CN114184981A - Low-voltage electric leakage positioning equipment and offline electric leakage evaluation method - Google Patents

Low-voltage electric leakage positioning equipment and offline electric leakage evaluation method Download PDF

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CN114184981A
CN114184981A CN202111509614.9A CN202111509614A CN114184981A CN 114184981 A CN114184981 A CN 114184981A CN 202111509614 A CN202111509614 A CN 202111509614A CN 114184981 A CN114184981 A CN 114184981A
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leakage
voltage
phase
low
line
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CN114184981B (en
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詹天源
刘时枝
纪代敏
郭进仕
王小花
伍晓冬
祝明
陈翠翠
游叶青
庄婷
柯宏杰
王慧凡
蒋海霞
张雨婷
王秋圆
徐圣烽
陈溪
张晨
练伟
魏农
林谢媛
乐开诚
杨文艳
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Nanping Power Supply Co Of State Grid Fujian Electric Power Co
State Grid Fujian Electric Power Co Ltd
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Nanping Power Supply Co Of State Grid Fujian Electric Power Co
State Grid Fujian Electric Power Co Ltd
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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
    • 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
    • G01R31/085—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution lines, e.g. overhead
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
    • Y04S10/52—Outage or fault management, e.g. fault detection or location

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  • General Physics & Mathematics (AREA)
  • Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)

Abstract

本发明提出低压漏电定位设备及离线漏电评估方法，用于对台区的漏电故障线路进行精准选线以及对漏电故障位置定位，在被测线路停电状态下，以低压漏电定位仪的主机通过向被测台区的A、B、C、N四相线路施加特定电压，通过电流采样电路向四相线路注入电流测量，进而计算得到被测线路的电阻值，再根据复杂漏电模型测量得到各相的对地电阻值，最后根据A、B、C、N对地电阻值计算该被测台区的各相线路漏电流及日均漏电量，对被测台区进行漏电评估，当任一相的对地电阻值小于阈值时，判定该台区存在漏电故障；本发明可规范农村配电台区漏电保护器的配置，提高台区保护的安装率、投运率，发挥漏电保护器的效能，最大限度保障人民群众生命财产安全。

Figure 202111509614

The invention proposes a low-voltage leakage locating device and an off-line leakage evaluation method, which are used for accurate line selection of the leakage fault line in the station area and locating the leakage fault position. The A, B, C, N four-phase lines in the test station area are applied with a specific voltage, and the current measurement is injected into the four-phase line through the current sampling circuit, and then the resistance value of the tested line is calculated, and then each phase is measured according to the complex leakage model. Finally, according to the resistance values of A, B, C, and N to the ground, calculate the leakage current of each phase line and the daily average leakage current in the tested station area, and conduct leakage evaluation on the tested station area. When the ground resistance value is less than the threshold value, it is determined that there is a leakage fault in the station area; the invention can standardize the configuration of the leakage protector in the rural distribution station area, improve the installation rate and commissioning rate of the station area protection, and give play to the effectiveness of the leakage protector. , to maximize the safety of people's lives and property.

