CN-122017361-A - Cable grounding resistance detection method and system based on three-phase decoupling harmonic injection

CN122017361ACN 122017361 ACN122017361 ACN 122017361ACN-122017361-A

Abstract

The invention relates to the technical field of cable resistance detection, and particularly discloses a cable grounding resistance detection method and system based on three-phase decoupling harmonic injection, wherein the method comprises the steps of constructing an equivalent circuit model; the method comprises the steps of carrying out excitation strategy mapping on an equivalent circuit model to obtain a time-sharing excitation configuration parameter, carrying out time-sharing harmonic injection on a cable line based on the time-sharing excitation configuration parameter, carrying out synchronous coherent detection on three-phase terminal voltage signals of the cable line in the time-sharing harmonic injection process to obtain three-phase voltage response data, carrying out circuit impedance analysis on the equivalent circuit model to obtain resistance parameters and inductance parameters of the equivalent circuit model, carrying out frequency-variant compensation on the resistance parameters and the inductance parameters to obtain a power frequency equivalent parameter, and calculating the grounding resistance value of the cable line by combining port power frequency operation parameters of the cable line.

Inventors

ZHOU MINGQUAN
Meng Kunkun
ZHOU JIE
LI PENGBO
NI XIAOLU
YAN LINGZHU
XU GELAN
ZHU YUQING
Hong Zhengtian
LIAO WENHAO

Assignees

杭州巨骐信息科技股份有限公司
杭州溢光量芯传感技术有限公司
浙江富盛智能装备有限公司
杭州正益新能源科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260414

Claims (10)

