CN203117256U - System for detecting bus capacitive current of medium voltage power grid - Google Patents
System for detecting bus capacitive current of medium voltage power grid Download PDFInfo
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- CN203117256U CN203117256U CN 201220741568 CN201220741568U CN203117256U CN 203117256 U CN203117256 U CN 203117256U CN 201220741568 CN201220741568 CN 201220741568 CN 201220741568 U CN201220741568 U CN 201220741568U CN 203117256 U CN203117256 U CN 203117256U
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- medium voltage
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- 238000001514 detection method Methods 0.000 claims abstract description 26
- 238000004804 winding Methods 0.000 claims description 24
- 239000003990 capacitor Substances 0.000 claims description 8
- 238000000034 method Methods 0.000 description 2
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N ferric oxide Chemical compound O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
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Abstract
The utility model relates to a system for detecting the bus capacitive current of a medium voltage power grid. The system is connected to a three-phase bus of the medium voltage power grid. The system comprises a voltage transformer, a signal generator, a zero-sequence voltage detection device and a processor, wherein the voltage transformer is connected with the three-phase bus of the medium voltage power grid, the signal generator and the zero-sequence voltage detection device are both connected with the voltage transformer, and the processor is connected with the signal generator and the zero-sequence voltage detection device. Compared with the prior art, the system provided by the utility model has the advantages of high safety and high detection precision.
Description
Technical field
The utility model relates to a kind of electrical network detection system, especially relates to a kind of bus capacitor current detecting system for medium voltage network.
Background technology
With the expansion of urban distribution network, the increasing of cable outlet, system capacitive current increases greatly.When system's generation singlephase earth fault, its ground arc can not put out certainly, very easily produces intermittence arc grounding superpotential, and the duration one is long, also can develop into the line to line fault accident in the line insulation weakness.Therefore, when network is enough big, just needs to adopt the arc suppression coil compensation capacitance current or directly act on tripping operation through the earthing mode of resistance, this is the important technique measure that guarantees safe operation of power system.For avoiding unsuitable earthing mode to bring threat to safe operation of power system, at first correctly the capacitance current value of mensuration system is determined the rational neutral point method of operation then, could not influence selectivity and the reliability of relay protection.
The utility model content
The purpose of this utility model is exactly that a kind of safe, system for detection of medium voltage network bus capacitor electric current that accuracy of detection is high is provided in order to overcome the defective that above-mentioned prior art exists.
The purpose of this utility model can be achieved through the following technical solutions:
A kind of system for detection of medium voltage network bus capacitor electric current, this system is connected on the three-phase bus of medium voltage network, comprise voltage transformer (VT), signal generator, zero sequence voltage detection device and processor, described voltage transformer (VT) connects the three-phase bus of medium voltage network, described signal generator all is connected with voltage transformer (VT) with the zero sequence voltage detection device, and described processor connects signal generator and zero sequence voltage detection device respectively.
Described voltage transformer (VT) comprises winding and Secondary Winding, a described winding directly is connected with the three-phase bus of medium voltage network, described Secondary Winding and a winding coupled, and adopt the mode of connection of open-delta, described signal generator and zero sequence voltage detection device all are connected the open delta end of Secondary Winding.
Described signal generator is exportable and signal generator electrical network power-frequency voltage different frequency current signal.
Compared with prior art, the utility model can detect the electric current on the ground capacitance of each phase bus exactly, because the voltage transformer (VT) that has adopted open-delta connection to insert electrical network is realized the input of measuring-signal, and carry out the collection of detection signal from the Secondary Winding side, avoided contacting with the direct of electrical network with the tester, thereby effectively improved security.
Description of drawings
Fig. 1 is structural representation of the present utility model;
Fig. 2 inserts the synoptic diagram of electrical network for voltage transformer (VT).
Embodiment
Below in conjunction with the drawings and specific embodiments the utility model is elaborated.
Embodiment
As shown in Figure 1, a kind of system for detection of medium voltage network bus capacitor electric current, this system is connected on the three-phase bus of medium voltage network 5, comprises voltage transformer (VT) 1, signal generator 2, zero sequence voltage detection device 3 and processor 4.
