CN111141991A - Method suitable for improving high-resistance grounding fault handling capacity of asymmetric power grid - Google Patents

Method suitable for improving high-resistance grounding fault handling capacity of asymmetric power grid Download PDF

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CN111141991A
CN111141991A CN201811305926.6A CN201811305926A CN111141991A CN 111141991 A CN111141991 A CN 111141991A CN 201811305926 A CN201811305926 A CN 201811305926A CN 111141991 A CN111141991 A CN 111141991A
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phase
power grid
asymmetric
voltage
ground
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CN111141991B (en
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李政洋
李景禄
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
    • G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors

Abstract

A method suitable for improving the high-resistance grounding fault handling capacity of an asymmetric power grid is used for detecting the neutral point displacement voltage U of the power distribution grid in real time when the power distribution grid operatesNAnd three phase voltage, if distribution network neutral point voltage UNAnd if the phase voltage amplitude is larger than a certain value, the phase to ground capacitance is input at the phase with higher phase voltage amplitude to reduce the asymmetry, so that the processing capacity of the ground fault processing device on the high-resistance ground fault of the asymmetric power grid is improved.

Description

Method suitable for improving high-resistance grounding fault handling capacity of asymmetric power grid
Technical Field
The invention belongs to the field of single-phase earth fault processing of a power distribution network, and is mainly used for improving the identification and processing capacity of an asymmetric power grid high-resistance earth fault.
Background
Because the parameters of the power grid to the earth are different, the asymmetry of the power grid is different, the displacement voltage of the neutral point of the power grid is different, the neutral point is not grounded, and the asymmetry coefficient K is differentCThe maximum value of (d) is: 5 percent. The running and the test show that: the identification of the asymmetry of the asymmetric electrical network to the high resistance ground of the ground fault handling device is directly related to the handling capacity. Generally, the larger the asymmetry of the power grid, the lower the identification and processing capability of the high-resistance ground of the ground fault processing device.
In an asymmetric power grid, asymmetric current is generated in a feeder line when the power grid normally operates under the action of asymmetric voltage, and the distribution of the asymmetric current in each feeder line is different due to different asymmetric parameters of each feeder line, so that great difficulty is caused in identifying and processing a high-resistance grounding fault, and a fault line cannot be selected.
The identification and processing capability of the high-resistance grounding of the grounding fault processing device has great influence on personal safety and power grid safety. Therefore, a method must be found for solving the fault identification and processing capability of the asymmetric power grid in the high-resistance earth fault so as to realize quick fault isolation to ensure personal safety and power grid safety.
Disclosure of Invention
Three-phase-to-ground switch QF is connected beside ground fault processing devicea、QFb、QFcAnd three-phase to ground capacitance Ca0、Cb0、Cc0. When the single-phase earth fault processing device is connected to a power grid, firstly, the displacement voltage U of a neutral point of the power distribution network is measuredNThree phase voltage Ua、Ub、UcWhen the displacement voltage U of the neutral point of the power grid is detectedNWhen the voltage is higher, closing a phase-to-ground switch with higher phase voltage amplitude, putting the phase-to-ground capacitor into the phase-to-ground switch, leveling the three-phase voltage by changing the capacitance of the capacitor, reducing the asymmetry degree of the power grid, and shifting the voltage U of the neutral point of the power gridNThe single-phase earth fault processing device is adjusted to a relatively small value, and the capacity of identifying and processing the high-resistance earth fault of the asymmetric power grid by the single-phase earth fault processing device is improved.
When the single-phase grounding fault processing device is a grounding line selection device, a grounding capacitor is put into a phase with high phase voltage amplitude, the asymmetry degree of a power grid is reduced, the influence of asymmetric zero-sequence current generated in a feeder line due to the asymmetry of the power grid on the grounding line selection is reduced, and the high-resistance line selection capability of the grounding line selection device on the asymmetric power grid is improved.
Three phase to ground capacitance Ca0、Cb0、Cc0The capacitance of the capacitor can be automatically adjusted by adopting an adjustable capacitor, and can also be manually adjusted according to the actual power grid.
The invention has the following advantages:
1. according to the invention, the ground capacitance is put into the phase with the highest phase voltage amplitude, so that the identification and processing capacity of the ground fault processing device on the high-resistance ground fault of the asymmetric power grid is improved, and the method is simple and easy to implement. .
2. The invention reduces the influence of the differential distribution of the asymmetric zero sequence current generated in the feeder line due to the asymmetry of the power grid on the grounding line selection, and effectively improves the high-resistance line selection capability of the grounding line selection device in the asymmetric power grid.
Drawings
FIG. 1 is a schematic diagram of the device, QFa、QFb、QFcIs a relative ground switch; ca0、Cb0、Cc0Is a relative capacitance to ground.
Detailed Description
Three-phase-to-ground switch QF is connected beside ground fault processing devicea、QFb、QFcAnd three-phase to ground capacitance Ca0、Cb0、Cc0. When the single-phase earth fault processing device is connected to a power grid, firstly, the displacement voltage U of a neutral point of the power distribution network is measuredNThree phase voltage Ua、Ub、UcWhen the displacement voltage U of the neutral point of the power grid is detectedNWhen the voltage is higher, closing a phase-to-ground switch with higher phase voltage amplitude, putting the phase-to-ground capacitor into the phase-to-ground switch, leveling the three-phase voltage by changing the capacitance of the capacitor, reducing the asymmetry degree of the power grid, and shifting the voltage U of the neutral point of the power gridNThe single-phase earth fault processing device is adjusted to a relatively small value, and the capacity of identifying and processing the high-resistance earth fault of the asymmetric power grid by the single-phase earth fault processing device is improved.
When the single-phase grounding fault processing device is a grounding line selection device, a grounding capacitor is put into a phase with high phase voltage amplitude, the asymmetry degree of a power grid is reduced, the influence of asymmetric zero-sequence current generated in a feeder line due to the asymmetry of the power grid on the grounding line selection is reduced, and the high-resistance line selection capability of the grounding line selection device on the asymmetric power grid is improved.
Three phase to ground capacitance Ca0、Cb0、Cc0The capacitance of the capacitor can be automatically adjusted by adopting an adjustable capacitor, and can also be manually adjusted according to the actual power grid.
The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that several modifications and adaptations to those skilled in the art without departing from the principles of the present invention should also be considered within the scope of the present invention.

