CN110346678A - A kind of method of quick lookup direct current system multipoint earth faults - Google Patents
A kind of method of quick lookup direct current system multipoint earth faults Download PDFInfo
- Publication number
- CN110346678A CN110346678A CN201910643498.6A CN201910643498A CN110346678A CN 110346678 A CN110346678 A CN 110346678A CN 201910643498 A CN201910643498 A CN 201910643498A CN 110346678 A CN110346678 A CN 110346678A
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- China
- Prior art keywords
- direct current
- current system
- ground
- branch
- switch
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Classifications
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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
- G01R31/085—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution lines, e.g. overhead
-
- 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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
Abstract
The invention discloses a kind of methods for quickly searching direct current system multipoint earthing, comprising: detect in direct current system all there are the fault branches of DC ground fault；For each fault branch: disconnecting the correspondence control switch of current failure branch and the switch of all DC loads of fault branch dc main；Close the correspondence total control switch of current failure branch, and successively close all DC load switches of current failure branch dc main, and measured when closing DC load switch every time and judge whether direct current system voltage-to-ground is normal: if there is exception, then indicate that ground fault occurs in circuit where the DC load currently closed switch, the DC load switch currently closed is disconnected, continues to close next DC load switch；If there is not exception, the DC load currently closed switch is made to be maintained at closed state, and continues to close next DC load switch.The present invention can quickly find out direct current system multipoint earthing, it is ensured that the safety of power supply system.
Description
Technical field
The present invention relates to a kind of methods of direct current system multipoint earth faults, more particularly to a kind of quickly lookup direct current system
The method of multipoint earth faults.
Background technique
DC power supply in power supply system is supplied with the power supply of the equipment such as relay protection, automatic device, control loop, once
Direct current system breaks down, it will the safe operation and economical operation of serious critical power supply system, especially generation DC earthing
It when failure, is likely to result in breaker mistrip or refuses to trip, the branch of direct current system is more, a little connects if direct current system occurs
Ground connection more than ground or two o'clock, is handled not in time, and consequence is extremely serious, will affect power supply system safe operation.
Such as Fig. 1, direct current system there are a plurality of branch (including branch 1, branch 2 ... branch n), each branch have phase
Total control switch QF1, QF2 for answering ... QFn, while each branch includes many DC loads or branch again, each direct current is negative
It carries or branch switchs with corresponding DC load.In Fig. 1, only there is ground connection in the branch of " 3# becomes protection " under branch 3
Failure since existing direct current system is each equipped with D.C. isolation detection device, can detect defective insulation or direct current in this case
The branch of ground connection reuses according to the result of detection out branch and draws the direct currents such as road lookup, segment processing, multimeter voltage measurement method
The lookup method of ground connection can find out the DC load there are ground fault.However, being connect if two o'clock as shown in Figure 2 occurs
Earth fault (" 3# becomes protection " and " 4# becomes protection " i.e. in branch 3 breaks down) situation, because of branch each in direct current system
There are tens subbranches, subbranch is various, and coverage is wide, searches extremely difficult.Again below 3 circuit of branch there are two therefore
Hinder point, draws road lookup method if continuing to take, drawn a fault point, another fault point is still in direct current system, direct current
Pressure cannot recover immediately normally, thus cause remaining fault point that can not find.
Summary of the invention
Goal of the invention: to overcome the shortcomings of existing technologies, the invention proposes a kind of direct current system multiple spots of quickly searching to connect
The method of earth fault can quickly find out direct current system multipoint earthing, it is ensured that the safety of power supply system.
Technical solution: one kind of the invention quickly search the method for direct current system multipoint earth faults the following steps are included:
(S1) with D.C. isolation device detect in the direct current system all there are the failure branch of DC ground fault
Road；
(S2) it is directed to each fault branch, all ground faults in each fault branch are found out by following below scheme:
(S21) the correspondence control switch and all DC loads of fault branch dc main of current failure branch are disconnected
Switch；
(S22) the correspondence total control switch of current failure branch is closed, and successively closes current failure branch dc main
All DC load switches, and measured when closing DC load switch every time and judge direct current system voltage-to-ground whether just
It is normal: if there is exception, then it represents that ground fault occurs in circuit where the DC load switch currently closed, and disconnection is currently closed
DC load switch, continue to close next DC load switch；If there is not exception, make the DC load currently closed
Switch is maintained at closed state, and continues to close next DC load switch.
Further, the total control switch of each branch and each branch dc main DC load switch in the direct current system
For air switch.
In step (S1), detect all in the direct current system there are DC ground fault with D.C. isolation device
Fault branch includes: to be detected using open line method.
