Power transmission line parameter estimation method and system and electric power system

Abstract

The application discloses a power transmission line parameter estimation method and system and an electric power system. The method comprises the following steps: via a multi-period PMU, voltages and currents of two ends of a power transmission line are collected, and a corresponding phasor quantity and a corresponding current phasor quantity are obtained; via the voltage phasor quantity, an actual measured value of a voltage magnitude phase angle vector is correspondingly determined; via the current phasor quantity and a pre-estimated object coefficient matrix, a mathematical estimated value of the voltage magnitude phase angle vector is calculated; a residual absolute value between the actual measured value and the mathematic estimated value is calculated; when the residual absolute value is smaller than or equal to a preset residual threshold value, the object coefficient matrix is determined as an optimal coefficient matrix; via the optimal coefficient matrix, series impedance and parallel admittance on the power transmission line are estimated. According to the power transmission line parameter estimation method and system and the electric power system, the preset residual threshold value which is obtained based on the voltage magnitude phase angle vector cannot be affected by heavy loads and light loads of the power transmission line, and therefore power transmission line parameter estimation error is reduced.

Description

technical field [0001] The invention relates to the technical field of power parameter estimation, in particular to a transmission line parameter estimation method, system and power system. Background technique [0002] The WAMS system (WAMS, Wide Area Measurement System, power grid wide-area monitoring system) is a key support technology for the new generation of power system. The real-time acquisition can be widely used in steady-state and transient analysis of various power systems. Different from traditional supervisory control and data acquisition (SCADA), PMU can directly collect key state information such as voltage, current amplitude, and phase angle, and transform the nonlinear iterative problem of traditional state estimation into As a linear estimation problem, the results of traditional state estimation can be directly measured, which is very useful for dynamic power system analysis, fault recording, etc. [0003] PMU-based parameter estimation can be subdivide...

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Problems solved by technology

However, heavy loads and light loads often occur on the transmission line, resulting in large fluctuations in various electrical parameters of the transmission line, so that the error threshold based on the rated capacity and safe current cannot fit the above actual situation well. The error threshold obtained based on the average value of real-time current amplitude will be unstable in the above situation. It can be seen from the above that in the current multi-period PMU parameter estimation, the set error threshold is easily affected by the heavy load and light load of the transmission line. The impact of the load, resulting in a large error in the final estimated parameters

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