The Indian Electricity Grid Code (IEGC) 2010 defines ancillary services in power system as “services necessary to support the power system (or grid) operation in maintaining power quality, reliability and security of grid. With stricter framework including ancillary services through FRAS and governance, the frequency remains in the acceptable band to a large extent, but still, it remains over and above the upper limit of 50.05Hz for around 25% times. T&D network upgradation can also be deferred with the use of BESS.
Application – Frequency & Voltage stabilization
BESS is connected to Grid and charge/ discharge based on an algorithm to keep grid frequency and voltage within desired ranges.
Application - T&D deferral
Enable deferral of utility investments by using relatively small amounts of storage for Congestion relief. This will also increase the life of infrastructure (ex. Transformer, distribution network etc.) by reducing the loading on them.
Application – Spinning reserve
BESS can quickly respond to the variation in load on utility and enables generators to work at optimum level without the need to keep the idle capacity for spinning reserve.
BESS rating for grid ancillary applications can be classified in following ranges:
a. 50kWh to 1000kWh
b. 1MWh to 5MWh
c. Above 5MWh