In step (S22), when closing DC load switch every time, direct current system voltage-to-ground is by multimeter or direct current
Insulation detection device measures.The direct current system voltage-to-ground includes: the voltage difference of DC transmission line anode and ground
Or the voltage difference of DC transmission line cathode and ground.When the voltage that the direct current system voltage-to-ground is DC transmission line anode and ground
Difference occurs abnormal including closing the direct current system voltage-to-ground after current DC load switchs to be reduced to beyond the first threshold
Value；When the voltage difference that the direct current system voltage-to-ground is DC transmission line cathode with ground, occur abnormal including closing currently
The direct current system voltage-to-ground is increased to beyond second threshold after DC load switch.
The utility model has the advantages that compared with prior art, two or more ground connection is occurring in face of direct current system for the present invention
When failure, direct current system multipoint earth faults can be rapidly found out, are provided to equipment such as relay protection, automatic device, control loops
Reliable DC power supply, while being provided safeguard to the safe operation of power supply system electrical equipment, there is indirect social benefit.
Detailed description of the invention
Fig. 1 is that one point earth schematic diagram occurs for direct current system；
Fig. 2 is that two points ground fault schematic diagram occurs for direct current system.
Specific embodiment
Below in conjunction with attached drawing, the present invention is described in detail.
Two or more ground fault, detailed process packet occur primarily directed to direct current system for method of the invention
It includes:
Step 1: with D.C. isolation device detect in the direct current system all there are the failures of DC ground fault
Branch.Road lookup method is drawn specifically, taking, (is propped up by the total trunk that D.C. isolation device finds out earth fault
Road).In this embodiment, it is assumed that the fault branch found out is branch 3.
Step 2: it is directed to each fault branch, finds out all ground faults in each fault branch.
By taking branch 3 as an example, the process of looking for of all ground faults includes following process in branch 3:
(1) the correspondence control switch and all DC loads of fault branch dc main of current failure branch are disconnected
Switch.It specifically includes: the total control switch of first disconnected branches 3, then which branch is judged by the power loss situation of each branch
For the DC load of branch 3.Then, according to all DC load air switches of judging result disconnected branches 3, thus also just disconnected
All earth faults on branch 3 are opened in direct current system.In the present embodiment, the total control switch of branch and each direct current of branch
Load switch is air switch.
(2) the correspondence total control switch of current failure branch is closed, and successively closes current failure branch dc main institute
There is DC load switch, and when closing DC load switch every time, is measured using D.C. isolation detection device or multimeter straight
Whether streaming system voltage-to-ground there is exception.Wherein, positive voltage-to-ground is+110V in 220V direct current system, and cathode is electric over the ground
Pressure is -110V, here normal, after referring to direct current system voltage-to-ground before closing and closing direct current system voltage-to-ground it
Difference is within threshold range, conversely, abnormal then refer to the voltage difference for closing front and back beyond the threshold range.Direct current system is electric over the ground
Pressure can be the voltage difference of DC transmission line positive ("+KM " in Fig. 2) and ground, be also possible to DC transmission line cathode (in Fig. 2
"-KM ") with ground voltage difference.When the voltage difference that direct current system voltage-to-ground is DC transmission line anode and ground, occur different
The direct current system voltage-to-ground after closing current DC load switch is referred to be reduced to beyond first threshold.When the direct current
System voltage-to-ground is the voltage difference of DC transmission line cathode and ground, occur it is abnormal refer to close current DC load switch after
The direct current system voltage-to-ground is increased to beyond second threshold.Here first threshold and second threshold is can be according to reality
Situation thinks setting.
When voltage is normal, then current DC load is kept to close the switch, and continues to close next DC load switch.
When detecting " 3# becomes protection " branch under branch 3, voltage occurs abnormal.This abnormal conditions show " 3# becomes protection " point
There are ground faults for branch or DC load circuit.At this point, first disconnecting the DC load circuit switching (i.e. disconnection " 3# of faulty point
Become protection " the corresponding switch of branch), waiting further searches for other earth faults, that is, continues to close next DC load
Switch (i.e. such as " 4# becomes protection " the corresponding switch of branch in Fig. 2).Since there is also ground connection events for " 4# becomes protection " branch in branch 3
Barrier, therefore switch also can detecte out electric voltage exception by multimeter or D.C. isolation detection device when closing herein.So
" 4# becomes protection " corresponding switch of branch is disconnected, continues to close " 5# becomes protection " corresponding switch of branch.Continue to operate remaining
Load air switch, it is all there are the branch of ground fault or DC load circuit until finding out branch 3.
