CN113253045A - Dynamic arc extinction and grounding line selection method of arc extinction coil grounding mode - Google Patents
Dynamic arc extinction and grounding line selection method of arc extinction coil grounding mode Download PDFInfo
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- CN113253045A CN113253045A CN202010696299.4A CN202010696299A CN113253045A CN 113253045 A CN113253045 A CN 113253045A CN 202010696299 A CN202010696299 A CN 202010696299A CN 113253045 A CN113253045 A CN 113253045A
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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
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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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
Abstract
The invention discloses a dynamic arc extinction and grounding line selection method of an arc extinction coil grounding mode, when a power grid normally operates in the arc extinction coil grounding mode, when a single-phase grounding fault occurs in the power grid, firstly, the arc extinction coil carries out compensation arc extinction on the grounding fault, if the grounding fault is a transient fault, and the fault is eliminated after arc extinction compensation; if the fault is a permanent fault, namely after a certain time T, if the ground fault is not eliminated, the fault is dynamically converted into a mode of resistance ground, and a ground fault line is selected by a feeder line zero sequence current increment method.
Description
Technical Field
The invention mainly belongs to the field of neutral point grounding of a power distribution network, and particularly relates to a fault judgment and grounding line selection method for an arc suppression coil grounding mode, which is used for solving the problem of fault judgment and grounding line selection of the neutral point arc suppression coil grounding mode of the power distribution network.
Background
When a single-phase earth fault occurs in a power distribution network compensated by an arc suppression coil, the zero-sequence current flowing through a fault circuit is residual current compensated by the arc suppression coil, the zero-sequence current flowing through a non-fault circuit is earth capacitance current of the circuit, and is influenced by the tuning difference of the arc suppression coil and the difference of capacitance current of each circuit, the zero-sequence current of the fault circuit and the non-fault circuit has no regularity, the fault circuit cannot be determined by adopting a zero-sequence current amplitude comparison method, the fault line selection cannot be carried out by adopting a zero-sequence current line selection method, and the zero-sequence current line selection method is the most reliable earth line selection method. Although various grounding line selection methods are developed for arc suppression coil compensation power grids at home and abroad in order to solve the grounding line selection problem of the arc suppression coil compensation power grid, for example: the method comprises a transient current method, a residual current increment method, a 5 th harmonic wave method, an S injection method, an arc suppression coil and resistance method, an active component method, an information fusion method and other grounding line selection methods, but the accuracy of compensating the grounding line selection of the power grid cannot be solved at present due to various reasons such as the influence of the network structure difference of the power distribution network, the influence of field interference, the influence of signal acquisition sensitivity, the influence of the working point drift of electronic components and the like, and particularly the accuracy of line selection when the line is disconnected and high-resistance grounding is generated is not solved. The existing power department still adopts the original method of breaking the feeder line one by one to search the single-phase earth fault when dealing with the single-phase earth, namely the reliability of power supply is reduced, and the fault line can not be cut off rapidly and timely when the personal single-phase electric shock accident happens. Therefore, the accuracy problem of the grounding and route selection of the arc suppression coil is still a technical bottleneck in the industry at present. The neutral point can not judge the grounding fault property through the neutral arc elimination coil grounding mode, can not cut out a permanent single-phase grounding fault line in time, can not break away from a power supply in time when a personal single-phase electric shock occurs, and particularly has great safety risk to a human body when a distribution line is broken and grounded. The neutral point is grounded through the neutral arc elimination coil, so that the accuracy of grounding and line selection is low, and the line selection is carried out in many places by adopting a mode of cutting a feeder line one by one. This is also the reason why the person can not be timely disconnected from the power supply when getting an electric shock.
Therefore, the method can be used for solving the problem that the grounding mode of the arc suppression coil can judge the fault property, can extinguish the arc when the transient fault occurs, improves the power supply reliability, can quickly select and remove the fault line when the permanent ground fault occurs so as to ensure the equipment and personal safety, and achieves the ideal dynamic grounding method which is the main target to be realized.
