CN101520484A - Grounded failure detection and judgment of DC system - Google Patents
Grounded failure detection and judgment of DC system Download PDFInfo
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- CN101520484A CN101520484A CN200910066688A CN200910066688A CN101520484A CN 101520484 A CN101520484 A CN 101520484A CN 200910066688 A CN200910066688 A CN 200910066688A CN 200910066688 A CN200910066688 A CN 200910066688A CN 101520484 A CN101520484 A CN 101520484A
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Abstract
The problem of correctly selecting a wire on the branch of the grounded failure of a DC system of a power system is always the difficult problem of the power system. The difficulty of correct wire selection is caused by the integrated reason on multiple aspects. The safety and the reliability of the DC system influence the running of a power plant and a transforming plant and relates to the safe production of the entire power network. The grounded failure detection and judgment of the DC system of the invention reaches the level of increasing the bus insulation monitoring alarm value from 48 kilohms to 100 kilohms. According to the requirements of (DL/T5044-95) design technical specification of DC systems of thermal power plants and transforming plants, the insulation check performance of corresponding branches is increased to the level of 300 kilohms from 20 kilohms, and the insulation detecting level of the branches covers various failure phenomena of the insulation alarm value of the DC system.
Description
Technical field
The present invention relates to the direct current streaming system earth fault line selection in the electric system, this fault-line selecting method, and discriminant criterion is effectively and can fast detecting be out of order branch road.
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
It is at present unique that what retrieve is that the index that requires of straight-flow system insulating Design standard " fuel-burning power plant, transforming station direct current system designing technique regulation " (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.
Insulating Design value by " fuel-burning power plant, transforming station direct current system designing technique regulation " system should be the alarming value of system insulation.System insulation is to should being that insulating monitoring alarming value and fault branch can correctly detect scope below the 100K Ω.Suppose that three branch road insulation of straight-flow system same polarity descends simultaneously, and on same polarity, every the branch road insulation values is slightly less than 300K Ω, the straight-flow system insulation values is during less than 100K Ω after the three bar insulation decline branch road parallel connections, at this moment require the bus insulation supervisory device correctly to report to the police, and detect three fault branches.But at this moment the detection level of branch trouble should reach the ability of 300K Ω.We can descend three branch road insulation simultaneously and be less than the most serious situation consideration of the identical value of 300K Ω as dc system fault.When system has three above branch roads to make system insulation value decline 100K Ω following owing to insulation fault, should all branch road insulation values all not 300K Ω, the easier so minimum branch road of insulation values of selecting.At this moment branch road insulation detection level should reach 300K Ω.
It has accomplished to constitute real current path.Again through the current-limiting resistance current limliting of design, with the safety that guarantees equipment and guarantee not malfunction of relay.Accomplish to constitute the purpose of stable Leakage Current controlled amount, guarantee security of system, the real controllable state of sensor signal thereby reach.
Figure of description 1 median generatrix 7, on branch road 8, main frame 5, sensor 4, earth point 6, circuit switching 1, insurance 2, current-limiting resistance 3 constitute.
The hidden earth fault device of straight-flow system field test method:
1, on a test branch road, causes unipolarity earth fault with 99K Ω resistance;
2, each causes unipolarity ground connection barrier with 198K Ω resistance on two same polarity test branch roads;
3, each causes unipolarity ground connection barrier with 297K Ω resistance on three same polarity test branch roads;
4, on a test branch road, cause bipolarity balanced to ground fault with two 99 Ω resistance.
5, on the different tests branch road, cause bipolarity balanced to ground fault with two 99K Ω resistance.
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 220v 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 2 median generatrixs 7, on branch road 8, main frame 5, sensor 4, earth point 6, stake resistance 10, and load 9 constitute.
Claims (5)
1, the present invention claim ＂ grounded failure detection and judgment of DC system ＂ it accomplished to constitute real current path.Again through the current-limiting resistance current limliting of design, with the safety that guarantees equipment and guarantee not malfunction of relay.Accomplish to constitute the purpose of stable Leakage Current controlled amount, guarantee security of system, the real controllable state of sensor signal thereby reach.Bus insulation supervision alarming value is brought up to the level of 100K Ω by 48K Ω.It is according to the requirement of (DL/T5044-95) " fuel-burning power plant, transforming station direct current system designing technique regulation ", corresponding branch road insulation detectability is brought up to the level of 300K Ω by 20K Ω, and its branch road insulation detection level has covered the various phenomena of the failure of straight-flow system insulation alarming value.