Figure 202111509614

Description

Low-voltage electric leakage positioning equipment and offline electric leakage evaluation method
Technical Field
The invention relates to the technical field of power grid operation and maintenance, in particular to low-voltage electric leakage positioning equipment and an off-line electric leakage evaluation method.
Background
The rural distribution network line electric leakage is a pain point and a difficulty which are puzzled on the safe and economic operation of a low-voltage rural distribution network, and an effective technical means is not available for a long time to accurately position an electric leakage fault, so that the following three problems are brought to a power grid enterprise: firstly, the power supply reliability is reduced, the leakage of a low-voltage line occurs sometimes, the total leakage protection tripping of a transformer area is easy to cause, and the normal production and life power utilization of customers is greatly influenced; secondly, the safety of power utilization is difficult to guarantee, in order to improve the reliability of power supply, part of transformer areas are withdrawn from leakage protection or are adjusted to a high fixed value, and when a leakage fault occurs, the leakage protection cannot act, so that a fire disaster or an electric shock casualty accident is caused; and thirdly, the economic benefit of the enterprise is damaged, intermittent electric leakage occurs sometimes, and the intermittent electric leakage is difficult to find and dispose in time, so that the benefit of the power grid enterprise is lost.
Disclosure of Invention
The invention provides low-voltage leakage positioning equipment and an off-line leakage evaluation method, which can standardize the configuration of leakage protectors of rural distribution substations, improve the installation rate and the commissioning rate of substation protection, exert the efficiency of the leakage protectors, and ensure the life and property safety of people to the maximum extent.
The invention adopts the following technical scheme.
The off-line leakage evaluation method of low-voltage leakage is used for accurately selecting lines of a leakage fault line of a transformer area and accurately positioning the position of the leakage fault, and comprises the steps of applying specific voltage to A, B, C, N four-phase lines of the transformer area by a host of a low-voltage leakage locator in the power failure state of the tested line, injecting current into the four-phase lines through a current sampling circuit for measurement, further calculating to obtain the resistance value of the tested line, then measuring to-ground resistance values of all phases according to a complex leakage model, finally calculating the leakage current and daily average leakage current of all the phase lines of the transformer area to be tested according to a A, B, C, N to-ground resistance value, evaluating the leakage of the transformer area to be tested, and judging that the transformer area has the leakage fault when the ground resistance value of any phase is smaller than a threshold value.
In the complex leakage model, RA0、RB0、RC0、RN0The method comprises the following steps that insulation resistance values of an A phase, a B phase, a C phase and an N phase which need to be measured during off-line leakage evaluation are evaluated, if the insulation resistance values are infinite, the phase is evaluated to have no leakage, if the insulation resistance values are specific values which can be measured in a measuring range, the phase is evaluated to have leakage, and the following formula exists in a model;
RAN＝RAN0//(RA0+RN0//(RBN0+RB0)//(RCN0+RC0) Formula nine;
RBN＝RBN0//(RB0+RN0//(RAN0+RA0)//(RCN0+RC0) Equation ten;
RCN＝RCN0//(RC0+RN0//(RAN0+RA0)//(RBN0+RB0) Formula eleven;
RAG＝RA0//[RAN0+(RBN0+RB0)//(RCN0+RC0)//RN0]a formula twelve;
RBG＝RB0//[RBN0+(RAN0+RA0)//(RCN0+RC0)//RN0]a formula thirteen;
RCG＝RC0//[RCN0+(RAN0+RA0)//(RBN0+RB0)//RN0]a formula fourteen;
RNG＝RN0//(RAN0+RA0)//(RBN0+RB0)//(RCN0+RC0) A formula fifteen;
in the formula nine to the formula fifteen, when the phase A is alternated with the phase N, the resistance RANPhase B and phase N interphase resistance RBNResistance R between C phase and N phaseCNPhase A and phase G interphase resistance RAGPhase B and phase G interphase resistance RBGResistance R between C phase and G phaseCGResistance R between N phase and G phaseNGFor the known quantity obtained by the measurement of the low-voltage leakage locator host, R can be calculated according to a formula from nine to fifteenA0、RB0、RC0、RN0、RAN0、RBN0、RCN0The value is obtained.
The off-line electric leakage evaluation method comprises the steps that under the power failure state of a tested line, a host of a low-voltage electric leakage locator applies specific voltage to an A, B, C, N four-phase line of a tested platform area, and a current sampling circuit of the host of the low-voltage electric leakage locator injects current into the four-phase line for measurement;
hardware of a host of the low-voltage leakage locator for offline leakage evaluation comprises an MCU, a current sampling circuit, a voltage division circuit and a voltage following circuit;
the current sampling circuit comprises a voltage source, a current sampling resistor and an IC1, wherein T is a resistor to be detected;
the voltage division circuit is used for enabling the full-range voltage range output by the current sampling circuit to meet the ADC acquisition range of the MCU.
The low-voltage leakage positioning equipment comprises a low-voltage leakage positioning instrument host and a low-voltage leakage positioning instrument slave, wherein the hardware part of the low-voltage leakage positioning instrument host comprises a battery charging circuit, a battery, a DC/DC circuit, a display, a key, a buzzer, an MCU, a gear shifting circuit, an integrating circuit, an amplifying circuit, a full-wave rectifying circuit, a filter circuit, an MCU, a signal conditioning circuit, a current limiting resistor, an analog channel switch, a current sampling circuit, a voltage dividing circuit and a voltage following circuit.
The hardware part of the low-voltage leakage locator host further comprises a Rogowski coil used for an online leakage evaluation method, and the hardware used for online leakage evaluation further comprises a shift circuit, an integrating circuit, an amplifying circuit, a full-wave rectifying circuit, a low-pass filter circuit and an MCU (microprogrammed control Unit);
the online electric leakage evaluation method comprises the steps that current vector sums of A, B, C, N phases of a tested station area are measured by low-voltage electric leakage positioning equipment through a Rogowski coil in an online working state, if the current vector sum of the tested station area measured by the Rogowski coil is not zero, the electric leakage exists in the station area, and if the current vector sum of the tested station area measured by the Rogowski coil is zero, the electric leakage does not exist in the station area;
when the phase current vector sum of the tested platform area A, B, C, N is measured, the Rogowski coil outputs a differential signal of A, B, C, N phase current vector sum, and the output signal is in a linear relation with the change rate of the tested current;
the output signal of the Rogowski coil enters an integrating circuit through a shifting circuit according to proportions of different weights, the integrating circuit performs integral reduction on a differential signal of a Rogowski coil output current vector sum, and an alternating voltage signal for accurately reproducing the waveform of the measured current signal is obtained after a voltage signal output by the Rogowski coil is integrated;
the amplifying circuit amplifies the signal output by the integrating circuit; the full-wave rectification circuit is connected with the amplifying circuit and performs full-wave rectification on the signal output by the amplifying circuit; the low-pass filter circuit is connected with the full-wave rectifying circuit, and performs low-pass filtering on the signal output by the full-wave rectifying circuit to output an effective value of the current to be measured.
The low-voltage leakage positioning equipment is used for carrying out leakage positioning on leakage current with loop characteristics, when the leakage positioning is carried out, a characteristic signal is injected into a fault line by using a low-voltage leakage positioning instrument host, due to the loop characteristics of the leakage current, the injected characteristic signal only exists in a loop to the ground, namely, the injected characteristic signal exists on the front side of a fault point and cannot be on the rear side of the fault point, and then the leakage fault position is positioned by judging whether the injected characteristic signal exists in a tested line, wherein the specific method comprises the following steps: the accurate positioning of the position of the leakage fault point is realized under the matching use of the slave machine of the low-voltage leakage position indicator, the rough sectional detection is firstly carried out, and then the accurate positioning is carried out.