1. The cable grounding resistance detection method based on three-phase decoupling harmonic injection is characterized by comprising the following steps of: S1, electrically decoupling a cable line to construct an electrical topological structure of the cable line, and binding parameters of the electrical topological structure to obtain an equivalent circuit model of the cable line; s2, performing excitation strategy mapping on the equivalent circuit model to obtain time-sharing excitation configuration parameters of the equivalent circuit model, and performing time-sharing harmonic injection on the cable line based on the time-sharing excitation configuration parameters; S3, in the time-sharing harmonic injection process, synchronous coherent detection is carried out on the three-phase terminal voltage signals of the cable line, and three-phase voltage response data of the cable line are obtained; s4, based on the time-sharing excitation configuration parameters and the three-phase voltage response data, carrying out circuit impedance analysis on the equivalent circuit model to obtain resistance parameters and inductance parameters of the equivalent circuit model; S5, performing frequency-dependent compensation on the resistance parameter and the inductance parameter to obtain a power frequency equivalent parameter of the equivalent circuit model, and calculating the grounding resistance value of the cable line by combining the port power frequency operation parameter of the cable line.
2. The method for detecting the cable grounding resistance based on three-phase decoupling harmonic injection according to claim 1, wherein the step of electrically decoupling the cable line to construct an electrical topology of the cable line and performing parameter binding on the electrical topology to obtain an equivalent circuit model of the cable line comprises the steps of: performing connection topology analysis on the cable lines to obtain physical layout information and electrical connection relation of the cable lines; Based on the physical layout information and the electrical connection relation, using a circulation path from a measuring point to a common grounding device in the cable line as an independent conductive path and using the common grounding device as a common electrical node to construct an electrical topological structure of the cable line; injecting electrical elements into the electrical topological structure to obtain a parameterized topological structure of the electrical topological structure; and constructing an equivalent circuit of the parameterized topological structure to obtain an equivalent circuit model of the cable line.
3. The method for detecting cable grounding resistance based on three-phase decoupling harmonic injection according to claim 1, wherein the performing excitation strategy mapping on the equivalent circuit model to obtain a time-sharing excitation configuration parameter of the equivalent circuit model comprises: carrying out channel information analysis on the equivalent circuit model to obtain the number of independent conductive paths and the identification of the independent conductive paths of the equivalent circuit model; according to the number of the independent conductive paths and the identification of the independent conductive paths, performing excitation strategy matching on the equivalent circuit model to obtain a time-sharing excitation time sequence strategy of the equivalent circuit model; and carrying out directional parameter precipitation on the time-sharing excitation time sequence strategy to obtain time-sharing excitation configuration parameters of the equivalent circuit model.
4. The method for detecting a cable grounding resistance based on three-phase decoupling harmonic injection as recited in claim 1, wherein the performing the time-sharing harmonic injection on the cable line based on the time-sharing excitation configuration parameter comprises: Based on the time-sharing excitation configuration parameters, performing instruction coding on the cable line to obtain a harmonic current control instruction of the cable line; The harmonic current control instruction is transmitted to a controllable current source of the cable line, and the controllable current source is driven to synthesize a harmonic current excitation signal; and according to the time sequence information of the harmonic current control instruction, the harmonic current excitation signal is injected into the independent conductive path corresponding to the cable line in a time-sharing single-phase manner.
5. The method for detecting cable grounding resistance based on three-phase decoupling harmonic injection according to claim 1, wherein in the time-sharing harmonic injection process, synchronous coherent detection is performed on three-phase terminal voltage signals of the cable line to obtain three-phase voltage response data of the cable line, and the method comprises the following steps: Synchronously collecting the voltage transient signals of the three-phase measuring points of the cable line to the ground in the current excitation period of the time-sharing harmonic injection; Based on the current injection frequency of the time-sharing harmonic injection, carrying out orthogonal coherent demodulation on the voltage transient signal to obtain a voltage response complex component of the cable line; Performing split-phase recombination on the voltage response complex components to obtain single-period three-phase voltage response data of the cable line; and carrying out data aggregation on the single-period three-phase voltage response to obtain three-phase voltage response data of the cable line.
6. The method for detecting a cable grounding resistance based on three-phase decoupling harmonic injection according to claim 1, wherein the performing circuit impedance analysis on the equivalent circuit model based on the time-sharing excitation configuration parameter and the three-phase voltage response data to obtain a resistance parameter and an inductance parameter of the equivalent circuit model comprises: based on the topological connection relation of the equivalent circuit model, carrying out circuit relation matching on the current excitation information in the time-sharing excitation configuration parameters and the three-phase voltage response data to obtain a matching result between the current excitation information and the three-phase voltage response data; Performing parameter inversion on the unknown parameter set of the equivalent circuit model based on the matching result to obtain estimated parameters of the equivalent circuit model; and carrying out separation analysis on the estimated parameters to obtain the resistance parameters and the inductance parameters of the equivalent circuit model.
7. The method for detecting the cable grounding resistance based on three-phase decoupling harmonic injection according to claim 1, wherein the performing frequency-dependent compensation on the resistance parameter and the inductance parameter to obtain the power frequency equivalent parameter of the equivalent circuit model comprises: Carrying out skin effect correction on the resistance parameters to obtain power frequency resistance parameters of the equivalent circuit model; Carrying out power frequency inductive reactance compensation on the inductance parameter to obtain a power frequency inductive reactance parameter of the equivalent circuit model; and carrying out impedance parameter integration on the power frequency resistance parameter and the power frequency inductance parameter to obtain the power frequency equivalent parameter of the equivalent circuit model.
8. The method for detecting a cable grounding resistance based on three-phase decoupling harmonic injection according to claim 1, wherein the calculating a grounding resistance value of the cable line by combining the port power frequency operation parameter of the cable line comprises: acquiring three-phase port grounding voltage measurement data and total grounding electrode current measurement data of the cable line in a power frequency running state; performing line voltage drop deduction on the power frequency equivalent parameters and the three-phase port grounding voltage measurement data to obtain the grounding electrode grounding voltage of the cable line; and calculating the grounding resistance value of the cable line based on the grounding voltage of the grounding electrode and the total current measurement data of the grounding electrode.
9. The method for detecting the cable grounding resistance based on three-phase decoupling harmonic injection as claimed in claim 8, wherein the calculation formula of the grounding resistance is as follows: ; In the formula, Represents the resistance value of the grounding resistance, Represent the first Independent conductive path port to ground voltage measurement data, Represent the first The power frequency current phasors of the independent conductive paths, Represent the first The resistance parameters of the independent conductive paths, Represent the first The inductance parameters of the independent conductive paths, Representing the total current measurement data of the earth electrode, The preset power frequency angular frequency is indicated, Representing the units of an imaginary number, Representing a complex number of modes.
10. A cable grounding resistance detection system based on three-phase decoupling harmonic injection, characterized in that the system is used for realizing the cable grounding resistance detection method based on three-phase decoupling harmonic injection as claimed in claim 1, and comprises: The equivalent circuit modeling module is used for electrically decoupling the cable line to construct an electrical topological structure of the cable line, and carrying out parameter binding on the electrical topological structure to obtain an equivalent circuit model of the cable line; the excitation strategy control module is used for carrying out excitation strategy mapping on the equivalent circuit model to obtain time-sharing excitation configuration parameters of the equivalent circuit model, and carrying out time-sharing harmonic injection on the cable line based on the time-sharing excitation configuration parameters; The synchronous coherent detection module is used for carrying out synchronous coherent detection on the three-phase terminal voltage signals of the cable line in the time-sharing harmonic injection process to obtain three-phase voltage response data of the cable line; the impedance parameter resolving module is used for carrying out circuit impedance analysis on the equivalent circuit model based on the time-sharing excitation configuration parameters and the three-phase voltage response data to obtain resistance parameters and inductance parameters of the equivalent circuit model; And the grounding resistance calculation module is used for performing frequency-dependent compensation on the resistance parameter and the inductance parameter to obtain a power frequency equivalent parameter of the equivalent circuit model, and calculating the grounding resistance of the cable line by combining the port power frequency operation parameter of the cable line.

