient amount；Third, based on additional diagnostic signal
Selection method；Fourth, the selection method based on present information integration technology.Technological deficiency for first two selection method is：Base
In the stable state selection method of failure steady-state quantity, it is less than normal stable state electric fault amount to be present, easily causes route selection failure phenomenon；Based on event
Hinder the transient line selection of transient, transient state electric fault amount existence time short the defects of being not easy to gather be present.
The content of the invention
The purpose of the present invention is exactly small in order to solve to be currently based on the stable state selection method electric fault amount of failure steady-state quantity
The problem of causing route selection accuracy rate low, there is provided a kind of method for improving low-current ground fault line selection accuracy rate, this method exist
When single-phase grounded malfunction in grounded system of low current occurs, if bus section breaker before failure（Breaker described herein refers both to mother
Line section switch）For off-state, closed after failure by measure and control device；If breaker is closure state before failure, therefore
First disconnected, then closed by measure and control device after barrier.The purpose is to the circuit that another section of bus is connected is sent out in system
Failure system is put into during raw singlephase earth fault, increases the fault current of faulty line, and the fault current of non-fault line is not
Become, so as to widen the gap of fault current between faulty line and non-fault line, improve the accuracy rate of route selection.
To achieve the above object, the present invention adopts the following technical scheme that.
A kind of method for improving low-current ground fault line selection accuracy rate, it is included by the bus of protection distribution system, institute
It is sectionalized single busbar connection system to state bus, and busbar sectional izing switch uses breaker, and breaker is connected with measure and control device, measure and control device and electricity
Transformer connection is pressed, voltage transformer is then connected with bus；Whether measure and control device detection small current neutral grounding system occurs single-phase connect
Earth fault, and earth current is carried out to help increasing by the connection of two sections of buses of breaker control.
The measure and control device is by three-phase voltage, residual voltage acquisition module, circuit-breaker status detection module, killer switch
Drive module, human-computer dialogue module and CPU compositions, monitor three-phase voltage and the residual voltage of small current neutral grounding system to judge to be
Whether system occurs singlephase earth fault, so as to control breaker actuation.Wherein, three-phase voltage, residual voltage acquisition module are by electricity
Pressure transmitter, RC LPFs, the pretreatment circuit being made up of operational amplifier and A/D change-over circuits are formed；Circuit-breaker status
Detection module is made up of auxiliary contacts of circuit breaker and detection circuit；Killer switch drive module is by relay drive circuit and control
Relay processed is formed；Human-computer dialogue module is made up of button and LCD MODULE；CPU is by STC12C5A60S2 monolithics mechanism
Into mainly judging whether to occur according to three-phase voltage and residual voltage single-phase to connect earth fault, storage circuit-breaker status detection mould
Breaker is sent to killer switch drive module when the state of breaker, singlephase earth fault occur before the failure of block collection
Point, the instruction closed, selection faulty line, the function such as human-computer dialogue.
The breaker is busbar sectional izing switch, and during small current neutral grounding system normal operation, the breaker is according to operation side
The needs of formula are in closure or off-state；When singlephase earth fault occurs for small current neutral grounding system, if breaker is before failure
Off-state, closed by measure and control device after failure；It is first by measure and control device after failure if breaker is closure state before failure
Disconnected, then closed.The purpose is to the circuit that another section of bus is connected system occur singlephase earth fault when
Failure system is put into, increases the fault current of faulty line, and the fault current of non-fault line is constant, so as to widen fault wire
The gap of fault current between road and non-fault line, improve the accuracy rate of route selection.
A kind of method for improving low-current ground fault line selection accuracy rate, its method is,
(1) during small current neutral grounding system normal operation, breaker needs to be opened or closed work, observing and controlling dress according to the method for operation
Real-time monitoring system three-phase voltage, residual voltage and circuit-breaker status are put, and judges whether system occurs singlephase earth fault；
(2) when there is no singlephase earth fault, repeat step (1)；When singlephase earth fault occurs, if breaker before failure
For off-state, closed after failure by measure and control device, the selection of faulty line is then carried out, after route selection terminates, by open circuit
Device disconnects；If breaker is closure state before failure, first disconnected by measure and control device after failure, then closed, Ran Houjin
The selection of row faulty line；
(3) continue to monitor busbar voltage and system residual voltage, and judge whether singlephase earth fault releases；
(4) if failure does not release, the operation of step (3) is continued；
(5) if failure has released, return to step (1) and re-start aforesaid operations.
The present invention the course of work be：For the small current neutral grounding system of operation, by measure and control device real-time monitoring system
The state of three-phase voltage, residual voltage and breaker, and whether real-time judge system occurs singlephase earth fault.System is normally transported
During row, breaker according to the method for operation need work is opened or closed.When singlephase earth fault occurs, if breaking before failure
Device is off-state, is closed after failure by measure and control device；If breaker is closure state before failure, filled after failure by observing and controlling
Put and first disconnected, then closed.The purpose is in system single-phase earthing event is occurred for the circuit that another section of bus is connected
Failure system is put into during barrier, increases the fault current of faulty line, and the fault current of non-fault line is constant, so as to widen event
Hinder the gap of fault current between circuit and non-fault line, improve the accuracy rate of route selection.After route selection terminates, breaker is recovered
To the state of former job requirement, the operation of system will not be adversely affected.
The beneficial effects of the invention are as follows：(1) present invention is after singlephase earth fault occurs for small current neutral grounding system, by disconnected
The circuit that road device connects another section of bus puts into failure system, increases the fault current of faulty line, and non-fault line
Fault current it is constant, so as to widen the gap of fault current between faulty line and non-fault line, make to be based on failure stable state
The stable state route selection and positioning protection of amount are more accurate.(2) improve the stable state route selection based on failure steady-state quantity and position protection
Anti- transition resistance ability, due to invention increases failure zero-sequence current, strengthening the fault degree of trouble point, being correspondingly improved
Anti- transition resistance ability.
In a word, the invention can effectively improve the accuracy rate of stable state route selection and positioning protection based on failure steady-state quantity.
Brief description of the drawings
Fig. 1 is the structural representation of the present invention.
Fig. 2 is measure and control device functional block diagram.
Fig. 3 is the inventive method flow chart.
Wherein, 1, bus, 2, bus section breaker, 3, measure and control device, 4, three-phase voltage, residual voltage acquisition module,
5th, circuit-breaker status detection module, 6, killer switch drive module, 7, human-computer dialogue module, 8, CPU, 9, voltage transformer.
Embodiment
In Fig. 1, bus section breaker 2 is connected in each phase of shielded small current neutral grounding system bus 1.Observing and controlling
Device 3 is used to monitor whether small current neutral grounding system occurs singlephase earth fault, so as to control breaker actuation, as shown in Figure 2.
Measure and control device 3 is by three-phase voltage, residual voltage acquisition module 4, circuit-breaker status detection module 5, killer switch drive module
6th, human-computer dialogue module 7 and CPU 8 are formed, and for the three-phase voltage of monitoring small current neutral grounding system, residual voltage in real time and are broken
The state of road device simultaneously judges whether system occurs singlephase earth fault, so as to control breaker actuation；Wherein, three-phase voltage, zero
Sequence voltage acquisition module 4 is changed by voltage transmitter, RC LPFs, the pretreatment circuit being made up of operational amplifier and A/D
Circuit is formed；Circuit-breaker status detection module 5 is made up of auxiliary contacts of circuit breaker and detection circuit；Killer switch drive module
6 are made up of relay drive circuit and control relay；Human-computer dialogue module 7 is made up of button and LCD MODULE；CPU 8
It is made up of STC12C5A60S2 single-chip microcomputers, is mainly judged whether that single-phase ground connection event occurs according to three-phase voltage and residual voltage
The state of bus section breaker 2, singlephase earth fault occur before the failure that barrier, storage circuit-breaker status detection module 5 gather
When the functions such as breaker point, the instruction closed, selection faulty line, human-computer dialogue are sent to killer switch drive module 6.Observing and controlling
Device 3 is also connected with voltage transformer 9, and one end of voltage transformer 9 is connected with bus 1.
