CN204422692U - A kind of small current grounding failure wire selection system - Google Patents
A kind of small current grounding failure wire selection system Download PDFInfo
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- CN204422692U CN204422692U CN201520117639.8U CN201520117639U CN204422692U CN 204422692 U CN204422692 U CN 204422692U CN 201520117639 U CN201520117639 U CN 201520117639U CN 204422692 U CN204422692 U CN 204422692U
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Abstract
A kind of small current grounding failure wire selection system, comprise the zero sequence current mutual inductor be arranged on each feeder line, be arranged on the voltage transformer (VT) on bus, the grounding transformer be connected with bus, be connected to the ground loop between grounding transformer high-pressure side neutral point and the earth, and line-selected earthing device, described ground loop is serially connected with stake resistance and the contactor for control loop break-make, described line-selected earthing device respectively with zero sequence current mutual inductor, voltage transformer (VT) is connected with contactor, for when voltage transformer (VT) detects residual voltage, control described ground loop conducting, then according to the current data failure judgement circuit that zero sequence current mutual inductor gathers.
Description
Technical field
The utility model relates to the grounding failure wire selection system of small current neutral grounding system.
Background technology
For 10kV isolated neutral power distribution network, when a certain bar circuit generation single-phase earthing, its principal character: the size of zero-sequence current on non-faulting line, equal the capacitive earth current of this circuit itself, direction flows to circuit by bus; The size of zero-sequence current on fault wire, equals all non-fault line capacitive earth current sums, direction by line flows to bus.At present, usually can only utilize the difference of above-mentioned zero-sequence current, adopt zero sequence power direction method or zero-sequence current amplitude com parison method to realize microcomputer earthing wire-selecting.Because isolated neutral system singlephase earth fault amount is little, fault signature is not obvious, and add the impact being subject to the many factors such as electric network composition, nature of trouble, zero sequence current mutual inductor precision, earthing wire-selecting accuracy rate is not high, is generally no more than 70%.
Utility model content
The purpose of this utility model is for the deficiencies in the prior art, provides a kind of small current grounding failure wire selection system of high-accuracy.
The purpose of this utility model realizes by following technical solution:
A kind of small current grounding failure wire selection system, for the earth fault line selection of isolated neutral power distribution network, this power distribution network comprises some feeder lines of substation bus bar and difference connection bus, it is characterized in that: described grounding failure wire selection system comprises the zero sequence current mutual inductor be arranged on each feeder line, be arranged on the voltage transformer (VT) on bus, the grounding transformer be connected with bus, be connected to the ground loop between grounding transformer high-pressure side neutral point and the earth, and line-selected earthing device, described ground loop is serially connected with stake resistance and the contactor for control loop break-make, described line-selected earthing device respectively with zero sequence current mutual inductor, voltage transformer (VT) is connected with contactor, for when voltage transformer (VT) detects residual voltage, control described ground loop conducting, then according to the current data failure judgement circuit that zero sequence current mutual inductor gathers.
Further, be 130-140 Ω for the resistance of stake resistance described in 10kV isolated neutral power distribution network.
The utility model has following beneficial effect:
Put into operation the initial stage at power distribution network, circuit is less, cable is less, and system is less, usually adopts isolated neutral mode to run (also not needing to install arc suppression coil).Property point isolated neutral system hereinto, the utility model, by dropping into the method for stake resistance instantaneously, is accurately grounded route selection, in theory, route selection accuracy rate for stabilized single phase earth fault can up to 100%, and the route selection accuracy rate for instantaneity arc grounding fault also can improve greatly.
When power distribution network development or cable large percentage, when singlephase earth fault capacitance current exceedes regulations stipulate value (overhead system 10A or full cable system 30A), system neutral adopts grounding through arc mode.At this moment, the equipment such as the resistor that early stage installs can utilize in the same old way, do not cause the waste in equipment investment.When generation singlephase earth fault, after arc suppression coil inductance current compensates earth fault capacity current, if fault disappears not yet, then be judged to be permanent earth fault, now, by dropping into the method for stake resistance instantaneously, accurately can be grounded route selection, solving the difficult problem that resonance grounding (neutral by arc extinction coil grounding) system earth route selection accuracy rate is low better equally.
Accompanying drawing explanation
Below in conjunction with accompanying drawing, the utility model is described in further detail.
Fig. 1 is structural representation of the present utility model.
Embodiment
With reference to shown in Fig. 1, small current grounding failure wire selection system is used for the earth fault line selection of 10kV isolated neutral power distribution network, and this power distribution network comprises some feeder lines 2 of bus 1 and difference connection bus 1.
