Designing Community Energy Storage System For Peak saving application with load pattern data

In coming years, the IIT Kanpur campus has planned to acquire smart grid infrastructure. Storage can play a vital role in development of the infrastructure. As the distribution system is aging and peak load is increasing, it is imperative to upgrade the distribution system which can provide reliability to cater the maximum demand of 8.5 MW. This paper focuses on peak saving application in IIT Kanpur campus. An approach is proposed to establish critical and maximum demand load profiles to size Community Energy Storages (CES), with load growth. Application of storage avoids unbalance between electricity used by end users and supply from upstream grid in distribution power system. The algorithms, which are simple to implement in real time, are proposed for peak saving and power balancing in the system with community energy storages while taking into account the State of Health (SOH) of batteries without consideration of PV generation. A scheme is proposed to analyse the different costs that may incur in installation and O&M of Battery Energy Storage System (BESS).

In distribution system, peak load demand growth of customers is more than the average demand growth and such peak demand may occur for a few hours on a few days in a year. So the distribution system equipment such as transformers may get more stressed due to overloading and also these will be aged more rapidly. To cater the enhanced load requirement there would be a need to upgrade the existing distribution system by replacing aged and over stressed transformers and/or re-conductoring distribution lines with heavy wires. In replacement, the equipment are sized to meet the load growth for next 15–20 years and hence a huge investment is required for such new equipment's life. Storage can be used to defer or avoid the equipment upgrade and life extension[1][7].

In IIT campus, the maximum demand is found to be as 7.4 MW on a day in 2013. As allowed and sanctioned demand in the campus is 8.5 MW which is just 15% more than the peak demand of year 2013, so there will be a need for upgrade of the distribution system. Battery Energy Storage System (BESS) can be a solution to defer the upgrade of distribution system. Sizing and cost benefit analyses are two big issues to be discussed for installation of BESS. Another challenge is to analyze the control, communications and management schemes during charging/discharging operations so that BESS should be utilized adequately to minimize its capacity loss during operations[8][11].

In this paper, a methodology is proposed to size the BESS based on 33 kV/11 kV substation electricity consumption data of IIT Kanpur campus of year 2013. A broadest peak demand, termed as critical load profile is found to decide the energy rating with different percentage of load growth. Algorithms are proposed for peak saving operation obeying all the constraints in the system during different charging/discharging operations of community energy storage.