Investigation of Battery Energy Storage Utilization Strategies for Reducing the Unscheduled Power Flows in the Interconnection Lines Caused by Multiple Electric Arc Furnace Operations

This paper evaluates various strategies for utilizing battery energy storage systems (BESSs) to reduce the unscheduled power flows in the interconnection lines caused by multiple electric arc furnace (EAF) operations in the electrical grid. Data from the Turkish power grid has been used to propose a realistic solution to the problem. Turkish electricity network is synchronously connected to the European Network of Transmission System Operators for Electricity (ENTSO-E) via three extra high voltage (EHV) transmission lines. Unscheduled power deviations at the intertie lines which result in a decline in the Area Control Error (ACE) performance are experienced due to the presence of large amounts of intermittent loads, such as EAFs supplied directly from the transmission system level. Hence, the Transmission System Operator (TSO) requires additional Automatic Frequency Restoration Reserve (aFRR) capacity while implementing automatic generation control (AGC) to counteract the effects of intermittent EAF loads. The fast nature of EAF loads is a challenge for the traditional generators participating in aFRR to keep the ACE between required performance limits. To alleviate the impact of these highly fluctuating loads on ACE, various AGC models that incorporate BESSs as secondary reserves are explored. A two-area dynamic simulation model, comprising IEEE 14 bus and IEEE 118 bus models with AGC models, is employed to simulate ACE variation between ENTSO-E and Turkey. Disturbance to the simulated power system is provided based on time-synchronized field measurements collected from 17 major EAFs operating in Turkish power grid. While considering the ACE performance, the research work also considers battery aging performance since BESSs are prone to high cyclic aging stress due to fast fluctuating control signals. The findings indicate that BESSs are effective in mitigating unscheduled power flows arising from multiple EAF operations and improves ACE performance.