AC or DC OPF based LMP's in a competitive electricity market?

In this paper five-bus test system as well as Polish power system consisting of 2750 nodes and 3500 branches have been used for calculations. For each case LMP values were determined by three methods: AC OPF with direct respecting voltage constraints, DCL OPF with power losses and DC OPF without power losses. Based on the results obtained, it can be concluded that the proposed method for determining the branch real power capacity limit it possible to meet voltage constraints in the network during DC optimization. It can also be stated that in the Polish power system it is possible apply both the exact AC model and a simplified DCL model, while the use of the DC model is not appropriate for the Polish system