CN112162170A - Rapid line selection method for single-phase earth fault of low-current grounding system - Google Patents

Rapid line selection method for single-phase earth fault of low-current grounding system Download PDF

Info

Publication number
CN112162170A
CN112162170A CN202010539548.9A CN202010539548A CN112162170A CN 112162170 A CN112162170 A CN 112162170A CN 202010539548 A CN202010539548 A CN 202010539548A CN 112162170 A CN112162170 A CN 112162170A
Authority
CN
China
Prior art keywords
line
fault
sequence current
zero sequence
current
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202010539548.9A
Other languages
Chinese (zh)
Other versions
CN112162170B (en
Inventor
胡秀明
张春芬
叶傲辉
程栋
江锋
唐亚夫
詹清铁
宋翔林
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Huanggang Power Supply Co of State Grid Hubei Electric Power Co Ltd
Original Assignee
Huanggang Power Supply Co of State Grid Hubei Electric Power Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Huanggang Power Supply Co of State Grid Hubei Electric Power Co Ltd filed Critical Huanggang Power Supply Co of State Grid Hubei Electric Power Co Ltd
Priority to CN202010539548.9A priority Critical patent/CN112162170B/en
Publication of CN112162170A publication Critical patent/CN112162170A/en
Application granted granted Critical
Publication of CN112162170B publication Critical patent/CN112162170B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • 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
    • G01R31/088—Aspects of digital computing
    • 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
    • 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
    • G01R31/58—Testing of lines, cables or conductors
    • G01R31/60—Identification of wires in a multicore cable

Abstract

The invention discloses a method for quickly selecting a single-phase earth fault of a low-current grounding system. Firstly, acquiring three-phase current instantaneous values at the outlet of each feeder line of a substation in real time; secondly, calculating a zero sequence current instantaneous value of the line according to the current instantaneous value, and solving a second derivative of each zero sequence current instantaneous value by using an interpolation method; then, by taking the fault occurrence time as zero time, finding out the maximum value and the minimum value of the second derivative of the zero sequence current instantaneous value of each line within 3 ms; and finally, solving the characteristic quantity of the change trend of the zero sequence current of each line, and finding out the line with the maximum characteristic quantity, namely judging that the line is a fault line. The method of the invention is little influenced by the length of the line, the transition resistance and the arc suppression coil, and can quickly carry out single-phase earth fault line selection.

