CN109901019A - A kind of resonant earthed system capacitance current measurement method and device - Google Patents
A kind of resonant earthed system capacitance current measurement method and device Download PDFInfo
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Abstract
The application discloses a kind of resonant earthed system capacitance current measurement method and device, and method includes three-phase voltage when acquisition system operates normallyNeutral point voltage E0With arc suppression coil loop current IL0；Output detection electric current It；Obtain output detection electric current ItNeutral point voltage E afterwards1With arc suppression coil loop current IL1；Stop output detection electric current It, computing system system capacitive current Ic；Device includes controllable current source 1, voltage detection unit 2, source current detection unit 3, arc suppression coil loop current detection unit 4, computing unit 5, arc suppression coil 6, over the ground distribution capacity 7 and grounding transformer 8；Resonant earthed system capacitance current measurement method and apparatus provided by the embodiments of the present application keep calculating more simple and easy to do, and are 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 resonant earthed 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.
It is single that earth current is fully compensated with controllable current source when the capacitance current of system is larger, required power supply capacity compared with
Greatly, it is difficult to realize, and use the full compensation of controllable current source cooperation arc suppression coil progress not only easy to accomplish, also improve economy
Property.Therefore, arc suppression coil is widely applied in network system, before arc suppression coil installation, needs measuring system capacitor
Electric current, it is main for the measurement method of resonator system capacitance current at present to determine the suitable capacity of arc suppression coil needed for system
Including estimation algorithm, the resonance method etc., but the calculated result accuracy of this two methods is not high, is easy to cause the arc suppression coil of selection
Capacity is unable to satisfy the needs of system balance.
Summary of the invention
The application provides a kind of resonant earthed system capacitance current measurement method and device, to solve system in the prior art
The inaccurate problem of capacitance current measurement, this method measuring signal intensity is high, ensure that measurement accuracy, and safety is good, easily
Independent capacitance current measurement device can be manufactured in realization and engineer application, and based on this method.
This application provides a kind of resonant earthed system capacitance current measurement methods, comprising:
Three-phase voltage when acquisition system operates normallyNeutral point voltage E0With arc suppression coil loop current IL0；
Output detection electric current It；
Obtain output detection electric current ItNeutral point voltage E afterwards1With arc suppression coil loop current IL1；
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；For three-phase 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；IL0Electric current I is detected for outputtPreceding disappears
Arc coil loop current；IL1Electric current I is detected for outputtArc suppression coil loop current afterwards；Abs () is modulus value function.
Optionally, the detection electric current I is exportedtFront and back keeps the inductance value of arc suppression coil constant.
Optionally, the detection electric current ItCurrent direction from current source pointing system.
Optionally, the neutral point voltage E0、E1It is system neutral voltage-to-ground；The arc suppression coil loop current
IL0、IL1It is arc suppression coil to earth-current.
Optionally, the detection electric current ItFrequency it is identical as system voltage frequency.
Optionally, the detection electric current ItWith arbitrary phase.
Optionally, the detection electric current ItValue range between 0.1A~1A.
Present invention also provides a kind of resonant earthed system capacitance current measurement device, including controllable current source, voltage inspections
Unit is surveyed, source current detection unit, arc suppression coil loop current detection unit, computing unit, arc suppression coil, distribution is electric over the ground
Appearance and grounding transformer；Wherein,
The grounding transformer, source current detection unit and controllable current source are connected in series in system busbar and ground
Between；
The arc suppression coil and the arc suppression coil loop current detection unit are located on compensation circuit, the compensation circuit
One end ground connection is another to be terminated between the source current detection unit and grounding transformer；
Described one end of distribution capacity over the ground is connect with system busbar, the other end ground connection of the distribution capacity over the ground；
The voltage detection unit is connected between system neutral and ground；
The voltage detection unit, source current detection unit and arc suppression coil loop current detection unit with the meter
Calculate unit connection.
The computing unit is used to obtain three-phase voltage when system operates normallyAnd before and after output detection electric current
Neutral point voltage, arc suppression coil loop current；It is also used to according to the Parameters Computing System system capacitive current I gotc。
Optionally, the arc suppression coil is preset arc suppression coil, has finite resistance value.
