CN109782055A - A kind of isolated neutral system capacitance current measurement method and device - Google Patents
A kind of isolated neutral system capacitance current measurement method and device Download PDFInfo
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- CN109782055A CN109782055A CN201910259660.4A CN201910259660A CN109782055A CN 109782055 A CN109782055 A CN 109782055A CN 201910259660 A CN201910259660 A CN 201910259660A CN 109782055 A CN109782055 A CN 109782055A
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Abstract
The application discloses a kind of isolated neutral system capacitance current measurement method and device, and method includes any line voltage U when acquisition system operates normallyS, neutral point voltage E0；Output detection electric current, obtains detection electric current It；Obtain output detection electric current ItNeutral point voltage E afterwards1, stop output detection electric current It；Computing system system capacitive current Ic；Device includes current output unit 1, control unit 2 and grounding transformer 3；Wherein, described control unit 2 includes electric current output control unit 21, voltage detection unit 22；Isolated neutral system capacitance current measurement method and device provided by the embodiments of the present application keeps calculating more simple and easy to do, and is easily achieved, while computational accuracy with higher.
Description
Technical field
The application is suitable for capacitance current measurement technical field, in particular to a kind of isolated neutral system capacitance current
Measurement method and device.
Background technique
In network system, especially in low and medium voltage distribution network system, singlephase earth fault accounts for the absolute majority of failure sum.
When system capacitive current is more than certain numerical value, ground arc when singlephase earth fault occurs is unable to self-extinguish, generates arc light
Overvoltage and other secondary harms.
When the capacitance current of system is larger, single that earth current is fully compensated with controllable current source, power supply capacity is larger, difficult
It to realize, and uses the full compensation of controllable current source cooperation arc suppression coil progress not only easy to accomplish, also improves economy.Cause
This, arc suppression coil is widely applied in network system, before arc suppression coil installation, measuring system capacitance current is needed,
To determine the suitable capacity of arc suppression coil needed for system, at present for the measurement method master of isolated neutral system capacitance current
It to include estimation algorithm, the additional capacitance method of neutral point, alien frequencies signal injection method, bigoted capacitance method and measurement method etc., but the above
Method is not satisfactory in measurement accuracy, and the arc suppression coil capacity of selection is easy to cause to be unable to satisfy the need of system balance
It wants.
Summary of the invention
The application provides a kind of isolated neutral system capacitance current measurement method and device, to solve in the prior art
Property point in the inaccurate problem of isolated neutral system capacitance current measurement, this method measuring signal intensity is high, ensure that measurement accuracy,
And safety is good, it is easy to accomplish and engineer application, and independent capacitance current measurement dress can be manufactured based on this method
It sets.
This application provides a kind of isolated neutral system capacitance current measurement methods, comprising:
Any line voltage U when acquisition system operates normallyS, neutral point voltage E0；
Output detection electric current, obtains detection electric current It；
Obtain output detection electric current ItNeutral point voltage E afterwards1, stop output detection electric current It；
Computing system system capacitive current Ic。
Optionally, the computing system system capacitive current IcIt is calculated using following equation:
Wherein, IcFor system capacitive current；USFor any line voltage；Imag () expression takes imaginary part function；E0For output detection
Electric current ItPreceding neutral point voltage；E1Electric current I is detected for outputtNeutral point voltage afterwards；Abs () indicates to calculate modulus value function.
After output detection electric current, the neutral point voltage E1Less than or equal to any line voltage US15%.
The detection electric current ItFrequency it is identical as system frequency.
The detection electric current ItInitial phase angle be any phase angle.
System centre point is drawn by main transformer or grounding transformer is drawn.
Present invention also provides a kind of isolated neutral system capacitance current measurement device, device includes that electric current output is single
Member, control unit and grounding transformer；Wherein, described control unit includes electric current output control unit, voltage detection unit, electricity
Flow detection unit and computing unit；
The grounding transformer, current detecting unit and current output unit are connected in series between system busbar and ground；
The voltage detection unit is connected between system neutral and ground；
The voltage detection unit, current detecting unit are connect with the computing unit；
The current control unit is connect with the current output unit.
Optionally, it is electric to be used to obtain any line that busbar voltage sensor measures when system operates normally for the computing unit
Press US, detect electric current ItAnd the neutral point voltage before and after output detection electric current；It is also used to according to the Parameters Computing System got
System capacitive current Ic。
Optionally, the current control unit adjusts output current amplitude for controlling the current output unit.
