CN101556319A - Ground fault detection and calibration method and device for direct current system - Google Patents
Ground fault detection and calibration method and device for direct current system Download PDFInfo
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- CN101556319A CN101556319A CNA2009100666897A CN200910066689A CN101556319A CN 101556319 A CN101556319 A CN 101556319A CN A2009100666897 A CNA2009100666897 A CN A2009100666897A CN 200910066689 A CN200910066689 A CN 200910066689A CN 101556319 A CN101556319 A CN 101556319A
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Abstract
The problem of correct wire selection of a branch with a ground fault of a direct current system of a power system is always a difficult problem for the power system. Comprehensive reasons on a plurality of aspects cause the phenomenon that the correct wire selection is difficult. The safety and the reliability of the direct current system affect the operation of power plants and transformer stations and are related to the safe production of the whole large power system. The ground fault detection and calibration method and the device for the direct current system improve the insulation supervision alarm value of a bus to the level of 100KO from 48KO. The ground fault detection and calibration method and the device are based on the requirements of (DL/T5044-95) technical regulations for design of direct current systems of fossil fuel power plants and transformer substations, and the corresponding branch insulating detection ability is improved to the level of 300KO from 20KO, and the branch insulating detection horizontally covers all the fault phenomena of the insulating alarm value of the direct current system. The calibration method and the device are used for detecting the calibration of a direct current insulating supervision device before access network. The invention aims at ensuring the safety of the system and the standards of access network.
Description
Technical field
The present invention relates to the direct current streaming system earth fault detection and calibration method in the electric system, belong to the category that the straight-flow system checkout equipment is used.
Background technology
1, the supervision level of present straight-flow system bus insulation:
Direct supply is one of power supply important in generating plant and the transformer station.The supervision of dc bus insulation at present is that the insulating monitoring electric current with 1.4mA is a benchmark, when leakage current during greater than 1.4mA, this straight-flow system integral insulation level has dropped to below the 48k Ω, and the dc bus insulating monitoring, resolution that detects and precision are to differentiate earth fault, start the foundation of further work.Theoretical Calculation is can detect bus insulation less than the phenomenon below the 48K Ω at present, and the detectability of actual bus insulation is less than Theoretical Calculation numerical value.
2, the detection level of branch road insulation at present:
The detection level of branch road insulation is the basic assurance of straight-flow system dielectric level.The detection level of branch road insulation at present can only reach below the 20K Ω, and often false alarm, the phenomenon of falsely dropping fault branch.
The correct route selection problem of the branch road of DC system earth fault is a difficult problem of electric system always.Causing this correct route selection difficulty phenomenon, is due to many-sided combined cause.The security of straight-flow system, reliability effect the operation of generating plant, transformer station, are concerning the safety in production of whole big electrical network.The generating plant, transformer station that all kinds, various scales are arranged in the power network all ubiquity accidents such as the mistakenly stop machine that causes because of DC system earth fault, switch mis-jumping lock, all causes great economic loss.As seen installment monitor DC system earth fault device is very necessary.Fault to DC power system is made diagnosis rapidly and accurately, can guarantee that just straight-flow system safely and steadily runs.When one point earth takes place when, do not cause any harm, but must in time handle, otherwise, when another ground connection is taken place, might make relay protection generation misoperation, tripping.Find that DC earthing not only can cause protective relaying maloperation, tripping in the operation practice, even can cause equipment malfunction, the tripping of using DC control,, cause the serious consequence of large-area power-cuts, system break-down down to damage equipment.Therefore,, can not only look at problem, go to consider from the safety that influences whole electrical network from a transformer station, power plant's angle for the harm of DC earthing problem.
Summary of the invention
This method of calibration and device are to detect the preceding verification to the insulating monitoring device of D.C. isolation supervisory device networking.Its purpose guarantees the safety of system and the standard of networking.
It is at present unique that what retrieve is that straight-flow system insulating Design standard " fuel-burning power plant, the transforming station direct current system designing technique regulation " index that requires (DL/T5044-95) is that straight-flow system dielectric level over the ground should be more than 100K Ω about straight-flow system insulation standard.And now when straight-flow system makes the straight-flow system dielectric level descend because of insulation fault after, the effect of the pick-up unit that existing market provides does not reach the requirement of (DL/T5044-95) straight-flow system designing technique regulation at all.
The detection alarm value of straight-flow system bus insulation is less than 48K Ω at present, and the detection level of branch road insulation detection device just can reach the following and frequent false alarm of 20K Ω.
The alarming value of the insulating Design value of " fuel-burning power plant, transforming station direct current system designing technique regulation " system as system insulation.System insulation is to being that insulating monitoring alarming value and fault branch can correctly detect scope below the 100K Ω, and branch road detects should reach 300K Ω level.Comprise that to it 1. straight-flow system wall scroll branch road insulation unipolarity descends; 2. two branch road insulation of straight-flow system same polarity descends simultaneously; 3. three branch road insulation of straight-flow system same polarity descends simultaneously; 4. straight-flow system wall scroll branch road insulation bipolarity descends simultaneously; 5. straight-flow system different branch insulation bipolarity descends simultaneously.It can accomplish system insulation below 100K Ω, covers the phenomenon of the various faults of fault branch during the insulating monitoring alarming value.
