CN111551821A - A method, device and equipment for identifying ground fault in distribution network - Google Patents

A method, device and equipment for identifying ground fault in distribution network Download PDF

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CN111551821A
CN111551821A CN202010407739.XA CN202010407739A CN111551821A CN 111551821 A CN111551821 A CN 111551821A CN 202010407739 A CN202010407739 A CN 202010407739A CN 111551821 A CN111551821 A CN 111551821A
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distribution network
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conductance
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CN111551821B (en
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丁晓兵
史泽兵
曾祥君
余江
喻锟
张弛
高宏慧
郑茂然
陈宏山
李正红
陈朝晖
万信书
黄慧
李越宇
李嘉康
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China Southern Power Grid Co Ltd
Changsha University of Science and Technology
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Changsha University of Science and Technology
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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
    • 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
    • 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
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    • 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
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Abstract

本发明公开了一种配电网接地故障辨识方法、装置及设备，其方法首先建立了由配电网中性点处注入同幅变频小电流信号，通过电压互感器测量反馈的电压信号，从而计算配电网的对地电导和对地电容，然后再利用对地电导和对地电容计算每种频率下的增量阻尼率，进而计算由故障过渡电阻所产生的增量阻尼率并进行叠加以根据预设的判据进行故障，实现故障特征量的有效放大，同时大幅降低干扰的影响，从而有效辨识高阻接地故障。本发明解决了谐振接地配电网高阻接地故障辨识困难的问题，可使接地故障特征得以突显，并具备较高的抗噪声能力，大幅提高了高阻接地故障的辨识能力。

Figure 202010407739

The invention discloses a method, device and equipment for identifying ground faults in a distribution network. The method first establishes that a small current signal of the same amplitude variable frequency is injected from the neutral point of the distribution network, and the feedback voltage signal is measured through a voltage transformer, thereby Calculate the ground conductance and ground capacitance of the distribution network, and then use the ground conductance and ground capacitance to calculate the incremental damping rate at each frequency, and then calculate and superimpose the incremental damping rate generated by the fault transition resistance The fault is carried out according to the preset criteria to realize the effective amplification of the fault characteristic quantity, and at the same time, the influence of interference is greatly reduced, so as to effectively identify the high-resistance grounding fault. The invention solves the problem of difficult identification of high-resistance grounding faults in the resonant grounding distribution network, can highlight the characteristics of grounding faults, has high anti-noise capability, and greatly improves the identification capability of high-resistance grounding faults.

Figure 202010407739

Description

一种配电网接地故障辨识方法、装置及设备A method, device and equipment for identifying ground fault in distribution network

技术领域technical field

本发明属于配电网接地故障检测领域，具体涉及一种基于多频增量阻尼率叠加的配电网接地故障辨识方法、装置及设备。The invention belongs to the field of distribution network grounding fault detection, and in particular relates to a distribution network grounding fault identification method, device and equipment based on the superposition of multi-frequency incremental damping rates.

背景技术Background technique

配电网深入用户终端，运行条件复杂多变，极易发生故障，其中80％约为单相接地故障，且相间故障也多由未及时检测并处理的单相接地故障发展形成。当配电网发生高阻接地故障(树障、避雷器不完全击穿等)时，过渡电阻往往高达数千欧姆，故障特征量十分微弱，中性点位移电压远小于国家标准的15％相电压，现有接地故障检测方法对高阻故障检测困难，故障点过渡介质持续放电直至过渡电阻降低到可检测范围才会被检测装置识别，期间可能导致故障扩大，严重威胁人身设备安全。The distribution network goes deep into the user terminal, the operating conditions are complex and changeable, and it is very prone to faults, 80% of which are about single-phase grounding faults, and the phase-to-phase faults are mostly developed from single-phase grounding faults that are not detected and handled in time. When a high-resistance grounding fault occurs in the distribution network (tree barrier, incomplete breakdown of lightning arrester, etc.), the transition resistance is often as high as several thousand ohms, the fault characteristic is very weak, and the neutral point displacement voltage is much smaller than the 15% phase voltage of the national standard. However, the existing ground fault detection methods are difficult to detect high resistance faults. The transition medium at the fault point continues to discharge until the transition resistance is reduced to a detectable range before being identified by the detection device. During this period, the fault may expand and seriously threaten the safety of personal equipment.

为了实现配电网单相接地故障高灵敏度辨识，需有效测量系统对地导纳参数。现有的对地参数测量方法包括直接法、间接法、注入信号法，间接法又包括外加电容、外加电压、调谐法、变频法等。其中直接法、间接法均需要改变系统一次参数或系统拓扑结构，操作复杂且有人身触电危险并不适用于实时测量系统参数。所以，实现可实时测量配电网参数，不受系统运行方式及高频干扰的影响，并且可从二次侧完成测量，不影响系统一次侧正常运行，提高故障判断的准确率具有十分重要的意义。In order to realize high-sensitivity identification of single-phase-to-ground fault in distribution network, it is necessary to effectively measure the system-to-ground admittance parameters. Existing ground parameter measurement methods include direct method, indirect method, injection signal method, and indirect method includes external capacitance, applied voltage, tuning method, frequency conversion method, etc. Among them, the direct method and the indirect method both need to change the primary parameters of the system or the system topology, and are not suitable for real-time measurement of system parameters due to complicated operations and the danger of personal electric shock. Therefore, it is very important to realize real-time measurement of distribution network parameters without being affected by system operation mode and high-frequency interference, and to complete the measurement from the secondary side without affecting the normal operation of the primary side of the system, and to improve the accuracy of fault judgment. significance.

发明内容SUMMARY OF THE INVENTION

本发明所要解决的技术问题在于，提供一种基于多频增量阻尼率叠加的配电网接地故障辨识方法、装置及设备，可以实现高阻接地故障辨识，提高接地故障的辨识灵敏度。The technical problem to be solved by the present invention is to provide a ground fault identification method, device and equipment for distribution network based on the superposition of multi-frequency incremental damping rates, which can realize high resistance ground fault identification and improve the ground fault identification sensitivity.

为实现上述技术目的，本发明采用如下技术方案：For realizing the above-mentioned technical purpose, the present invention adopts following technical scheme:

一种基于多频增量阻尼率叠加的配电网接地故障辨识方法，包括以下步骤：A method for identifying ground faults in a distribution network based on the superposition of multi-frequency incremental damping rates, comprising the following steps:

向配电网注入同幅变频小电流信号

Figure BDA0002492022420000011
通过电压互感器测量反馈的电压信号
Figure BDA0002492022420000012
其中的下标i表示小电流信号的不同频率编号；Inject the same amplitude variable frequency small current signal into the distribution network
Figure BDA0002492022420000011
Measure the feedback voltage signal through the voltage transformer
Figure BDA0002492022420000012
The subscript i represents the different frequency numbers of the small current signal;

根据配电网的等效对地导纳计算公式以及小电流信号

Figure BDA0002492022420000013
和反馈的电压信号
Figure BDA0002492022420000014
计算配电网产生LC谐振时的对地电导G和对地电容C；According to the calculation formula of the equivalent ground admittance of the distribution network and the small current signal
Figure BDA0002492022420000013
and feedback voltage signal
Figure BDA0002492022420000014
Calculate the ground-to-ground conductance G and ground-to-ground capacitance C when the distribution network produces LC resonance;

其中，配电网的等效对地导纳计算公式为：Among them, the calculation formula of the equivalent ground admittance of the distribution network is:

Figure BDA0002492022420000015
Figure BDA0002492022420000015

配电网产生LC谐振的条件为：The conditions for the distribution network to generate LC resonance are:

Figure BDA0002492022420000021
Figure BDA0002492022420000021

由公式(1)(2)可得配电网产生LC谐振时的对地电导G和对地电容C为：From formulas (1) and (2), it can be obtained that the ground-to-ground conductance G and the ground-to-ground capacitance C when the distribution network generates LC resonance are:

Figure BDA0002492022420000022
Figure BDA0002492022420000022

Figure BDA0002492022420000023
Figure BDA0002492022420000023

其中，

Figure BDA0002492022420000024
为二次侧注入的小电流信号
Figure BDA0002492022420000025
归算到一次侧的电流，且有
Figure BDA0002492022420000026
k1为电流归算系数；
Figure BDA0002492022420000027
为二次侧反馈的电压信号
Figure BDA0002492022420000028
归算至一次侧的反馈电压，且有
Figure BDA0002492022420000029
k2为电压归算系数；fi为小电流信号
Figure BDA00024920224200000210
的频率，L为配电网中消弧线圈的等效电感；Iim、fim、Uim，分别为二次侧注入的小电流信号
Figure BDA00024920224200000211
的幅值、二次侧注入的小电流信号
Figure BDA00024920224200000212
的频率fi、二次侧反馈的电压信号
Figure BDA00024920224200000213
的幅值分别在配电网产生LC谐振时的表示符号；in,
Figure BDA0002492022420000024
Small current signal injected for the secondary side
Figure BDA0002492022420000025
is reduced to the current on the primary side, and has
Figure BDA0002492022420000026
k 1 is the current reduction coefficient;
Figure BDA0002492022420000027
is the voltage signal fed back by the secondary side
Figure BDA0002492022420000028
is reduced to the feedback voltage on the primary side, and has
Figure BDA0002492022420000029
k 2 is the voltage reduction coefficient; f i is the small current signal
Figure BDA00024920224200000210
The frequency of , L is the equivalent inductance of the arc suppression coil in the distribution network; I im , f im , U im , respectively, are the small current signals injected by the secondary side
Figure BDA00024920224200000211
The amplitude of , the small current signal injected by the secondary side
Figure BDA00024920224200000212
The frequency f i of , the voltage signal of the secondary side feedback
Figure BDA00024920224200000213
The amplitudes of , respectively, represent the symbols when the distribution network produces LC resonance;