The embodiment of the present application provides a kind of resonant earthed system capacitance current measurement method and device, makes to calculate easier
It is easy, 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 resonant earthed system capacitance current measurement method of the application；
Fig. 2 is a kind of circuit connection diagram of resonant earthed system capacitance current measurement device of the application；
In figure, 1- controllable current source, 2- voltage detection unit, 3- source current detection unit, 4- arc suppression coil circuit electricity
Flow detection unit, 5- computing unit, 6- arc suppression coil, 7- distribution capacity over the ground, 8- grounding transformer.
Specific embodiment
It is a kind of flow chart of resonant earthed system capacitance current measurement method of the application referring to Fig. 1；
As shown in Figure 1, this application provides a kind of resonant earthed system capacitance current measurement method, method includes:
S10: three-phase voltage when system operates normally is obtainedNeutral point voltage E0With arc suppression coil loop current IL0；
Firstly, operating normally system, three-phase voltage is measured by the way that voltage measuring apparatus is arranged on system busbarAnd by being located in
Voltage measuring apparatus between property point and ground measures a neutral point voltage E under this state0, by being located on arc suppression coil circuit
Current measuring device measure an arc suppression coil loop current I under this stateL0；
S20: output detection electric current It；It is to detect electric current to the output of system orientation from controllable current source output current direction
It；
S30: output detection electric current I is obtainedtNeutral point voltage E afterwards1With arc suppression coil loop current IL1；When output detects
Electric current ItAfterwards, a neutral point voltage E under this state is measured using the voltage measuring apparatus being located between neutral point and ground02,
Meanwhile an arc suppression coil loop current under this state is measured using the current measuring device being located on arc suppression coil circuit
IL1；
S40: stop output detection electric current It, computing system system capacitive current Ic；Specifically, being obtained according in above-mentioned steps
The parameters taken, are calculated using following equation:
Wherein, IcFor system capacitive current；For three-phase 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；IL0Electric current I is detected for outputtPreceding disappears
Arc coil loop current；IL1Electric current I is detected for outputtArc suppression coil loop current afterwards；Abs () is modulus value function.
Further, the detection electric current I is exportedtFront and back keeps the inductance value of arc suppression coil constant.
Further, the detection electric current ItFrequency it is identical as system voltage frequency.
Further, the detection electric current ItWith arbitrary phase.
Further, the detection electric current ItValue range between 0.1A~1A.
Further, the neutral point voltage E0、E1It is system neutral voltage-to-ground；The arc suppression coil circuit electricity
Flow IL0、IL1It is arc suppression coil to earth-current.
This application provides a kind of resonant earthed system capacitance current measurement methods, including obtaining when system operates normally
Three-phase voltageNeutral point voltage E0With arc suppression coil loop current IL0；Output detection electric current It；Obtain output detection electric current It
Neutral point voltage E afterwards1With arc suppression coil loop current IL1；Stop output detection electric current It, computing system system capacitive current
Ic；The embodiment of the present application provides a kind of resonant earthed system capacitance current measurement method, makes to calculate more simple and easy to do and easy
In realization, while computational accuracy with higher.
It referring to fig. 2, is a kind of circuit connection diagram of resonant earthed system capacitance current measurement device of the application；
As shown in Figure 2, present invention also provides a kind of resonant earthed system capacitance current measurement device, described device includes
Controllable current source 1, voltage detection unit 2, source current detection unit 3, arc suppression coil loop current detection unit 4 calculate single
Member 5, arc suppression coil 6, over the ground distribution capacity 7 and grounding transformer 8；Wherein,
The grounding transformer 8, source current detection unit 3 and controllable current source 1 are connected in series in system busbar and ground
Between；
The arc suppression coil 6 and the arc suppression coil loop current detection unit 4 are located on compensation circuit, described to compensate back
Road one end ground connection is another to be terminated between the source current detection unit 3 and grounding transformer 8；The arc suppression coil 6 is optional
With for preset arc suppression coil, there is finite resistance value.
Described 7 one end of distribution capacity over the ground is connect with system busbar, the other end ground connection of the distribution capacity over the ground 7；
The voltage detection unit 2 is connected between system neutral and ground；
The voltage detection unit 2, source current detection unit 3 and arc suppression coil loop current detection unit 4 are and institute
State the connection of computing unit 5.
