CN202166682U - Fault detecting device of direct grounding - Google Patents
Fault detecting device of direct grounding Download PDFInfo
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- CN202166682U CN202166682U CN2011202559464U CN201120255946U CN202166682U CN 202166682 U CN202166682 U CN 202166682U CN 2011202559464 U CN2011202559464 U CN 2011202559464U CN 201120255946 U CN201120255946 U CN 201120255946U CN 202166682 U CN202166682 U CN 202166682U
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Abstract
The utility model provides a fault detecting device of direct grounding. The fault detecting device has a simple hardware circuit, high detection precision, and has no bad effect on a DC system. The detecting device includes a first voltage dividing circuit (110), a second voltage dividing circuit (120), a voltage sharing circuit (130), an insulation resistor RX1 to be detected and an insulation resistor RX2 to be detected. In the utility model, two valid circuit states are generated through the control of breakover and turn-off of a switching tube in the voltage sharing circuit (130). The direct grounding resistor detection having low cost and high precision is realized by utilizing the relationship of a neutral point voltage and a bus voltage under the two states. The utility model discloses a comparatively accurate formula for calculating positive and negative insulation resistance for the DC system when both of insulation values of a positive bus and a negative bus are deceased by utilizing an unbalanced bridge method, thereby providing a scientific and effective detection method for eliminating malfunction caused by direct grounding.
Description
Technical field
The utility model relates to power system insulation monitoring field, relates in particular to a kind of direct ground insulation failure detector.
Background technology
In straight-flow system; Insulating property directly influence the reliability of DC loop; If 2 ground connection are taken place in the straight-flow system then may cause the misoperation of telltale, control loop and protective relaying device; Cause circuit breaker trip, or directly cause the direct current operative power source short circuit, thereby cause the generation of power system accident.In order to prevent the generation of above-mentioned situation, must in straight-flow system, install continuous working and have the insulation detection device of enough sensitivity.
Existing detection straight-flow system insulating method mainly contains bridge balance method and low frequency signal injection method.The insulation monitoring and warning device of realizing according to the bridge balance method is widely used; It is when positive pole insulation or negative pole insulation decline; Can monitor the insulation effect situation of change of insulation resistance; But it can not monitor the situation of straight-flow system positive and negative electrode insulation resistance when descending on an equal basis, and can not directly obtain system's insulation resistance size over the ground.The low frequency signal injection method is the insulation status with electric bridge monitoring bus; In case the discovery Abnormal Insulation is promptly injected low-frequency ac signal to electrical network, with the electric current of each branch road of D.C mutual-inductor monitoring; Draw insulation resistance through certain algorithm computation then, confirm fault branch.Yet its shortcoming is: need ac signal circuit, increased the complicacy of system; The low-frequency ac signal that injects has increased the ripple coefficient of voltage of straight-flow system; Monitoring result is influenced by system's distributed capacitance; Low-frequency ac signal receives extraneous various interference easily.
In sum, the power system insulation monitoring in the prior art at present exist hardware circuit complicacy, accuracy of detection low, to the influential defective of straight-flow system itself.
The utility model content
The utility model problem to be solved is the deficiency that overcomes above-mentioned prior art, provides that a kind of to have a hardware circuit simple, and accuracy of detection is high, to the straight-flow system direct ground insulation failure detector that has no adverse effects itself.
The technical scheme of the utility model is: the direct ground insulation failure detector in the utility model comprises first bleeder circuit, second bleeder circuit, equalizer circuit and tested insulation resistance RX1 that is in series and tested insulation resistance RX2; Said first bleeder circuit comprises resistance R 1, resistance R 2; Said equalizer circuit comprises resistance R 3, resistance R 4, switching tube S1, resistance R 5 and the resistance R 6 that is connected in series successively; Resistance R 5 is formed said second bleeder circuit with resistance R 6; After connecting successively, said resistance R 3, resistance R 4 and switching tube S1 be parallel to said tested insulation resistance RX1 two ends; Said second bleeder circuit is parallel to said tested insulation resistance RX2 two ends, and said first bleeder circuit is connected in parallel on said tested insulation resistance RX1 that is in series and tested insulation resistance RX2 two ends.