As it can be seen that above-mentioned lookup method of the invention is not only able to achieve the lookup of multipoint earth faults, but also search speed is fast,
The processing time that DC ground fault can be reduced improves the safety in operation and reliability of power supply system.
Claims (6)
1. a kind of method for quickly searching direct current system multipoint earth faults, which comprises the following steps:
(S1) with D.C. isolation device detect in the direct current system all there are the fault branches of DC ground fault；
(S2) it is directed to each fault branch, all earth faults in each fault branch are found out by following below scheme:
(S21) the correspondence control switch of current failure branch and opening for all DC loads of fault branch dc main are disconnected
It closes；
(S22) the correspondence total control switch of current failure branch is closed, and it is all successively to close current failure branch dc main
DC load switch, and measured when closing DC load switch every time and to judge whether direct current system voltage-to-ground occurs different
It is normal: if there is exception, then it represents that earth fault occurs in circuit where the DC load switch currently closed, disconnects current close
On DC load switch, continue to close next DC load switch；If there is not exception, keep the direct current currently closed negative
Load switch is maintained at closed state, and continues to close next DC load switch.
2. the method for quick lookup direct current system multipoint earth faults according to claim 1, which is characterized in that described straight
The total control switch of each branch and each branch dc main DC load switch are air switch in streaming system.
3. the method for quick lookup direct current system multipoint earth faults according to claim 1, which is characterized in that step
(S1) in, with D.C. isolation device detect in the direct current system all there are the fault branch packets of DC ground fault
It includes: being detected using open line method.
4. the method for quick lookup direct current system multipoint earth faults according to claim 1, which is characterized in that step
(S22) in, when closing DC load switch every time, direct current system voltage-to-ground is by multimeter or D.C. isolation detection device
Come what is measured.
5. quickly searching the method for direct current system multipoint earth faults according to claim 1, which is characterized in that step
(S22) in, the direct current system voltage-to-ground include: DC transmission line anode and ground voltage difference or DC transmission line cathode with
The voltage difference on ground.
6. quickly searching the method for direct current system multipoint earth faults according to claim 5, which is characterized in that step
(S22) in, when the voltage difference that the direct current system voltage-to-ground is DC transmission line anode and ground, occur abnormal including closing
The direct current system voltage-to-ground is reduced to beyond first threshold after current DC load switch；When the direct current system is electric over the ground
Pressure is the voltage difference of DC transmission line cathode and ground, occurs abnormal including closing the direct current system after current DC load switch
System voltage-to-ground is increased to beyond second threshold.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201910643498.6A CN110346678A (en) | 2019-07-17 | 2019-07-17 | A kind of method of quick lookup direct current system multipoint earth faults |
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| CN201910643498.6A CN110346678A (en) | 2019-07-17 | 2019-07-17 | A kind of method of quick lookup direct current system multipoint earth faults |
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| CN110346678A true CN110346678A (en) | 2019-10-18 |
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| CN201910643498.6A Pending CN110346678A (en) | 2019-07-17 | 2019-07-17 | A kind of method of quick lookup direct current system multipoint earth faults |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110736936A (en) * | 2019-10-31 | 2020-01-31 | 深圳供电局有限公司 | Direct current system ground fault detection device and control method thereof |
| CN112666490A (en) * | 2021-01-11 | 2021-04-16 | 国网安徽省电力有限公司淮北供电公司 | Method and device for rapidly detecting multipoint ground fault of direct current system |
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2019
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| CN201449433U (en) * | 2009-01-09 | 2010-05-05 | 王道龙 | Device for locating ground fault of DC system |
| CN101916986A (en) * | 2010-07-19 | 2010-12-15 | 武汉供电公司变电检修公司 | Method and device for automatically isolating and positioning earth faults of Dc system |
| CN203310954U (en) * | 2013-05-28 | 2013-11-27 | 合肥新在线科技发展有限公司 | Voltage insulation-monitoring line-selection device for direct-current system |
| CN104198873A (en) * | 2014-10-08 | 2014-12-10 | 国网河南省电力公司南阳供电公司 | Grounding detection method for secondary loop of voltage transformer |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110736936A (en) * | 2019-10-31 | 2020-01-31 | 深圳供电局有限公司 | Direct current system ground fault detection device and control method thereof |
| CN110736936B (en) * | 2019-10-31 | 2022-04-19 | 深圳供电局有限公司 | Direct current system ground fault detection device and control method thereof |
| CN112666490A (en) * | 2021-01-11 | 2021-04-16 | 国网安徽省电力有限公司淮北供电公司 | Method and device for rapidly detecting multipoint ground fault of direct current system |
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Application publication date: 20191018 |