Description

Cable grounding resistance detection method and system based on three-phase decoupling harmonic injection Technical Field The invention relates to the technical field of cable resistance detection, in particular to a cable grounding resistance detection method and system based on three-phase decoupling harmonic injection. Background Accurate on-line detection of the grounding resistance of the cable line is a key link for guaranteeing safe and stable operation of the power system. The existing detection method has limitation in the process of treating the electric coupling problem of the three-phase cable line, and is difficult to realize effective decoupling of the three-phase conductive path, so that the injected excitation signals interfere with each other, the acquisition accuracy of voltage response data is further affected, and the analysis results of the resistance parameters and the inductance parameters have larger deviation. The prior art does not fully consider the influence of frequency-dependent characteristics in the detection process, has insufficient compensation of the skin effect of the resistor and the power frequency inductance of the inductor, further aggravates the error of calculation of the resistance value of the grounding resistor, and lacks a time-sharing excitation and synchronous coherent detection mechanism aiming at a three-phase independent path, so that the detection process is easily interfered by power frequency operation parameters, and the detection efficiency and reliability are difficult to meet the actual application demands. Therefore, how to improve the accuracy and efficiency of online detection of the grounding resistor of the cable line becomes a problem to be solved urgently. Disclosure of Invention The invention provides a cable grounding resistance detection method and system based on three-phase decoupling harmonic injection, which are used for solving the problems in the background technology. In order to achieve the above object, the method for detecting the cable grounding resistance based on three-phase decoupling harmonic injection provided by the invention comprises the following steps: S1, electrically decoupling a cable line to construct an electrical topological structure of the cable line, and binding parameters of the electrical topological structure to obtain an equivalent circuit model of the cable line; s2, performing excitation strategy mapping on the equivalent circuit model to obtain time-sharing excitation configuration parameters of the equivalent circuit model, and performing time-sharing harmonic injection on the cable line based on the time-sharing excitation configuration parameters; S3, in the time-sharing harmonic injection process, synchronous coherent detection is carried out on the three-phase terminal voltage signals of the cable line, and three-phase voltage response data of the cable line are obtained; s4, based on the time-sharing excitation configuration parameters and the three-phase voltage response data, carrying out circuit impedance analysis on the equivalent circuit model to obtain resistance parameters and inductance parameters of the equivalent circuit model; S5, performing frequency-dependent compensation on the resistance parameter and the inductance parameter to obtain a power frequency equivalent parameter of the equivalent circuit model, and calculating the grounding resistance value of the cable line by combining the port power frequency operation parameter of the cable line. In a preferred embodiment, the electrically decoupling the cable line to construct an electrical topology of the cable line, and parameter binding the electrical topology to obtain an equivalent circuit model of the cable line includes: performing connection topology analysis on the cable lines to obtain physical layout information and electrical connection relation of the cable lines; Based on the physical layout information and the electrical connection relation, using a circulation path from a measuring point to a common grounding device in the cable line as an independent conductive path and using the common grounding device as a common electrical node to construct an electrical topological structure of the cable line; injecting electrical elements into the electrical topological structure to obtain a parameterized topological structure of the electrical topological structure; and constructing an equivalent circuit of the parameterized topological structure to obtain an equivalent circuit model of the cable line. In a preferred embodiment, the performing excitation strategy mapping on the equivalent circuit model to obtain a time-sharing excitation configuration parameter of the equivalent circuit model includes: carrying out channel information analysis on the equivalent circuit model to obtain the number of independent conductive paths and the identification of the independent conductive paths of the equivalent circuit model; according