2, detection according to claim 1 is differentiated, and it is characterized in that described detection differentiation proposes new standard, with the equipment of assurance straight-flow system and the safety of electric system.
3, detection according to claim 1 is differentiated, and it is characterized in that described detection differentiation proposes new standard, have the relevant detection standard.
4, detection according to claim 1 is differentiated, and it is characterized in that described detection differentiation proposes new standard, is the Design of device foundation.
5, detection according to claim 1 is differentiated, and it is characterized in that described detection differentiation proposes new standard, is the various phenomena of the failure for corresponding system insulation alarming value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910066688A CN101520484A (en) | 2009-03-25 | 2009-03-25 | Grounded failure detection and judgment of DC system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN200910066688A CN101520484A (en) | 2009-03-25 | 2009-03-25 | Grounded failure detection and judgment of DC system |
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| CN101520484A true CN101520484A (en) | 2009-09-02 |
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| CN200910066688A Pending CN101520484A (en) | 2009-03-25 | 2009-03-25 | Grounded failure detection and judgment of DC system |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101750540B (en) * | 2009-12-25 | 2011-11-02 | 上海希明电气技术有限公司 | Method for detecting parasitic loop of transformer station direct current system |
| CN103701092A (en) * | 2013-12-18 | 2014-04-02 | 北京恺思维特科技有限责任公司 | Insulation resistance detection and ground protection device of DC electric system |
| CN104678264A (en) * | 2013-11-30 | 2015-06-03 | 中国科学院沈阳自动化研究所 | Online insulation detection and fault processing device and method of AUV (Autonomous Underwater Vehicle) direct-current power supply system |
| CN109188166A (en) * | 2018-08-28 | 2019-01-11 | 厦门科华恒盛股份有限公司 | Ground fault detection device and method |
| CN109188167A (en) * | 2018-08-28 | 2019-01-11 | 厦门科华恒盛股份有限公司 | Ground fault detection device and method |
| CN109782106A (en) * | 2019-01-07 | 2019-05-21 | 邯郸钢铁集团有限责任公司 | A kind of DC system earth fault lookup device and method |
| CN113933626A (en) * | 2021-09-30 | 2022-01-14 | 滁州市智宏工程咨询有限责任公司 | Fault detection and correction control method for direct-current system of transformer substation |
-
2009
- 2009-03-25 CN CN200910066688A patent/CN101520484A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101750540B (en) * | 2009-12-25 | 2011-11-02 | 上海希明电气技术有限公司 | Method for detecting parasitic loop of transformer station direct current system |
| CN104678264A (en) * | 2013-11-30 | 2015-06-03 | 中国科学院沈阳自动化研究所 | Online insulation detection and fault processing device and method of AUV (Autonomous Underwater Vehicle) direct-current power supply system |
| CN103701092A (en) * | 2013-12-18 | 2014-04-02 | 北京恺思维特科技有限责任公司 | Insulation resistance detection and ground protection device of DC electric system |
| CN103701092B (en) * | 2013-12-18 | 2016-03-09 | 北京恺思维特科技有限责任公司 | A kind of DC electrical system insulation resistance detects and earth protective device |
| CN109188166A (en) * | 2018-08-28 | 2019-01-11 | 厦门科华恒盛股份有限公司 | Ground fault detection device and method |
| CN109188167A (en) * | 2018-08-28 | 2019-01-11 | 厦门科华恒盛股份有限公司 | Ground fault detection device and method |
| CN109782106A (en) * | 2019-01-07 | 2019-05-21 | 邯郸钢铁集团有限责任公司 | A kind of DC system earth fault lookup device and method |
| CN109782106B (en) * | 2019-01-07 | 2021-03-09 | 邯郸钢铁集团有限责任公司 | Direct current system ground fault searching device and method |
| CN113933626A (en) * | 2021-09-30 | 2022-01-14 | 滁州市智宏工程咨询有限责任公司 | Fault detection and correction control method for direct-current system of transformer substation |
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Application publication date: 20090902 |