Description of drawings
Figure of description median generatrix 1, on branch road 2, sensor 3, main frame 4, earth point 5, stake resistance 6, load 7 constitute.
The hidden earth fault device of straight-flow system field test method:
1, accompanying drawing 1 causes unipolarity earth fault with 99K Ω resistance on a test branch road;
2, each causes unipolarity ground connection barrier with 198K Ω resistance to accompanying drawing 2 on two same polarity test branch roads;
3, each causes unipolarity ground connection barrier with 297K Ω resistance to accompanying drawing 3 on three same polarity test branch roads;
4, accompanying drawing 4 causes bipolarity balanced to ground fault with two 99 Ω resistance on a test branch road.
5, accompanying drawing 5 causes bipolarity balanced to ground fault with two 99K Ω resistance on the different tests branch road.
Application example
The failure line selection that the insulation of straight-flow system branch road descends is used: the route selection that is applied in the fault branch in the direct current DC220v system.When the insulation of three branch roads of straight-flow system descends simultaneously, and on same polarity, every branch road insulation values is 297K Ω, and the straight-flow system insulation values is during less than 99K Ω after the three bar insulation decline branch road parallel connections, and at this moment the fault branch electric current is near 0.5mA.Its two point failure such as Figure of description 3 median generatrixs 1, on branch road 2, sensor 3, main frame 4,, earth point 5, stake resistance 6, and load 7 constitute.
Claims (5)
1, the present invention claims that " DC system earth fault detection and calibration method and device " is to detect the method for using simulation before the D.C. isolation supervisory device networks, to the verification of insulating monitoring device.Its purpose guarantees the safety of system and the standard that equipment networks, and is 100k Ω at its straight-flow system alarming value of DC bus-bar voltage DC220V, and the branch road detection level is 300k Ω.
2, detection check according to claim 1 is characterized in that described detection differentiation proposes the new standard of verification, and output voltage can be DC220V, DC110V, DC48V, DC48V.
3, detection according to claim 1 is differentiated, and it is characterized in that described detection differentiation proposes new standard, in that 0k Ω-500k Ω is adjustable, can satisfy system's phenomenon according to different DC voltage corresponding resistors.
4, detection according to claim 1 is differentiated, and it is characterized in that described detection differentiation proposes new standard, and the simulation of 0uf-300uf tunable capacitor is arranged, and can satisfy system's phenomenon.
5, detection according to claim 1 is differentiated, and it is characterized in that described detection differentiation proposes new standard, and it comprises the device of unifrequency injection method, bifrequency injection method and direct current differential technique.
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CNA2009100666897A CN101556319A (en) | 2009-03-25 | 2009-03-25 | Ground fault detection and calibration method and device for direct current system |
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CNA2009100666897A CN101556319A (en) | 2009-03-25 | 2009-03-25 | Ground fault detection and calibration method and device for direct current system |
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102879755A (en) * | 2012-09-20 | 2013-01-16 | 保定供电公司 | Testing instrument for acting performance of insulation monitoring device |
CN103792505A (en) * | 2014-01-16 | 2014-05-14 | 国家电网公司 | Ground fault simulation device for electric power direct current system |
CN104062616A (en) * | 2014-06-22 | 2014-09-24 | 国家电网公司 | Direct-current earthing and alternating current-directing current series simulation device |
CN104793164A (en) * | 2015-03-31 | 2015-07-22 | 国家电网公司 | Branch insulation warning function verifying device of direct-current system |
CN108572278A (en) * | 2017-03-14 | 2018-09-25 | 深圳市艾华迪技术有限公司 | The detection circuit and its detection method of DC bus insulation against ground resistance |
CN112327207A (en) * | 2020-10-31 | 2021-02-05 | 贵州电网有限责任公司 | Portable direct current system ground fault judgment device and use method thereof |
-
2009
- 2009-03-25 CN CNA2009100666897A patent/CN101556319A/en active Pending
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102879755A (en) * | 2012-09-20 | 2013-01-16 | 保定供电公司 | Testing instrument for acting performance of insulation monitoring device |
CN103792505A (en) * | 2014-01-16 | 2014-05-14 | 国家电网公司 | Ground fault simulation device for electric power direct current system |
CN103792505B (en) * | 2014-01-16 | 2016-08-17 | 国家电网公司 | A kind of electric power DC system earth fault analog |
CN104062616A (en) * | 2014-06-22 | 2014-09-24 | 国家电网公司 | Direct-current earthing and alternating current-directing current series simulation device |
CN104062616B (en) * | 2014-06-22 | 2017-10-31 | 国家电网公司 | DC earthing and exchange string direct current simulator |
CN104793164A (en) * | 2015-03-31 | 2015-07-22 | 国家电网公司 | Branch insulation warning function verifying device of direct-current system |
CN108572278A (en) * | 2017-03-14 | 2018-09-25 | 深圳市艾华迪技术有限公司 | The detection circuit and its detection method of DC bus insulation against ground resistance |
CN112327207A (en) * | 2020-10-31 | 2021-02-05 | 贵州电网有限责任公司 | Portable direct current system ground fault judgment device and use method thereof |
CN112327207B (en) * | 2020-10-31 | 2022-09-16 | 贵州电网有限责任公司 | Portable direct current system ground fault judgment device and use method thereof |
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Application publication date: 20091014 |