The embodiment of the present application provides a kind of isolated neutral system capacitance current measurement method and device, makes to calculate more
It is simple and easy to do, and be easily achieved, while computational accuracy with higher.
Detailed description of the invention
In order to illustrate more clearly of the technical solution of the application, letter will be made to attached drawing needed in the embodiment below
Singly introduce, it should be apparent that, for those of ordinary skills, without any creative labor,
It is also possible to obtain other drawings based on these drawings.
Fig. 1 is a kind of flow chart of isolated neutral system capacitance current measurement method of the application；
Fig. 2 is a kind of circuit connection diagram of isolated neutral system capacitance current measurement device of the application；
In figure, 1- current output unit, 2- control unit, 3- grounding transformer, 4- bus-bar potential transformer, 21- electric current
Output control unit, 22- voltage detection unit, 23- current detecting unit, 24- computing unit.
Specific embodiment
It is a kind of flow chart of isolated neutral system capacitance current measurement method of the application referring to Fig. 1；
As shown in Figure 1, this application provides a kind of isolated neutral system capacitance current measurement method, method includes:
S10: any line voltage U when system operates normally is obtainedS, neutral point voltage E0；Firstly, system is operated normally,
Any line voltage U is measured by the way that voltage measuring apparatus is arranged on system busbarS, and the voltage by being located between neutral point and ground
Measuring device measures a neutral point voltage E under this state0；
S20: output detection electric current obtains detection electric current It；It is to system orientation from controllable current source output current direction
Output detect electric current It, meanwhile, electric current is read by current detection means and is sent to computing unit；
S30: output detection electric current I is obtainedtNeutral point voltage E afterwards1, stop output detection electric current It；When output detection electricity
Flow ItAfterwards, a neutral point voltage E under this state is measured using the voltage measuring apparatus being located between neutral point and ground02；
S40: computing system system capacitive current Ic；Specifically, according to the parameters obtained in above-mentioned steps, under
Column formula is calculated:
Wherein, IcFor system capacitive current；USFor any line voltage；Imag () expression takes imaginary part function；E0For output detection
Electric current ItPreceding neutral point voltage；E1Electric current I is detected for outputtNeutral point voltage afterwards；Abs () indicates to calculate modulus value function.
Further, after output detection electric current, the neutral point voltage E1Less than or equal to any line voltage US15%.
Further, the detection electric current ItFrequency it is identical as system frequency.
Further, the detection electric current ItInitial phase angle be any phase angle.
Further, system centre point is drawn by main transformer or grounding transformer is drawn.
This application provides a kind of isolated neutral system capacitance current measurement methods, including obtain system and operate normally
When any line voltage US, neutral point voltage E0；Output detection electric current, obtains detection electric current It；Obtain output detection electric current ItAfterwards
Neutral point voltage E1, stop output detection electric current It；Computing system system capacitive current Ic；The embodiment of the present application provides one
Kind isolated neutral system capacitance current measurement method, keeps calculating more simple and easy to do, and be easily achieved, while having higher
Computational accuracy.
It referring to fig. 2, is a kind of circuit connection diagram of isolated neutral system capacitance current measurement device of the application；
As shown in Figure 2, present invention also provides a kind of isolated neutral system capacitance current measurement device, described devices
Including current output unit 1, control unit 2 and grounding transformer 3；Wherein, described control unit 2 includes that electric current output control is single
Member 21, voltage detection unit 22, current detecting unit 23 and computing unit 24；
The grounding transformer 3, current detecting unit 23 and current output unit 1 are connected in series in system busbar and ground
Between；
The voltage detection unit 22 is connected between system neutral and ground；
The voltage detection unit 22, current detecting unit 23 are connect with the computing unit 24；
The current control unit 21 is connect with the current output unit 1.
In the present embodiment, when the computing unit 24 measures system normal operation for obtaining bus-bar potential transformer 4
Any line voltage US, detect electric current ItAnd the neutral point voltage before and after output detection electric current；It is also used to according to the ginseng got
Number computing system system capacitive current Ic；Specifically, the parameter obtained needed for the computing unit 24 is according to provided by the present application
Method obtains, and the computing unit 24 executes the process calculated and also carried out according to method provided by the present application, for the present embodiment
The course of work of the device of offer, details are not described herein.
