Idaho power experience of implementing cascade analysis study using the node/breaker model

The goal of this paper is to present a practical approach for performing the steady-state cascading analysis of a power system represented as a node/breaker (NB) model using real-time State Estimator (SE) cases. This paper discusses advantages of using the NB model in cascading analyses compared to the bus/branch (BB) model. The paper presents how the breaker configuration can impact outages and contingencies. In the BB model, only branch limits can be modeled. But in the NB model breaker, disconnect and other switch limits can be modeled and can impact the outcome based on the configurations and equipment limits. North American Electric Reliability Corporation (NERC) reliability standard CIP-014-2 specifically requires proper methodology to be developed and used to perform cascading analyses. The methodology presented in this paper is tested using the 90,000 node West Wide System Model (WSM). The extensive simulations performed to validate the methodology demonstrate its practicality for performing cascading analyses in the steady-state domain. It is applied and successfully used by Idaho Power to identify critical substations and weak links in the system. Further, results of cascading analyses are discussed.