CN109449912A - Neutral earthing devices and its control method - Google Patents
Neutral earthing devices and its control method Download PDFInfo
- Publication number
- CN109449912A CN109449912A CN201811418747.3A CN201811418747A CN109449912A CN 109449912 A CN109449912 A CN 109449912A CN 201811418747 A CN201811418747 A CN 201811418747A CN 109449912 A CN109449912 A CN 109449912A
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- Prior art keywords
- resistance
- resistance unit
- controller
- earthing devices
- neutral
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/08—Limitation or suppression of earth fault currents, e.g. Petersen coil
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- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
Abstract
The present invention provides a kind of neutral earthing devices and its control methods, wherein neutral earthing devices, comprising: arc suppression coil, one end are connect with neutral point, other end ground connection；Resistance unit, it is in parallel with the arc suppression coil, for providing the resistance of a changeable resistance value；Controller, for controlling the resistance value size of the resistance unit and the on-off of the resistance unit circuit.Neutral earthing devices provided by the invention and its control method, resistance value is maximum when initially putting into adjustable resistance, can determine whether out the very big wired foil ground connection of accounting, middle low resistance earthing failure, and fault current is small, ensure that personal safety；It is the ground fault of high resistant for only a few transition resistance, does not determine faulty line, adjustable resistance is automatically adjusted to minimum at this time, further increases fault signature, improves the accuracy rate of failure selection.
Description
Technical field
The present invention relates to transmission & distribution electro-technical field, especially a kind of neutral earthing devices and its control method.
Background technique
Power Network Neutral includes: earth-free mode, through a variety of sides such as grounding through arc and low resistance earthing
Formula.Different earthing modes have the shortcomings that itself advantage and: isolated neutral mode allows to continue to run 2 in single-phase earthing
Hour, but when earth current is more than certain value, electric arc is unable to self-extinguishment, is easy to produce arc grounding over-voltage；Neutral point is through disappearing
Arc coil earthing mode can compensate for the biggish capacity current of power grid generation, but may be because of the measurement inaccuracy of capacitance current
Compensate it is improper cause resonance overvoltage, when the capacity of arc suppression coil is unsatisfactory for requiring, need upgrading；Neutral point is through low electricity
Earth current is big under resistance earthing mode, is conducive to failure line selection, but trip-out rate is high, when local resistance selects too small, ground connection
Fault current is big, brings security risk to equipment, communication line and personal safety.
The advantages of comprehensive arc suppression coil and low resistance grounding mode, in recent years, there is connecing for arc suppression coil parallel resistance
Ground mode.The resistance of arc suppression coil parallel connection is fixed resistance, if resistance is big, sensitivity is low, if resistance is small,
Fault current is big, is unfavorable for personal safety.In addition, the selection of fault characteristic value is mainly the size according to zero-sequence current, and
It, can not effective Judging fault route according only to the size of zero-sequence current when transition resistance is larger.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of neutral earthing devices and its control methods, improve sensitive
Degree provides safety, while effectively Judging fault route.
The present invention provides a kind of neutral earthing devices, comprising:
Arc suppression coil, one end are connect with neutral point, other end ground connection；
Resistance unit, it is in parallel with the arc suppression coil, for providing the resistance of a changeable resistance value；
Controller, for controlling the resistance value size of the resistance unit and the on-off of the resistance unit circuit.
Further, the resistance unit includes: concatenated switch and adjustable resistance, and the controller is opened with described respectively
Pass is connected with the adjustable resistance, for controlling the resistance value switched on-off with the adjustable resistance.
The present invention also provides the control methods of above-mentioned neutral earthing devices, include the following steps:
The controller, which controls the resistance unit, makes its circuit keep off state；
After the failure occurred and after continuing first time period, the controller, which controls the resistance unit, makes its circuit communication, together
When, the resistance value of the resistance unit is adjusted to maximum；
Judge faulty line, if successfully judging faulty line, the controller, which controls the resistance unit, keeps its circuit
Off state, if failing to judge that faulty line, the controller adjust the resistance value of the resistance unit to minimum, judge again
Faulty line；
After continuing second time period after the resistance value to minimum that the controller adjusts the resistance unit, the controller control
The resistance unit makes its circuit keep off state.
Further, judge the method for faulty line are as follows: each route zero-sequence current active component either active component
Maximum increment is faulty line.
Further, the first time period is 3 ~ 7s.
Further, the first time period is 5s.
Further, the second time period is 2s.
