Transmission System Planning under Uncertainties Including Renewable Penetration Regime in Indian Context

摘要

Indian electricity demand is growing at an accelerated pace. It is expected that electricity demand of the country shall reach to about 150 GWby year 2022. To meet growing demand and to reduce supply-demand gap, there is a need for large capacity addition through conventional as well as renewable energy sources. India is bestowed with abundant renewable potential. Govt, of India has set an ambitious plan for establishing about 175 GW renewable generation capacity by 2022 including 100 GW of Solar, 65GW wind and 10 GW other renewable sources.Increasing renewable penetration presents numerous challenges to the system planner as well as grid operator. From transm ission system planner perspective, differences in gestation period ofrenewable generation and transmission, uncertainties in development of Renewable generation complexes, no firm beneficiaries at the development stage of generation project are key challenges. In India, above uncertainties have been addressed through series of measures including a proactive initiative viz. evolutionof Green Energy Corridors, where transmission for high potential renewable zones was planned in anticipation of subsequent Renewable development. Green Energy Corridors comprises Intra state transmission system i.e. transmission facility from Renewable generation projects to the state grid network at 132 kV/220 kV/400 kVlevel within the host state as well as at Inter state transmission system (ISTS) for transfer of power across the states.For evolution of Green Energy Corridors, integrated system study were conducted which were developed based on capacities and transmission available/anticipated during study time frames for national grid including various high capacity transmission corridors as a whole. Thereafter maximized Renewable dispatch scenarios as well as various other sensitivity scenarios like peak demand, off peak demand scenarios were developed. Study of historical patterns such as demand patterns, wind & solar generation patterns over the days/season in various regions were also taken into account while building above scenarios. The study involved State wise Renewable Purchase Obligations (RPO) requirements both solar, nonsolar to generate Renewable Surplus/deficit situation across each control area (state). With above inputs, detailed simulations were carried out in PSS/E software for all India transmission system to evolve Intra and Inter state transmission as part of Green Energy Corridors.In order to integrate high quantum of renewable energy, it is necessary to introduce more flexibility into system. Considering envisaged Renewable penetration scenarios, balancing studies were also carried out using "Net Load" methodology for different RE scenario viz.