The Impact of Operational Constraints on the Uniqueness of Locational Marginal Price: Simulation and Analysis

Over the past two decades, Locational Marginal Prices (LMP) theory has not only been continuously revised and developed in large-scale applications but also has become an essential component of the construction of China's electricity market, so researching the uniqueness of LMP is crucial. This paper first briefly analyzes the nodal pricing mechanism and uniqueness of solutions for the Security Constrained Economic Dispatch (SCED) problem and its dual problem. Subsequently, a full-time spot market clearing optimization model which considers relevant operational constraints is established, mainly used for computing the marginal nodal prices for power units, and a method for determining price multiplicities suitable for general cases is proposed. Lastly, numerical results show that line thermal capacity constraints and N-1 security constraint impacts the uniqueness of prices.