将配电网在注入每种频率的小电流信号时的对地电导和对地电容，均取值为配电网产生LC谐振时的对地电导和对地电容；然后根据以下公式(5)以及对地电导G和对地电容C，计算每种频率下的增量阻尼率ddi：The conductance to ground and capacitance to ground when the distribution network injects small current signals of each frequency are taken as the conductance to ground and capacitance to ground when the distribution network generates LC resonance; then according to the following formula (5) As well as the conductance to ground G and the capacitance to ground C, calculate the incremental damping rate ddi at each frequency:

Figure BDA00024920224200000214
Figure BDA00024920224200000214

式中，g0、rL为配电网在故障前的对地电导和消弧线圈的等值损耗电阻，ωi为小电流信号

Figure BDA00024920224200000215
的角频率；In the formula, g 0 and r L are the ground conductance of the distribution network and the equivalent loss resistance of the arc suppression coil before the fault, and ω i is the small current signal
Figure BDA00024920224200000215
angular frequency;

根据以下公式(6)预设的判据，变频的不同频率编号i从1叠加至n的多频叠加过程中，判断是否满足判据中的不等式，若满足则判断配电网发生接地故障，若均不满足且出现中性点电压位移则认为配电网为三相不平衡状态，预设的判据为：According to the preset criteria of the following formula (6), in the multi-frequency superposition process of the different frequency numbers i of the frequency conversion from 1 to n, it is judged whether the inequality in the criterion is satisfied. If both are not satisfied and the neutral point voltage displacement occurs, the distribution network is considered to be in a three-phase unbalanced state. The preset criteria are:

Figure BDA00024920224200000216
Figure BDA00024920224200000216

其中，dset为预设的阻尼率启动值，d0为配电网的固有阻尼率、dL为消弧线圈的附加阻尼率，gset为整定过渡电导，n为多频增量阻尼率的叠加次数，ωim为配电网的LC谐振角频率，INT()为取整函数。Among them, d set is the preset damping rate starting value, d 0 is the inherent damping rate of the distribution network, d L is the additional damping rate of the arc suppression coil, g set is the set transition conductance, and n is the multi-frequency incremental damping rate The superposition times of , ω im is the LC resonance angular frequency of the distribution network, and INT() is the rounding function.

在更优的技术方案中，注入同幅变频小电流信号

Figure BDA00024920224200000217
的频率范围为：f0±5Hz，f0为配电网的工频。In a better technical solution, inject the same amplitude variable frequency small current signal
Figure BDA00024920224200000217
The frequency range is: f 0 ±5Hz, f 0 is the power frequency of the distribution network.

在更优的技术方案中，在计算得到每种频率下的增量阻尼率后，将其归算到工频角频率，归算后的增量阻尼率d′di为：

Figure BDA0002492022420000031
In a better technical solution, after calculating the incremental damping rate at each frequency, it is reduced to the power frequency angular frequency, and the reduced incremental damping rate d' di is:
Figure BDA0002492022420000031

本发明还提供一种基于多频增量阻尼率叠加的配电网接地故障辨识装置，包括：The present invention also provides a distribution network grounding fault identification device based on the superposition of multi-frequency incremental damping rates, including:

信号注入与反馈模块，用于：向配电网注入同幅变频小电流信号

Figure BDA0002492022420000032
通过电压互感器测量反馈的电压信号
Figure BDA0002492022420000033
其中的下标i表示小电流信号的不同频率编号；Signal injection and feedback module, used to inject the same amplitude variable frequency small current signal into the distribution network
Figure BDA0002492022420000032
Measure the feedback voltage signal through the voltage transformer
Figure BDA0002492022420000033
The subscript i represents the different frequency numbers of the small current signal;

对地导纳参数计算模块，用于：根据配电网的等效对地导纳计算公式以及小电流信号

Figure BDA0002492022420000034
和反馈的电压信号
Figure BDA0002492022420000035
计算配电网产生LC谐振时的对地电导G和对地电容C；The ground admittance parameter calculation module is used for: according to the calculation formula of the equivalent ground admittance of the distribution network and the small current signal
Figure BDA0002492022420000034
and feedback voltage signal
Figure BDA0002492022420000035
Calculate the ground-to-ground conductance G and ground-to-ground capacitance C when the distribution network produces LC resonance;

其中，配电网的等效对地导纳计算公式为：Among them, the calculation formula of the equivalent ground admittance of the distribution network is:

Figure BDA0002492022420000036
Figure BDA0002492022420000036

配电网产生LC谐振的条件为：The conditions for the distribution network to generate LC resonance are:

Figure BDA0002492022420000037
Figure BDA0002492022420000037

由公式(1)(2)可得配电网产生LC谐振时的对地电导G和对地电容C为：From formulas (1) and (2), it can be obtained that the ground-to-ground conductance G and the ground-to-ground capacitance C when the distribution network generates LC resonance are:

Figure BDA0002492022420000038
Figure BDA0002492022420000038

Figure BDA0002492022420000039
Figure BDA0002492022420000039

其中，

Figure BDA00024920224200000310
为二次侧注入的小电流信号
Figure BDA00024920224200000311
归算到一次侧的电流，且有
Figure BDA00024920224200000312
k1为电流归算系数；
Figure BDA00024920224200000313
为二次侧反馈的电压信号
Figure BDA00024920224200000314
归算至一次侧的反馈电压，且有
Figure BDA00024920224200000315
k2为电压归算系数；fi为小电流信号
Figure BDA00024920224200000316
的频率，L为配电网中消弧线圈的等效电感；Iim、fim、Uim，分别为二次侧注入的小电流信号
Figure BDA00024920224200000317
的幅值、二次侧注入的小电流信号
Figure BDA00024920224200000318
的频率fi、二次侧反馈的电压信号
Figure BDA00024920224200000319
的幅值分别在配电网产生LC谐振时的表示符号；in,
Figure BDA00024920224200000310
Small current signal injected for the secondary side
Figure BDA00024920224200000311
is reduced to the current on the primary side, and has
Figure BDA00024920224200000312
k 1 is the current reduction coefficient;
Figure BDA00024920224200000313
is the voltage signal fed back by the secondary side
Figure BDA00024920224200000314
is reduced to the feedback voltage on the primary side, and has
Figure BDA00024920224200000315
k 2 is the voltage reduction coefficient; f i is the small current signal
Figure BDA00024920224200000316
The frequency of , L is the equivalent inductance of the arc suppression coil in the distribution network; I im , f im , U im , respectively, are the small current signals injected by the secondary side
Figure BDA00024920224200000317
The amplitude of , the small current signal injected by the secondary side
Figure BDA00024920224200000318
The frequency f i of , the voltage signal of the secondary side feedback
Figure BDA00024920224200000319
The amplitudes of , respectively, represent the symbols when the distribution network produces LC resonance;

增量阻尼率计算模块，用于：将配电网在注入每种频率的小电流信号时的对地电导和对地电容，均取值为配电网产生LC谐振时的对地电导和对地电容；然后根据以下公式(5)以及对地电导G和对地电容C，计算每种频率下的增量阻尼率ddi：The incremental damping rate calculation module is used to: take the conductance to ground and the capacitance to ground when the distribution network injects small current signals of each frequency as the conductance to ground and the capacitance to ground when the distribution network generates LC resonance. capacitance to ground; then calculate the incremental damping rate d di at each frequency according to the following formula (5) and the conductance to ground G and capacitance C to ground:

Figure BDA00024920224200000320
Figure BDA00024920224200000320

式中，g0、rL为配电网在故障前的对地电导和消弧线圈的等值损耗电阻，ωi为小电流信号

Figure BDA0002492022420000041
的角频率；In the formula, g 0 and r L are the ground conductance of the distribution network and the equivalent loss resistance of the arc suppression coil before the fault, and ω i is the small current signal
Figure BDA0002492022420000041
angular frequency;

故障辨识模块，用于：根据以下公式(6)预设的判据，变频的不同频率编号i从1叠加至n的多频叠加过程中，判断是否满足判据中的不等式，若满足则判断配电网发生接地故障，若均不满足且出现中性点电压位移则认为配电网为三相不平衡状态，预设的判据为：The fault identification module is used for: according to the preset criterion of the following formula (6), in the multi-frequency superposition process of the different frequency numbers i of the frequency conversion from 1 to n, judge whether the inequality in the criterion is satisfied, and if so, judge whether When a ground fault occurs in the distribution network, if it is not satisfied and there is a neutral point voltage displacement, the distribution network is considered to be in a three-phase unbalanced state. The preset criteria are:

Figure BDA0002492022420000042
Figure BDA0002492022420000042

其中，dset为预设的阻尼率启动值，d0为配电网的固有阻尼率、dL为消弧线圈的附加阻尼率，gset为整定过渡电导，n为多频增量阻尼率的叠加次数，ωim为配电网的LC谐振角频率，INT()为取整函数。Among them, d set is the preset damping rate starting value, d 0 is the inherent damping rate of the distribution network, d L is the additional damping rate of the arc suppression coil, g set is the set transition conductance, and n is the multi-frequency incremental damping rate The superposition times of , ω im is the LC resonance angular frequency of the distribution network, and INT() is the rounding function.

