Impact of Flexible Operation on Hydro Asset - A Case Study on Tehri HPP

Tehri HPP has achieved a milestone of 50K MU generation in Nov’22. The plants hold a commendable position in northern grid not only for its peaking generation support but also for range of ancillary services in its arsenal and capability of generation flexing. With time, these grid supports capabilities have become vital for smoothening net load profile in grid as more RES(Renewable energy Sources), known for their volatility and uncertainty, are getting integrated. For smooth Grid operation proper Scheduling & Dispatch, Imbalance management, Congestion Management and Ancillary Services are four critical aspects and Hon’ble CERC has always preempted road maps through Regulations/Petitions for grid management. Ancillary Services regulation has been notified in January 2022 (effective from Dec’ 22). The 5th amendments in Indian Electricity Grid Code (IEGC) in April, 2017 mandated periodic testing of primary response. Automatic Generation Control (AGC) has also been implemented nationwide against CERC order dt Oct’15. CERC has also taken Su-Motu cognizance on energy settlement system based on 5-minute time block [1].

This article discusses impact on operational capabilities of 250MW machines of Tehri HPP due to flexible operation and ancillary support provided to grid.