The embodiment of the present application provides a kind of isolated neutral system capacitance current measurement device, and described device includes electricity
Flow output unit 1, control unit 2, grounding transformer 3；Wherein, described control unit 2 includes electric current output control unit 21, electricity
Press detection unit 22；Device provided by the present application keeps the calculating for compensating electric current entirely more simple and easy to do, and is easily achieved.
Those skilled in the art after considering the specification and implementing the invention disclosed here, will readily occur to of the invention its
Its embodiment.This application is intended to cover any variations, uses, or adaptations of the invention, these modifications, purposes or
Person's adaptive change follows general principle of the invention and including the undocumented common knowledge in the art of the present invention
Or conventional techniques.The description and examples are only to be considered as illustrative, and true scope and spirit of the invention are by following
Claim is pointed out.
It should be understood that the present invention is not limited to the precise structure already described above and shown in the accompanying drawings, and
And various modifications and changes may be made without departing from the scope thereof.The scope of the present invention is limited only by the attached claims.
Claims (9)
1. a kind of isolated neutral system capacitance current measurement method, which is characterized in that the described method includes:
Any line voltage U when acquisition system operates normallyS, neutral point voltage E0；
Output detection electric current, obtains detection electric current It；
Obtain output detection electric current ItNeutral point voltage E afterwards1, stop output detection electric current It；
Computing system system capacitive current Ic。
2. a kind of isolated neutral system capacitance current measurement method according to claim 1, which is characterized in that described
Computing system system capacitive current IcIt is calculated using following equation:
Wherein, IcFor system capacitive current；USFor any line voltage；Imag () expression takes imaginary part function；E0Electric current is detected for output
ItPreceding neutral point voltage；E1Electric current I is detected for outputtNeutral point voltage afterwards；Abs () indicates to calculate modulus value function.
3. a kind of isolated neutral system capacitance current measurement method according to claim 1, which is characterized in that output
After detecting electric current, the neutral point voltage E1Less than or equal to any line voltage US15%.
4. a kind of isolated neutral system capacitance current measurement method according to claim 1, which is characterized in that described
Detect electric current ItFrequency it is identical as system frequency.
5. a kind of isolated neutral system capacitance current measurement method according to claim 1, which is characterized in that described
Detect electric current ItInitial phase angle be any phase angle.
6. a kind of isolated neutral system capacitance current measurement method according to claim 1, which is characterized in that system
Central point is drawn by main transformer or grounding transformer is drawn.
7. a kind of isolated neutral system capacitance current measurement device, which is characterized in that described device includes that electric current output is single
First (1), control unit (2) and grounding transformer (3)；Wherein, described control unit (2) includes electric current output control unit
(21), voltage detection unit (22), current detecting unit (23) and computing unit (24)；
The grounding transformer (3), current detecting unit (23) and current output unit (1) are connected in series in system busbar and ground
Between；
The voltage detection unit (22) is connected between system neutral and ground；
The voltage detection unit (22), current detecting unit (23) are connect with the computing unit (24)；
The current control unit (21) connect with the current output unit (1).
8. a kind of isolated neutral system capacitance current measurement device according to claim 7, which is characterized in that described
Computing unit (24) is used to obtain any line voltage U when busbar voltage sensor measures system normal operationS, detect electric current It
And the neutral point voltage before and after output detection electric current；It is also used to according to the Parameters Computing System system capacitive current got
Ic。
9. a kind of isolated neutral system capacitance current measurement device according to claim 7, which is characterized in that described
Current control unit (21) adjusts output current amplitude for controlling the current output unit (1).
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| CN201910259660.4A CN109782055B (en) | 2019-04-02 | 2019-04-02 | Method and device for measuring capacitance current of ungrounded neutral system |
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| CN201910259660.4A CN109782055B (en) | 2019-04-02 | 2019-04-02 | Method and device for measuring capacitance current of ungrounded neutral system |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112269049A (en) * | 2020-10-14 | 2021-01-26 | 广西电网有限责任公司电力科学研究院 | Method and system for measuring capacitance-to-ground current of power distribution network |
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| CN104779602A (en) * | 2014-12-23 | 2015-07-15 | 中国矿业大学 | Flexible control method of zero-sequence voltage of resonant earthed system based on active inversion |
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| CN112269049A (en) * | 2020-10-14 | 2021-01-26 | 广西电网有限责任公司电力科学研究院 | Method and system for measuring capacitance-to-ground current of power distribution network |
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