状态估计中选取量测权值的新原则

估计结果的准确性和数值稳定性是状态估计的两个重要方面，通常按量测精度选取量测权值，能使估计结果有较高的准确性，但可能对数值稳定性不利。文中在分析量测权值变化对状态估计数值稳定性影响的基础上，提出了状态估计中选取量测权值的新原则：非关键量测的权值反映量测精度，以量测方差的倒数为其权值；关键量测的权值根据数值稳定性的要求选取，以其他量测权值的平均值为关键量测的权值。这样能较好地协调数值稳定性与估计结果准确性之间的关系。在附录中论述了估计精度与关键量测的权值无关。

A NEW CRITERION OF DETERMINING MEASUREMENT WEIGHTS IN POWER SYSTEM STATE ESTIMATION

Numerical stability and veracity of estimation are important aspects in power system state estimation.Conventionally. the measurement weight is determined according to its veracity. This method is beneficial to veracity ofestimation, but may be harmful to numerical stability. This paper analyzes the situation that changes of measurement weightsaffect the numerical stability. In order that changing weights of critical measurements doesn't reduce accuracy of estimation toimprove numerical stability, the paper puts forward a new criterion of determining measurement weights. In the light of thenew criterion, weight of non--critical measurement is determined on the basis of measurement accuracy, and, weight of criticalmeasurement is determined to improve numerical stability. Weight of non-critical measurement is the reciprocal of itsvariance. Weight of critical measurement is the average of weights of other measurements. As a result it can coordinate therelationship between veracity of estimation and numerical stability. It is demonstrated in the appendix that veracity ofestimation has nothing to do with weights of critical measurements.This project is supported by National Key Basic Research Special Fund of China (No. G19980203) and State PowerCorporation of China (1999SKPJ010-20).