在更优的技术方案中，所述信号注入与反馈模块，向配电网注入同幅变频小电流信号

Figure BDA0002492022420000044
的频率范围为：f0±5Hz，f0为配电网的工频。In a more optimal technical solution, the signal injection and feedback module injects the same amplitude variable frequency small current signal into the distribution network
Figure BDA0002492022420000044
The frequency range is: f 0 ±5Hz, f 0 is the power frequency of the distribution network.

在更优的技术方案中，所述装置还包括归一化模块，用于：在计算得到每种频率下的增量阻尼率后，将其归算到工频角频率，归算后的增量阻尼率d′di为：

Figure BDA0002492022420000043
In a more optimal technical solution, the device further includes a normalization module for: after calculating the incremental damping rate at each frequency, it is reduced to the power frequency angular frequency, and the incremental damping rate after the reduction is calculated. The damping rate d' di is:
Figure BDA0002492022420000043

本发明还提供一种设备，包括处理器和存储器；其中：所述存储器用于存储计算机指令；所述处理器用于执行所述存储器存储的计算机指令，具体执行上述任一方法技术方案所述的方法。The present invention also provides a device, including a processor and a memory; wherein: the memory is used to store computer instructions; the processor is used to execute the computer instructions stored in the memory, specifically performing any of the above methods and technical solutions. method.

有益效果beneficial effect

本发明通过向配电网注入同幅变频的小电流信号作为检测故障的特征信号，通过测量配电网在多个不同频率下的增量阻尼率并进行叠加，以放大高阻接地故障反映在阻尼率中的故障特征，实现高阻接地故障辨识，提高高阻接地故障辨识的灵敏度。同时，本发明还不受系统高频噪声的干扰，进一步提高故障辨识的灵敏度。The invention injects a small current signal of the same amplitude and frequency conversion into the distribution network as a characteristic signal for detecting faults, and measures the incremental damping rates of the distribution network at multiple different frequencies and superimposes them to amplify the high-resistance grounding fault reflected in the The fault characteristics in the damping rate can realize high-resistance grounding fault identification and improve the sensitivity of high-resistance grounding fault identification. At the same time, the present invention is not disturbed by the high-frequency noise of the system, and further improves the sensitivity of fault identification.

另外，本发明提供的基于注入信号的配电网对地导纳测量方法考虑到实际运行情况时，大部分变电站内既有零序电压互感器又有母线电压互感器(PT)，若母线PT二次侧没有安装消谐电阻，可利用站内的两个PT进行测量。当母线PT接有消谐电阻时，需退出消谐电阻或外接PT，即从接地变压器中性点或者三相补偿电容器组中性点外加两个电压互感器测量配网的对导纳。所以本发明的优势还有：测试人员无需考虑母线PT组的接线方式以及是否安装有零序PT，使用电压互感器即可实时测量配电网参数，不受系统运行方式及高频干扰的影响，避免了PT磁饱和导致测量不准确的问题；可从二次侧完成测量，不影响系统一次侧正常运行，测量过程便捷可靠。In addition, when the method for measuring the ground admittance of the distribution network based on the injection signal provided by the present invention takes into account the actual operating conditions, there are both zero-sequence voltage transformers and busbar voltage transformers (PTs) in most substations. If the busbar PT There is no harmonic elimination resistor installed on the secondary side, and the two PTs in the station can be used for measurement. When the busbar PT is connected with a harmonic elimination resistor, it is necessary to withdraw the harmonic elimination resistor or connect an external PT, that is, from the neutral point of the grounding transformer or the neutral point of the three-phase compensation capacitor bank, plus two voltage transformers to measure the pair admittance of the distribution network. Therefore, the advantages of the present invention are as follows: the tester does not need to consider the wiring mode of the bus PT group and whether there is a zero-sequence PT installed, and can use the voltage transformer to measure the parameters of the distribution network in real time, which is not affected by the system operation mode and high-frequency interference. , avoiding the problem of inaccurate measurement caused by PT magnetic saturation; the measurement can be completed from the secondary side without affecting the normal operation of the primary side of the system, and the measurement process is convenient and reliable.

附图说明Description of drawings

图1是本发明提供的等效后的配电网零序回路图；Fig. 1 is the zero-sequence circuit diagram of the distribution network after the equivalent provided by the present invention;

图2注入信号等效流通回路Figure 2 Equivalent flow loop of injection signal

图3注入特征信号简化等效回路Figure 3. Simplified equivalent circuit by injecting characteristic signal

图4反馈电压信号Figure 4 Feedback voltage signal

图5是本发明提供的接地故障识别方法的故障辨别流程图；Fig. 5 is the fault identification flowchart of the ground fault identification method provided by the present invention;

图6是本发明进行仿真后得到的单相200Ω低阻接地故障残流随时间变化的图；Fig. 6 is the graph of the residual current of single-phase 200Ω low-resistance grounding fault obtained after the simulation of the present invention changes with time;

图7是本发明进行仿真后得到的单相1500Ω高阻接地故障残流随时间变化的图；Fig. 7 is the graph of the residual current of single-phase 1500Ω high-resistance grounding fault obtained after the simulation of the present invention changes with time;

图8是本发明进行仿真后得到的单相间歇性弧光接地故障点残流随时间变化的图；Fig. 8 is the graph of the residual current of the single-phase intermittent arc ground fault point obtained after the simulation of the present invention changes with time;

图9是本发明进行仿真后得到的30db白噪声情况下高阻接地故障残流随时间变化的图；Fig. 9 is the graph of the residual current of high-resistance grounding fault with time variation under the condition of 30db white noise obtained after simulation by the present invention;

具体实施方式Detailed ways

下面对本发明的实施例作详细说明，本实施例以本发明的技术方案为依据开展，给出了详细的实施方式和具体的操作过程，对本发明的技术方案作进一步解释说明。The embodiments of the present invention are described in detail below. This embodiment is carried out on the basis of the technical solutions of the present invention, and provides a detailed implementation manner and a specific operation process, and further explains the technical solutions of the present invention.

如图1所示，其为对单相接地故障时的配电网进行了完全换位(CA＝CB＝CC＝C0，rA＝rB＝rC＝r0)、且负荷对称得到意想接地故障时的配电网零序等值回路，其中

Figure BDA0002492022420000051
为配电网的中性点电压，对地电导
Figure BDA0002492022420000052
rL为消弧线圈等值损耗电阻，rd为故障过渡电阻；L为消弧线圈等值电感，C＝3C0为配电网的总对地电容。As shown in Fig. 1, it is a complete transposition of the distribution network at the time of single-phase ground fault (C A =C B =C C =C 0 , r A =r B =r C =r 0 ), and The load symmetry obtains the zero-sequence equivalent circuit of the distribution network when an intentional ground fault occurs, where
Figure BDA0002492022420000051
is the neutral point voltage of the distribution network, the conductance to ground
Figure BDA0002492022420000052
r L is the equivalent loss resistance of the arc suppression coil, r d is the fault transition resistance; L is the equivalent inductance of the arc suppression coil, and C=3C0 is the total ground capacitance of the distribution network.