Voltage transformer (VT) 1 connects the three-phase bus of medium voltage network 5, its concrete connected mode as shown in Figure 2, because voltage transformer (VT) 1 comprises winding 11 and Secondary Winding 12, one time winding 11 directly is connected with the three-phase bus of medium voltage network 5, and Secondary Winding 12 and winding 11 couplings, and adopt the mode of connection of open-delta to connect signal generator 2 and zero sequence voltage detection device 3.Signal generator 2 and zero sequence voltage detection device 3 all are connected the open delta end 13 of Secondary Winding 12, and 4 of processors connect signal generator 2 and zero sequence voltage detection device 3 respectively.
Principle of work of the present utility model is:
At first by the signal generator output frequency less current signal different with the electrical network power-frequency voltage, this current signal can induce an electric current that reduces in the umber of turn ratio in a winding side of voltage transformer (VT), because this current signal can not circulate between power supply and electrical network load, therefore can only form the loop by the ground capacitance on the three-phase bus, therefore provide theoretical foundation for the utility model.Because the electric current that this winding side induces can produce pressure drop at winding resistance, leakage reactance and the electrical network lead ground capacitance of voltage transformer (VT), because each resistance of going up mutually of winding, the leakage reactance of voltage transformer (VT) are basic symmetries, and the three-phase bus ground capacitance also is basic equating, then the pressure drop of this electric current generation also is essentially identical, therefore can detect a residual voltage signal at the triangle openend of Secondary Winding.By the current signal of the many groups of many groups signal generator output different frequency, and detect corresponding residual voltage signal, will organize these two signals more and input to processor, can calculate the electric current of medium voltage network median generatrix ground capacitance according to the relation of correspondence.
Claims (3)
1. system for detection of medium voltage network bus capacitor electric current, this system is connected on the three-phase bus of medium voltage network, it is characterized in that, comprise voltage transformer (VT), signal generator, zero sequence voltage detection device and processor, described voltage transformer (VT) connects the three-phase bus of medium voltage network, described signal generator all is connected with voltage transformer (VT) with the zero sequence voltage detection device, and described processor connects signal generator and zero sequence voltage detection device respectively.
2. a kind of system for detection of medium voltage network bus capacitor electric current according to claim 1, it is characterized in that, described voltage transformer (VT) comprises winding and Secondary Winding, a described winding directly is connected with the three-phase bus of medium voltage network, described Secondary Winding and a winding coupled, and adopt the mode of connection of open-delta, described signal generator and zero sequence voltage detection device all are connected the open delta end of Secondary Winding.
3. a kind of system for detection of medium voltage network bus capacitor electric current according to claim 1 is characterized in that, described signal generator is exportable and signal generator electrical network power-frequency voltage different frequency current signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220741568 CN203117256U (en) | 2012-12-28 | 2012-12-28 | System for detecting bus capacitive current of medium voltage power grid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220741568 CN203117256U (en) | 2012-12-28 | 2012-12-28 | System for detecting bus capacitive current of medium voltage power grid |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203117256U true CN203117256U (en) | 2013-08-07 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220741568 Expired - Lifetime CN203117256U (en) | 2012-12-28 | 2012-12-28 | System for detecting bus capacitive current of medium voltage power grid |
Country Status (1)
| Country | Link |
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| CN (1) | CN203117256U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103076485A (en) * | 2012-12-28 | 2013-05-01 | 上海市电力公司 | Medium-voltage power grid bus capacitance and current detection system |
| CN106093682A (en) * | 2016-06-27 | 2016-11-09 | 国网天津市电力公司 | A kind of confirmation method of medium voltage distribution network neutral grounding mode |
-
2012
- 2012-12-28 CN CN 201220741568 patent/CN203117256U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103076485A (en) * | 2012-12-28 | 2013-05-01 | 上海市电力公司 | Medium-voltage power grid bus capacitance and current detection system |
| CN106093682A (en) * | 2016-06-27 | 2016-11-09 | 国网天津市电力公司 | A kind of confirmation method of medium voltage distribution network neutral grounding mode |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130807 |