Neutral earthing devices provided by the invention and its control method, resistance value is maximum when initially putting into adjustable resistance, can
Judge the very big wired foil ground connection of accounting, middle low resistance earthing failure, and fault current is small, ensure that personal safety；
It is the ground fault of high resistant for only a few transition resistance, does not determine faulty line, adjustable resistance is automatically adjusted at this time
Minimum further increases fault signature, improves the accuracy rate of failure selection.
Detailed description of the invention
Fig. 1 is the schematic diagram of neutral earthing devices of the present invention；
Fig. 2 is the flow chart of the control method of neutral earthing devices of the present invention.
In figure, 1. neutral points, 2. arc suppression coils, 3. adjustable resistances, 4. switches, 5. controllers.
Specific embodiment
The present invention will be further explained below with reference to the attached drawings and specific examples, so that those skilled in the art can be with
It more fully understands the present invention and can be practiced, but illustrated embodiment is not as a limitation of the invention.
A kind of neutral earthing devices, as shown in Figure 1, comprising:
Arc suppression coil 2, one end are connect with neutral point 1, other end ground connection；
Resistance unit, it is in parallel with the arc suppression coil 2, for providing the resistance of a changeable resistance value；
Controller 5, for controlling the resistance value size of the resistance unit and the on-off of the resistance unit circuit.
In one optional embodiment of the present embodiment, the resistance unit includes: concatenated switch 4 and adjustable resistance 3, institute
It states controller 5 to connect with the switch 4 and the adjustable resistance 3 respectively, for controlling the on-off of the switch 4 and described adjustable
The resistance value of resistance 5.Certainly, resistance unit may be other structures form.
A kind of control method of the neutral earthing devices of any of the above-described embodiment, as shown in Fig. 2, including following step
It is rapid:
The controller 5, which controls the resistance unit, makes its circuit keep off state；
After the failure occurred and after continuing first time period, the controller 5, which controls the resistance unit, makes its circuit communication, together
When, the resistance value of the resistance unit is adjusted to maximum；
Judge faulty line, if successfully judging faulty line, the controller 5, which controls the resistance unit, keeps its circuit
Off state, if failing to judge that faulty line, the controller 5 adjust the resistance value of the resistance unit to minimum, sentence again
Disconnected faulty line；
After continuing second time period after the resistance value to minimum that the controller 5 adjusts the resistance unit, the controller 5 is controlled
Making the resistance unit makes its circuit keep off state.
In one optional embodiment of the present embodiment, the method for faulty line is judged are as follows: active point of each route zero-sequence current
The maximum increment of amount either active component is faulty line.
In one optional embodiment of the present embodiment, the first time period is 3 ~ 7s, it is preferable that the first time period is
5s。
In one optional embodiment of the present embodiment, the second time period is 2s.
By taking 10kV power distribution network as an example, the control method of neutral earthing devices is described:
After singlephase earth fault occurs for system, arc suppression coil is adjusted to compensating coefficient, does not access resistance in the failure initial stage
Unit, if arc suppression coil compensation capacity current to 10A hereinafter, transient fault, then fault electric arc can automatic distinguishing, improve
Transient fault self- recoverage probability.May be configured as 5s through 3~7s(after a period of time, adjusted by operating condition), such as zero sequence electricity
Pressure holding renews, and illustrates that failure still has, and puts into resistance unit at this time (resistance value is set as 150 Ω of maximum value).Pass through acquisition
The zero-sequence current of each route is sentenced with putting into increment the maximum of zero-sequence current active component or active component after resistance unit
Break as faulty line, and then protection act cuts off faulty line.If failure line selection is accurate, resistance runs the operation of 2s backed off after random；
If resistance is automatically adjusted to 45 Ω of minimum value without correct route selection, regardless of whether correct route selection, runs using 2s backed off after random.
In this way, first passing through grounding through arc compensating electric capacity electric current after failure occurs, it is single-phase that most of instantaneitys can be eliminated
Ground fault puts into the resistance unit of maximum value for permanent fault, generates biggish current in resistance property, is improving route selection just
True rate can differentiate most permanent fault；If not differentiating correctly for a small number of high resistive faults, the electricity of resistance unit
Resistance value is adjusted to 45 Ω, increases fault signature, improves the accuracy rate of route selection.By above-mentioned a series of measures, route selection is greatly improved
Accuracy, while the danger for further preventing the person to get an electric shock.
The scope of protection of the present invention is not limited to this.Those skilled in the art are made equivalent on the basis of the present invention
Substitution or transformation, it is within the scope of the present invention.Protection scope of the present invention is subject to claims.