根据故障零序等效回路，可求出残流

Figure BDA0002492022420000053
大小：：According to the fault zero-sequence equivalent circuit, the residual current can be obtained
Figure BDA0002492022420000053
size::

Figure BDA0002492022420000054
Figure BDA0002492022420000054

式中：Ig为残流中的有功分量，Ig＝U0G；IC为对地电容电流，IC＝3ωC0U0；IL为消弧线圈的电感电流；d为配电网系统的阻尼率，d＝Ig/IC，一般用百分比表示；v为谐振接地配电网的失谐度，v＝(IC-IL)/IC，一般也用百分比表示，且v＝1-K，K为谐振接地配电网的合谐度。In the formula: I g is the active component in the residual current, I g =U 0 G; I C is the capacitance current to the ground, I C =3ωC 0 U 0 ; I L is the inductance current of the arc suppression coil; d is the power distribution The damping rate of the grid system, d = I g / IC , is generally expressed as a percentage; v is the detuning degree of the resonant grounded distribution network, v=( IC -IL )/ IC , generally expressed as a percentage, And v=1-K, K is the harmonic degree of the resonant grounded distribution network.

由公式(7)可知，残留

Figure BDA0002492022420000061
的大小、相位与配电网系统的阻尼率d和失谐度v相关。由于消弧线圈一般设置为靠近谐振点运行，v为定值，因此，通过准确测算系统阻尼率，即可根据残留
Figure BDA0002492022420000062
对配电网的运行状态进行有效识别。故本发明实施例即是以该原理为基础提出对配电网接地进行故障辨识。From formula (7), it can be seen that the residual
Figure BDA0002492022420000061
The size and phase of the distribution network are related to the damping rate d and the detuning degree v of the distribution network system. Since the arc suppression coil is generally set to run close to the resonance point, and v is a fixed value, by accurately measuring the damping rate of the system, the residual
Figure BDA0002492022420000062
Effectively identify the operating status of the distribution network. Therefore, the embodiment of the present invention proposes to perform fault identification on the grounding of the distribution network based on this principle.

10kV配电网正常运行时，架空线路的阻尼率约为3％～5％，线路绝缘受潮时可达8％～10％；电缆线路阻尼率较小，约为2％～4％，当绝缘老化时会增加至10％。由于不同规模的配电网参数大不相同，一般情况下，辨识故障发生的配电网阻尼率整定值dset为20％，此时接地故障过渡电阻约为200～400Ω；配电网阻尼率整定值dset为15％时，过渡电阻阻值约为400～600Ω。对于过渡电阻大于1000Ω甚至更高的高阻接地单频阻尼率辨识方法将失效。针对该技术问题，本发明提供一种基于多频增量阻尼率叠加的配电网接地故障辨识方法，通过注入多个频率的小电流信号来对故障过渡电阻产生的增量阻尼率进行累加，以突显故障特征，从而提高对高阻过渡电阻的单相接地故障进行辨识。When the 10kV distribution network is in normal operation, the damping rate of the overhead line is about 3% to 5%, and it can reach 8% to 10% when the line insulation is damp; the damping rate of the cable line is small, about 2% to 4%. It increases to 10% when aged. Since the parameters of distribution networks of different scales are very different, in general, the damping rate setting value dset of the distribution network for identifying the fault occurrence is 20%, and the ground fault transition resistance is about 200-400Ω; the distribution network damping rate is 20%. When the setting value d set is 15%, the resistance value of the transition resistance is about 400-600Ω. The single-frequency damping rate identification method for high-resistance grounding with a transition resistance greater than 1000Ω or even higher will fail. In view of this technical problem, the present invention provides a method for identifying grounding faults in distribution networks based on the superposition of multi-frequency incremental damping rates. In order to highlight the fault characteristics, so as to improve the identification of single-phase ground faults with high resistance transition resistance.

以下通过实施例对本发明技术方案进行解释说明。The technical solutions of the present invention will be explained below through examples.

本实施例提供的基于多频增量阻尼率叠加的配电网接地故障辨识方法，如图5所示，包括以下步骤：The method for identifying ground faults in a distribution network based on the superposition of multi-frequency incremental damping rates provided in this embodiment, as shown in Figure 5, includes the following steps:

步骤S10，向配电网注入同幅变频小电流信号

Figure BDA0002492022420000063
通过电压互感器测量反馈的电压信号
Figure BDA0002492022420000064
其中的下标i表示小电流信号的不同频率编号；Step S10, inject the same amplitude variable frequency small current signal into the distribution network
Figure BDA0002492022420000063
Measure the feedback voltage signal through the voltage transformer
Figure BDA0002492022420000064
The subscript i represents the different frequency numbers of the small current signal;

其中的变频，是指小电流信号的频率随时间变化，具体是每次改变小电流信号的频率并维持该频率一段时间，然后再进行下一次增频，即注入另一频率的小电流信号。The frequency conversion refers to the change of the frequency of the small current signal over time. Specifically, the frequency of the small current signal is changed each time and the frequency is maintained for a period of time, and then the next frequency increase is performed, that is, a small current signal of another frequency is injected.

测量反馈的电压信号在注入小电流信号的同时即开始进行测量，且是采用配电网零序电压互感器测量。其中，注入小电流信号的等效流通回路如图2所示，小电流频率为fi所对应的配电网阻尼率可表示为以下公式(8)所示：The voltage signal of the measurement feedback starts to be measured when the small current signal is injected, and is measured by the distribution network zero-sequence voltage transformer. Among them, the equivalent circulation loop of the injected small current signal is shown in Figure 2, and the damping rate of the distribution network corresponding to the small current frequency f i can be expressed as the following formula (8):

Figure BDA0002492022420000065
Figure BDA0002492022420000065

式中：IiR为注入电流的实部；IiC为注入电流的虚部；αi为注入电流信号与反馈电压的相角差，即注入小电流信号的功角；ωi为注入小电流信号的角频率。where I iR is the real part of the injected current; I iC is the imaginary part of the injected current; α i is the phase angle difference between the injected current signal and the feedback voltage, that is, the power angle of the injected small current signal; ω i is the injected small current The angular frequency of the signal.

步骤S20，根据配电网的等效对地导纳计算公式以及小电流信号

Figure BDA0002492022420000071
和反馈的电压信号
Figure BDA0002492022420000072
计算配电网产生LC谐振时的对地电导G和对地电容C。Step S20, according to the calculation formula of the equivalent ground admittance of the distribution network and the small current signal
Figure BDA0002492022420000071
and feedback voltage signal
Figure BDA0002492022420000072
Calculate the ground-to-ground conductance G and ground-to-ground capacitance C when the distribution network produces LC resonance.

图2中，

Figure BDA0002492022420000073
为二次侧注入的小电流信号
Figure BDA0002492022420000074
归算到一次侧的电流，且有
Figure BDA0002492022420000075
k1为电流归算系数；
Figure BDA0002492022420000076
为二次侧反馈的电压信号
Figure BDA0002492022420000077
归算至一次侧的反馈电压，且有
Figure BDA0002492022420000078
k2为电压归算系数。L1δ为消弧线圈内部电压互感器的原边漏电感，L′2δ为副边漏电感归算到一次侧的值，由于L1δ、L′2δ远小于消弧线圈的等效电感L，因此，电压互感器原、副边漏电感对于测量的影响可以忽略。由此，得到如图3所示的向配电网注入频率为fi的小电流信号的简化等效回路。且由图3可得配电网的等效对地导纳计算公式为：In Figure 2,
Figure BDA0002492022420000073
Small current signal injected for the secondary side
Figure BDA0002492022420000074
is reduced to the current on the primary side, and has
Figure BDA0002492022420000075
k 1 is the current reduction coefficient;
Figure BDA0002492022420000076
is the voltage signal fed back by the secondary side
Figure BDA0002492022420000077
is reduced to the feedback voltage on the primary side, and has
Figure BDA0002492022420000078
k 2 is the voltage reduction coefficient. L 1δ is the primary side leakage inductance of the voltage transformer inside the arc suppression coil, L′ 2δ is the value of the secondary side leakage inductance reduced to the primary side, since L 1δ and L′ 2δ are much smaller than the equivalent inductance L of the arc suppression coil, Therefore, the influence of the leakage inductance of the primary and secondary sides of the voltage transformer on the measurement can be ignored. As a result, a simplified equivalent circuit for injecting a small current signal of frequency f i into the distribution network as shown in Figure 3 is obtained. And the calculation formula of the equivalent ground admittance of the distribution network can be obtained from Figure 3:

Figure BDA0002492022420000079
Figure BDA0002492022420000079

其中，配电网中消弧线圈的等效电感L可根据档位设定获得。Among them, the equivalent inductance L of the arc suppression coil in the distribution network can be obtained according to the gear setting.