Claims (3)

1. AA method for improving the high-resistance ground fault handling capability of an asymmetric power grid is characterized in that a ground switch QF is adopteda、QFb、QFcAnd three-phase to ground capacitance Ca0、Cb0、Cc0The structure is characterized in that: when the single-phase earth fault processing device is connected to a power grid, firstly, the displacement voltage U of a neutral point of the power distribution network is measuredNThree phase voltage Ua、Ub、UcWhen the displacement voltage U of the neutral point of the power grid is detectedNWhen the voltage is higher, closing a phase-to-ground switch with higher phase voltage amplitude, putting the phase-to-ground capacitor into the phase-to-ground switch, leveling the three-phase voltage by changing the capacitance of the capacitor, reducing the asymmetry degree of the power grid, and shifting the voltage U of the neutral point of the power gridNThe single-phase earth fault processing device is adjusted to a relatively small value, and the capacity of identifying and processing the high-resistance earth fault of the asymmetric power grid by the single-phase earth fault processing device is improved.
2. The method for improving the high resistance earth fault handling capacity of the asymmetric power grid according to claim 1, wherein the method comprises the following steps: when the single-phase grounding fault processing device is a grounding line selection device, a grounding capacitor is put into a phase with high phase voltage amplitude, the asymmetry degree of a power grid is reduced, the influence of asymmetric zero-sequence current generated in a feeder line due to the asymmetry of the power grid on the grounding line selection is reduced, and the high-resistance line selection capability of the grounding line selection device on the asymmetric power grid is improved.
3. The method for improving the high resistance earth fault handling capacity of the asymmetric power grid according to claim 1, wherein the method comprises the following steps: three phase to ground capacitance Ca0、Cb0、Cc0The capacitance of the capacitor can be automatically adjusted by adopting an adjustable capacitor, and can also be manually adjusted according to the actual power grid.
CN201811305926.6A 2018-11-05 2018-11-05 Method suitable for improving high-resistance grounding fault handling capacity of asymmetric power grid Active CN111141991B (en)

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Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080297163A1 (en) * 2007-05-18 2008-12-04 Abb Technology Ag Method for determining location of phase-to-earth fault
CN102798795A (en) * 2012-08-14 2012-11-28 大连电力勘察设计院有限公司 Method capable of realizing low-current route selection and fault location
CN103545796A (en) * 2013-09-16 2014-01-29 国家电网公司 Single-phase grounding fault handling device and method for power distribution network with non-effectively grounded neutral points
CN103887805A (en) * 2014-01-07 2014-06-25 中国石油大学(华东) Asymmetric voltage control method of small current grounding system
CN104880647A (en) * 2015-06-15 2015-09-02 中国矿业大学 Earth fault phase identification method based on injection method
CN105119257A (en) * 2015-07-25 2015-12-02 李景禄 Dynamic processing method for single-phase transition resistor grounding fault of power distribution network
CN106771648A (en) * 2016-12-30 2017-05-31 国网天津市电力公司 A kind of capacitance current of distribution network measuring method based on improvement signal injection method
CN107508296A (en) * 2017-07-26 2017-12-22 国网山东省电力公司莱芜供电公司 A kind of system and method for the regulating time for reducing control asymmetrical voltage
CN108287296A (en) * 2018-02-07 2018-07-17 李景禄 One kind being suitable for unbalance grid high resistance earthing fault reverse starting and route selection method
CN208046228U (en) * 2018-03-23 2018-11-02 大连依诺维电气有限公司 Neutral point variable resistance earthed system

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080297163A1 (en) * 2007-05-18 2008-12-04 Abb Technology Ag Method for determining location of phase-to-earth fault
CN102798795A (en) * 2012-08-14 2012-11-28 大连电力勘察设计院有限公司 Method capable of realizing low-current route selection and fault location
CN103545796A (en) * 2013-09-16 2014-01-29 国家电网公司 Single-phase grounding fault handling device and method for power distribution network with non-effectively grounded neutral points
CN103887805A (en) * 2014-01-07 2014-06-25 中国石油大学(华东) Asymmetric voltage control method of small current grounding system
CN104880647A (en) * 2015-06-15 2015-09-02 中国矿业大学 Earth fault phase identification method based on injection method
CN105119257A (en) * 2015-07-25 2015-12-02 李景禄 Dynamic processing method for single-phase transition resistor grounding fault of power distribution network
CN106771648A (en) * 2016-12-30 2017-05-31 国网天津市电力公司 A kind of capacitance current of distribution network measuring method based on improvement signal injection method
CN107508296A (en) * 2017-07-26 2017-12-22 国网山东省电力公司莱芜供电公司 A kind of system and method for the regulating time for reducing control asymmetrical voltage
CN108287296A (en) * 2018-02-07 2018-07-17 李景禄 One kind being suitable for unbalance grid high resistance earthing fault reverse starting and route selection method
CN208046228U (en) * 2018-03-23 2018-11-02 大连依诺维电气有限公司 Neutral point variable resistance earthed system

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
JIE ZHOU: "Measuring phase-to-ground capacitance based on displacement voltage method", 《PREPRINTS OF THE 5TH INTERNATIONAL CONFERENCE ON ELECTRIC UTILITY DEREGULATION AND RESTRUCTURING AND POWER TECHNOLOGIES》 *
汤放奇: "补偿电网中性点位移电压异常的原因及对策", 《高电压技术》 *
王怡轩: "适用于高阻接地故障的谐振接地系统故障选线技术研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅱ辑》 *

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