In the low-voltage leakage locator host, a hardware part for positioning leakage comprises an MCU, a signal conditioning circuit, a current-limiting resistor and an analog channel switch;
when the power-off-state transformer area line is subjected to leakage positioning, a low-voltage leakage positioning instrument host injects characteristic signals into a fault line, the characteristic signals comprise voltage signals for leakage evaluation and pulse signals for leakage positioning, the low-voltage leakage positioning instrument slave receives the characteristic signals and outputs induction signals from a magnetic core coil sensor, and the induction voltage of the induction signals is in direct proportion to the voltage change rate of the characteristic signals injected by the low-voltage leakage positioning instrument host.
The low-voltage leakage locator host machine adopts a pulse signal as a characteristic signal injected into a fault line; the pulse signal is generated by a half-bridge circuit in a low-voltage electric leakage locator host.
In the electric leakage positioning, a low-voltage electric leakage positioning instrument host computer generates a coded frequency signal to be injected into a fault line according to the agreement of a master-slave machine, signal injection characteristic coding signals are only carried out on one phase in the fault line each time, then a low-voltage electric leakage positioning instrument slave computer is used for carrying out characteristic signal decoding in a non-contact mode along the electric leakage fault line, the position of an electric leakage fault point is roughly segmented, and then the electric leakage fault point is accurately positioned.
The software of the low-voltage leakage locator host is based on a Linux + QT framework, and when leakage assessment operation which consumes longer time is executed, independent thread operation is adopted to avoid influencing the execution of other software modules;
when generating the encoded frequency signal for signal injection, the injection signals of the A phase, the B phase, the C phase and the N phase adopt the same encoding mode, and the signal contents of the injection signals of the A phase, the B phase, the C phase and the N phase are different;
the low-voltage leakage locator slave machine comprises a magnetic core coil sensor, a low-voltage leakage locator slave machine PCB and a battery;
after the low-voltage electric leakage locator host computer injects characteristic signal into the fault line, characteristic signal produces magnetic field around the fault line, and it is V to establish the voltage that low-voltage electric leakage locator host computer injects characteristic signal into the electric leakage fault line, and the frequency is F, and fault line ground resistance R, the fault line electric current I of flowing through, then can obtain the magnetic induction strength B who locates apart from fault line d according to biot-savart law and be:
Figure BDA0003405266010000041
wherein mu0Is a vacuum permeability, mu0＝4π×10-7Tesla meters per ampere;
the low-voltage leakage locator slave machine receives the magnetic field of the characteristic signal through the magnetic core coil sensor and interprets the characteristic signal from the magnetic field, and the magnetic core coil sensor outputs the magnitude of the induced electromotive force xi and the change rate of the magnetic flux passing through the loop according to the Faraday's law of electromagnetic induction
Figure BDA0003405266010000042
In a direct proportion to the total weight of the composition,
Figure BDA0003405266010000043
and the low-voltage leakage locator slave machine receives and demodulates the output signal of the magnetic core coil sensor, and further identifies whether the demodulated signal is a characteristic signal injected by the low-voltage leakage locator host machine.
The invention can realize accurate line selection of a leakage fault line and accurate positioning of a leakage fault position, can better implement DL/T736-2010 rural power grid leakage protector installation and operation rules and national power grid company rural low-voltage power grid leakage protector configuration principles (State grid rural safety No. 2012/39), can standardize the configuration of the leakage protector of a rural power distribution station, improve the installation rate and the commissioning rate of station protection, exert the efficiency of the leakage protector, furthest ensure the life and property safety of people, and has important social significance and economic benefit.
The invention innovatively provides that a characteristic signal is injected into a line to be detected by using the characteristics of a low-voltage leakage fault line through a low-voltage leakage position indicator host, and if the line injected by the characteristic signal is a leakage fault line, the characteristic signal injected by the low-voltage leakage position indicator host exists in a fault loop, so that the leakage fault line selection function is realized. And the low-voltage leakage locator host injects a characteristic coding signal into the leakage fault line, and the low-voltage leakage locator slave is used for decoding the characteristic signal along the leakage fault line in a non-contact mode. Before the fault point, the injected characteristic coding signal continuously exists, and after the fault point, the injected characteristic coding signal disappears. The fault location can be determined quickly by performing rough segmentation and then performing accurate positioning.
Drawings
The invention is described in further detail below with reference to the following figures and detailed description:
FIG. 1 is a schematic diagram of the low voltage leakage location principle of the present invention;
FIG. 2 is another schematic diagram of the low voltage leakage localization principle of the present invention;
FIG. 3 is a schematic diagram of the hardware principle of a low-voltage leakage locator host;
FIG. 4 is a schematic diagram of a complex leakage model for offline leakage assessment;
FIG. 5 is a schematic diagram of an A, B, C, N phase coil of a tested station area circuit into a Rogowski coil in the online leakage evaluation;
fig. 6 is a schematic diagram of the operation of the leakage current location of the present invention.
Detailed Description
As shown in the figure, the offline leakage evaluation method of low-voltage leakage is used for accurately selecting a line of a leakage fault line of a transformer area and accurately positioning a leakage fault position, and the offline leakage evaluation method is characterized in that under the power failure state of a tested line, a host of a low-voltage leakage locator applies specific voltage to A, B, C, N four-phase lines of the tested transformer area, current is injected into the four-phase lines through a current sampling circuit for measurement, the resistance value of the tested line is calculated, the ground resistance value of each phase is measured according to a complex leakage model, the leakage current and the daily average leakage current of each phase line of the tested transformer area are calculated according to a A, B, C, N ground resistance value, the leakage evaluation of the tested transformer area is performed, and when the ground resistance value of any phase is smaller than a threshold value, the existence of the leakage fault in the transformer area is determined.
In the complex leakage model, RA0、RB0、RC0、RN0The method comprises the following steps that insulation resistance values of an A phase, a B phase, a C phase and an N phase which need to be measured during off-line leakage evaluation are evaluated, if the insulation resistance values are infinite, the phase is evaluated to have no leakage, if the insulation resistance values are specific values which can be measured in a measuring range, the phase is evaluated to have leakage, and the following formula exists in a model;
RAN＝RAN0//(RA0+RN0//(RBN0+RB0)//(RCN0+RC0) Formula nine;
RBN＝RBN0//(RB0+RN0//(RAN0+RA0)//(RCN0+RC0) Equation ten;
RCN＝RCN0//(RC0+RN0//(RAN0+RA0)//(RBN0+RB0) Formula eleven;
RAG＝RA0//[RAN0+(RBN0+RB0)//(RCN0+RC0)//RN0]a formula twelve;
RBG＝RB0//[RBN0+(RAN0+RA0)//(RCN0+RC0)//RN0]a formula thirteen;
RCG＝RC0//[RCN0+(RAN0+RA0)//(RBN0+RB0)//RN0]a formula fourteen;
RNG＝RN0//(RAN0+RA0)//(RBN0+RB0)//(RCN0+RC0) A formula fifteen;
in the formula nine to the formula fifteen, when the phase A is alternated with the phase N, the resistance RANPhase B and phase N interphase resistance RBNResistance R between C phase and N phaseCNPhase A and phase G interphase resistance RAGPhase B and phase G interphase resistance RBGResistance R between C phase and G phaseCGResistance R between N phase and G phaseNGFor the known quantity obtained by the measurement of the low-voltage leakage locator host, R can be calculated according to a formula from nine to fifteenA0、RB0、RC0、RN0、RAN0、RBN0、RCN0The value is obtained.
The off-line electric leakage evaluation method comprises the steps that under the power failure state of a tested line, a host of a low-voltage electric leakage locator applies specific voltage to an A, B, C, N four-phase line of a tested platform area, and a current sampling circuit of the host of the low-voltage electric leakage locator injects current into the four-phase line for measurement;
