On-line Calibration Method For Overhead Transmission Line Parameters Under Complex Conditions

Transmission lines as an important part of the power system,the accurate of its parameter is of great importance in power system security.The characteristics of equivalent single-circuit transmission line models are analyzed.The zero-order lumped parameter model of multi-circuit transmission line is established,and the equivalent circuit equation of the model is transformed.Which laid a theoretical foundation for the calibration of transmission line parameters.The method of calculating the transmission line sequence component is deduced by the basic principle of electromagnetism.Respectively,the use of computing methods and electromagnetic simulation software to analyze the impact of the original line parameters,verify the accuracy of the calculation method.At the same time,summarize the influence of electromagnetic coupling of multi-circuit transmission line on the original transmission line parameters.In this paper,a method of on-line calibration of multi-circuit transmission line parameters is studied for parallel transmission lines in the vicinity of the existing transmission lines.The specific parameter calibration scheme is proposed for different line combinations.The parameters of the original line after the new ground line are modified by using the electromagnetic calculation method.The voltage and current phasors of the transmission line are measured synchronously by using the incremental method.Then,the zero-sequence parameters of the multi-circuit transmission line are calculated by using the lumped parameter model of the multi-circuit transmission line.Decoupled parameters of multi-circuit transmission lines are decoupled by completely parallel transmission line parameter decoupling method.It can get the original line parameters after calibration.A simulation model of parameter calibration of transmission line is established,and the calibration method of transmission line parameter is simulated and analyzed to verify the accuracy of parameter calibration method of transmission line.