本实施例在步骤S10向配电网注入同幅变频小电流信号

Figure BDA00024920224200000717
后测量配电网反馈的电压信号如图4所示，5.425s时的反馈电压信号幅值最大，说明配电网的总对地电纳与消弧线圈电感发生非工频并联谐振，谐振频率fim为54.25Hz，对应该频率下系统对地导纳最小。根据公式(9)可得，配电网产生LC谐振的条件为：In this embodiment, the same-amplitude variable-frequency low-current signal is injected into the distribution network in step S10
Figure BDA00024920224200000717
After measuring the voltage signal fed back by the distribution network, as shown in Figure 4, the amplitude of the feedback voltage signal at 5.425s is the largest, indicating that the total ground susceptance of the distribution network and the inductance of the arc suppression coil have non-power frequency parallel resonance, and the resonance frequency f im is 54.25Hz, corresponding to the minimum ground admittance of the system at this frequency. According to formula (9), the conditions for the distribution network to generate LC resonance are:

Figure BDA00024920224200000710
Figure BDA00024920224200000710

由公式(9)(10)可得配电网产生LC谐振时的对地电导G和对地电容C为：From formulas (9) and (10), it can be obtained that the ground-to-ground conductance G and the ground-to-ground capacitance C when the distribution network generates LC resonance are:

Figure BDA00024920224200000711
Figure BDA00024920224200000711

Figure BDA00024920224200000712
Figure BDA00024920224200000712

其中，Iim、fim、Uim，分别为二次侧注入的小电流信号

Figure BDA00024920224200000713
的幅值、二次侧注入的小电流信号
Figure BDA00024920224200000714
的频率fi、二次侧反馈的电压信号
Figure BDA00024920224200000715
的幅值分别在配电网产生LC谐振时的表示符号；Among them, I im , f im , U im , respectively, are the small current signals injected by the secondary side
Figure BDA00024920224200000713
The amplitude of , the small current signal injected by the secondary side
Figure BDA00024920224200000714
The frequency f i of , the voltage signal of the secondary side feedback
Figure BDA00024920224200000715
The amplitudes of , respectively, represent the symbols when the distribution network produces LC resonance;

步骤S30，配电网在注入每种频率的小电流信号时的对地电导和对地电容，均取值为配电网产生LC谐振时的对地电导和对地电容；然后根据以下公式(13)以及对地电导G和对地电容C，计算每种频率下的增量阻尼率ddi：Step S30, the conductance to ground and the capacitance to ground when the distribution network injects the small current signal of each frequency, both are taken as the conductance to ground and the capacitance to ground when the distribution network generates LC resonance; then according to the following formula ( 13) and the conductance to ground G and capacitance C to ground, calculate the incremental damping rate d di at each frequency:

Figure BDA00024920224200000716
Figure BDA00024920224200000716

式中，d0i、dLi分别为配电网在注入小电流信号的频率为fi时的固有阻尼率和消弧线圈附加阻尼率；g0、rL分别为配电网在故障前的对地电导和消弧线圈的等值损耗电阻，ωi为小电流信号

Figure BDA0002492022420000081
的角频率。In the formula, d 0i and d Li are the inherent damping rate and the additional damping rate of the arc suppression coil when the frequency of the injected small current signal is f i respectively; g 0 and r L are the Conductance to ground and equivalent loss resistance of arc suppression coil, ω i is a small current signal
Figure BDA0002492022420000081
angular frequency.

因为消弧线圈的补偿容量的表达式为QL＝ILUph，所以可用百分值的形式表示小电流信号的频率为fi时的消弧线圈有功损耗Pi：Because the expression of the compensation capacity of the arc suppression coil is QL = I L U ph , the active loss P i of the arc suppression coil can be expressed in the form of a percentage value when the frequency of the small current signal is f i :

Figure BDA0002492022420000082
Figure BDA0002492022420000082

即Pi是消弧线圈有功电流与电感电流之比，或感抗与等值损耗电阻之比。联立式(13)、式(14)得增量阻尼率为：That is, P i is the ratio of the active current of the arc suppression coil to the inductive current, or the ratio of the inductive reactance to the equivalent loss resistance. The incremental damping rate obtained from the simultaneous equations (13) and (14) is:

Figure BDA0002492022420000083
Figure BDA0002492022420000083

步骤S40，根据以下公式(16)预设的判据，变频的不同频率编号i从1叠加至n的多频叠加过程中，判断是否满足判据中的不等式，若满足则判断配电网发生接地故障，若均不满足且出现中性点电压位移则认为配电网为三相不平衡状态，预设的判据为：Step S40, according to the preset criterion of the following formula (16), in the multi-frequency superposition process in which the different frequency numbers i of the frequency conversion are superimposed from 1 to n, it is judged whether the inequality in the criterion is satisfied, and if it is satisfied, it is judged that the distribution network occurs. If the ground fault is not satisfied and the neutral point voltage displacement occurs, the distribution network is considered to be in a three-phase unbalanced state. The preset criteria are:

Figure BDA0002492022420000084
Figure BDA0002492022420000084

其中，dset为预设的阻尼率启动值，d0为配电网的固有阻尼率、dL为消弧线圈的附加阻尼率；gset为整定过渡电导，变换为过渡电阻形式为rdset，表示期望测量的过渡电阻阻值；n为多频增量阻尼率的叠加次数，其值受期望测量的最大过渡电阻阻值影响，一般过渡电阻为1kΩ时，n取2或3；ωim为配电网的LC谐振角频率，INT()为取整函数。Among them, d set is the preset damping rate starting value, d 0 is the inherent damping rate of the distribution network, d L is the additional damping rate of the arc suppression coil; g set is the set transition conductance, which is transformed into the transition resistance form as r dset , represents the resistance value of the transition resistance expected to be measured; n is the number of superpositions of the multi-frequency incremental damping rate, and its value is affected by the maximum resistance value of the transition resistance expected to be measured. Generally, when the transition resistance is 1kΩ, n is 2 or 3; ω im is the LC resonance angular frequency of the distribution network, and INT() is the rounding function.

本实施例通过向配电网注入同幅变频的小电流信号作为检测故障的特征信号，通过测量配电网在多个不同频率下的增量阻尼率并进行叠加，以放大高阻接地故障反映在阻尼率中的故障特征，实现高阻接地故障辨识，提高高阻接地故障辨识的灵敏度。同时，本发明还不受系统高频噪声的干扰，进一步提高故障辨识的灵敏度。In this embodiment, a small current signal of the same amplitude and frequency conversion is injected into the distribution network as the characteristic signal for fault detection, and the incremental damping rate of the distribution network at multiple different frequencies is measured and superimposed to amplify the reflection of high-resistance grounding faults. The fault characteristics in the damping rate can realize high-resistance grounding fault identification and improve the sensitivity of high-resistance grounding fault identification. At the same time, the present invention is not disturbed by the high-frequency noise of the system, and further improves the sensitivity of fault identification.

由公式(16)可知配电网在注入小电流信号改变了配电网的增量阻尼率，因此在更优的实施例中，注入的小电流信号的频率尽量靠近工频，即限制注入同幅变频小电流信号

Figure BDA0002492022420000085
的频率范围为：f0±5Hz，f0为配电网的工频。从而可最大程度上消除小电流信号注入对配电网本身的影响，进而提高对配电网故障的辨识度。It can be seen from formula (16) that the distribution network injects a small current signal to change the incremental damping rate of the distribution network. Therefore, in a better embodiment, the frequency of the injected small current signal is as close to the power frequency as possible, that is, the injection is limited to the same frequency. Amplitude frequency conversion small current signal
Figure BDA0002492022420000085
The frequency range is: f 0 ±5Hz, f 0 is the power frequency of the distribution network. Therefore, the influence of small current signal injection on the distribution network itself can be eliminated to the greatest extent, thereby improving the identification of distribution network faults.

由前述可知，配电网产生LC谐振时的对地导纳最小，故在计算每个频率的增量阻尼率时，均采用配电网产生LC谐振时的对地电导G和对地电容C，但这与实际值存在偏差，使得由该对地电导G和对地电容C计算得到的增量阻尼率也都存在偏差。为减小偏差的影响以提高故障辨识度，本发明在更优的实施例中，在计算得到每种频率下的增量阻尼率后，按公式

Figure BDA0002492022420000091
将其归算到工频角频率，再按步骤S40根据公式(16)对配电网进行故障辨识。It can be seen from the foregoing that the ground admittance when the distribution network generates LC resonance is the smallest, so when calculating the incremental damping rate of each frequency, the ground conductance G and the ground capacitance C when the distribution network generates LC resonance are used. , but there is a deviation from the actual value, so that the incremental damping rate calculated from the ground-to-ground conductance G and the ground-to-ground capacitance C also has deviations. In order to reduce the influence of the deviation and improve the fault identification degree, in a more preferred embodiment of the present invention, after calculating the incremental damping rate at each frequency, according to the formula
Figure BDA0002492022420000091
It is reduced to the power frequency angular frequency, and then the fault identification of the distribution network is carried out according to the formula (16) in step S40.

为了验证本发明所描述的一种基于多频导纳测量的配电网接地故障辨识方法的可靠性，在PSCAD/EMTDC仿真软件中搭建图1所示10kV谐振接地配电网模型。参数设置如表1，并进行低阻接地故障、高阻接地故障、弧光接地故障的仿真分析验证。In order to verify the reliability of the method for identifying grounding faults in distribution network based on multi-frequency admittance measurement described in the present invention, the 10kV resonance grounding distribution network model shown in Figure 1 is built in PSCAD/EMTDC simulation software. The parameter settings are shown in Table 1, and the simulation analysis and verification of low-resistance ground fault, high-resistance ground fault and arc ground fault are carried out.