hardware of a host of the low-voltage leakage locator for offline leakage evaluation comprises an MCU, a current sampling circuit, a voltage division circuit and a voltage following circuit;
the current sampling circuit comprises a voltage source, a current sampling resistor and an IC1, wherein T is a resistor to be detected;
the voltage division circuit is used for enabling the full-range voltage range output by the current sampling circuit to meet the ADC acquisition range of the MCU.
The low-voltage leakage positioning equipment comprises a low-voltage leakage positioning instrument host and a low-voltage leakage positioning instrument slave, wherein the hardware part of the low-voltage leakage positioning instrument host comprises a battery charging circuit, a battery, a DC/DC circuit, a display, a key, a buzzer, an MCU, a gear shifting circuit, an integrating circuit, an amplifying circuit, a full-wave rectifying circuit, a filter circuit, an MCU, a signal conditioning circuit, a current limiting resistor, an analog channel switch, a current sampling circuit, a voltage dividing circuit and a voltage following circuit.
The hardware part of the low-voltage leakage locator host further comprises a Rogowski coil used for an online leakage evaluation method, and the hardware used for online leakage evaluation further comprises a shift circuit, an integrating circuit, an amplifying circuit, a full-wave rectifying circuit, a low-pass filter circuit and an MCU (microprogrammed control Unit);
the online electric leakage evaluation method comprises the steps that current vector sums of A, B, C, N phases of a tested station area are measured by low-voltage electric leakage positioning equipment through a Rogowski coil in an online working state, if the current vector sum of the tested station area measured by the Rogowski coil is not zero, the electric leakage exists in the station area, and if the current vector sum of the tested station area measured by the Rogowski coil is zero, the electric leakage does not exist in the station area;
when the phase current vector sum of the tested platform area A, B, C, N is measured, the Rogowski coil outputs a differential signal of A, B, C, N phase current vector sum, and the output signal is in a linear relation with the change rate of the tested current;
the output signal of the Rogowski coil enters an integrating circuit through a shifting circuit according to proportions of different weights, the integrating circuit performs integral reduction on a differential signal of a Rogowski coil output current vector sum, and an alternating voltage signal for accurately reproducing the waveform of the measured current signal is obtained after a voltage signal output by the Rogowski coil is integrated;
the amplifying circuit amplifies the signal output by the integrating circuit; the full-wave rectification circuit is connected with the amplifying circuit and performs full-wave rectification on the signal output by the amplifying circuit; the low-pass filter circuit is connected with the full-wave rectifying circuit, and performs low-pass filtering on the signal output by the full-wave rectifying circuit to output an effective value of the current to be measured.
The low-voltage leakage positioning equipment is used for carrying out leakage positioning on leakage current with loop characteristics, when the leakage positioning is carried out, a characteristic signal is injected into a fault line by using a low-voltage leakage positioning instrument host, due to the loop characteristics of the leakage current, the injected characteristic signal only exists in a loop to the ground, namely, the injected characteristic signal exists on the front side of a fault point and cannot be on the rear side of the fault point, and then the leakage fault position is positioned by judging whether the injected characteristic signal exists in a tested line, wherein the specific method comprises the following steps: the accurate positioning of the position of the leakage fault point is realized under the matching use of the slave machine of the low-voltage leakage position indicator, the rough sectional detection is firstly carried out, and then the accurate positioning is carried out.
In the low-voltage leakage locator host, a hardware part for positioning leakage comprises an MCU, a signal conditioning circuit, a current-limiting resistor and an analog channel switch;
when the power-off-state transformer area line is subjected to leakage positioning, a low-voltage leakage positioning instrument host injects characteristic signals into a fault line, the characteristic signals comprise voltage signals for leakage evaluation and pulse signals for leakage positioning, the low-voltage leakage positioning instrument slave receives the characteristic signals and outputs induction signals from a magnetic core coil sensor, and the induction voltage of the induction signals is in direct proportion to the voltage change rate of the characteristic signals injected by the low-voltage leakage positioning instrument host.
The low-voltage leakage locator host machine adopts a pulse signal as a characteristic signal injected into a fault line; the pulse signal is generated by a half-bridge circuit in a low-voltage electric leakage locator host.
In the electric leakage positioning, a low-voltage electric leakage positioning instrument host computer generates a coded frequency signal to be injected into a fault line according to the agreement of a master-slave machine, signal injection characteristic coding signals are only carried out on one phase in the fault line each time, then a low-voltage electric leakage positioning instrument slave computer is used for carrying out characteristic signal decoding in a non-contact mode along the electric leakage fault line, the position of an electric leakage fault point is roughly segmented, and then the electric leakage fault point is accurately positioned.
The software of the low-voltage leakage locator host is based on a Linux + QT framework, and when leakage assessment operation which consumes longer time is executed, independent thread operation is adopted to avoid influencing the execution of other software modules;
when generating the encoded frequency signal for signal injection, the injection signals of the A phase, the B phase, the C phase and the N phase adopt the same encoding mode, and the signal contents of the injection signals of the A phase, the B phase, the C phase and the N phase are different;
the low-voltage leakage locator slave machine comprises a magnetic core coil sensor, a low-voltage leakage locator slave machine PCB and a battery;
after the low-voltage electric leakage locator host computer injects characteristic signal into the fault line, characteristic signal produces magnetic field around the fault line, and it is V to establish the voltage that low-voltage electric leakage locator host computer injects characteristic signal into the electric leakage fault line, and the frequency is F, and fault line ground resistance R, the fault line electric current I of flowing through, then can obtain the magnetic induction strength B who locates apart from fault line d according to biot-savart law and be:
Figure BDA0003405266010000081
wherein mu0Is a vacuum permeability, mu0＝4π×10-7Tesla meters per ampere;
the low-voltage leakage locator slave machine receives the magnetic field of the characteristic signal through the magnetic core coil sensor and interprets the characteristic signal from the magnetic field, and the magnetic core coil sensor outputs the magnitude of the induced electromotive force xi and the change rate of the magnetic flux passing through the loop according to the Faraday's law of electromagnetic induction
Figure BDA0003405266010000082
In a direct proportion to the total weight of the composition,
Figure BDA0003405266010000083
and the low-voltage leakage locator slave machine receives and demodulates the output signal of the magnetic core coil sensor, and further identifies whether the demodulated signal is a characteristic signal injected by the low-voltage leakage locator host machine.
Example 1:
when the fault line is detected from the slave machine to locate the leakage fault point, the whole fault line is roughly segmented, and a plurality of points to be detected are selected. Starting the slave machine, opening the assistant APP of the off/on-line double-channel micro-current leakage diagnosis device, connecting Bluetooth, clicking to start monitoring, enabling a detection area of the slave machine to be close to a measured line and to be vertical to the measured line, and after the assistant APP sounds a tic, going to the next point to be tested until the tic is no longer heard, determining a rough fault position (the line fault point is between the tic and the silent) according to the principle, and gradually reducing the range until the line fault point is found.
And after the fault points of the line are processed, performing off-line electric leakage evaluation on the fault line again, if the result shows that the fault line is a fault-free line, indicating that the fault is removed, and if the line is still detected to be a fault line and indicating that the line has a plurality of fault points, performing secondary machine detection again to continue removing the fault.