Adopt the detection method of said apparatus to comprise the steps:
Step 1, operation said apparatus are gathered the busbar voltage V at said tested insulation resistance RX1 and tested insulation resistance RX2 two ends
Bus
Step 2, actuating switch pipe S1 gather the mid-point voltage V between said tested insulation resistance RX1 and the tested insulation resistance RX2
Pc
Step 3, on-off switching tube S1 gather the mid-point voltage V between said tested insulation resistance RX1 and the tested insulation resistance RX2
Po
Step 4, the data on the above-mentioned collection corresponding point are inserted in following relational expression, calculate the size that comprises said tested insulation resistance RX1 and tested insulation resistance RX2, to judge insulation effect;
The resistance of said resistance R 1, resistance R 3, resistance R 5 is identical, and the resistance of said resistance R 2, resistance R 4, resistance R 6 is identical.
The beneficial effect of the utility model is: the utility model is through producing two kinds of efficient circuit states to the conducting of switching tube in this device and the control of shutoff; Utilize mid-point voltage and the relation between the busbar voltage under the two states, can realize low cost, the high Precision Detection of direct stake resistance.The utility model utilize unbalanced electric bridge provided one comparatively accurate, be used for the formula that straight-flow system is calculated the positive and negative insulation resistance under the situation that to reduce all appear in positive and negative bus insulation value, because of DC earthing causes misoperation scientific and effective detection means is provided for stopping electric system.
Description of drawings
Fig. 1 is the equivalent circuit diagram for traditional balanced bridge detection method;
Fig. 2 is the schematic equivalent circuit of a kind of novel direct ground insulation fault detection method that the utility model adopted;
Schematic equivalent circuit when Fig. 3 is switching tube S1 conducting;
Schematic equivalent circuit when Fig. 4 turn-offs for switching tube S1.
Embodiment
Comprise monitoring device and the detection method of using this pick-up unit in the present embodiment; Said pick-up unit comprises first bleeder circuit 110, second bleeder circuit 120, equalizer circuit 130 and tested insulation resistance RX1 that is in series and tested insulation resistance RX2; Said first bleeder circuit 110 comprises resistance R 1, resistance R 2; Said equalizer circuit 130 comprises resistance R 3, resistance R 4, switching tube S1, resistance R 5 and the resistance R 6 that is connected in series successively; Resistance R 5 is formed said second bleeder circuit 120 with resistance R 6; Be parallel to said tested insulation resistance RX1 two ends after said resistance R 3, resistance R 4 and switching tube S1 connect successively, said second bleeder circuit 120 is parallel to said tested insulation resistance RX2 two ends, and said first bleeder circuit 110 is connected in parallel on said tested insulation resistance RX1 that is in series and tested insulation resistance RX2 two ends.
The purpose and the principle of the utility model are: be used for straight-flow system insulating monitoring median generatrix insulation effect over the ground and judge; When simplifying circuit, can judge accurately and calculates raising insulating monitoring reliability and accuracy the resistance decline situation of insulation resistance; Through sampling divider resistance R
2On magnitude of voltage V
Ad-busReflect busbar voltage V
BusValue, through sampling divider resistance R
6On magnitude of voltage V
Ad-pReflect busbar voltage V
pValue, R
3, R
4, R
5, R
6, insulation resistance R
X1And R
X2And switching tube S1 forms equalizer circuit, V
pBe mid-point voltage, its magnitude of voltage is because of the conducting of switching tube S1 and the control of shutoff being had the magnitude of voltage under the two states, V during through sampling switch pipe S1 conducting and shutoff
Ad-pDifferent magnitudes of voltage try to achieve mid-point voltage V
pSize, and then can be in the hope of insulation resistance R
X1And R
X2Size, to judge insulation effect.
Do further explain below in conjunction with accompanying drawing and specific embodiment.
