State estimator for CA ISO market and security applications - relevance and readiness

In this paper, the relevance of the state estimator (SE) solution used in real time operations and the availability and performance criteria used to determine SEpsilas readiness for these applications for grid security and market operations at California ISO (CAISO) are discussed. In order to enhance the performance of the SE, CAISO updated the SE algorithm from the fast decoupled (FD) method to the orthogonal method. The detailed comparisons of the SE performance based on the two methods are presented in this paper. While the SE solutions continue to be used by traditional EMS applications at CAISO, this paper focuses on SE solutions used by two new applications in real time. These are (1) CAISO nodal LMP real time market and (2) security applications such as voltage stability analysis (VSA). The approach used to transfer the real time SE solution to these new applications, using the XML data format, is also discussed.