Development of hybrid ROCOF and RPV method for anti-islanding protection

摘要

Distributed generation (DG) must have the capability to quickly and accurately detect islanding operations under various operating conditions. An ideal islanding detection method should be without a non-detection zone (NDZ) and exempt from deteriorating power quality. A novel Anti-islanding protection technology that is a hybrid of rate of change of frequency (ROCOF) and reactive power variation (RPV) is proposed in this paper. The method can differentiate between a DG that falls into the NDZ for ROCOF and one that does not, and the RPV method will be initiated when the DG is within the NDZ. The amplitude of the reactive power variable can be accurately calculated using the proposed method. Thus, the degree of deterioration of power quality and power consumption can be effectively limited. The method has been implemented on a 3 kW DG to prove its feasibility. The experimental results demonstrated that in the proposed method, the DG was able to use the minimal amplitude of RPV to detect islanding in the NDZ. The breaker tripping time under various operating conditions conformed to the criteria specified in IEEE Std. 1547.