Description

Rapid line selection method for single-phase earth fault of low-current grounding system
Technical Field
The invention belongs to the field of power systems, relates to a single-phase earth fault line selection technology of a power distribution network, and particularly relates to a quick single-phase earth fault line selection method of a low-current earth system.
Background
The 10kV power distribution network system in China generally adopts a neutral point indirect grounding mode, wherein the neutral point is not grounded, and is grounded through an arc suppression coil and a resistor. In a neutral point indirect grounding system, when a single-phase grounding fault occurs, the fault point current is small, and therefore, the system is also called a low-current grounding system. During single-phase earth fault, the neutral point voltage is increased from zero to the phase voltage, the line voltage between three phases is kept symmetrical, and normal power supply is not influenced, so that the system is generally allowed to continuously operate for 1-2 hours. However, the post-fault non-fault voltage to ground increases
Figure BDA0002538413640000011
In order to prevent the fault from further enlarging to cause two-point or multi-point grounding short circuit, a fault line should be screened out in time, so that operation and maintenance personnel can find out the fault quickly and take measures to process in time. Therefore, in a low-current grounding system, a single-phase ground fault line selection technology is particularly important.
At present, the single-phase earth fault line selection method mainly comprises a current and power signal based method, a 5 th harmonic wave method, a wavelet method and a line selection method based on an injection signal principle. The method based on current signals usually utilizes the difference of zero-mode current amplitudes of a fault line and a sound line to compare the amplitudes so as to achieve the purpose of line selection, and also utilizes the principle that zero-mode currents of the fault line and the sound line are suddenly changed to provide a zero-mode current direction method. Based on the difference between the zero sequence active power of the fault line and the healthy line, the fault line selection can be carried out by comparing the zero sequence active components, but when the line resistance is smaller, the requirement on the precision of the detection device is very high. By comparing the 5 th harmonic currents of the faulty line and the non-faulty line, the 5 th harmonic method is proposed, but the 5 th harmonic is small and difficult to propose. The wavelet method analyzes the transient zero-sequence current signal through the wavelet transformation theory, can perform fault line selection, but is very difficult to select a proper wavelet base. The S injection method in the injection signal line selection method is characterized in that a signal is injected at the secondary side of a voltage transformer, a primary side is induced, the signal strength is detected at the wire outlet end of a power distribution network to judge a fault line, and the method has weak capacity of identifying a high-resistance grounding fault; the other signal injection method is to inject a power grid resonant frequency signal from a neutral point voltage transformer, measure zero sequence signal voltage to identify a high resistance grounding fault, measure the power angle of each outgoing line zero sequence signal to calculate the line damping rate, and perform fault line selection. Therefore, it is very important to provide a simple, effective and fast single-phase earth fault line selection method by using the existing detection device in the distribution network.
Disclosure of Invention
In order to overcome the defects of the existing single-phase earth fault line selection method, the invention aims to provide the quick single-phase earth fault line selection method of the small-current grounding system, which only utilizes single-end current information to quickly screen fault lines and has higher precision.
In order to achieve the purpose, the invention adopts the technical scheme that:
a method for quickly selecting a line of a single-phase earth fault of a low-current grounding system is characterized by comprising the following steps:
step 1: at the outlet of a feeder line of a substation, a current transformer is utilized to collect three-phase current instantaneous values of each line (for example, n lines) in real time and respectively record the three-phase current instantaneous values as iA(t)k、iB(t)k、iC(t)kWherein k is 1, 2, 3 … … n.
Step 2: calculating zero sequence current of each line according to the three-phase current instantaneous value of the line obtained by samplingInstantaneous value, denoted as i0(t)kWherein k is 1, 2, 3 … … n. The formula is as follows:
i0(t)k＝iA(t)k+iB(t)k+iC(t)k(1)
and step 3: according to the obtained zero sequence current instantaneous value, calculating the second derivative of the zero sequence current instantaneous value by an interpolation method, and recording the second derivative as the zero sequence current instantaneous value
Figure BDA0002538413640000031
The formula is as follows:
Figure BDA0002538413640000032
where Δ T is the sampling period, and k is 1, 2, 3 … … n.
And 4, step 4: recording the time when the ground fault occurs as zero time, namely when the fault occurs, t is 0, and finding out the maximum value point of the second derivative of the zero sequence current instantaneous value of each line within 3ms after the fault occurs
Figure BDA0002538413640000033
Minimum point
Figure BDA0002538413640000034
And t is the value at 3ms
Figure BDA0002538413640000035
Wherein k is 1, 2, 3 … … n.
And 5: calculating characteristic quantity P of change trend of zero sequence current of each linek. The formula is as follows:
Figure BDA0002538413640000036
wherein k is 1, 2, 3 … … n.
Step 6: comparing characteristic quantity P of change trend of zero sequence current of each linekIf the characteristic quantity of the variation trend of the zero sequence current of a certain line is maximum, the line is in order to avoid the faultAnd (4) a barrier line.
Compared with the existing line selection method, the invention has the following advantages:
the method for quickly selecting the single-phase earth fault of the small-current grounding system is specially used for a distribution network system, is strong in purpose, only needs to utilize transient current information of the head end of a line (namely only needs to acquire three-phase current of the head end of the line), is very short in sampling data window, and has low requirement on storage space; the adopted calculation method is very simple, the calculation amount is small, the requirement on a CPU of the device is low, and the requirement on quick line selection can be met. The method utilizes the zero sequence current change trend characteristic quantity comparison to select the line, can reduce the influence of the line length, the transition resistance and the arc suppression coil on the line selection accuracy, and improves the line selection accuracy.
When the small current grounding system operates normally, the zero sequence current of the line is zero. The invention carries out fault analysis by using transient information of zero-sequence current after a fault occurs, and the proposed second derivative of the zero-sequence current instantaneous value flow is more sensitive to the fault compared with the fundamental frequency component and the first derivative of the zero-sequence current, so that the invention has higher sensitivity; aiming at the condition that the maximum value of the transient zero-sequence current variation trend of the fault line is not necessarily larger than the maximum value of the zero-sequence current variation trend of the sound line, the characteristic quantity of the zero-sequence current second derivative is obtained in a power frequency period, so that the influence of the line length, the transition resistance and the arc suppression coil on the line selection accuracy is reduced.
