Two-step procedures for wide-area Distribution System State Estimation

This paper presents the application of multi-area approaches to the state estimation in wide-area distribution systems. The main goal of the paper is to analyze the possibility to accurately estimate the status of a large scale distribution network, relying on a distributed measurement system, in a multi-area framework: to this aim, two-step state estimation procedures are considered. First of all, the network is divided into sub-areas, according to geographical and/or topological constraints. Then, in the first step, for each sub-area, a dedicated estimator is used, exploiting all the measurement devices available on the field. In the second step, data provided by sub-area estimators are processed, using different methods, in order to improve the knowledge on the operating conditions of the network, while keeping the communication “cost” low. Both first and second step can be performed in a decentralized way and with parallel processing, thus leading to reduced overall execution times. Test results, obtained on the 123-bus IEEE test network, are presented and discussed.