Zero-sequence pilot frequency excitation method for double-circuit line in incomplete power failure environment

By using the heterofrequency power supply excitation method in an incomplete power outage environment, the zero-sequence heterofrequency signals of the dual-return circuit are measured, and the problems of large calculation errors and safety hazards in the prior art are solved, and accurate mutual inductance parameter measurement and safe testing process are realized.

CN120446591APending Publication Date: 2025-08-08이너 몽골리아 일렉트릭 파워 그룹 컴퍼니 리미티드 이너 몽골리아 일렉트릭 파워 리서치 인스티튜트 브랜치
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Patent Information

Application Number
CN202510585976.8
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-05-08
Publication Date
2025-08-08

AI Technical Summary

Technical Problem

In an incomplete power outage environment, it is difficult for the prior art to accurately measure the mutual inductance parameters of the dual-return circuit, which has large errors in the calculation results and safety risks.

Method used

The heterofrequency power supply is used as the excitation signal source, and the zero-sequence heterofrequency signal is applied to the power outage line. By measuring the heterofrequency induced current and voltage on the secondary side of the current transformer and voltage transformer, the mutual impedance is calculated and frequency conversion is performed to build a zero-sequence mutual inductance impedance measurement system of the incomplete stopping dual-return line.

Benefits of technology

Accurately measuring the mutual impedance of the double-return line under complex interference conditions, avoiding the safety risk of single-phase reclosing operation and improving the accuracy and safety of measurement.

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Abstract

The invention discloses a zero-sequence pilot-frequency excitation method for a double-circuit line in an incomplete power failure environment, which comprises the following steps of: applying zero-sequence pilot-frequency signal excitation on a power failure line by using a pilot-frequency power supply as an excitation signal source of a zero-sequence network of the double-circuit line, different-frequency induced current and voltage are measured at secondary sides of a current transformer and a voltage transformer at two sides of the operation line, and different-frequency zero-sequence voltage and different-frequency zero-sequence current in the double-circuit line zero-sequence network are obtained; simultaneously solving a zero-sequence network equation, and calculating mutual impedance between double circuits; performing frequency conversion to obtain the power frequency mutual impedance of the line; and finally, carrying out simulation verification by constructing a non-full-stop double-circuit line zero-sequence mutual inductance impedance measurement system. According to the method, the multi-path coupling caused by the existing power frequency interference method and the accuracy problem caused by the signal measurement error of the zero sequence increment method are solved, the test calculation can be accurately completed under the complex interference working condition, and the safety risk caused by the single-phase reclosing operation is avoided.
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