A Highly Robust Transmission Line Parameter Estimation Method Based on Multi-period PMU

Abstract

The invention relates to a high robustness electric transmission line parameter estimating method based on a multi-time period PMU, which belongs to the power system scheduling automation field. In this method, a parameter estimating model constituted of an objective function and constraint conditions is established; the objective function is the smallest among residual error weighted sum squares in N time periods; based on the KKT complementary slack condition corresponding to the parameter estimating model, the parameter estimating model is solved to acquire an optimum solution X; the time periods are arranged in descending order according to the maximum residual error of each of the time period; the time period of the optimum residual error is recorded as k; if the maximum residual error in the time period is smaller than a measuring residual error threshold, the parameter estimation is finished; and the acquired optimum solution is used as the estimation result of the parameter. According to the invention, the analytical form of the optimum solution of the model is solved based on the KKT condition, thus the calculating efficiency is ensured to be high; through the exclusion of the damaged datum and the iterative process of the parameter estimation, the damaged datum are eliminated effectively, thus improving the accuracy of the parameter estimation and ensuring the practicality of the method.

Description

technical field [0001] The invention relates to a highly robust transmission line parameter estimation method based on a multi-period PMU, which belongs to the field of power system scheduling automation. Background technique [0002] Traditional transmission line parameter estimation is based on the data acquisition and monitoring control system SCADA. Common data acquisition usually includes active and reactive power at the beginning and end of the line. The estimation methods based on this mainly include two kinds, the augmented state estimation method and the residual sensitivity method, in which the augmented state estimation method adds the static parameters of the transmission line as the quantity to be demanded into the state estimation equation, which will reduce the measurement Redundancy, and even lead to Jacobian matrix ill-conditioned. The residual sensitivity method estimates the parameter error through the sensitivity matrix of the measurement residual and th...

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Problems solved by technology

[0004] The PMU-based parameter estimation method can be divided into single-period parameter estimation and multi-period parameter estimation according to the time period involved in the calculation. The single-period parameter estimation has high requirements on the data quality of the PMU. Usually, the current and voltage law of the line is directly used to solve the problem. Its practicality has always been difficult to guarantee

[0005] Wang Maohai, Bao Jie and others in "Online Estimation Method of Transmission Line Parameters Based on PMU Measured Data" (Power System Automation, 2010, Volume 34, Issue 1), based on single-period PMU data, directly according to the voltage of the transmission line π model The current law solves the parameters, but this method does not have any error elimination and noise processing links. The selected line PMU has extremely high precision and is difficult to be practical

[0006] In the patent "Identification and Estimation Method of Power Line Parameters Based on PMU Measurement Data" (patent number: 201110024996.6), parameter estimation is performed based on multi-period PMU data. The method used depends on some data of the line, and the line parameters are completely unknown. In this case, the accuracy of the method is greatly reduced; and the estimation result is closely related to the artificially set residual threshold

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