CN107942203A - A kind of small current earthing wire-selecting method for strengthening fault signature - Google Patents
A kind of small current earthing wire-selecting method for strengthening fault signature Download PDFInfo
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- CN107942203A CN107942203A CN201810021388.1A CN201810021388A CN107942203A CN 107942203 A CN107942203 A CN 107942203A CN 201810021388 A CN201810021388 A CN 201810021388A CN 107942203 A CN107942203 A CN 107942203A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
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Abstract
The invention discloses a kind of small current earthing wire-selecting method for strengthening fault signature.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 closure or capacitor fling-cut switch close; 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 busbar of protection distribution system; capacitor be installed on the busbar help to be installed in addition with and put, busbar sectional izing switch uses breaker, capacitor help be installed in addition with put, the connection of breaker and measure and control device; measure and control device is connected with voltage transformer, and voltage transformer is then connected with busbar；Whether measure and control device detection small current neutral grounding system occurs singlephase earth fault, and helps increasing to earth current by controlling the state of capacitor and breaker to realize.
Description
Technical field
The present invention relates to Earth Fault Detection technology in a kind of electric system, more particularly to a kind of strengthen the small of fault signature
Current earthing selection method.
Background technology
At present, 6-35kV power distribution networks in China mainly use small current neutral grounding mode.It is single in low current neutral grounding system fault
Phase earth fault odds highest, therefore single-phase earth fault line selection remains a great problem in relay protection.
By years of researches, existing a variety of route selection criterions come out and put into onsite application, but most location designs are all
It is criterion based on less fault characteristic value, in high transition Resistance Fault, route selection accuracy rate is not high.The event of small current neutral grounding at present
Barrier location design mainly has 4 classes：First, the low-current ground fault line selection principle based on steady state fault amount, this method mainly utilize
Steady state fault amount during singlephase earth fault is criterion, and method is simple, but fault characteristic value is small, is not easy to detect.Second, based on temporary
The low-current ground fault line selection principle of state failure amount, this method mainly using singlephase earth fault when transient fault amount to sentence
According to, it is bigger than steady state fault characteristic quantity, but the duration is shorter, hardly possible detection.Third, the small current neutral grounding based on additional diagnosis principle
Failure line selection principle, the principle have been broken in the past just with circuit fault-signal itself as route selection criterion, have been filled using injection
Put and special signal is mutually injected to failure, but influenced by distribution capacity and transition resistance, Injection Signal is smaller, and need to increase note
Enter device, cost increase.Four be the route selection criterion based on signal fused technology, and criterion fusion is a variety of based on stable state and transient state event
Hinder the location design of characteristic quantity, improve route selection accuracy rate to a certain extent, but because each route selection criterion is still with less spy
Sign amount is criterion, therefore route selection accuracy rate is low during high transition Resistance Fault, does not solve the problems, such as that route selection accuracy rate is low fundamentally.
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 small current earthing wire-selecting method for strengthening fault signature, this method is small
When current grounding system singlephase earth fault occurs, if breaker is off-state before failure, after failure by measure and control device by its
Closure；If breaker is closure state before failure, capacitor switching is switched by measure and control device after failure and is closed.The purpose is to
System occurs to increase the zero-sequence current of faulty line during singlephase earth fault in short-term, and the zero-sequence current of non-fault line is still line
The capacitance current of road in itself, so as to widen the gap of zero-sequence current between faulty line and non-fault line, improves the standard of route selection
True rate.
To achieve the above object, the present invention adopts the following technical scheme that.
A kind of small current earthing wire-selecting method for strengthening fault signature, it is included by the busbar of protection distribution system, described
Capacitor is installed on busbar helps to be installed in addition with and put, busbar sectional izing switch uses breaker（Breaker described herein refers both to bus section
Breaker）, capacitor help be installed in addition with put, the connection of breaker and measure and control device, measure and control device is connected with voltage transformer, mutual induction of voltage
Device is then connected with busbar；Whether measure and control device detection small current neutral grounding system occurs singlephase earth fault, and by controlling capacitance
The state of device and breaker is realized helps increasing to earth current.
The measure and control device is by three-phase voltage, residual voltage acquisition module, circuit-breaker status detection module, killer switch
Drive module, capacitor switching switch drive module, human-computer dialogue module and CPU compositions, monitor the three of small current neutral grounding system
Phase voltage and residual voltage judge whether system occurs singlephase earth fault, so as to control breaker and capacitor switching to switch
Action.Wherein, three-phase voltage, residual voltage acquisition module are by voltage transmitter, RC low-pass filtering, be made of operational amplifier
Pre-process circuit and A/D conversion circuits are formed；Circuit-breaker status detection module is made of auxiliary contacts of circuit breaker and detection circuit；
Killer switch drive module and capacitor switching switch drive module are made of relay drive circuit and control relay；People
Machine session module is made of button and LCD MODULE；CPU is made of STC12C5A60S2 microcontrollers, mainly according to three-phase electricity
Pressure and residual voltage judge whether that single-phase open circuit before connecing earth fault, the failure of storage circuit-breaker status detection module collection occurs
The state of device, singlephase earth fault send out killer switch drive module and capacitor switching switch drive module when occurring
The functions such as pass point, the instruction closed, selection faulty line, human-computer dialogue.
