An Effective Islanding Detection Method With Wavelet-Based Nuisance Tripping Suppressing

Abstract

The reactive power control (RPC) technique is a hopeful solution for the islanding issue in distributed generation (DG). Existing RPC approaches have downsides of inhibiting the required load reactive power or injecting/drawing undesirable excessive reactive power into the utility during normal operation. To overcome these limitations, the positive sequence voltage of point common coupling (PCC) is included in the reference of reactive power, which helps the frequency to deviate rapidly outside its thresholds. Further, power system transients which considered normal events can drift the frequency and result in a false islanding detection. In this article, different operating conditions such as load switching, voltage variations, and faults are considered. To address this issue, the suggested strategy includes a second decision-making criterion based on the discrete wavelet transform of the subtraction of sensed and nominal positive sequences of the PCC voltage. Simulation and experimental findings show that the suggested islanding detection method detects islanding rapidly and with zero nondetection zone. Furthermore, the DG and load reactive powers are closely matched under normal operation, and nonislanding situations are successfully prevented.