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

In this paper, utilization strategies for battery energy storage systems (BESS) are assessed in order to reduce the unscheduled power flows in the interconnection lines caused by multiple electric arc furnace operations in Turkey. Turkish electricity network is synchronously connected to the European Network of Transmission System Operators for Electricity (ENTSO-E) via 3 EHV transmission lines. Extensive amount of intermittent loads like electric arc furnaces (EAF) in the electricity network cause unscheduled power deviations at the intertie lines hence Area Control Error (ACE) performance decreases. Therefore, automatic generation control (AGC) operated by the Transmission System Operator (TSO) requires more automatic Frequency Restoration Reserve (aFRR or Secondary Reserves) capacity to counteract the intermittent EAF loads. Nevertheless, the fast nature of EAF loads cannot be followed by the traditional generators participating in aFRR to keep the ACE between required performance limits. In order to mitigate the effects of these highly fluctuating loads on ACE, different AGC models incorporating BESS as secondary reserves in AGC is investigated. Time synchronized measurements collected for 17 major EAFs are used as disturbance to the power system. A two area dynamic simulation model comprising IEEE 14 bus and IEEE 118 bus models with AGC models are used to simulate the ACE variation between ENTSO-E and Turkey. Since batteries will be in high cyclic aging stress due to fast control signals, battery aging performance is also investigated. It is shown that BESS systems are effective in mitigating the unscheduled power flows due to the multiple EAF operations.

Keyword: automatic generation controller (AGC); battery energy storage systems(BESS); electric arc furnace (EAF); state of charge (SOC); unscheduled power flows. dynamic simulation