Claims (9)

1.低压漏电的离线漏电评估方法，用于对台区的漏电故障线路进行精准选线以及对漏电故障位置精确定位，其特征在于：所述离线漏电评估方法是在被测线路停电状态下，以低压漏电定位仪的主机通过向被测台区的A、B、C、N四相线路施加特定电压，通过电流采样电路向四相线路注入电流测量，进而计算得到被测线路的电阻值，再根据复杂漏电模型测量得到各相的对地电阻值，最后根据A、B、C、N对地电阻值计算该被测台区的各相线路漏电流及日均漏电量，对被测台区进行漏电评估，当任一相的对地电阻值小于阈值时，判定该台区存在漏电故障。1. The off-line leakage assessment method of low-voltage leakage is used for accurate line selection of the leakage fault line in the platform area and accurate positioning of the leakage fault position, and it is characterized in that: the offline leakage assessment method is that under the state of power failure of the line under test, The host of the low-voltage leakage locator applies a specific voltage to the A, B, C, and N four-phase lines in the tested station area, injects current measurement into the four-phase line through the current sampling circuit, and then calculates the resistance value of the tested line. Then, the earth resistance value of each phase is measured according to the complex leakage model. Finally, the leakage current and daily average leakage current of each phase line in the tested station area are calculated according to the resistance values of A, B, C, and N. Leakage assessment is carried out in the area, and when the resistance value to ground of any phase is less than the threshold value, it is determined that there is a leakage fault in the station area. 2.根据权利要求1所述的低压漏电的离线漏电评估方法，其特征在于：所述复杂漏电模型中，RA0、RB0、RC0、RN0为离线漏电评估时需测量的A相、B相、C相、N相的绝缘电阻值，若绝缘电阻值无穷大，则评估该相未发生漏电，若绝缘电阻值为量程内可测得的具体数值，则评估该相发生漏电，模型中存在以下公式；2. The off-line leakage assessment method of low-voltage leakage according to claim 1, characterized in that: in the complex leakage model, R A0 , R B0 , R C0 , R N0 are the A-phases that need to be measured during off-line leakage assessment, R B0 , R N0 Insulation resistance values of B-phase, C-phase and N-phase, if the insulation resistance value is infinite, it is estimated that no leakage occurs in this phase; if the insulation resistance value is a specific value that can be measured within the range, it is estimated that leakage occurs in the The following formula exists; RAN＝RAN0//(RA0+RN0//(RBN0+RB0)//(RCN0+RC0)) 公式九；R AN =R AN0 //(R A0 +R N0 //(R BN0 +R B0 )//(R CN0 +R C0 )) Formula 9; RBN＝RBN0//(RB0+RN0//(RAN0+RA0)//(RCN0+RC0)) 公式十；R BN =R BN0 //(R B0 +R N0 //(R AN0 +R A0 )//(R CN0 +R C0 )) Formula 10; RCN＝RCN0//(RC0+RN0//(RAN0+RA0)//(RBN0+RB0)) 公式十一；R CN =R CN0 //(R C0 +R N0 //(R AN0 +R A0 )//(R BN0 +R B0 )) Formula 11; RAG＝RA0//[RAN0+(RBN0+RB0)//(RCN0+RC0)//RN0] 公式十二；R AG = R A0 //[R AN0 +(R BN0 +R B0 )//(R CN0 +R C0 )//R N0 ] Formula 12; RBG＝RB0//[RBN0+(RAN0+RA0)//(RCN0+RC0)//RN0] 公式十三；R BG =R B0 //[R BN0 +(R AN0 +R A0 )//(R CN0 +R C0 )//R N0 ] Formula 13; RCG＝RC0//[RCN0+(RAN0+RA0)//(RBN0+RB0)//RN0] 公式十四；R CG =R C0 //[R CN0 +(R AN0 +R A0 )//(R BN0 +R B0 )//R N0 ] Formula 14; RNG＝RN0//(RAN0+RA0)//(RBN0+RB0)//(RCN0+RC0) 公式十五；R NG =R N0 //(R AN0 +R A0 )//(R BN0 +R B0 )//(R CN0 +R C0 ) Formula 15; 公式九至公式十五中，当A相与N相间电阻RAN、B相与N相间电阻RBN、C相与N相间电阻RCN、A相与G相间电阻RAG、B相与G相间电阻RBG、C相与G相间电阻RCG、N相与G相间电阻RNG为通过低压漏电定位仪主机测量得到的已知量，则根据公式九至公式十五可计算得到RA0、RB0、RC0、RN0、RAN0、RBN0、RCN0值。In formula 9 to formula 15, when the resistance between A-phase and N-phase R AN , between B-phase and N-phase R BN , between C-phase and N-phase R CN , between A-phase and G-phase R AG , between B-phase and G-phase The resistance R BG , the resistance between C-phase and G-phase R CG , and the resistance between N-phase and G-phase R NG are known quantities measured by the low-voltage leakage locator host, then R A0 , R can be calculated according to formula 9 to formula 15 B0 , R C0 , R N0 , R AN0 , R BN0 , R CN0 values. 3.根据权利要求2所述的低压漏电的离线漏电评估方法，其特征在于：所述离线漏电评估方法是在被测线路停电状态下，以低压漏电定位仪的主机通过向被测台区的A、B、C、N四相线路施加特定电压，以低压漏电定位仪的主机的电流采样电路向四相电路注入电流测量；3. The off-line leakage assessment method of low-voltage leakage according to claim 2 is characterized in that: the off-line leakage assessment method is to pass the host of the low-voltage leakage locator to the measured station area under the power failure state of the line under test. A, B, C, N four-phase lines apply a specific voltage, and the current sampling circuit of the host of the low-voltage leakage locator injects current measurement into the four-phase circuit; 所述低压漏电定位仪的主机用于离线漏电评估的硬件包括MCU、电流采样电路、分压电路以及电压跟随电路；The hardware used by the host of the low-voltage leakage locator for off-line leakage assessment includes an MCU, a current sampling circuit, a voltage divider circuit and a voltage follower circuit; 所述电流采样电路包括电压源、电流采样电阻以及IC1，T为被测电阻；The current sampling circuit includes a voltage source, a current sampling resistor and IC1, where T is the measured resistor; 所述分压电路用于使电流采样电路输出的全量程电压范围内满足MCU的ADC采集范围。The voltage divider circuit is used to make the full-scale voltage range output by the current sampling circuit meet the ADC acquisition range of the MCU. 4.低压漏电定位设备，其特征在于：所述低压漏电定位设备包括低压漏电定位仪主机和低压漏电定位仪从机，低压漏电定位仪主机的硬件部分包括电池充电电路、电池、DC\DC电路、显示、按键、蜂鸣器、MCU、换挡电路、积分电路、放大电路、全波整流电路、滤波电路、MCU、信号调理电路、限流电阻、模拟通道开关、电流采样电路、分压电路、电压跟随电路。4. The low-voltage leakage locating device is characterized in that: the low-voltage leakage locating device includes a low-voltage leakage locator host and a low-voltage leakage locator slave, and the hardware part of the low-voltage leakage locator host includes a battery charging circuit, a battery, and a DC/DC circuit. , display, buttons, buzzer, MCU, shift circuit, integration circuit, amplifier circuit, full-wave rectifier circuit, filter circuit, MCU, signal conditioning circuit, current limiting resistor, analog channel switch, current sampling circuit, voltage divider circuit , Voltage follower circuit. 5.根据权利要求4所述的低压漏电定位设备，其特征在于：低压漏电定位设备用于对具备回路特性的漏电电流进行漏电定位，在进行漏电定位时，以低压漏电定位仪主机向故障线路注入特征信号，由于漏电电流的回路特性，注入的特征信号只存在于对地的回路中，即在故障点前侧存在注入的特征信号不会故障点后侧，然后通过判断被测线路中是否存在注入的特征信号进行漏电故障位置定位，具体方法为：在低压漏电定位仪从机的配合使用下实现漏电故障点位置精确定位，先进行粗略分段检测，再精确定点。