Voltage Security Enhancement for SCED with Generalized DC Power Flow Model

This paper discusses the integration of a Security Constrained Economic Dispatch (SCED) algorithm with Generalized DC (GenDC) power flow model into an existing regional transmission organization (RTO) market clearing engine. Compared with conventional DC power flow-based SCED algorithms, sensitivity-based voltage security constraints that include voltage constraints and reactive power dispatches, are considered in the proposed algorithm. The effectiveness and efficiency of the GenDC-based SCED model has been validated using Southwest Power Pool (SPP) market data during a pre-contingency low voltage event. The results provide convincing evidence that the proposed GenDC-based voltage constraint model can effectively mitigate power system voltage issues through minor modifications of the existing market design. Therefore, it can overcome the shortcomings of current operational voltage mitigation strategies such as creating surrogate flow-based constraints and outside-of-market unit commitment decisions that are common practices among RTO markets today. Numerical experiments are conducted on a practical system model with greater than 18,000 buses to illustrate the effectiveness of the proposed approach.