Drawings
FIG. 1 is a flow chart of the method of the present invention.
FIG. 2 is a simulation model diagram of a low current grounding system.
Fig. 3 is a waveform diagram of the zero sequence current instantaneous value of each line before and after a single-phase ground fault occurs for 0.102s under certain conditions.
Fig. 4 is a waveform diagram of the second derivative of the instantaneous value of the zero-sequence current of the line 1 in case of the 1 st situation, where the time 0 on the horizontal axis is the time of the fault occurrence, when the single-phase ground fault occurs at 0.102 s.
Fig. 5 is a waveform diagram of the second derivative of the instantaneous value of the zero-sequence current of the line 1 in case of the 2 nd situation, where the time 0 on the horizontal axis is the time of the fault occurrence, when the single-phase ground fault occurs at 0.102 s.
Fig. 6 is a waveform diagram of the second derivative of the instantaneous value of the zero-sequence current of the line 1 in case of the single-phase ground fault occurring at 0.102s in case of the 3 rd situation, wherein the time 0 on the horizontal axis is the time of the fault occurrence.
Fig. 7 is a waveform diagram of the second derivative of the instantaneous value of the zero-sequence current of the line 1 in the case of the 4 th situation, in which the time 0 on the horizontal axis is the time of the fault occurrence, when the single-phase ground fault occurs at 0.102 s.
Fig. 8 is a waveform diagram of the second derivative of the instantaneous value of the zero-sequence current of the line 1 in the case of the 5 th situation, in which the time 0 on the horizontal axis is the time of the fault occurrence, when the single-phase ground fault occurs at 0.102 s.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples.
As shown in a simulation model diagram of a 110kV/10.5kV low-current grounding system shown in figure 2, S is a 110kV power supply, a 10kV bus is provided with 4 10kV feeders and respectively carries a certain load, and the grounding mode of a neutral point of a transformer, namely the grounding is not grounded or the grounding is grounded through an arc suppression coil, is changed by controlling the on-off of a switch k. Line 1 is a cable line, line 2 is an overhead line, line 3 is an overhead line, and line 4 is a cable line.
The fault point is set at f on the line 1 at a distance of 1km from the 10kV bus, and the fault time is 0.102s respectively. In order to verify that the method of the invention is basically not influenced by the line length, the transition resistance and the arc suppression coil, the following 5 conditions are set:
case 1: the length of the line 1 is 3km, the length of the line 2 is 15km, the length of the line 3 is 1km, the length of the line 4 is 2km, the transition resistance is 1 ohm, and no arc suppression coil is arranged.
Table 1 shows the zero sequence current variation trend characteristic quantities and the line selection results calculated in this case.
Figure BDA0002538413640000051
TABLE 1
Case 2: the length of the line 1 is 3km, the length of the line 2 is 15km, the length of the line 3 is 12km, the length of the line 4 is 2km, the transition resistance is 1 ohm, and no arc suppression coil is arranged.
Table 2 shows the zero sequence current variation trend characteristic quantities and the line selection results calculated in this case.
Figure BDA0002538413640000052
Figure BDA0002538413640000061
TABLE 2
Case 3: the length of the line 1 is 3km, the length of the line 2 is 15km, the length of the line 3 is 12km, the length of the line 4 is 2km, the transition resistance is 100 ohms, and no arc suppression coil is arranged.
Table 3 shows the zero sequence current variation trend characteristic quantities and the line selection results calculated in this case.
Figure BDA0002538413640000062
TABLE 3
Case 4: the length of the line 1 is 3km, the length of the line 2 is 15km, the length of the line 3 is 1km, the length of the line 4 is 2km, the transition resistance is 1 ohm, and an arc suppression coil (coil inductance L is 5H) is provided.
Table 4 shows the calculated characteristic quantities of the zero-sequence current variation trend and the line selection result in this case.
Figure BDA0002538413640000063
Figure BDA0002538413640000071
TABLE 4
Case 5: the line 1 has a length of 3km, the line 2 has a length of 15km, the line 3 has a length of 1km, the line 4 has a length of 2km, the transition resistance is 100 ohms, and an arc suppression coil (coil inductance L5H) is provided.
Table 5 shows the zero sequence current variation trend characteristic quantities and the line selection results calculated in this case.
Figure BDA0002538413640000072
TABLE 5
The method provided by the invention can be used for rapidly selecting the line of the single-phase earth fault. As shown in fig. 1, the method comprises the following steps:
step 1: at the outlet of a feeder line of a substation, a current transformer is utilized to collect three-phase current instantaneous values of each line (4 lines in the example) in real time and respectively record the three-phase current instantaneous values as iA(t)k、iB(t)k、iC(t)kWherein k is 1, 2, 3, 4.
Step 2: respectively calculating zero sequence current instantaneous values of 4 lines according to the three-phase current instantaneous values of the lines obtained by sampling, and recording as i0(t)kWherein k is 1, 2, 3, 4. The formula is as follows:
i0(t)k＝iA(t)k+iB(t)k+iC(t)k (1)
and step 3: according to the obtained zero sequence current instantaneous value, calculating the second derivative of the zero sequence current instantaneous value by an interpolation method, and recording the second derivative as the zero sequence current instantaneous value
Figure BDA0002538413640000073
The formula is as follows:
Figure BDA0002538413640000081
since the sampling frequency is 10kHz, Δ T in the formula is 0.1ms, and k is 1, 2, 3, or 4.
And 4, step 4: recording the time when the ground fault occurs as zero time, namely when the fault occurs, t is 0, and finding out the maximum value point of the second derivative of the zero sequence current instantaneous value of each line within 3ms after the fault occurs
Figure BDA0002538413640000082
Minimum point
Figure BDA0002538413640000083
Meanwhile, the value of the second derivative of the zero sequence current instantaneous value at the position where t is 3ms is recorded as
Figure BDA0002538413640000084
Wherein k is 1, 2, 3, 4.
And 5: calculating the characteristic quantity P of the change trend of the zero sequence current of 4 linesk. The formula is as follows:
Figure BDA0002538413640000085
wherein k is 1, 2, 3, 4.
Step 6: comparing characteristic quantity P of change trend of zero sequence current of each linekIn 5 cases set by the example, the characteristic quantity of the zero sequence current variation trend of the line 1 is found to be the maximum, so that the line 1 is determined to be a fault line.
Compared with the 1 st situation and the 2 nd situation, the length change of the line 3 can not cause the wrong selection; compared with the situations 2 and 3, the transition resistance is changed from 1 ohm to 100 ohm, so that the characteristic quantities of the line 1 and the line 2 are very close to each other, and the wrong selection is still avoided; compared with the situations 1 and 4, the arc suppression coil cannot cause wrong selection; in case 5, the maximum value of the second derivative of the zero sequence current instantaneous value of the line 2 in 3ms is found to be larger than that of the line 1, but the method can still select the line correctly.