5. The low-voltage leakage locating device according to claim 4, wherein the low-voltage leakage locating device is used to locate the leakage current with loop characteristics, and when performing the leakage locating, use the low-voltage leakage locator host to the fault line. Inject the characteristic signal, due to the circuit characteristics of the leakage current, the injected characteristic signal only exists in the circuit to the ground, that is, the injected characteristic signal exists in the front side of the fault point but not the back side of the fault point, and then by judging whether the circuit under test is not There is an injected characteristic signal to locate the leakage fault location. The specific method is as follows: with the cooperation of the low-voltage leakage locator slave machine, the precise location of the leakage fault point can be achieved, first perform rough segmentation detection, and then accurately determine the point. 6.根据权利要求4所述的低压漏电定位设备，其特征在于：所述低压漏电定位仪主机中，用于漏电定位的硬件部分包括MCU、信号调理电路、限流电阻、模拟通道开关；6. The low-voltage leakage locating device according to claim 4, characterized in that: in the low-voltage leakage locator host, the hardware part used for leakage locating comprises MCU, signal conditioning circuit, current limiting resistor, and analog channel switch; 在对停电状态的台区线路进行漏电定位时，由低压漏电定位仪主机向故障线路注入特征信号，该特征信号包括用于漏电评估的电压信号和用于漏电定位的脉冲信号，由低压漏电定位仪从机的磁芯线圈传感器接收特征信号并输出感应信号，所述感应信号的感应电压与低压漏电定位仪主机注入特征信号电压变化率成正比。When locating the electric leakage of the station area line in the state of power failure, the low-voltage electric leakage locator host injects the characteristic signal into the faulty line. The characteristic signal includes the voltage signal for electric leakage evaluation and the pulse signal for electric leakage localization. The magnetic core coil sensor of the instrument slave receives the characteristic signal and outputs the induction signal. The induced voltage of the induction signal is proportional to the voltage change rate of the characteristic signal injected by the low-voltage leakage locator host. 7.根据权利要求4所述的低压漏电定位设备，其特征在于：所述低压漏电定位仪主机采用脉冲信号作为注入故障线路的特征信号；所述脉冲信号由低压漏电定位仪主机中的半桥电路产生。7. The low-voltage leakage locating device according to claim 4, characterized in that: the low-voltage leakage locator host adopts a pulse signal as the characteristic signal injected into the faulty line; circuit is generated. 8.根据权利要求7所述的低压漏电定位设备，其特征在于：所述漏电定位中，低压漏电定位仪主机按主从机协议约定，生成编码后的频率信号注入故障线路，每次只对故障线路中的一相进行信号注入特征编码信号，然后在漏电故障线路沿途使用低压漏电定位仪从机采用非接触方式进行特征信号解码，先对漏电故障点所在位置进行粗略分段，再对漏电故障点进行精确定位。8. The low-voltage leakage locating device according to claim 7, wherein in the leakage locating, the host of the low-voltage leakage locator generates a coded frequency signal and injects it into the faulty line according to the master-slave agreement, and each time only the One phase in the fault line is injected with the characteristic coding signal, and then the low-voltage leakage locator is used along the fault line to decode the characteristic signal in a non-contact way. The location of the leakage fault point is roughly segmented, and then the leakage The fault point is precisely located. 9.根据权利要求7所述的低压漏电定位设备，其特征在于：低压漏电定位仪主机的软件基于Linux+QT架构，当执行耗时较长的漏电评估作业时，采用单独线程操作以避免影响其它软件模块的执行；9. The low-voltage leakage locating device according to claim 7, characterized in that: the software of the low-voltage leakage locator host is based on Linux+QT architecture, and when performing a long-consuming leakage assessment operation, a separate thread operation is adopted to avoid affecting the execution of other software modules; 在生成用于信号注入的编码后频率信号时，A相、B相、C相、N相的注入信号采用相同编码方式，A相、B相、C相、N相的注入信号的信号内容不同；When generating the encoded frequency signal for signal injection, the injection signals of A-phase, B-phase, C-phase, and N-phase use the same encoding method, and the signal contents of the A-phase, B-phase, C-phase, and N-phase injection signals are different. ; 所述低压漏电定位仪从机包括磁芯线圈传感器、低压漏电定位仪从机PCB以及电池；The low-voltage leakage locator slave includes a magnetic core coil sensor, a low-voltage leakage locator slave PCB and a battery; 低压漏电定位仪主机向故障线路注入特征信号后，特征信号在故障线路周围产生磁场，设低压漏电定位仪主机向漏电故障线路注入特征信号的电压为V、频率为F，故障线路接地电阻R，流经故障线路电流I，则根据毕奥—萨伐尔定律可以得到距离故障线路d处的磁感应强度B为：After the low-voltage leakage locator host injects the characteristic signal into the fault line, the characteristic signal generates a magnetic field around the fault line. Let the voltage of the low-voltage leakage locator host inject the characteristic signal to the leakage fault line be V, the frequency is F, and the grounding resistance of the fault line is R, The current I flowing through the faulty line, according to the Biot-Savart law, the magnetic induction intensity B at the distance d from the faulty line can be obtained as:
Figure FDA0003405265000000031
Figure FDA0003405265000000031
 其中μ0为真空磁导率，μ0＝4π×10-7特斯拉·米/安培；Wherein μ 0 is the vacuum permeability, μ 0 =4π×10 -7Tesla ·m/Ampere; 低压漏电定位仪从机通过磁芯线圈传感器接收特征信号的磁场并从中解译特证信号，根据法拉第电磁感应定律，磁芯线圈传感器输出感应电动势ξ的大小与穿过回路磁通量的变化率
Figure FDA0003405265000000033
成正比，The low-voltage leakage locator slave receives the magnetic field of the characteristic signal through the magnetic core coil sensor and interprets the special signal from it. According to Faraday's law of electromagnetic induction, the magnetic core coil sensor outputs the magnitude of the induced electromotive force ξ and the rate of change of the magnetic flux passing through the loop
Figure FDA0003405265000000033
proportional,
Figure FDA0003405265000000032
Figure FDA0003405265000000032
 低压漏电定位仪从机接收磁芯线圈传感器的输出信号并对其解调，进而识别解调所得的信号是否为低压漏电定位仪主机注入的特征信号。The low-voltage leakage locator slave receives the output signal of the magnetic core coil sensor and demodulates it, and then identifies whether the demodulated signal is the characteristic signal injected by the low-voltage leakage locator host.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115951262A (en) * 2023-03-13 2023-04-11 青岛鼎信通讯股份有限公司 Natural fault leakage current detection method applied to power distribution area

Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5990685A (en) * 1996-09-11 1999-11-23 Cegelec Controls Limited Apparatus for and method of monitoring an earth-leakage state of a power distribution system
JP2002125313A (en) * 2000-10-16 2002-04-26 Kansai Denki Hoan Kyokai Leakage detector, and leakage alarm and leakage breaker therewith
CN202502189U (en) * 2012-02-27 2012-10-24 江苏省电力公司扬州供电公司 Low-voltage line leakage fault finding device
JP2014173843A (en) * 2013-03-05 2014-09-22 Omron Corp Electric leak detection device and electric leak detection method
CN106226652A (en) * 2016-08-10 2016-12-14 国网浙江台州市黄岩区供电公司 A kind of low-voltage overhead line electric leakage long range positioning detection device
US20180164361A1 (en) * 2016-12-14 2018-06-14 General Electric Company System and method for leakage current and fault location detection in electric vehicle dc power circuits
CN108303615A (en) * 2017-12-29 2018-07-20 广东电网有限责任公司江门供电局 A kind of localization method of low voltage electric network leakage point of electricity
CN108732425A (en) * 2018-07-07 2018-11-02 国网福建省电力有限公司 A kind of low-voltage distribution network supply line resistance value method of real-time
CN109100615A (en) * 2018-10-19 2018-12-28 河海大学 A kind of cable fault localization method based on frequency characteristic
CN109375120A (en) * 2018-10-29 2019-02-22 积成电子股份有限公司 The monitoring method of alternating current is scurried into DC power system
CN109507539A (en) * 2018-12-20 2019-03-22 孟小晶 Low pressure fault to ground point searches instrument and lookup method
CN109932609A (en) * 2019-03-05 2019-06-25 国网浙江诸暨市供电有限公司 Fault leakage current measurement tool in rural low-voltage power supply station area
CN110231552A (en) * 2019-07-08 2019-09-13 冯琛 Coal mine cable insulating monitoring selection method, injection circuit and related device
CN212031692U (en) * 2020-04-18 2020-11-27 国网福建省电力有限公司电力科学研究院 Wireless leakage current detector for all-type lines of low-voltage power distribution network
CN112731057A (en) * 2020-12-21 2021-04-30 青岛鼎信通讯股份有限公司 Offline low-voltage cable ground fault positioning device based on pulse coding