The capacitor, which is helped in each phase for being installed in addition with and putting and be included in busbar, sets at least one capacitor, they form capacitance
Device group, one end of each capacitor are connected respectively at respective fling-cut switch, another ground connection.
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, and detect circuit-breaker status by circuit-breaker status detection module；Small current neutral grounding system
When singlephase earth fault occurs for system, if breaker is off-state before failure, closed after failure by measure and control device；If failure
Preceding breaker is closure state, switchs capacitor switching by measure and control device after failure and closes.It is single the purpose is to occur in system
Increase the zero-sequence current of faulty line during phase earth fault in short-term, and the zero-sequence current of non-fault line is still the electricity of circuit in itself
Capacitance current, so as to widen the gap of zero-sequence current between faulty line and non-fault line, improves the accuracy rate of route selection.
A kind of small current earthing wire-selecting method for strengthening fault signature, 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, by open circuit
Device disconnects；If breaker is closure state before failure, capacitor switching is switched by measure and control device after failure and is closed, is then carried out
The selection of faulty line, after route selection, capacitor switching is switched off；
(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, aforesaid operations are re-started back to step (1).
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 needs to be opened or closed work according to the method for operation, and capacitor switching switch is to disconnect, and capacitor helps increasing
Device is not put into.When singlephase earth fault occurs, if breaker is off-state before failure, after failure by measure and control device by its
Closure；If breaker is closure state before failure, capacitor switching is switched by measure and control device after failure and is closed.The purpose is to
Increase the zero-sequence current of faulty line when failure occurs, and capacitance of the zero-sequence current of non-fault line still for circuit in itself is electric
Stream, so as to widen the gap of zero-sequence current between faulty line and non-fault line, improves the accuracy rate of route selection.Route selection terminates
Afterwards, breaker is returned to the state of former job requirement, immediately switches off capacitor switching, the operation of system will not be made
Into adverse effect.
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
Road device or capacitor help the zero-sequence current for being installed in addition with and putting and increasing faulty line in short-term, and the zero-sequence current of non-fault line is still circuit
The capacitance current of itself, so as to widen the gap of zero-sequence current between faulty line and non-fault line, makes 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 zero-sequence current, strengthening the fault degree of trouble point, being correspondingly improved anti-
Transition resistance ability.
In short, 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 structure diagram of the present invention.
Fig. 2 is measure and control device functional block diagram.
Fig. 3 is the method for the present invention flow chart.
Wherein, 1, I sections of busbares, 2, bus section breaker, 3, capacitor switching switch, 4, capacitor, 5, measure and control device,
6th, three-phase voltage, residual voltage acquisition module, 7, circuit-breaker status detection module, 8, killer switch drive module, 9, capacitance
Device fling-cut switch drive module, 10, human-computer dialogue module, 11, CPU, 12, voltage transformer, 13, II sections of busbar institute links.
Embodiment
In Fig. 1, capacitor 4, bus section are installed in each phase of shielded small current neutral grounding system I sections of busbares 1
Switch uses breaker 2, its other end connects II section of busbar institute link 13.Measure and control device 5 is used to monitor small current neutral grounding system
Whether system occurs singlephase earth fault, so as to control breaker 2 and capacitor 4 to act, as shown in Figure 2.Measure and control device 5 is by three-phase
Voltage, residual voltage acquisition module 6, circuit-breaker status detection module 7, killer switch drive module 8, capacitor switching switch
Drive module 9, human-computer dialogue module 10 and CPU 11 are formed, and the three-phase voltage and residual voltage for monitoring small current neutral grounding system come
Judge whether system occurs singlephase earth fault, so as to control breaker and capacitor switching switch motion.Wherein, three-phase electricity
Pressure, residual voltage acquisition module 6 are by voltage transmitter, RC low-pass filtering, the pretreatment circuit and A/D being made of operational amplifier
Conversion circuit is formed；Circuit-breaker status detection module 7 is made of auxiliary contacts of circuit breaker and detection circuit；Killer switch drives
Module 8 and capacitor switching switch drive module 9 are made of relay drive circuit and control relay；Human-computer dialogue module 10
It is made of button and LCD MODULE；CPU 11 is made of STC12C5A60S2 microcontrollers, mainly according to three-phase voltage and zero
Sequence voltage judges whether to occur single-phase to connect breaker 2 before earth fault, the failure of 7 collection of storage circuit-breaker status detection module
State, singlephase earth fault send switch when occurring to killer switch drive module 8 and capacitor switching switch drive module 9
Point, the instruction closed, selection faulty line, the function such as human-computer dialogue.Measure and control device 5 is also connected with voltage transformer 12, and voltage is mutual
One end of sensor 12 is connected with I sections of busbares 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, by open circuit
Device disconnects；If breaker is closure state before failure, capacitor switching is switched by measure and control device after failure and is closed, is then carried out
The selection of faulty line, after route selection, capacitor switching is switched off；
(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, aforesaid operations are re-started back to step (1).
