Abstract
This paper describes the wrong detection preventive method, which is useful to the inter-harmonics injection type islanding detector that detects a ground fault of primary distribution line within 0.1 seconds indirectly. The results are as follows. Injection of single-phase inter-harmonics current equals to injection of inter-harmonics current which consists of the same quantity of positive-phase-sequence and negative-phase-sequence components. Therefore, the quantity of inter-harmonics positive-phase-sequence admittance, which is calculated by inter-harmonics positive-phase-sequence current and voltage, equals to the quantity of inter-harmonics negative-phase-sequence admittance. Islanding phenomena which is three-phase-circuit breaking phenomena causes to the same change between the inter-harmonics positive-phase-sequence admittance and the negative-phase-sequence admittance. But the transient phenomena causes to the different change between the inter-harmonics positive-phase-sequence admittance and the negative-phase-sequence admittance. This paper proposes the wrong detection preventive method using this relation (the different change or the same change) between the inter-harmonics positive-phase-sequence admittance and the negative-phase-sequence admittance. This paper shows that this method is appropriate for the wrong detection prevention through simulation and experiment.