A kind of small current grounding failure wire selection system, comprise the zero sequence current mutual inductor 4 be arranged on each feeder line 2, be arranged on the voltage transformer (VT) 5 on bus 1, the grounding transformer 6 be connected with bus 1, be connected to the ground loop 7 between grounding transformer 6 high-pressure side (Z-type wiring) neutral point and the earth, and line-selected earthing device 3, ground loop 7 is serially connected with stake resistance 71 that resistance is 135 Ω and the vacuum contactor 72 for control loop break-make, line-selected earthing device 3 respectively with zero sequence current mutual inductor 4, voltage transformer (VT) 5 is connected with vacuum contactor 72, for when voltage transformer (VT) 5 detects residual voltage, control ground loop 7 conducting, then according to the current data failure judgement circuit that zero sequence current mutual inductor 4 gathers.
The selection method of above-mentioned small current grounding failure wire selection system, comprises the steps:
(1), when generation singlephase earth fault, voltage transformer (VT) 5 detects residual voltage and feeds back to line-selected earthing device 3, when residual voltage exceedes preset value, as secondary side 25V, then line-selected earthing device 3 control vacuum contactor 72 close a floodgate stake resistance 71 is come into operation and disconnected after about 1 second;
(2), within the blink that stake resistance 71 comes into operation, each zero sequence current mutual inductor 4 gathers the zero-sequence current of each feeder line and feeds back to line-selected earthing device 3, the zero-sequence current of line-selected earthing device 3 to each feeder line 2 carries out transverse and longitudinal and compares, wherein, zero-sequence current has compared with macromutation amount or has obvious current in resistance property increment, be then judged to be earth fault line.
The above, be only preferred embodiment of the present utility model, therefore can not limit with this scope that the utility model implements, the equivalence namely done according to the utility model claim and description change with modify, all should still belong in scope that the utility model patent contains.
Claims (2)
1. a small current grounding failure wire selection system, for the earth fault line selection of isolated neutral power distribution network, this power distribution network comprises some feeder lines of substation bus bar and difference connection bus, it is characterized in that: described grounding failure wire selection system comprises the zero sequence current mutual inductor be arranged on each feeder line, be arranged on the voltage transformer (VT) on bus, the grounding transformer be connected with bus, be connected to the ground loop between grounding transformer high-pressure side neutral point and the earth, and line-selected earthing device, described ground loop is serially connected with stake resistance and the contactor for control loop break-make, described line-selected earthing device respectively with zero sequence current mutual inductor, voltage transformer (VT) is connected with contactor, for when voltage transformer (VT) detects residual voltage, control described ground loop conducting, then according to the current data failure judgement circuit that zero sequence current mutual inductor gathers.
2. a kind of small current grounding failure wire selection system according to claim 1, is characterized in that: be 130-140 Ω for the resistance of stake resistance described in 10kV isolated neutral power distribution network.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201520117639.8U CN204422692U (en) | 2015-02-27 | 2015-02-27 | A kind of small current grounding failure wire selection system |
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| CN201520117639.8U CN204422692U (en) | 2015-02-27 | 2015-02-27 | A kind of small current grounding failure wire selection system |
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| CN204422692U true CN204422692U (en) | 2015-06-24 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104635107A (en) * | 2015-02-27 | 2015-05-20 | 国网福建晋江市供电有限公司 | Small-current grounding fault line selection system and line selection method |
| CN105158641A (en) * | 2015-09-18 | 2015-12-16 | 合肥海畅电气技术有限公司 | Small-current grounding line selection device line-outgoing system |
| CN109490709A (en) * | 2018-11-19 | 2019-03-19 | 国网山东省电力公司潍坊供电公司 | A kind of system and method assisting small current earthing wire-selecting |
| CN110261737A (en) * | 2019-07-09 | 2019-09-20 | 安徽亚辉电气技术有限公司 | A kind of smart grounding route selection complexes |
| CN112540322A (en) * | 2020-12-29 | 2021-03-23 | 广东电网有限责任公司电力科学研究院 | Line selection method, device and equipment for single-phase earth fault line of feeder line of transformer substation |
-
2015
- 2015-02-27 CN CN201520117639.8U patent/CN204422692U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104635107A (en) * | 2015-02-27 | 2015-05-20 | 国网福建晋江市供电有限公司 | Small-current grounding fault line selection system and line selection method |
| CN105158641A (en) * | 2015-09-18 | 2015-12-16 | 合肥海畅电气技术有限公司 | Small-current grounding line selection device line-outgoing system |
| CN109490709A (en) * | 2018-11-19 | 2019-03-19 | 国网山东省电力公司潍坊供电公司 | A kind of system and method assisting small current earthing wire-selecting |
| CN110261737A (en) * | 2019-07-09 | 2019-09-20 | 安徽亚辉电气技术有限公司 | A kind of smart grounding route selection complexes |
| CN112540322A (en) * | 2020-12-29 | 2021-03-23 | 广东电网有限责任公司电力科学研究院 | Line selection method, device and equipment for single-phase earth fault line of feeder line of transformer substation |
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