In Fig. 1, it is assumed that singlephase earth fault occurs for the C phases of circuit II.If breaker 2 is off-state before failure, failure
Closed afterwards by measure and control device 5；If breaker 2 is closure state before failure, by measure and control device by capacitor switching after failure
The closure of switch 3.The purpose is to increase the zero-sequence current of faulty line in short-term when singlephase earth fault occurs for system, and non-faulting
The zero-sequence current of circuit is still the capacitance current of circuit in itself, so as to widen zero-sequence current between faulty line and non-fault line
Gap, it is possible to increase utilize failure steady-state quantity stable state route selection and positioning protection judging nicety rate.
Claims (5)
1. a kind of small current earthing wire-selecting method for strengthening fault signature, it is included by the busbar of protection distribution system, the mother
Capacitor be installed on line help to be installed in addition with and put, busbar sectional izing switch uses breaker, capacitor help be installed in addition with put, breaker and observing and controlling dress
Connection is put, measure and control device is connected with voltage transformer, and voltage transformer is then connected with busbar；Measure and control device detects small current neutral grounding
Whether system occurs singlephase earth fault, and helps increasing to earth current by controlling the state of capacitor and breaker to realize.
2. a kind of small current earthing wire-selecting method for strengthening fault signature according to claim 1, it is characterized in that：The survey
Device is controlled by three-phase voltage, residual voltage acquisition module, circuit-breaker status detection module, killer switch drive module, capacitance
Device fling-cut switch drive module, human-computer dialogue module and CPU compositions, monitor the three-phase voltage and zero sequence electricity of small current neutral grounding system
Press to judge whether system occurs singlephase earth fault, so as to control breaker and capacitor switching switch motion；Wherein, three-phase
Voltage, residual voltage acquisition module are by voltage transmitter, RC low-pass filtering, the pretreatment circuit and A/ being made of operational amplifier
D conversion circuits are formed；Circuit-breaker status detection module is made of auxiliary contacts of circuit breaker and detection circuit；Killer switch drives
Module and capacitor switching switch drive module are made of relay drive circuit and control relay；Human-computer dialogue module by by
Key and LCD MODULE are formed；CPU is made of STC12C5A60S2 microcontrollers, is mainly sentenced according to three-phase voltage and residual voltage
It is disconnected that the single-phase state of breaker before earth fault, the failure of storage circuit-breaker status detection module collection, single-phase of connecing whether occurs
Earth fault occur when to killer switch drive module and capacitor switching switch drive module send switch division instruction,
Select the functions such as faulty line, human-computer dialogue.
3. a kind of small current earthing wire-selecting method for strengthening fault signature according to claim 1, it is characterized in that：The electricity
Container, which is helped in each phase for being installed in addition with and putting and be included in busbar, sets at least one capacitor, they form capacitor group, each capacitance
One end of device is connected respectively at respective fling-cut switch, other end ground connection.
4. a kind of small current earthing wire-selecting method for strengthening fault signature according to claim 1, it is characterized in that：It is described disconnected
Road device is busbar sectional izing switch, and during small current neutral grounding system normal operation, which is according to the needs of the method for operation and closes
Conjunction or off-state, and circuit-breaker status is detected by circuit-breaker status detection module；Single-phase earthing occurs for small current neutral grounding system
During failure, if breaker is off-state before failure, closed after failure by measure and control device；If breaker is closure before failure
State, capacitor switching is switched after failure close by measure and control device；The purpose is to short when singlephase earth fault occurs for system
The zero-sequence current of Shi Zeng great faulty lines, and the zero-sequence current of non-fault line is still the capacitance current of circuit in itself, so as to draw
The gap of zero-sequence current between major break down circuit and non-fault line, improves the accuracy rate of route selection.
5. a kind of small current earthing wire-selecting method for strengthening fault signature according to claim 1, it is characterized in that：Its side
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, by open circuit
Device disconnects；If breaker is closure state before failure, capacitor switching is switched by measure and control device after failure and is closed, is then carried out
The selection of faulty line, after route selection, capacitor switching is switched off；
(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, aforesaid operations are re-started back to step (1).
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| CN201810021388.1A CN107942203B (en) | 2018-01-09 | 2018-01-09 | Low-current grounding line selection method for enhancing fault characteristics |
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| CN201810021388.1A CN107942203B (en) | 2018-01-09 | 2018-01-09 | Low-current grounding line selection method for enhancing fault characteristics |
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| CN110535116A (en) * | 2019-09-10 | 2019-12-03 | 北京华电瑞通电力工程技术有限公司 | A kind of arc extinction cabinet and small current neutral grounding system |
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| CN107942203B (en) | 2020-02-07 |
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