CN-120874719-B - Transformer high-frequency circuit equivalent model construction method and system for HFCT current analysis

CN120874719BCN 120874719 BCN120874719 BCN 120874719BCN-120874719-B

Abstract

The invention provides a method and a system for constructing a transformer high-frequency circuit equivalent model for HFCT current analysis, which belong to the technical field of transformer partial discharge fault detection, and are used for constructing a winding radial coupling parameter MPCLTL model, constructing a winding axial inter-cake coupling parameter LP model according to an electric parameter between winding axial cakes, constructing a full winding MPCLTL-LP model by combining a MPCLTL model and the LP model, carrying out high-frequency equivalent modeling on an iron core according to a core structure parameter, a material parameter and a stacking coefficient to obtain the high-frequency equivalent model of the iron core, and constructing a coupling model between the full winding and the iron core by combining the full winding MPCLTL-LP model and the high-frequency equivalent model of the iron core. The invention can accurately model the internal winding and the iron core of the transformer according to the physical structure and the characteristics of the transformer, and verify the rationality of a high-frequency pulse current detection method by adding a high-frequency pulse current signal at the winding side and detecting the signal on the grounding wire of the iron core.

Inventors

YANG CHEN
ZENG SHENG
LIU YANG
CHEN SHICONG
ZHANG GANG
Wen Runan
ZHOU CHAOHUI
DUAN RAN
TIAN JINDONG
LI CHENXU
LUO XIAO
WANG QIANG
ZHANG DA
WEI TAO
WANG LIQIANG

Assignees

北京市地铁运营有限公司供电分公司

Dates

Publication Date: 20260512
Application Date: 20250707
Priority Date: 20250317

Claims (9)

1. The transformer high-frequency circuit equivalent model construction method for HFCT current analysis is characterized by comprising the following steps of: According to the loss parameters of each transmission line, combining an actual line structure to construct a winding radial coupling parameter MPCLTL model, expanding each line cake of the winding into a section of MTL along the radial direction, sectionally connecting the loss parameters of each transmission line in a centralized parameter mode, enabling each transmission line to become a lossless transmission line and a centralized resistor in series connection so as to obtain a MPCLTL model of each cake, and sequentially connecting all single cake MPCLTL models according to the actual structure to form a MPCLTL model of the full winding; constructing a winding axial inter-cake coupling parameter LP model according to the winding axial inter-cake electrical parameters; Combining the MPCLTL model and the LP model according to the actual physical structure of the winding, selecting the middle part of each wire turn as an access point of the LP model, and embedding the LP model into the MPCLTL model; Performing high-frequency equivalent modeling on the iron core according to the iron core structural parameters, the material parameters and the stacking coefficients to obtain a high-frequency equivalent model of the iron core; And combining the full winding MPCLTL-LP model and a high-frequency equivalent model of the iron core to construct a coupling model between the full winding and the iron core.
2. The method for constructing the equivalent model of the high-frequency circuit of the transformer for the HFCT current analysis according to claim 1, wherein the LP model is used for constructing an axial coupling model of the full winding according to the electrical parameters among axial cakes of the winding, the axial electrical parameters adopt concentrated parameters because the axial dimension is far smaller than the wavelength of high-frequency pulse current, the winding is firstly discretized along the axial direction and divided into a plurality of equivalent units, each unit consists of inductance, capacitance and resistance so as to represent the electromagnetic characteristic of the winding, the self inductance coefficient of each unit is calculated by the geometric parameters and magnetic flux distribution of the winding, the mutual inductance coefficient between adjacent units is determined according to the magnetic coupling relation, the inter-turn capacitance, interlayer capacitance and capacitance of the winding are used for representing the distributed capacitance characteristic of the winding, and the equivalent resistance is introduced so as to reflect the loss and damping characteristic of the winding, and finally, the concentrated parameter LP equivalent circuit model of the winding is formed by establishing the connection relation among the equivalent circuit elements.
3. The method for constructing the equivalent model of the transformer high-frequency circuit for HFCT current analysis according to claim 1 is characterized in that full windings MPCLTL-LP models are built in EMTP software, wherein a coupling mode is adopted in the modeling process, only coupling parameters between two coils which are opposite in position in adjacent cakes are considered, an axial LP model and a MPCLTL model of the transformer high-voltage winding are built under EMTP according to the coupling mode, and mutual inductance between corresponding coils of upper and lower cakes is ignored by the two models.
4. The method for constructing the transformer high-frequency circuit equivalent model for the HFCT current analysis according to claim 1 is characterized in that modeling of an iron core can be regarded as a pure capacitor series-parallel circuit, wherein simplification is achieved by omitting the influence of an oil passage in the iron core, omitting insulation resistance and electric conduction between silicon steel sheets of the iron core, leading out an iron core grounding wire from a lamination in the middle of the iron core, dividing an iron core column into two half cylinders which are completely equal left and right from the leading-out position of the grounding wire according to the simplification, dividing each half cylinder into a plurality of cuboids according to a multi-stage iron core circular structure, and calculating the equivalent total capacitance of each cuboid according to the structural parameters, the material parameters and the lamination coefficient of the iron core.
5. The method for constructing the equivalent model of the transformer high-frequency circuit for the HFCT current analysis according to claim 1, wherein the high-frequency signal is coupled to the iron core through a capacitor between the inner turns of the winding and the iron core and finally flows into the ground through the grounding line of the iron core, the innermost turns of each wire cake are divided into left and right half turns according to the physical structure of the winding and the iron core, and the coupling is respectively established with the iron core through the equivalent capacitor between the wire cake and the iron core, and the coupling model between the full winding and the iron core can be constructed by establishing the coupling between all wire cakes of the full winding and the iron core.
6. A transformer high frequency circuit equivalent model building system for HFCT current analysis, comprising: The first construction module is used for constructing a radial coupling parameter MPCLTL model of the winding according to the loss parameter of each transmission line and combining an actual line structure, and comprises the steps of expanding each line cake of the winding into a section of MTL along the radial direction, sectionally connecting the loss parameter of each transmission line in a centralized parameter mode, enabling each transmission line to become a lossless transmission line and a centralized resistor in series connection so as to obtain a MPCLTL model of each cake, and sequentially connecting all single cake MPCLTL models according to the actual structure to form a MPCLTL model of the full winding; The second construction module is used for constructing a winding axial inter-cake coupling parameter LP model according to the winding axial inter-cake electrical parameters; Combining the MPCLTL model and the LP model according to the actual physical structure of the winding, selecting the middle part of each wire turn as an access point of the LP model, and embedding the LP model into the MPCLTL model; The fourth construction module is used for carrying out high-frequency equivalent modeling on the iron core according to the iron core structural parameters, the material parameters and the stacking coefficients to obtain a high-frequency equivalent model of the iron core; and a fifth construction module for combining the full winding MPCLTL-LP model and the high-frequency equivalent model of the iron core to construct a coupling model between the full winding and the iron core.
7. A non-transitory computer readable storage medium storing computer instructions which, when executed by a processor, implement the method for constructing a transformer high frequency circuit equivalent model for HFCT current analysis according to any of claims 1 to 5.
8. A computer device comprising a memory and a processor, the processor and the memory being in communication with each other, the memory storing program instructions executable by the processor, the processor invoking the program instructions to perform the method of constructing the equivalent model of the transformer high frequency circuit for HFCT amperometric analysis as in any of claims 1-5.
9. An electronic device comprising a processor, a memory and a computer program, wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory to cause the electronic device to execute instructions for implementing the method for constructing the equivalent model of the high frequency circuit of the transformer for HFCT amperometric analysis as claimed in any one of claims 1to 5.