Patent Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5990685A (en) * 1996-09-11 1999-11-23 Cegelec Controls Limited Apparatus for and method of monitoring an earth-leakage state of a power distribution system
JP2002125313A (en) * 2000-10-16 2002-04-26 Kansai Denki Hoan Kyokai Leakage detector, and leakage alarm and leakage breaker therewith
CN202502189U (en) * 2012-02-27 2012-10-24 江苏省电力公司扬州供电公司 Low-voltage line leakage fault finding device
JP2014173843A (en) * 2013-03-05 2014-09-22 Omron Corp Electric leak detection device and electric leak detection method
CN106226652A (en) * 2016-08-10 2016-12-14 国网浙江台州市黄岩区供电公司 A kind of low-voltage overhead line electric leakage long range positioning detection device
US20180164361A1 (en) * 2016-12-14 2018-06-14 General Electric Company System and method for leakage current and fault location detection in electric vehicle dc power circuits
CN108303615A (en) * 2017-12-29 2018-07-20 广东电网有限责任公司江门供电局 A kind of localization method of low voltage electric network leakage point of electricity
CN108732425A (en) * 2018-07-07 2018-11-02 国网福建省电力有限公司 A kind of low-voltage distribution network supply line resistance value method of real-time
CN109100615A (en) * 2018-10-19 2018-12-28 河海大学 A kind of cable fault localization method based on frequency characteristic
CN109375120A (en) * 2018-10-29 2019-02-22 积成电子股份有限公司 The monitoring method of alternating current is scurried into DC power system
CN109507539A (en) * 2018-12-20 2019-03-22 孟小晶 Low pressure fault to ground point searches instrument and lookup method
CN109932609A (en) * 2019-03-05 2019-06-25 国网浙江诸暨市供电有限公司 Fault leakage current measurement tool in rural low-voltage power supply station area
CN110231552A (en) * 2019-07-08 2019-09-13 冯琛 Coal mine cable insulating monitoring selection method, injection circuit and related device
CN212031692U (en) * 2020-04-18 2020-11-27 国网福建省电力有限公司电力科学研究院 Wireless leakage current detector for all-type lines of low-voltage power distribution network
CN112731057A (en) * 2020-12-21 2021-04-30 青岛鼎信通讯股份有限公司 Offline low-voltage cable ground fault positioning device based on pulse coding

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115951262A (en) * 2023-03-13 2023-04-11 青岛鼎信通讯股份有限公司 Natural fault leakage current detection method applied to power distribution area

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