Disclosure of Invention
The invention aims at the problems existing in the neutral point grounding of the existing power distribution network, and provides a fault judgment and grounding line selection method for an arc suppression coil grounding modeLSeries, switch QFLNeutral point voltage transformer TV connected in parallel besideNAnd a second resistive branch, the second resistive branch routing switch QFR2Resistance R to ground2Are connected in series; switch QFLThe secondary side of the transformer is connected with an arc suppression coil branch, and the arc suppression coil branch consists of an adjustable reactor L and a damping resistor RZThe first resistance branch is connected in parallel beside the arc suppression coil branch and is formed by a switch QFR1Resistance R to ground1Are connected in series.
When the power grid normally operates, the knife switch K is switched on and QFLSwitch-on, QFR2Separating brake and QFR2Switching off, operating the power grid in an arc suppression coil grounding mode, and acquiring neutral point displacement voltage U of the power grid in real time through a neutral point voltage transformer and a zero sequence current transformer of each feeder lineNAnd each feeder zero sequence current I10、I20、…Ij0When at T0Constantly detected neutral point displacement voltage U of power gridNSteady increment of (delta) UNNot less than delta, and the stable increment delta I of the zero sequence current of any feeder linej0If the voltage is more than or equal to gamma, the power grid is judged to have a stable single-phase earth fault, and T is set0As a starting point of the occurrence of the ground fault, the arc suppression coil performs arc suppression processing on the ground fault.
By a time delay T1Then, e.g. the neutral point of the network shifts the voltage UNSteady increment of (delta) UN<Delta, delta I of feeder with maximum zero sequence current increment in feeder at the same timej0<And gamma, judging the grounding fault as a transient fault, and successfully extinguishing the arc of the arc suppression coil.
By a time delay T1Then, if e.g. the neutral point of the network shifts the voltage UNSteady increment of (delta) UNNot less than delta, and the stable increment delta I of the zero sequence current of any feeder linej0If the ground fault is more than or equal to gamma, judging that the ground fault is a permanent fault, and arc extinction failure of the arc extinction coil; at the moment, after zero sequence current of each feeder line is collected, QF is closedR1、QFR2Then, break QFLDynamic conversion into neutral point of power grid via resistor R2Grounding, detecting to find out the grounding mode of arc suppression coil switched to the grounding mode through resistor R2And the feeder line with the largest zero sequence current increment in the feeder lines before and after grounding is the grounding fault line.
After the earth fault line is selected, a trip should be sent out immediately to cut off the fault line, and after the fault line, the QF is closedLBreak QFR1、QFR2And returning to the arc suppression coil grounding mode.
Delta is shift voltage U of neutral point of power grid for judging whether ground fault occurs or notNA stable increment criterion value of (a); gamma is a zero sequence current stable increment standard value in the feeder line for judging whether the ground fault occurs; t is1And eliminating the maximum arc extinction time of the transient fault for the arc extinction coil.
The invention has the following advantages:
1. the advantages of the grounding mode of the arc suppression coil are fully utilized, arc is rapidly extinguished when transient grounding faults occur, and the power supply reliability of the power distribution network is improved.
2. When a permanent single-phase grounding fault occurs in the power distribution network, the dynamic switching is carried out to a resistance grounding mode, a fault line is accurately selected by a zero-sequence current maximum increment method, and the worldwide technical problem that the power distribution network is grounded and selected by a neutral point arc suppression coil grounding mode is solved.
3. The method can be used for transforming the operated arc suppression coil, and is simple, economic and feasible.
4. The device effectively limits the internal overvoltage by disconnecting the arc suppression coil branch after the first resistance branch is closed.
Drawings
FIG. 1 is a wiring diagram of the device.
