Research

Development of Energy and Reserve Pre-dispatch and Re-dispatch Models for Real-time Price Risk and Reliability Assessment

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Abstract

In the future energy framework of European Union and other countries, renewable energy plays an important role tackling the problems of the climate change and security of energy supply. The share of fluctuating and less predictable renewable power production will increase significantly the needs of securing proper balancing between generation and demand. The high penetration of renewable energy sources will also increase the burden of system operator for maintaining system reliabilities. However the current strategy of reliability management developed for conventional power systems and existing electricity market design may not cope with the future challenges the power system faces. The development of smart grid will enable power system scheduling and the electricity market to operate in a shorter time horizon for better integrating renewable energy sources into power systems. This paper presents an electricity market scheme including a multi-period energy and reserve predispatch model and an energy re-dispatch model for real time operation considering their coupling with the day-ahead market, respectively. The multi-period energy and reserve pre-dispatch model is formulated using the multi-period optimal power flow technique, which pre-schedules the generation output for satisfying the expected demand and determines up and down spinning reserve for each time interval in the operational hour. The ex-ante electricity prices and reserve capacity prices are also evaluated correspondingly. During the real time operation, the energy re-dispatch model is used for contingency management and providing balancing services based on the results of the energy and reserve pre-dispatch model. The energy re-dispatch model is formulated as a single-period AC OPF model, which is used to determine generation re-dispatch, load curtailment as well as real-time electricity prices. The modified IEEE-RTS has been analyzed to illustrate the techniques. The proposed market scheme coupled with a contingency analysis methodology has been used to evaluate both real-time electricity price risk and short term reliabilities during the operational hour in the new environment.