Fig. 1 is the equivalent circuit diagram of traditional balanced bridge detection method, through detecting sampled voltage V
Ad-busAnd V
p, add given resistance R and calculate R
X1And R
X2, but under the situation that reducing all appears in positive and negative insulation, the result of detection will not meet in actual conditions.
Fig. 2 is the schematic equivalent circuit of a kind of novel direct ground insulation fault detection method that the utility model adopted, the V among the figure
BusThe busbar voltage of expression input; V
Ad-busThe busbar voltage of expression sampling; V
pThe expression mid-point voltage; V
Ad-pThe mid-point voltage of expression sampling; R
1, R
2It is the divider resistance of first bleeder circuit; R
3, R
4, R
5, R
6Resistance for equalizer circuit; R
X1, R
X2Be insulation resistance.Through conducting and the shutoff of CS pipe S1, to V
Ad-pMagnitude of voltage sample.
Fig. 3 is the schematic equivalent circuit during switching tube S1 conducting among Fig. 2, supposes R
X1Resistance be K
1(R
1+ R
2), R
X2Resistance be K
2(R
1+ R
2), K
1, K
2Be scale-up factor; When the S1 conducting, sampling resistor R
6Voltage be V
Ad-pc, V
PcCan be by V
Ad-pcDraw, its relational expression is:
Sampling resistor R
2Voltage be V
Ad-bus, V
BusCan be by V
Ad-busDraw, its relational expression is:
Can draw relational expression according to equivalent circuit diagram shown in Figure 3:
Formula (3) is carried out abbreviation to be got:
Relational expression is promptly arranged:
Fig. 4 is the schematic equivalent circuit when switching tube S1 turn-offs among Fig. 2, supposes R
X1Resistance be K
1(R
3+ R
4), R
X2Resistance be K
2(R
3+ R
4), K
1, K
2Be scale-up factor; When S1 turn-offs, sampling resistor R
6Voltage be V
Ad-po, V
PoCan be by V
Ad-poDraw, its relational expression is:
（6）
Can draw following relational expression according to equivalent circuit diagram shown in Figure 4:
Formula (7) is carried out abbreviation to be got:
Relational expression is promptly arranged:
Simultaneous formula (5) and formula (9) can draw scale-up factor K
1And K
2Value, its relational expression is:
Thereby can be by calculating insulation resistance R
X1Resistance and R
X2Resistance, its relational expression is following:
Through to the conducting of switching tube S1 and the control of shutoff, can calculate insulation resistance R according to busbar voltage that samples and mid-point voltage
X1And R
X2Value.As insulation resistance R
X1And R
X2Insulation effect just often, turn-offing under the situation of S1 V
Ad-poBe tending towards 0, R
X1Can be considered infinitely great, under the situation of conducting S1, R
X2Also can be considered infinitely great; As insulation resistance R
X1Insulation effect when diminishing, R
X2Insulation resistance be regarded as infinity, this moment V
Ad-pBe tending towards V
Ad-busAs insulation resistance R
X2Insulation effect when diminishing, R
X1Insulation resistance be regarded as infinity, this moment V
Ad-pBe tending towards 0; As insulation resistance R
X1With insulation resistance R
X2Insulation effect descend when identical V
Ad-pThe corresponding variation; But above situation all through type (12), formula (13) is obtained its concrete resistance.
It should be noted last that: above embodiment is the technical scheme of unrestricted the utility model in order to explanation only; Although the utility model is specified with reference to the foregoing description; Those of ordinary skill in the art is to be understood that: still can make amendment or be equal to replacement the utility model; And not breaking away from any modification or the local replacement of spirit and the scope of the utility model, it all should be encompassed among the claim scope of the utility model.
