Effect of wind units on market clearing price, transmission congestion and network reliability in transmission expansion planning
In this study, a transmission expansion planning problem is studied considering the effects of wind units on transmission congestion and power system reliability in a uniform electricity market. Market clearing price (MCP) is determined based on the maximisation of social welfare. Also, the congestion cost of a transmission system is defined as the difference between the cost of power supply before market clearing disregarding the transmission system (dispatching cost) and the operation cost of generating wind units of power suppliers considering transmission lines limit (re-dispatching cost). Dispatching cost is calculated using economic load dispatch and the re-dispatching cost is determined using optimal power flow. Moreover, the effect of wind units on transmission network reliability is studied through the relationship between wind units and lines loading and coherence between lines loading and lines failure rate. In addition, the effects of wind generation on composite transmission and generation reliability is formulated via the relationship between wind units and MCP and considering this price in loss of load and load shedding cost of customers. The proposed model is applied to the IEEE reliability test system and the results are discussed.