A time-varying impedance and capacitive resistance chain equivalent modeling method for electrified railway traction network

By dynamically updating the time-varying resistivity and capacitance parameters within the equivalent modeling framework of chain circuits, a functional mapping relationship between conductor voltage and current is constructed. This solves the deviation problem caused by the constant values ​​of impedance and capacitive reactance in the existing chain model, and improves the accuracy of grid voltage assessment and regenerative braking voltage stability analysis of electrified railway traction networks.

CN122197769APending Publication Date: 2026-06-12SOUTHWEST JIAOTONG UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
SOUTHWEST JIAOTONG UNIV
Filing Date
2026-03-13
Publication Date
2026-06-12

AI Technical Summary

Technical Problem

Existing chain circuit modeling methods treat conductor self-resistance, mutual resistance, self-inductance, mutual inductance, capacitance to ground, and inter-conductor mutual capacitance as constant values. This leads to unavoidable deviations in the static chain model for steady-state grid voltage assessment and regenerative braking voltage stability analysis. In particular, when the power supply arm is long and the train speed changes significantly, the time-varying nature of the traction grid impedance and capacitive reactance is ignored, which affects the accuracy of the train's power receiving voltage analysis.

Method used

Within the chain circuit equivalent modeling framework of multi-conductor traction networks, the time-varying resistance and capacitance parameters are dynamically updated to construct the functional mapping relationship between conductor voltage and current. Time-varying impedance and capacitive reactance are simulated using controlled voltage and current sources. The model is implemented through the Simulink platform and is applicable to electrified railway traction network systems.

Benefits of technology

It realizes the time-varying law of the resistance, inductance and self- and mutual capacitance of the traction network system as the train position and operating state changes within the equivalent framework of the chain circuit, which improves the accuracy and applicability of network voltage assessment and regenerative braking voltage stability analysis. The model implementation method is clear and easy to reproduce in engineering.

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Abstract

This invention discloses a time-varying impedance and capacitive reactance chain equivalent modeling method for electrified railway traction networks. Within the chain circuit equivalent modeling framework of multi-conductor traction networks, time-varying models of the traction network system's resistance and capacitance parameters are established simultaneously. The time-varying resistance modeling is achieved by expanding the traditional chain resistance module with only n conductor inputs and outputs to a time-varying resistance module with 2n inputs and 2n outputs. Based on the original conductor ports, n controlled voltage sources and n controlled current sources are added, and a controlled source parameter module is constructed to establish the functional relationship between controlled voltage and controlled current, so that the traction network's self / mutual resistance parameters are dynamically updated according to the real-time position and operating status of the train. The time-varying self / mutual capacitance modeling, while maintaining the connection method of self and mutual capacitance in the π-type chain equivalent, replaces the fixed capacitor with a time-varying capacitor module and its electrical behavior is equivalent to a controlled current source. The output of the controlled current source is determined by the voltage across the capacitor and its rate of change over time.
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