Claims (2)

1. A method for quickly selecting a line of a single-phase earth fault of a low-current grounding system is characterized by comprising the following steps:
step 1: at the outlet of the feeder line of the substation, a current transformer is utilized to collect each line in real time, for example, n lines are provided, and the instantaneous values of three-phase current are respectively recorded as iA(t)k、iB(t)k、iC(t)kWherein k is 1, 2, 3 … … n;
step 2: according to the sampled instantaneous values of the three-phase current of the line, calculating the instantaneous value of the zero-sequence current of each line, and recording as i0(t)kWherein k is 1, 2, 3 … … n; the formula is as follows:
i0(t)k＝iA(t)k+iB(t)k+iC(t)k (1)
and step 3: according to the obtained zero sequence current instantaneous value, calculating the second derivative of the zero sequence current instantaneous value by an interpolation method, and recording the second derivative as the zero sequence current instantaneous value
Figure FDA0002538413630000011
The formula is as follows:
Figure FDA0002538413630000012
in the formula, Δ T is a sampling period, k is 1, 2, 3 … … n;
and 4, step 4: recording the time of occurrence of the ground fault as zero time, namely, when the fault occurs, t is 0, and finding out the maximum value point of the second derivative of the zero sequence current instantaneous value of each line within a certain time after the fault occurs
Figure FDA0002538413630000013
Minimum point
Figure FDA0002538413630000014
And t is the value at 3ms
Figure FDA0002538413630000015
Wherein k is 1, 2, 3 … … n;
and 5: calculating characteristic quantity P of change trend of zero sequence current of each linek(ii) a The formula is as follows:
Figure FDA0002538413630000016
wherein k is 1, 2, 3 … … n;
step 6: comparing line zerosSequence current variation trend characteristic quantity PkAnd if the characteristic quantity of the change trend of the zero sequence current of a certain line is the maximum, the line is a fault line.
2. The method for selecting the single-phase earth fault line of the small-current grounding system according to claim 1, wherein the method comprises the following steps: and 4, taking 3ms as a certain time after the fault.
CN202010539548.9A 2020-06-15 2020-06-15 Single-phase earth fault rapid line selection method for small current grounding system Active CN112162170B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010539548.9A CN112162170B (en) 2020-06-15 2020-06-15 Single-phase earth fault rapid line selection method for small current grounding system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010539548.9A CN112162170B (en) 2020-06-15 2020-06-15 Single-phase earth fault rapid line selection method for small current grounding system

Publications (2)

Publication Number Publication Date
CN112162170A true CN112162170A (en) 2021-01-01
CN112162170B CN112162170B (en) 2022-05-10

Family

ID=73859533

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010539548.9A Active CN112162170B (en) 2020-06-15 2020-06-15 Single-phase earth fault rapid line selection method for small current grounding system

Country Status (1)