Detailed Description
A disconnecting link K, a disconnecting link K and a switch QF are connected in series at a neutral point of the grounding transformer JDBLSeries, switch QFLNeutral point voltage transformer TV connected in parallel besideNAnd a second resistive branch, the second resistive branch routing switch QFR2Resistance R to ground2Are connected in series; switch QFLThe secondary side of the transformer is connected with an arc suppression coil branch, and the arc suppression coil branch consists of an adjustable reactor L and a damping resistor RZThe first resistance branch is connected in parallel beside the arc suppression coil branch and is formed by a switch QFR1Resistance R to ground1Are connected in series.
When the power grid normally operates, the knife switch K is switched on and QFLSwitch-on, QFR2Separating brake and QFR2Switching off, operating the power grid in an arc suppression coil grounding mode, and acquiring neutral point displacement voltage U of the power grid in real time through a neutral point voltage transformer and a zero sequence current transformer of each feeder lineNAnd each feeder zero sequence current I10、I20、…Ij0When at T0Constantly detected neutral point displacement voltage U of power gridNSteady increment of (delta) UNNot less than delta, and the stable increment delta I of the zero sequence current of any feeder linej0If the voltage is more than or equal to gamma, the power grid is judged to have a stable single-phase earth fault, and T is set0As a starting point of the occurrence of the ground fault, the arc suppression coil performs arc suppression processing on the ground fault.
By a time delay T1Then, e.g. the neutral point of the network shifts the voltage UNSteady increment of (delta) UN<Delta, delta I of feeder with maximum zero sequence current increment in feeder at the same timej0<And gamma, judging the grounding fault as a transient fault, and successfully extinguishing the arc of the arc suppression coil.
By a time delay T1Then, if e.g. the neutral point of the network shifts the voltage UNSteady increment of (delta) UNNot less than delta, and the stable increment delta I of the zero sequence current of any feeder linej0If the ground fault is more than or equal to gamma, judging that the ground fault is a permanent fault, and arc extinction failure of the arc extinction coil; at the moment, after zero sequence current of each feeder line is collected, QF is closedR1、QFR2Then, break QFLDynamic conversion into neutral point of power grid via resistor R2Grounding, detecting to find out the grounding mode of arc suppression coil switched to the grounding mode through resistor R2And the feeder line with the largest zero sequence current increment in the feeder lines before and after grounding is the grounding fault line.
After the earth fault line is selected, a trip should be sent out immediately to cut off the fault line, and after the fault line, the QF is closedLBreak QFR1、QFR2And returning to the arc suppression coil grounding mode.
Delta is shift voltage U of neutral point of power grid for judging whether ground fault occurs or notNA stable increment criterion value of (a); gamma is a zero sequence current stable increment standard value in the feeder line for judging whether the ground fault occurs; t is1And eliminating the maximum arc extinction time of the transient fault for the arc extinction coil.
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 modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.
Claims (2)
1. A dynamic arc extinction and grounding line selection method of an arc extinction coil grounding mode is characterized in that: a disconnecting link K, a disconnecting link K and a switch QF are connected in series at a neutral point of the grounding transformer JDBLSeries, switch QFLNeutral point voltage transformer TV connected in parallel besideNAnd a second resistive branch, the second resistive branch routing switch QFR2Resistance R to ground2Are connected in series; switch QFLThe secondary side of the transformer is connected with an arc suppression coil branch, and the arc suppression coil branch consists of an adjustable reactor L and a damping resistor RZThe first resistance branch is connected in parallel beside the arc suppression coil branch and is formed by a switch QFR1Resistance R to ground1Are connected in series;
