Analysis and Implementation of Adaptive Defense Scheme for Island Operation Stability on the Bangka Subsystem

Bangka Island electricity is an interconnection subsystem with the Sumatra System. The interconnection uses a hybrid transmission consisting of submarine cables and overhead transmission lines. In the present condition, power transfer through submarine cables is 100 MW to maintain system reliability at the N-2 criterion. Disturbances in the electric power system, such as lightning strikes, cause the interconnection to the Sumatra System to be lost and the system frequency to decrease, potentially leading to a blackout in the Bangka Subsystem. The Under Frequency Relay (UFR) scheme is less effective in this condition, because the load shedding is static. To address system imbalance, a mechanism called the Adaptive Defense Scheme (ADS). The ADS scheme works to maintain the electricity system resilience for island operations. The ADS implementation is capable of adjusting power transfer in real time. In this study, the ADS system was assessed according to PLN standards. The telecommunications network assessment showed a bandwidth of more than 2 Mbps and 0% packet loss. The scan interval assessment of the transmission metering and feeders was less than 10 seconds. The Generic Object-Oriented Substation Event (GOOSE) response time assessment was very fast at 61.6 milliseconds, below 140 milliseconds. The load shedding target optimization testing followed the real-time power transfer. Comparing the UFR simulation assessment with ADS that island operation has a maximum nadir frequency deviation of 1.01 Hz, where Kenten-Tanjung Api transmission transfer of 103 MW ADS frequency is 48.67 Hz, while the UFR frequency is 47.66 Hz. Based on the simulation results, the ADS scheme is more effective in maintaining load balance compared to UFR.