Country Link
CN (1) CN112162170B (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102928728A (en) * 2012-10-30 2013-02-13 清华大学 High-resistance grounding fault detection method based on zero-sequence current waveform distortion convexity and concavity
CN106771850A (en) * 2016-11-21 2017-05-31 西安交通大学 Distribution network fault line selection method based on cascade bistable system
RU2017100844A (en) * 2017-01-10 2018-07-13 Федеральное государственное бюджетное образовательное учреждение высшего образования "Вятский государственный университет" (ВятГУ) METHOD FOR DETERMINING THE SINGLE-PHASE LOCATION ON THE GROUND IN A BRANCHED AIR POWER LINE WITH ISOLATED NEUTRAL
US20180284180A1 (en) * 2015-04-30 2018-10-04 General Electric Technology Gmbh Fault location detection and distance protection apparatus and associated method
CN109683063A (en) * 2019-02-22 2019-04-26 中国石油大学(华东) A kind of single-phase grounded malfunction in grounded system of low current direction detection method using zero-sequence current and voltage derivative linearity relationship

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102928728A (en) * 2012-10-30 2013-02-13 清华大学 High-resistance grounding fault detection method based on zero-sequence current waveform distortion convexity and concavity
US20180284180A1 (en) * 2015-04-30 2018-10-04 General Electric Technology Gmbh Fault location detection and distance protection apparatus and associated method
CN106771850A (en) * 2016-11-21 2017-05-31 西安交通大学 Distribution network fault line selection method based on cascade bistable system
RU2017100844A (en) * 2017-01-10 2018-07-13 Федеральное государственное бюджетное образовательное учреждение высшего образования "Вятский государственный университет" (ВятГУ) METHOD FOR DETERMINING THE SINGLE-PHASE LOCATION ON THE GROUND IN A BRANCHED AIR POWER LINE WITH ISOLATED NEUTRAL
CN109683063A (en) * 2019-02-22 2019-04-26 中国石油大学(华东) A kind of single-phase grounded malfunction in grounded system of low current direction detection method using zero-sequence current and voltage derivative linearity relationship

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
薛太林等: ""基于零序特征量的小电流接地系统单相接地故障仿真分析"", 《自动化技术与应用》 *

Also Published As

Publication number Publication date
CN112162170B (en) 2022-05-10

Similar Documents

Publication Publication Date Title
CN109683063B (en) Small current ground fault direction detection method using current and voltage derivative
CN110703040B (en) Distribution network single-phase earth fault positioning method based on fault phase and non-fault phase current mutation difference
CN111007427B (en) Distribution line single-phase earth fault line selection method and computer readable storage medium
EP3069426B1 (en) Method and apparatus of reactor turn-to-turn protection
CN103454555B (en) Based on the one-phase earthing failure in electric distribution network Section Location of parameter identification
CN104166067A (en) Single-phase earth fault positioning detection method and device
CN109188193B (en) Power distribution network fault line selection method based on characteristic frequency band convergence Min's distance
CN103490404A (en) Tuning method of following-setting-type arc suppression coil of power distribution network system and fault line selection method
CN112305375B (en) High-resistance grounding fault line selection method for resonant grounding system
CN110456218A (en) Fast failure selection method based on power frequency increment coefficient before and after medium resistance switching
CN2802517Y (en) Automatic tracking compensation and earthing wire selecting positioning device using arc suppression coil
CN107255774B (en) Line selection method based on trip and closing information of mistakenly selected line
CN104280663A (en) Online monitoring and line selecting method for single-phase earth faults of small current grounding system
CN112305374A (en) Power distribution network single-phase earth fault line selection method
CN112162170B (en) Single-phase earth fault rapid line selection method for small current grounding system
CN113358978B (en) Fault type identification method and device for single-phase fault of power distribution network
CN100539353C (en) Be applicable to the selection method of fast automatic arc suppression coil earthing system
CN110568313A (en) single-phase earth fault positioning method and system for small current earthing system
CN114252736A (en) Active power distribution network single-phase fault line selection method based on background harmonic
CN112649694B (en) Method for judging single-phase grounding fault of low-current grounding system
CN112578228A (en) Zero-sequence-independent single-phase earth fault discrimination algorithm for power distribution network
Liu et al. Single-phase Grounding Fault Line Selection Method Based on the Difference of Electric Energy Information Between the Distribution End and the Load End
Baù et al. Phase-to-ground fault location methods in unearthed sub-transmission networks: A review
CN113484673B (en) Single-phase arc grounding fault section positioning method based on zero-mode component similarity
CN110687403B (en) Power distribution network single-phase earth fault detection method and device

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant