Bus Differential Protection for Buses Interconnecting Battery Storage Systems

This paper presents an implementation of the bus-differential protection for buses that interconnect battery storage systems (BSSs). The proposed implementation is based on employing the αß0 components of the apparent powers flowing in all branches connected to the protected bus. The αß0 components of the apparent powers are employed to accommodate changes in the direction of power flow in branches hosting BSSs. The apparent powers are determined using the measured currents in all branches and the voltage at the protected bus. The proposed implementation of the bus-differential protection is tested for various internal and external faults occurring during the charging and discharging of BSSs. Test results demonstrate the ability of the αß0 apparent power components-based bus differential protection to initiate fast, accurate, and reliable responses to internal and external faults. These response features are found to have minor sensitivity to the mode of operation of the BSS, fault location, and/or fault type.