In the present embodiment, the computing unit 3 is used to obtain three-phase voltage when system operates normallyAnd output
Neutral point voltage, arc suppression coil loop current before and after detection electric current；It is also used to according to the Parameters Computing System system got
Capacitance current Ic；Specifically, the parameter obtained needed for the computing unit 3 is obtained according to method provided by the present application, the meter
It calculates unit 3 and executes work of the process calculated also according to method provided by the present application progress, for device provided in this embodiment
Process, details are not described herein.
The embodiment of the present application provides a kind of resonant earthed system capacitance current measurement device, and described device includes controllable electric
Stream source 1, voltage detection unit 2, source current detection unit 3, arc suppression coil loop current detection unit 4, computing unit 5 disappear
Arc coil 6, over the ground distribution capacity 7 and grounding transformer 8；Device provided by the present application keeps the calculating for compensating electric current entirely easier
It is easy, and be 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 (10)
1. a kind of resonant earthed system capacitance current measurement method, which is characterized in that the described method includes:
Three-phase voltage when acquisition system operates normallyNeutral point voltage E0With arc suppression coil loop current IL0；
Output detection electric current It；
Obtain output detection electric current ItNeutral point voltage E afterwards1With arc suppression coil loop current IL1；
Stop output detection electric current It, computing system system capacitive current Ic。
2. a kind of resonant earthed system capacitance current measurement method according to claim 1, which is characterized in that the calculating
Service system capacitance current IcIt is calculated using following equation:
Wherein, IcFor system capacitive current；For three-phase 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；IL0Electric current I is detected for outputtPreceding arc blowout wire
Enclose loop current；IL1Electric current I is detected for outputtArc suppression coil loop current afterwards；Abs () is modulus value function.
3. a kind of resonant earthed system capacitance current measurement method according to claim 1, which is characterized in that described in output
Detect electric current ItFront and back keeps the inductance value of arc suppression coil constant.
4. a kind of resonant earthed system capacitance current measurement method according to claim 1, which is characterized in that the detection
Electric current ItCurrent direction from current source pointing system.
5. a kind of resonant earthed system capacitance current measurement method according to claim 1, which is characterized in that the detection
Electric current ItFrequency it is identical as system voltage frequency.
6. a kind of resonant earthed system capacitance current measurement method according to claim 1, which is characterized in that the detection
Electric current ItWith arbitrary phase.
7. a kind of resonant earthed system capacitance current measurement method according to claim 1, which is characterized in that the detection
Electric current ItValue range between 0.1A~1A.
8. a kind of resonant earthed system capacitance current measurement method according to claim 1, which is characterized in that the neutrality
Point voltage E0、E1It is system neutral voltage-to-ground；The arc suppression coil loop current IL0、IL1It is that arc suppression coil is electric over the ground
Stream.
9. a kind of resonant earthed system capacitance current measurement device, which is characterized in that described device includes controllable current source (1),
Voltage detection unit (2), source current detection unit (3), arc suppression coil loop current detection unit (4), computing unit (5),
Arc suppression coil (6), over the ground distribution capacity (7) and grounding transformer (8)；Wherein,
The grounding transformer (8), source current detection unit (3) and controllable current source (1) be connected in series in system busbar with
Between ground；
The arc suppression coil (6) and the arc suppression coil loop current detection unit (4) are located on compensation circuit, described to compensate back
Road one end ground connection is another to be terminated between the source current detection unit (3) and grounding transformer (8)；
Described distribution capacity over the ground (7) one end is connect with system busbar, the other end ground connection of the distribution capacity over the ground (7)；
The voltage detection unit (2) is connected between system neutral and ground；
The voltage detection unit (2), source current detection unit (3) and arc suppression coil loop current detection unit (4) with
Computing unit (5) connection；
The computing unit (3) is used to obtain three-phase voltage when system operates normallyAnd output detects in front of and after electric current
Property point voltage, arc suppression coil loop current；It is also used to according to the Parameters Computing System system capacitive current I gotc。
10. a kind of resonant earthed system capacitance current measurement device according to claim 9, which is characterized in that described to disappear
Arc coil (6) is preset arc suppression coil, has finite resistance value.
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| CN201910263606.7A CN109901019B (en) | 2019-04-02 | 2019-04-02 | Method and device for measuring capacitance current of resonant grounding system |
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| CN201910263606.7A CN109901019B (en) | 2019-04-02 | 2019-04-02 | Method and device for measuring capacitance current of resonant grounding system |
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