Comparison of LMP simulation using two DCOPF algorithms and the ACOPF algorithm

In this paper, a brief review is firstly presented for Locational Marginal Price (LMP) calculation using the lossless DCOPF algorithm and the FND (Fictitious Nodal Demand)- based iterative DCOPF algorithm with losses considered. Also reviewed is the ACOPF model to calculate LMP. Then, a comparison of these three models is presented with the results from ACOPF as a benchmark. Simulation is performed on the PJM 5-bus system and the IEEE 30-bus test system. The results clearly show that the FND algorithm is a better estimation of the LMP calculated from the ACOPF algorithm and outperforms the conventional lossless DCOPF algorithm. This is reasonable since the FND model considers the line losses. In addition, analysis is presented to address when the different models may lead to large difference, which can be the guidelines for LMP simulation. An approximate algorithm may work well when the LMP difference resulting from approximation tends to be small. This is highly possible when all unbinding constraints are not close to their limits. On the contrary, a more accurate model is desired in the case that the approximation may potentially lead to larger errors when there is one or more constraints close to their limits.