when the power grid normally operates, the knife switch K is switched on and QFLSwitch-on, QFR2Separating brake and QFR2Switching off, operating the power grid in an arc suppression coil grounding mode, and acquiring neutral point displacement voltage U of the power grid in real time through a neutral point voltage transformer and a zero sequence current transformer of each feeder lineNAnd each feeder zero sequence current I10、I20、…Ij0When at T0Constantly detected neutral point displacement voltage U of power gridNSteady increment of (delta) UNNot less than delta, and the stable increment delta I of the zero sequence current of any feeder linej0If the voltage is more than or equal to gamma, the power grid is judged to have a stable single-phase earth fault, and T is set0As a starting point of the occurrence of the ground fault, firstly carrying out arc extinction treatment on the ground fault by an arc extinction coil;
by a time delay T1Then, e.g. the neutral point of the network shifts the voltage UNSteady increment of (delta) UN<Delta, delta I of feeder with maximum zero sequence current increment in feeder at the same timej0<Gamma, judging that the ground fault is a transient fault, and successfully extinguishing the arc of the arc suppression coil;
by a time delay T1Later, if e.g. the neutral point of the grid shiftsVoltage UNSteady increment of (delta) UNNot less than delta, and the stable increment delta I of the zero sequence current of any feeder linej0If the ground fault is more than or equal to gamma, judging that the ground fault is a permanent fault, and arc extinction failure of the arc extinction coil; at the moment, after zero sequence current of each feeder line is collected, QF is closedR1、QFR2Then, break QFLDynamic conversion into neutral point of power grid via resistor R2Grounding, detecting to find out the grounding mode of arc suppression coil switched to the grounding mode through resistor R2The feeder line with the largest zero sequence current increment in the feeder lines before and after grounding is a grounding fault line;
after the earth fault line is selected, a trip should be sent out immediately to cut off the fault line, and after the fault line, the QF is closedLBreak QFR1、QFR2Resetting to the arc suppression coil grounding mode;
delta is shift voltage U of neutral point of power grid for judging whether ground fault occurs or notNA stable increment criterion value of (a); gamma is a zero sequence current stable increment standard value in the feeder line for judging whether the ground fault occurs; t is1And eliminating the maximum arc extinction time of the transient fault for the arc extinction coil.
2. The method of claim 1, wherein the method comprises the following steps: t is1And obtaining the voltage by a laboratory experiment or field experiment method according to the lowest insulation working condition and the maximum residual current in the power grid.
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| CN202010696299.4A CN113253045A (en) | 2020-07-20 | 2020-07-20 | Dynamic arc extinction and grounding line selection method of arc extinction coil grounding mode |
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| CN202010696299.4A CN113253045A (en) | 2020-07-20 | 2020-07-20 | Dynamic arc extinction and grounding line selection method of arc extinction coil grounding mode |
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Citations (5)
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| CN102623984A (en) * | 2012-03-23 | 2012-08-01 | 上海市电力公司 | System for grounding neutral point in power grid through controllable reactor and resistor in combined manner |
| CN103293446A (en) * | 2013-05-20 | 2013-09-11 | 国家电网公司 | Small-current grounding fault line selection method based on arc suppression coil |
| CN107681646A (en) * | 2017-10-27 | 2018-02-09 | 国网河南省电力公司漯河供电公司 | It is a kind of to be used for guard method of the arc suppression coil under chopping current |
| CN207910448U (en) * | 2018-03-08 | 2018-09-25 | 安徽伊格瑞德电气设备有限公司 | A kind of high pressure novel bus voltage rapid protection system |
| CN111141990A (en) * | 2018-10-17 | 2020-05-12 | 李景禄 | Ground fault identification and ground line selection method based on zero sequence current resistive component |
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2020
- 2020-07-20 CN CN202010696299.4A patent/CN113253045A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102623984A (en) * | 2012-03-23 | 2012-08-01 | 上海市电力公司 | System for grounding neutral point in power grid through controllable reactor and resistor in combined manner |
| CN103293446A (en) * | 2013-05-20 | 2013-09-11 | 国家电网公司 | Small-current grounding fault line selection method based on arc suppression coil |
| CN107681646A (en) * | 2017-10-27 | 2018-02-09 | 国网河南省电力公司漯河供电公司 | It is a kind of to be used for guard method of the arc suppression coil under chopping current |
| CN207910448U (en) * | 2018-03-08 | 2018-09-25 | 安徽伊格瑞德电气设备有限公司 | A kind of high pressure novel bus voltage rapid protection system |
| CN111141990A (en) * | 2018-10-17 | 2020-05-12 | 李景禄 | Ground fault identification and ground line selection method based on zero sequence current resistive component |
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