Description

Transformer high-frequency circuit equivalent model construction method and system for HFCT current analysis Technical Field The invention relates to the technical field of transformer partial discharge fault detection, in particular to a method and a system for constructing a transformer high-frequency circuit equivalent model for HFCT current analysis, and particularly relates to a principle that HFCT is connected to a transformer grounding wire to detect high-frequency pulse current generated when partial discharge occurs in a transformer winding, and the transformer is subjected to high-frequency modeling to analyze a high-frequency pulse current detection method. Background The subway traction rectifying dry-type transformer plays a key role in converting electric energy from high-voltage alternating current into direct current required by the subway traction rectifying dry-type transformer and is supplied to a traction system. However, as the operation period increases, the inside of the transformer is at risk of faults such as insulation degradation and part loosening, thereby generating partial discharge and the like, and certain potential safety hazards exist. The generation of partial discharge is generally accompanied by phenomena such as heat, light, electromagnetic waves, and high-frequency pulse currents. The current common detection method for partial discharge of the transformer comprises an electromagnetic wave method, an infrared thermal imaging method, an ultrasonic wave method, a current method, a transient voltage to ground method and the like. However, the methods have the advantages and disadvantages that the electromagnetic wave method and the ultrasonic wave method have low requirements on the internal structure of the transformer and are sensitive to environmental interference, the infrared thermal imaging method can intuitively observe fault positions and is greatly influenced by environmental light, the current method can accurately detect discharge signals and needs shutdown maintenance of the transformer, and the transient voltage law can detect the discharge signals in an operating state and needs more complex data processing and analysis. Therefore, a high-frequency pulse current detection method is widely used in many scenes, and the method has the advantages of high sensitivity, high anti-interference performance and the like. The principle of high-frequency pulse current detection is that after a high-frequency pulse discharge signal is acquired, a high-frequency pulse (HFCT) sensor is connected to a transformer grounding wire. Disclosure of Invention The invention aims to provide a method and a system for constructing a transformer high-frequency circuit equivalent model for HFCT current analysis, which are used for solving at least one technical problem in the background art. In order to achieve the above purpose, the present invention adopts the following technical scheme: In a first aspect, the present invention provides a method for constructing an equivalent model of a high-frequency circuit of a transformer for HFCT current analysis, including: according to the loss parameter of each transmission line, combining an actual line structure to construct a winding radial coupling parameter MPCLTL model; constructing a winding axial inter-cake coupling parameter LP model according to the winding axial inter-cake electrical parameters; combining MPCLTL model and LP model to build full winding MPCLTL-LP model; Performing high-frequency equivalent modeling on the iron core according to the iron core structural parameters, the material parameters and the stacking coefficients to obtain a high-frequency equivalent model of the iron core; And combining the full winding MPCLTL-LP model and a high-frequency equivalent model of the iron core to construct a coupling model between the full winding and the iron core. As a further limitation of the first aspect of the present invention, the loss parameters of each transmission line are segmented and connected in a centralized parameter manner, so that each transmission line becomes a lossless transmission line and a centralized resistor are connected in series, thereby obtaining MPCLTL models of each cake, and then all single cake MPCLTL models are sequentially connected according to an actual structure to form a MPCLTL model of the full winding. As a further limitation of the first aspect of the invention, the LP model is based on the electrical parameters between the axial cakes of the windings to construct a full-winding axial coupling model, and the axial electrical parameters are concentrated parameters because the axial dimension is much smaller than the wavelength of the high-frequency pulse current. As a further limitation of the first aspect of the invention, a full winding MPCLTL-LP model is built in EMTP software, wherein a coupling mode is adopted in the modeling process, namely only coupling parameters between two opposit