表1 10kV配电网对地参数Table 1 Ground parameters of 10kV distribution network

Figure BDA0002492022420000092
Figure BDA0002492022420000092

配电网单相接地故障导致中性点电压偏移，故障点残流大小受过渡电阻阻值的影响。仿真在0.05秒设置接地故障，低阻接地、高阻接地、弧光接地故障波形如图6-8所示。The single-phase grounding fault in the distribution network leads to the offset of the neutral point voltage, and the residual current at the fault point is affected by the resistance value of the transition resistance. The ground fault is set in the simulation at 0.05 seconds, and the low-resistance grounding, high-resistance grounding, and arc grounding fault waveforms are shown in Figure 6-8.

低阻接地故障时暂态特征明显，通过采集暂态特征信号即能有效辨识接地故障，但是经高阻抗接地或发生弧光高阻接地故障时该方法易受系统噪声的干扰，很难有效捕捉故障暂态信号。基于多频导纳测量的接地故障辨识结果如表2。分别对不同启动值dset、不同过渡电阻、不同故障距离情况进行仿真，通过公式(16)计算得到故障辨识情况及过渡电阻范围。The transient characteristics of low-resistance grounding faults are obvious, and the grounding fault can be effectively identified by collecting transient characteristic signals. However, this method is easily interfered by system noise when high-resistance grounding or arc high-resistance grounding fault occurs, and it is difficult to effectively capture the fault. transient signal. The ground fault identification results based on the multi-frequency admittance measurement are shown in Table 2. Simulations are carried out for different start-up values d set , different transition resistances, and different fault distances, respectively, and the fault identification conditions and transition resistance ranges are calculated by formula (16).

表2不同故障情况下辨识结果Table 2 Identification results under different fault conditions

Figure BDA0002492022420000093
Figure BDA0002492022420000093

Figure BDA0002492022420000101
Figure BDA0002492022420000101

从表2可知，不同故障情况时，单一频率下测量阻尼率参数无法辨识高阻故障，采用多频增量阻尼率叠加的检测方法，通过放大了高阻接地故障特征，实现高阻接地故障检测；通过设置不同的过渡电阻、整定值rset以及启动值dset进行大量仿真，结果显示，本发明方法可以有效判断过渡电阻为3kΩ的单相接地故障，验证了理论分析的结果。It can be seen from Table 2 that under different fault conditions, the high-resistance fault cannot be identified by measuring the damping rate parameter at a single frequency. The detection method of multi-frequency incremental damping rate superposition is adopted, and the high-resistance grounding fault detection is realized by amplifying the characteristics of the high-resistance grounding fault. By setting different transition resistance, setting value r set and starting value d set to carry out a large number of simulations, the results show that the method of the present invention can effectively judge the single-phase grounding fault with transition resistance of 3kΩ, and the results of theoretical analysis are verified.

表3含噪声情况下故障辨识结果Table 3 Fault identification results with noise

Figure BDA0002492022420000102
Figure BDA0002492022420000102

为了验证本文所提方法不受电力电子开关频率以及系统噪声的影响，论文在仿真中叠加了不同分贝的高斯白噪声，图9为30db白噪声情况下高阻接地故障残流，正常时中性点电压已发生偏移，故障辨识结果如表3所示。由于该方法本质上是对稳态特征参数进行处理，受系统干扰影响小。系统中存在30db高斯白噪声时依然能够有效判断过渡电阻为3kΩ的接地故障。In order to verify that the method proposed in this paper is not affected by the power electronic switching frequency and system noise, the paper superimposes Gaussian white noise of different decibels in the simulation. Figure 9 shows the high-resistance ground fault residual current in the case of 30db white noise, and it is neutral when it is normal. The point voltage has shifted, and the fault identification results are shown in Table 3. Since this method essentially processes the steady-state characteristic parameters, it is less affected by system disturbances. When there is 30db white Gaussian noise in the system, the ground fault with transition resistance of 3kΩ can still be effectively judged.

本发明还提供一种基于多频增量阻尼率叠加的配电网接地故障辨识装置实施例，与上述方法实施相对应，包括：The present invention also provides an embodiment of a distribution network grounding fault identification device based on the superposition of multi-frequency incremental damping rates, which corresponds to the implementation of the above method, including:

信号注入与反馈模块，用于：向配电网注入同幅变频小电流信号

Figure BDA0002492022420000103
通过电压互感器测量反馈的电压信号
Figure BDA0002492022420000104
其中的下标i表示小电流信号的不同频率编号；Signal injection and feedback module, used to inject the same amplitude variable frequency small current signal into the distribution network
Figure BDA0002492022420000103
Measure the feedback voltage signal through the voltage transformer
Figure BDA0002492022420000104
The subscript i represents the different frequency numbers of the small current signal;

对地导纳参数计算模块，用于：根据配电网的等效对地导纳计算公式以及小电流信号

Figure BDA0002492022420000105
和反馈的电压信号
Figure BDA0002492022420000106
计算配电网产生LC谐振时的对地电导G和对地电容C；The ground admittance parameter calculation module is used for: according to the calculation formula of the equivalent ground admittance of the distribution network and the small current signal
Figure BDA0002492022420000105
and feedback voltage signal
Figure BDA0002492022420000106
Calculate the ground-to-ground conductance G and ground-to-ground capacitance C when the distribution network produces LC resonance;

其中，配电网的等效对地导纳计算公式为：Among them, the calculation formula of the equivalent ground admittance of the distribution network is:

Figure BDA0002492022420000107
Figure BDA0002492022420000107

配电网产生LC谐振的条件为：The conditions for the distribution network to generate LC resonance are:

Figure BDA0002492022420000108
Figure BDA0002492022420000108

由公式(1)(2)可得配电网产生LC谐振时的对地电导G和对地电容C为：From formulas (1) and (2), it can be obtained that the ground-to-ground conductance G and the ground-to-ground capacitance C when the distribution network generates LC resonance are:

Figure BDA0002492022420000111
Figure BDA0002492022420000111

Figure BDA0002492022420000112
Figure BDA0002492022420000112

其中，

Figure BDA0002492022420000113
为二次侧注入的小电流信号
Figure BDA0002492022420000114
归算到一次侧的电流，且有
Figure BDA0002492022420000115
k1为电流归算系数；
Figure BDA0002492022420000116
为二次侧反馈的电压信号
Figure BDA0002492022420000117
归算至一次侧的反馈电压，且有
Figure BDA0002492022420000118
k2为电压归算系数；fi为小电流信号
Figure BDA0002492022420000119
的频率，L为配电网中消弧线圈的等效电感；Iim、fim、Uim，分别为二次侧注入的小电流信号
Figure BDA00024920224200001110
的幅值、二次侧注入的小电流信号
Figure BDA00024920224200001111
的频率fi、二次侧反馈的电压信号
Figure BDA00024920224200001112
的幅值分别在配电网产生LC谐振时的表示符号；in,
Figure BDA0002492022420000113
Small current signal injected for the secondary side
Figure BDA0002492022420000114
is reduced to the current on the primary side, and has
Figure BDA0002492022420000115
k 1 is the current reduction coefficient;
Figure BDA0002492022420000116
is the voltage signal fed back by the secondary side
Figure BDA0002492022420000117
is reduced to the feedback voltage on the primary side, and has
Figure BDA0002492022420000118
k 2 is the voltage reduction coefficient; f i is the small current signal
Figure BDA0002492022420000119
The frequency of , L is the equivalent inductance of the arc suppression coil in the distribution network; I im , f im , U im , respectively, are the small current signals injected by the secondary side
Figure BDA00024920224200001110
The amplitude of , the small current signal injected by the secondary side
Figure BDA00024920224200001111
The frequency f i of , the voltage signal of the secondary side feedback
Figure BDA00024920224200001112
The amplitudes of , respectively, represent the symbols when the distribution network produces LC resonance;

增量阻尼率计算模块，用于：将配电网在注入每种频率的小电流信号时的对地电导和对地电容，均取值为配电网产生LC谐振时的对地电导和对地电容；然后根据以下公式(5)以及对地电导G和对地电容C，计算每种频率下的增量阻尼率ddi：The incremental damping rate calculation module is used to: take the conductance to ground and the capacitance to ground when the distribution network injects small current signals of each frequency as the conductance to ground and the capacitance to ground when the distribution network generates LC resonance. capacitance to ground; then calculate the incremental damping rate d di at each frequency according to the following formula (5) and the conductance to ground G and capacitance C to ground:

Figure BDA00024920224200001113
Figure BDA00024920224200001113

式中，g0、rL为配电网在故障前的对地电导和消弧线圈的等值损耗电阻，ωi为小电流信号

Figure BDA00024920224200001114
的角频率；In the formula, g 0 and r L are the ground conductance of the distribution network and the equivalent loss resistance of the arc suppression coil before the fault, and ω i is the small current signal
Figure BDA00024920224200001114
angular frequency;

故障辨识模块，用于：根据以下公式(6)预设的判据，变频的不同频率编号i从1叠加至n的多频叠加过程中，判断是否满足判据中的不等式，若满足则判断配电网发生接地故障，若均不满足且出现中性点电压位移则认为配电网为三相不平衡状态，预设的判据为：The fault identification module is used for: according to the preset criterion of the following formula (6), in the multi-frequency superposition process of the different frequency numbers i of the frequency conversion from 1 to n, judge whether the inequality in the criterion is satisfied, and if so, judge whether When a ground fault occurs in the distribution network, if it is not satisfied and there is a neutral point voltage displacement, the distribution network is considered to be in a three-phase unbalanced state. The preset criteria are:

Figure BDA00024920224200001115
Figure BDA00024920224200001115

其中，dset为预设的阻尼率启动值，d0为配电网的固有阻尼率、dL为消弧线圈的附加阻尼率，gset为整定过渡电导，n为多频增量阻尼率的叠加次数，ωim为配电网的LC谐振角频率，INT()为取整函数。Among them, d set is the preset damping rate starting value, d 0 is the inherent damping rate of the distribution network, d L is the additional damping rate of the arc suppression coil, g set is the set transition conductance, and n is the multi-frequency incremental damping rate The superposition times of , ω im is the LC resonance angular frequency of the distribution network, and INT() is the rounding function.

在更优的装置的实施例中，所述信号注入与反馈模块，向配电网注入同幅变频小电流信号

Figure BDA00024920224200001116
的频率范围为：f0±5Hz，f0为配电网的工频。In an embodiment of a better device, the signal injection and feedback module injects the same amplitude variable frequency small current signal into the distribution network
Figure BDA00024920224200001116
The frequency range is: f 0 ±5Hz, f 0 is the power frequency of the distribution network.

在更优的装置的实施例中，还包括归一化模块，用于：在计算得到每种频率下的增量阻尼率后，将其归算到工频角频率，归算后的增量阻尼率d′di为：

Figure BDA0002492022420000121
In an embodiment of a more optimal device, a normalization module is also included, for: after calculating the incremental damping rate at each frequency, it is reduced to the power frequency angular frequency, and the calculated increment The damping rate d' di is:
Figure BDA0002492022420000121

本发明还提供一种设备实施例，包括处理器和存储器；其中：所述存储器用于存储计算机指令；所述处理器用于执行所述存储器存储的计算机指令，具体执行上述任一方法实施例所述的方法。The present invention also provides a device embodiment, including a processor and a memory; wherein: the memory is used to store computer instructions; the processor is used to execute the computer instructions stored in the memory, and specifically execute any of the above method embodiments. method described.

以上实施例为本申请的优选实施例，本领域的普通技术人员还可以在此基础上进行各种变换或改进，在不脱离本申请总的构思的前提下，这些变换或改进都应当属于本申请要求保护的范围之内。The above embodiments are the preferred embodiments of the application, and those of ordinary skill in the art can also carry out various transformations or improvements on this basis. Without departing from the general concept of the application, these transformations or improvements should belong to the present application. within the scope of the application for protection.

Claims (7)

