| With the vigorous development of green and clean smart grids in China,more and more distributed power sources are encouraged by national policies to be integrated into the distribution network for power generation.However,the high penetration rate of distributed power sources has uncertainties and normalized random fluctuations and the often neglected output correlation,have an impact on the situational awareness of the distribution network,and bring challenges to the operation and control,safety and stability of the distribution network.This paper proposes an affine state estimation scheme.After affine modeling of the distributed power output,a branch current estimation model containing pseudomeasurement points is generated based on the micro-synchronous phasor measurement and the improved affine number calculation is performed to solve the state.The goal of completeness and non-conservative estimation results.First of all,in view of the influence of insufficient measurement of distribution network and low accuracy of pseudo measurement on the state estimation of distribution network,a branch current-based state estimation method containing pseudo-measurement points generated by micro-synchronous phasor measurement is studied.The micro-synchronized phasor measurement pseudo-measurement point generation model,and the measurement error formed by the measurement uncertainty propagation theory is used to ensure the measurement accuracy from the data input terminal,thereby improving the performance of state estimation.Secondly,the method of improving the affine operation is studied,using the affine noise element to add the dependence and coupling between interval variables,and the problem of interval expansion is caused by the large number of new noise elements generated during the nonlinear operation of the affine number.Make improvements to reduce the conservativeness of the solution on the basis of satisfying the completeness of the solution.Finally,an affine state estimation method that comprehensively considers the uncertainty and correlation of the distributed power output is proposed.The affine number conversion model of the uncertainty interval is established for the injected power of the distributed power supply,and the parallelogram affine of the correlation Number conversion model.Combining the operating characteristics of the distribution network,a measurement transformation strategy suitable for affine operations is proposed.The method of Taylor series approximation is used to linearize the measurement transformation process,reducing new noise elements and reducing computational complexity,and adopting improvements The affine operation method effectively solves the affine state estimation model.The effectiveness of the research scheme under different conditions is verified by the IEEE-33、IEEE118 node test system,and simulation analysis proves that the method used in this paper can reduce the conservativeness of the state estimation results,and provide an intuitive form with upper and lower limits close to the real solution interval.The state estimation results provide a data basis for the further regulation and operation of the distribution network. |