Claims (1)
1. direct ground insulation failure detector; It is characterized in that: said pick-up unit comprises first bleeder circuit (110), second bleeder circuit (120), equalizer circuit (130) and tested insulation resistance RX1 that is in series and tested insulation resistance RX2; Said first bleeder circuit (110) comprises resistance R 1, resistance R 2; Said equalizer circuit (130) comprises resistance R 3, resistance R 4, switching tube S1, resistance R 5 and the resistance R 6 that is connected in series successively; Resistance R 5 is formed said second bleeder circuit (120) with resistance R 6; After connecting successively, said resistance R 3, resistance R 4 and switching tube S1 be parallel to said tested insulation resistance RX1 two ends; Said second bleeder circuit (120) is parallel to said tested insulation resistance RX2 two ends, and said first bleeder circuit (110) is connected in parallel on said tested insulation resistance RX1 that is in series and tested insulation resistance RX2 two ends.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011202559464U CN202166682U (en) | 2011-07-20 | 2011-07-20 | Fault detecting device of direct grounding |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011202559464U CN202166682U (en) | 2011-07-20 | 2011-07-20 | Fault detecting device of direct grounding |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202166682U true CN202166682U (en) | 2012-03-14 |
Family
ID=45802499
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011202559464U Expired - Fee Related CN202166682U (en) | 2011-07-20 | 2011-07-20 | Fault detecting device of direct grounding |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202166682U (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102279340A (en) * | 2011-07-20 | 2011-12-14 | 珠海泰坦新能源系统有限公司 | Direct-grounding insulation fault detection device and method |
| CN103770650A (en) * | 2012-10-22 | 2014-05-07 | 中国北车集团大同电力机车有限责任公司 | Locomotive traction and auxiliary system integrated grounding protection device |
| CN107622644A (en) * | 2017-09-13 | 2018-01-23 | 无锡商业职业技术学院 | Novel switching signal acquisition method |
| CN108008171A (en) * | 2017-12-29 | 2018-05-08 | 深圳市锐能微科技有限公司 | A kind of circuit parameter detection circuit, method and electric energy meter |
| CN108303588A (en) * | 2018-04-09 | 2018-07-20 | 骆驼集团武汉光谷研发中心有限公司 | A kind of Insulation Inspection Device for Direct-Current System based on nonequilibrium bridge |
| CN109030953A (en) * | 2018-08-29 | 2018-12-18 | 天津市海诺电子有限公司 | A kind of busbar grounding detection protection circuit |
-
2011
- 2011-07-20 CN CN2011202559464U patent/CN202166682U/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102279340A (en) * | 2011-07-20 | 2011-12-14 | 珠海泰坦新能源系统有限公司 | Direct-grounding insulation fault detection device and method |
| CN103770650A (en) * | 2012-10-22 | 2014-05-07 | 中国北车集团大同电力机车有限责任公司 | Locomotive traction and auxiliary system integrated grounding protection device |
| CN103770650B (en) * | 2012-10-22 | 2016-08-31 | 中车大同电力机车有限公司 | Locomotive traction and aid system Integral grounding protection device |
| CN107622644A (en) * | 2017-09-13 | 2018-01-23 | 无锡商业职业技术学院 | Novel switching signal acquisition method |
| CN108008171A (en) * | 2017-12-29 | 2018-05-08 | 深圳市锐能微科技有限公司 | A kind of circuit parameter detection circuit, method and electric energy meter |
| CN108008171B (en) * | 2017-12-29 | 2023-09-01 | 深圳市锐能微科技有限公司 | Circuit parameter detection circuit and electric energy meter |
| CN108303588A (en) * | 2018-04-09 | 2018-07-20 | 骆驼集团武汉光谷研发中心有限公司 | A kind of Insulation Inspection Device for Direct-Current System based on nonequilibrium bridge |
| CN108303588B (en) * | 2018-04-09 | 2023-09-01 | 骆驼集团武汉光谷研发中心有限公司 | DC system insulation monitoring device based on unbalanced bridge |
| CN109030953A (en) * | 2018-08-29 | 2018-12-18 | 天津市海诺电子有限公司 | A kind of busbar grounding detection protection circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120314 Termination date: 20140720 |
|
| EXPY | Termination of patent right or utility model |