1.一种基于多频增量阻尼率叠加的配电网接地故障辨识方法，其特征在于，包括以下步骤：1. a power distribution network ground fault identification method based on the superposition of multi-frequency incremental damping rates, is characterized in that, comprises the following steps: 向配电网注入同幅变频小电流信号
Figure FDA0002492022410000011
通过电压互感器测量反馈的电压信号
Figure FDA0002492022410000012
其中的下标i表示小电流信号的不同频率编号；Inject the same amplitude variable frequency small current signal into the distribution network
Figure FDA0002492022410000011
Measure the feedback voltage signal through the voltage transformer
Figure FDA0002492022410000012
The subscript i represents the different frequency numbers of the small current signal; 根据配电网的等效对地导纳计算公式以及小电流信号
Figure FDA0002492022410000013
和反馈的电压信号
Figure FDA0002492022410000014
计算配电网产生LC谐振时的对地电导G和对地电容C；According to the calculation formula of the equivalent ground admittance of the distribution network and the small current signal
Figure FDA0002492022410000013
and feedback voltage signal
Figure FDA0002492022410000014
Calculate the ground-to-ground conductance G and ground-to-ground capacitance C when the distribution network produces LC resonance; 其中，配电网的等效对地导纳计算公式为：Among them, the calculation formula of the equivalent ground admittance of the distribution network is:
Figure FDA0002492022410000015
Figure FDA0002492022410000015
 配电网产生LC谐振的条件为：The conditions for the distribution network to generate LC resonance are:
Figure FDA0002492022410000016
Figure FDA0002492022410000016
 由公式(1)(2)可得配电网产生LC谐振时的对地电导G和对地电容C为：From formulas (1) and (2), it can be obtained that the ground-to-ground conductance G and the ground-to-ground capacitance C when the distribution network generates LC resonance are:
Figure FDA0002492022410000017
Figure FDA0002492022410000017
Figure FDA0002492022410000018
Figure FDA0002492022410000018
 其中，
Figure FDA0002492022410000019
为二次侧注入的小电流信号
Figure FDA00024920224100000110
归算到一次侧的电流，且有
Figure FDA00024920224100000111
k1为电流归算系数；
Figure FDA00024920224100000112
为二次侧反馈的电压信号
Figure FDA00024920224100000113
归算至一次侧的反馈电压，且有
Figure FDA00024920224100000114
k2为电压归算系数；fi为小电流信号
Figure FDA00024920224100000115
的频率，L为配电网中消弧线圈的等效电感；Iim、fim、Uim，分别为二次侧注入的小电流信号
Figure FDA00024920224100000116
的幅值、二次侧注入的小电流信号
Figure FDA00024920224100000117
的频率fi、二次侧反馈的电压信号
Figure FDA00024920224100000118
的幅值分别在配电网产生LC谐振时的表示符号；in,
Figure FDA0002492022410000019
Small current signal injected for the secondary side
Figure FDA00024920224100000110
is reduced to the current on the primary side, and has
Figure FDA00024920224100000111
k 1 is the current reduction coefficient;
Figure FDA00024920224100000112
is the voltage signal fed back by the secondary side
Figure FDA00024920224100000113
is reduced to the feedback voltage on the primary side, and has
Figure FDA00024920224100000114
k 2 is the voltage reduction coefficient; f i is the small current signal
Figure FDA00024920224100000115
The frequency of , L is the equivalent inductance of the arc suppression coil in the distribution network; I im , f im , U im , respectively, are the small current signals injected by the secondary side
Figure FDA00024920224100000116
The amplitude of , the small current signal injected by the secondary side
Figure FDA00024920224100000117
The frequency f i of , the voltage signal of the secondary side feedback
Figure FDA00024920224100000118
The amplitudes of , respectively, represent the symbols when the distribution network produces LC resonance; 将配电网在注入每种频率的小电流信号时的对地电导和对地电容，均取值为配电网产生LC谐振时的对地电导和对地电容；然后根据以下公式(5)以及对地电导G和对地电容C，计算每种频率下的增量阻尼率ddi：The conductance to ground and capacitance to ground when the distribution network injects small current signals of each frequency are taken as the conductance to ground and capacitance to ground when the distribution network generates LC resonance; then according to the following formula (5) As well as the conductance to ground G and the capacitance to ground C, calculate the incremental damping rate ddi at each frequency:
Figure FDA00024920224100000119
Figure FDA00024920224100000119
 式中，g0、rL为配电网在故障前的对地电导和消弧线圈的等值损耗电阻，ωi为小电流信号
Figure FDA00024920224100000120
的角频率；In the formula, g 0 and r L are the ground conductance of the distribution network and the equivalent loss resistance of the arc suppression coil before the fault, and ω i is the small current signal
Figure FDA00024920224100000120
angular frequency; 根据以下公式(6)预设的判据，变频的不同频率编号i从1叠加至n的多频叠加过程中，判断是否满足判据中的不等式，若满足则判断配电网发生接地故障，若均不满足且出现中性点电压位移则认为配电网为三相不平衡状态，预设的判据为：According to the preset criteria of the following formula (6), in the multi-frequency superposition process of the different frequency numbers i of the frequency conversion from 1 to n, it is judged whether the inequality in the criterion is satisfied. If both are not satisfied and the neutral point voltage displacement occurs, the distribution network is considered to be in a three-phase unbalanced state. The preset criteria are:
Figure FDA0002492022410000021
Figure FDA0002492022410000021
 其中，dset为预设的阻尼率启动值，d0为配电网的固有阻尼率、dL为消弧线圈的附加阻尼率，gset为整定过渡电导，n为多频增量阻尼率的叠加次数，ωim为配电网的LC谐振角频率，INT()为取整函数。Among them, d set is the preset damping rate starting value, d 0 is the inherent damping rate of the distribution network, d L is the additional damping rate of the arc suppression coil, g set is the set transition conductance, and n is the multi-frequency incremental damping rate The superposition times of , ω im is the LC resonance angular frequency of the distribution network, and INT() is the rounding function. 2.根据权利要求1所述的方法，其特征在于，注入同幅变频小电流信号
Figure FDA00024920224100000217
的频率范围为：f0±5Hz，f0为配电网的工频。2. The method according to claim 1, characterized in that, injecting the same amplitude variable frequency small current signal
Figure FDA00024920224100000217
The frequency range is: f 0 ±5Hz, f 0 is the power frequency of the distribution network. 3.根据权利要求1所述的方法，其特征在于，在计算得到每种频率下的增量阻尼率后，将其归算到工频角频率，归算后的增量阻尼率dd′i为：
Figure FDA0002492022410000022
3. The method according to claim 1, characterized in that, after calculating the incremental damping rate under each frequency, it is reduced to the power frequency angular frequency, and the reduced incremental damping rate d d ' i is:
Figure FDA0002492022410000022
 4.一种基于多频增量阻尼率叠加的配电网接地故障辨识装置，其特征在于，包括：4. A distribution network ground fault identification device based on the superposition of multi-frequency incremental damping rates, characterized in that, comprising: 信号注入与反馈模块，用于：向配电网注入同幅变频小电流信号
Figure FDA0002492022410000023
通过电压互感器测量反馈的电压信号
Figure FDA0002492022410000024
其中的下标i表示小电流信号的不同频率编号；Signal injection and feedback module, used to inject the same amplitude variable frequency small current signal into the distribution network
Figure FDA0002492022410000023
Measure the feedback voltage signal through the voltage transformer
Figure FDA0002492022410000024
The subscript i represents the different frequency numbers of the small current signal; 对地导纳参数计算模块，用于：根据配电网的等效对地导纳计算公式以及小电流信号
Figure FDA0002492022410000025
和反馈的电压信号
Figure FDA0002492022410000026
计算配电网产生LC谐振时的对地电导G和对地电容C；The ground admittance parameter calculation module is used for: according to the calculation formula of the equivalent ground admittance of the distribution network and the small current signal
Figure FDA0002492022410000025
and feedback voltage signal
Figure FDA0002492022410000026
Calculate the ground-to-ground conductance G and ground-to-ground capacitance C when the distribution network produces LC resonance; 其中，配电网的等效对地导纳计算公式为：Among them, the calculation formula of the equivalent ground admittance of the distribution network is:
Figure FDA0002492022410000027
Figure FDA0002492022410000027
 配电网产生LC谐振的条件为：The conditions for the distribution network to generate LC resonance are:
Figure FDA0002492022410000028
Figure FDA0002492022410000028
 由公式(1)(2)可得配电网产生LC谐振时的对地电导G和对地电容C为：From formulas (1) and (2), it can be obtained that the ground-to-ground conductance G and the ground-to-ground capacitance C when the distribution network generates LC resonance are:
Figure FDA0002492022410000029
Figure FDA0002492022410000029
Figure FDA00024920224100000210
Figure FDA00024920224100000210
 其中，
Figure FDA00024920224100000211
为二次侧注入的小电流信号
Figure FDA00024920224100000212
归算到一次侧的电流，且有
Figure FDA00024920224100000213
k1为电流归算系数；
Figure FDA00024920224100000214
为二次侧反馈的电压信号
Figure FDA00024920224100000215
归算至一次侧的反馈电压，且有
Figure FDA00024920224100000216
k2为电压归算系数；fi为小电流信号
Figure FDA0002492022410000031
的频率，L为配电网中消弧线圈的等效电感；Iim、fim、Uim，分别为二次侧注入的小电流信号
Figure FDA0002492022410000032
的幅值、二次侧注入的小电流信号
Figure FDA0002492022410000033
的频率fi、二次侧反馈的电压信号
Figure FDA0002492022410000034
的幅值分别在配电网产生LC谐振时的表示符号；in,
Figure FDA00024920224100000211
Small current signal injected for the secondary side
Figure FDA00024920224100000212
is reduced to the current on the primary side, and has
Figure FDA00024920224100000213
k 1 is the current reduction coefficient;
Figure FDA00024920224100000214
is the voltage signal fed back by the secondary side
Figure FDA00024920224100000215
is reduced to the feedback voltage on the primary side, and has
Figure FDA00024920224100000216
k 2 is the voltage reduction coefficient; f i is the small current signal
Figure FDA0002492022410000031
The frequency of , L is the equivalent inductance of the arc suppression coil in the distribution network; I im , f im , U im , respectively, are the small current signals injected by the secondary side
Figure FDA0002492022410000032
The amplitude of , the small current signal injected by the secondary side
Figure FDA0002492022410000033
The frequency f i of , the voltage signal of the secondary side feedback
Figure FDA0002492022410000034
The amplitudes of , respectively, represent the symbols when the distribution network produces LC resonance; 增量阻尼率计算模块，用于：将配电网在注入每种频率的小电流信号时的对地电导和对地电容，均取值为配电网产生LC谐振时的对地电导和对地电容；然后根据以下公式(5)以及对地电导G和对地电容C，计算每种频率下的增量阻尼率ddi：The incremental damping rate calculation module is used to: take the conductance to ground and the capacitance to ground when the distribution network injects a small current signal of each frequency as the conductance to ground and the capacitance to ground when the distribution network generates LC resonance. capacitance to ground; then calculate the incremental damping rate d di at each frequency according to the following formula (5) and the conductance to ground G and capacitance C to ground:
Figure FDA0002492022410000035
Figure FDA0002492022410000035
 式中，g0、rL为配电网在故障前的对地电导和消弧线圈的等值损耗电阻，ωi为小电流信号
Figure FDA0002492022410000036
的角频率；In the formula, g 0 and r L are the ground conductance of the distribution network and the equivalent loss resistance of the arc suppression coil before the fault, and ω i is the small current signal
Figure FDA0002492022410000036
angular frequency; 故障辨识模块，用于：根据以下公式(6)预设的判据，变频的不同频率编号i从1叠加至n的多频叠加过程中，判断是否满足判据中的不等式，若满足则判断配电网发生接地故障，若均不满足且出现中性点电压位移则认为配电网为三相不平衡状态，预设的判据为：The fault identification module is used for: according to the preset criterion of the following formula (6), in the multi-frequency superposition process of the different frequency numbers i of the frequency conversion from 1 to n, judge whether the inequality in the criterion is satisfied, and if so, judge whether When a ground fault occurs in the distribution network, if it is not satisfied and there is a neutral point voltage displacement, the distribution network is considered to be in a three-phase unbalanced state. The preset criteria are:
Figure FDA0002492022410000037
Figure FDA0002492022410000037
 其中，dset为预设的阻尼率启动值，d0为配电网的固有阻尼率、dL为消弧线圈的附加阻尼率，gset为整定过渡电导，n为多频增量阻尼率的叠加次数，ωim为配电网的LC谐振角频率，INT()为取整函数。Among them, d set is the preset damping rate starting value, d 0 is the inherent damping rate of the distribution network, d L is the additional damping rate of the arc suppression coil, g set is the set transition conductance, and n is the multi-frequency incremental damping rate , ω im is the LC resonance angular frequency of the distribution network, and INT() is the rounding function. 5.根据权利要求4所述的装置，其特征在于，所述信号注入与反馈模块，向配电网注入同幅变频小电流信号
Figure FDA0002492022410000039
的频率范围为：f0±5Hz，f0为配电网的工频。5. The device according to claim 4, wherein the signal injection and feedback module injects the same amplitude variable frequency small current signal into the distribution network
Figure FDA0002492022410000039
The frequency range is: f 0 ±5Hz, f 0 is the power frequency of the distribution network. 6.根据权利要求4所述的装置，其特征在于，还包括归一化模块，用于：在计算得到每种频率下的增量阻尼率后，将其归算到工频角频率，归算后的增量阻尼率d′di为：
Figure FDA0002492022410000038
6. The device according to claim 4, further comprising a normalization module for: after calculating the incremental damping rate under each frequency, it is reduced to the power frequency angular frequency, and the normalization The calculated incremental damping rate d' di is:
Figure FDA0002492022410000038
 7.一种设备，其特征在于，包括处理器和存储器；其中：所述存储器用于存储计算机指令；所述处理器用于执行所述存储器存储的计算机指令，具体执行如权利要求1-3任一所述的方法。7. A device, characterized in that it comprises a processor and a memory; wherein: the memory is used to store computer instructions; the processor is used to execute the computer instructions stored in the memory, specifically performing any one of claims 1-3. a described method.
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