Comprehensive Day-Ahead Marketing Model Considering N-1 Security and Renewables

Abstract

Integrating renewable energies into the electricity grid is a challenge that requires an in-depth investigation. This paper presents a model of the day-ahead electricity market, including wind and photovoltaic (PV) generators, and contingency analysis. The comprehensive day-ahead marketing model is designed as a modular structure so that the individual modules can be easily modified in the future. First, the day-ahead electricity marketing of an electricity grid with and without renewable energies is studied. A market model solves the problem of unit commitment and economic dispatch. A grid model was used to calculate the power flow of the branches and the grid losses. Congestions in the branches were handled by redispatching. For this purpose, the generators were redispatched using mixed-integer linear programming and the power transfer distribution factor. A contingency analysis, investigating the outage of one branch, was applied by using the line outage distribution factor. The redispatch process was operated with these calculated increased power flows, which need to be handled by the grid to achieve N-1 security. The simulations were carried out using 30-bus 118-bus systems. Historic wind speed and solar radiation data of Germany were used as input data for renewable energy production. The load data of the 118-bus system were generated based on a standard load profile from Germany. The results show that both systems were able to meet the demand without violation of the grid capacity during normal conditions, with and without renewable energies. However, when applying the contingency analysis, an outrageous amount of load curtailment is needed.