Claims (7)
1. a kind of neutral earthing devices characterized by comprising
Arc suppression coil, one end are connect with neutral point, other end ground connection；
Resistance unit, it is in parallel with the arc suppression coil, for providing the resistance of a changeable resistance value；
Controller, for controlling the resistance value size of the resistance unit and the on-off of the resistance unit circuit.
2. neutral earthing devices described in claim 1, which is characterized in that the resistance unit include: it is concatenated switch and
Adjustable resistance, the controller connects with the switch and the adjustable resistance respectively, for switch on-off described in controlling with
The resistance value of the adjustable resistance.
3. the control method of neutral earthing devices of any of claims 1 or 2, which comprises the steps of:
The controller, which controls the resistance unit, makes its circuit keep off state；
After the failure occurred and after continuing first time period, the controller, which controls the resistance unit, makes its circuit communication, together
When, the resistance value of the resistance unit is adjusted to maximum；
Judge faulty line, if successfully judging faulty line, the controller, which controls the resistance unit, keeps its circuit
Off state, if failing to judge that faulty line, the controller adjust the resistance value of the resistance unit to minimum, judge again
Faulty line；
After continuing second time period after the resistance value to minimum that the controller adjusts the resistance unit, the controller control
The resistance unit makes its circuit keep off state.
4. the control method of neutral earthing devices as claimed in claim 3, which is characterized in that judge the method for faulty line
Are as follows: the maximum increment of each route zero-sequence current active component either active component is faulty line.
5. the control method of neutral earthing devices as claimed in claim 3, which is characterized in that the first time period be 3 ~
7s。
6. the control method of neutral earthing devices as claimed in claim 5, which is characterized in that the first time period is
5s。
7. the control method of neutral earthing devices as claimed in claim 3, which is characterized in that the second time period is
2s。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811418747.3A CN109449912B (en) | 2018-11-26 | 2018-11-26 | Neutral point grounding device and control method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811418747.3A CN109449912B (en) | 2018-11-26 | 2018-11-26 | Neutral point grounding device and control method thereof |
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| Publication Number | Publication Date |
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| CN109449912A true CN109449912A (en) | 2019-03-08 |
| CN109449912B CN109449912B (en) | 2022-03-04 |
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| CN201811418747.3A Active CN109449912B (en) | 2018-11-26 | 2018-11-26 | Neutral point grounding device and control method thereof |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112103934A (en) * | 2020-08-19 | 2020-12-18 | 许继电气股份有限公司 | Resistor switching device and method in low-current line selection parallel connection |
| CN112986862A (en) * | 2021-04-27 | 2021-06-18 | 重庆大学 | Single-phase earth fault identification method of small current grounding system |
| CN114280415A (en) * | 2021-12-14 | 2022-04-05 | 国网江苏省电力有限公司常州供电分公司 | Power distribution network ground fault processing method based on parallel resistors of arc suppression coils |
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| CN103560501A (en) * | 2013-11-19 | 2014-02-05 | 上海翱辰电气科技有限公司 | Controlled type small-resistor arc extinction device and method |
| CN104092206A (en) * | 2014-06-20 | 2014-10-08 | 国家电网公司 | Power distribution network grounding self-adaptive control system and method |
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| US20120063047A1 (en) * | 2005-01-31 | 2012-03-15 | Georgia Tech Research Corporation | Active Current Surge Limiters |
| CN101378192A (en) * | 2007-08-31 | 2009-03-04 | 中冶赛迪工程技术股份有限公司 | Resistance-grounded system |
| US20120275070A1 (en) * | 2011-04-28 | 2012-11-01 | Freescale Semiconductor, Inc. | Load control and protection system |
| CN103560501A (en) * | 2013-11-19 | 2014-02-05 | 上海翱辰电气科技有限公司 | Controlled type small-resistor arc extinction device and method |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112103934A (en) * | 2020-08-19 | 2020-12-18 | 许继电气股份有限公司 | Resistor switching device and method in low-current line selection parallel connection |
| CN112986862A (en) * | 2021-04-27 | 2021-06-18 | 重庆大学 | Single-phase earth fault identification method of small current grounding system |
| CN112986862B (en) * | 2021-04-27 | 2024-04-09 | 重庆大学 | Power distribution network fault indicator sensitivity improving method based on neutral point resistance control |
| CN114280415A (en) * | 2021-12-14 | 2022-04-05 | 国网江苏省电力有限公司常州供电分公司 | Power distribution network ground fault processing method based on parallel resistors of arc suppression coils |
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| CN109449912B (en) | 2022-03-04 |
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