The method of the present invention is as shown in Figure 3：
(1) during small current neutral grounding system normal operation, breaker needs to be opened or closed work, observing and controlling dress according to the method for operation
Real-time monitoring system three-phase voltage, residual voltage and circuit-breaker status are put, and judges whether system occurs singlephase earth fault；
(2) when there is no singlephase earth fault, repeat step (1)；When singlephase earth fault occurs, if breaker before failure
For off-state, closed after failure by measure and control device, the selection of faulty line is then carried out, after route selection terminates, by open circuit
Device disconnects；If breaker is closure state before failure, first disconnected by measure and control device after failure, then closed, Ran Houjin
The selection of row faulty line；
(3) continue to monitor busbar voltage and system residual voltage, and judge whether singlephase earth fault releases；
(4) if failure does not release, the operation of step (3) is continued；
(5) if failure has released, return to step (1) and re-start aforesaid operations.
In Fig. 1, it is assumed that singlephase earth fault occurs for the C phases of circuit II, if bus section breaker 2 is disconnection shape before failure
State, closed by measure and control device 3 after failure；If bus section breaker 2 is closure state before failure, filled after failure by observing and controlling
Put 3 first to be disconnected, then closed；The purpose is to the circuit III that another bus is connected and circuit IV to occur in failure
When put into failure system, faulty line zero-sequence current is circuit I, circuit III and zero-sequence current sum caused by circuit IV.It can be seen that
This method is after singlephase earth fault occurs for small current neutral grounding system, and the circuit that another section of bus is connected is in breaker closing
When put into failure system, increase the fault current of faulty line, and the fault current of non-fault line is constant, so as to widen failure
The gap of fault current between circuit and non-fault line, it is possible to increase protected using the stable state route selection and positioning of failure steady-state quantity
Judging nicety rate.
Claims (4)
1. a kind of method for improving low-current ground fault line selection accuracy rate, it is included by the bus of protection distribution system, described
Bus is sectionalized single busbar connection system, and busbar sectional izing switch uses breaker, and breaker is connected with measure and control device, measure and control device and voltage
Transformer is connected, and voltage transformer is then connected with bus；Whether measure and control device detection small current neutral grounding system occurs single-phase earthing
Failure, and earth current is carried out to help increasing by the connection of two sections of buses of breaker control.
2. a kind of method for improving low-current ground fault line selection accuracy rate according to claim 1, it is characterized in that：It is described
Measure and control device is by three-phase voltage, residual voltage acquisition module, circuit-breaker status detection module, killer switch drive module, people
Machine session module and CPU compositions, monitor three-phase voltage and the residual voltage of small current neutral grounding system to judge whether system occurs
Singlephase earth fault, so as to control breaker actuation；Wherein, three-phase voltage, residual voltage acquisition module are by voltage transmitter, RC
LPF, the pretreatment circuit being made up of operational amplifier and A/D change-over circuits are formed；Circuit-breaker status detection module is by breaking
Road device auxiliary contact and detection circuit are formed；Killer switch drive module is by relay drive circuit and control relay structure
Into；Human-computer dialogue module is made up of button and LCD MODULE；CPU is made up of STC12C5A60S2 single-chip microcomputers, main basis
Three-phase voltage and residual voltage judge whether that the single-phase failure for connecing earth fault, storing the collection of circuit-breaker status detection module occurs
The state of preceding breaker, singlephase earth fault send breaker point, the instruction closed, choosing to killer switch drive module when occurring
Select the functions such as faulty line, human-computer dialogue.
3. a kind of method for improving low-current ground fault line selection accuracy rate according to claim 1, it is characterized in that：It is described
Breaker is busbar sectional izing switch, and during small current neutral grounding system normal operation, the breaker is according to the needs of the method for operation
Closure or off-state；When singlephase earth fault occurs for small current neutral grounding system, if breaker is off-state before failure, failure
Closed afterwards by measure and control device；If breaker is closure state before failure, first disconnected by measure and control device after failure, then will
It is closed；The purpose is to which the circuit that another section of bus is connected is put into failure system when singlephase earth fault occurs for system,
Increase the fault current of faulty line, and the fault current of non-fault line is constant, so as to widen faulty line and non-faulting line
The gap of fault current between road, improve the accuracy rate of route selection.
