Total Transfer Capability calculation considering variation of ambient temperature - a case study

Abstract

The deregulation of Power Sector in India has led to the development of a vibrant power market. The Short Term Power Markets in India have gained momentum following the Electricity Act of 2003. The inter-regional Short Term Markets in India are run based on the inter-regional Available Transfer Capability (ATC). The ATC is an indicator of the feasible trade between the regions involved in trade. ATC calculation must consider the violation of thermal limit, voltage limit and stability limit for an accurate analysis. This paper presents a method to calculate the Total Transfer Capability (TTC) which is the basis of calculation of ATC based on the thermal limits of the transmission lines considering the variation of ambient temperature across the Indian subcontinent. IEEE standard for calculating the current temperature of bare overhead conductor is used to determine the thermal ratings of the line. The thermal ratings obtained are used to determine the Inter-regional TTC of the system. The case study is conducted on the All India N-E-W Grid 3771 equivalent bus data. The TTC without considering the variation in Temperature across the Indian landmass is compared to the TTC values obtained after the consideration of the variation of temperature across the sub-continent.