4. a kind of method for improving low-current ground fault line selection accuracy rate according to claim 1, it is characterized in that：It
Method is,
(1) during small current neutral grounding system normal operation, breaker needs to be opened or closed work, observing and controlling dress according to the method for operation
Real-time monitoring system three-phase voltage, residual voltage and circuit-breaker status are put, and judges whether system occurs singlephase earth fault；
(2) when there is no singlephase earth fault, repeat step (1)；When singlephase earth fault occurs, if breaker before failure
For off-state, closed after failure by measure and control device, the selection of faulty line is then carried out, after route selection terminates, by open circuit
Device disconnects；If breaker is closure state before failure, first disconnected by measure and control device after failure, then closed, Ran Houjin
The selection of row faulty line；
(3) continue to monitor busbar voltage and system residual voltage, and judge whether singlephase earth fault releases；
(4) if failure does not release, the operation of step (3) is continued；
(5) if failure has released, return to step (1) and re-start aforesaid operations.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108152683A (en) * | 2018-01-10 | 2018-06-12 | 济南大学 | Based on the earth fault line selection method for helping increasing principle |
| CN109669097A (en) * | 2019-01-28 | 2019-04-23 | 济南大学 | A kind of neutral by arc extinction coil grounding system single-phase earth fault route selecting method |
| CN109669095A (en) * | 2019-01-21 | 2019-04-23 | 济南大学 | A kind of isolated neutral system fault line selection method for single-phase-to-ground fault |
| CN110568316A (en) * | 2019-10-16 | 2019-12-13 | 国网四川省电力公司绵阳供电公司 | Method for quickly selecting line of ground fault of low-current grounding system |
| CN112526389A (en) * | 2020-11-04 | 2021-03-19 | 国网湖北省电力有限公司电力科学研究院 | Single-phase earth fault line selection device and multidimensional determination method |
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| JP2006136158A (en) * | 2004-11-08 | 2006-05-25 | Mitsubishi Heavy Ind Ltd | Apparatus coping with ground fault |
| CN100384044C (en) * | 2005-07-20 | 2008-04-23 | 北京四方继保自动化股份有限公司 | Adaptive regulation method of bus protection ratio brake coefficient based on bus connection current |
| CN100511908C (en) * | 2007-05-10 | 2009-07-08 | 济南大学 | Stable status zero-sequence current increase and assistance device and method |
| CN102623965A (en) * | 2011-01-27 | 2012-08-01 | 宝山钢铁股份有限公司 | Implementation method and device for bus protection in double bus system |
| CN102495330A (en) * | 2011-11-21 | 2012-06-13 | 广西星宇智能电气有限公司 | Realization method of undercurrent grounding line selection apparatus adaptive coupler operation mode |
| CN104035003B (en) * | 2014-06-28 | 2017-08-01 | 国家电网公司 | Sectionalized single busbar connection PT small current earthing wire-selecting logic decision methods arranged side by side |
| CN104635107A (en) * | 2015-02-27 | 2015-05-20 | 国网福建晋江市供电有限公司 | Small-current grounding fault line selection system and line selection method |
| JP6517667B2 (en) * | 2015-11-05 | 2019-05-22 | 関西電力株式会社 | Ground fault detection device |
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- 2017-08-28 CN CN201710751482.8A patent/CN107561408B/en not_active Expired - Fee Related
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108152683A (en) * | 2018-01-10 | 2018-06-12 | 济南大学 | Based on the earth fault line selection method for helping increasing principle |
| CN109669095A (en) * | 2019-01-21 | 2019-04-23 | 济南大学 | A kind of isolated neutral system fault line selection method for single-phase-to-ground fault |
| CN109669095B (en) * | 2019-01-21 | 2020-12-25 | 济南大学 | Single-phase earth fault line selection method for neutral point ungrounded system |
| CN109669097A (en) * | 2019-01-28 | 2019-04-23 | 济南大学 | A kind of neutral by arc extinction coil grounding system single-phase earth fault route selecting method |
| CN109669097B (en) * | 2019-01-28 | 2020-10-09 | 济南大学 | Single-phase earth fault line selection method for neutral point arc suppression coil grounding system |
| CN110568316A (en) * | 2019-10-16 | 2019-12-13 | 国网四川省电力公司绵阳供电公司 | Method for quickly selecting line of ground fault of low-current grounding system |
| CN112526389A (en) * | 2020-11-04 | 2021-03-19 | 国网湖北省电力有限公司电力科学研究院 | Single-phase earth fault line selection device and multidimensional determination method |
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