Fast and accurate islanding detection technique for microgrid connected to photovoltaic system

Abstract

Islanding condition means the case of feeding the loads from any distributed generator (DG) with a complete disconnection of the utility grid at the point of common coupling. The main technical issue in DG integration with the primary grid is the islanding condition. Hence, islanding must be detected using an appropriate anti-islanding technique which is needed to be faster in terms of time detection and accuracy. This paper illustrates the phenomenon of islanding and the passive methods which are used for preventing it. The main contribution of this paper is to detect this phenomenon as fast and accurately as possible using the technique of rate of change of power (ROCOP) based on the terminal voltage (TV) (ROCOP-TV) of the Photovoltaic (PV) inverter. The results of the proposed technique have been studied through extensive simulations using the MATLAB/Simulink platform. The ROCOP-TV technique results are compared with various types of passive detection relays after synchronization between the grid side and PV side. Furthermore, the proposed technique was not only able to detect islanding at the instance of its occurrence but also can distinguish between islanding and regular grid faults. The simulation results illustrate the proposed scheme's effectiveness and flexibility based on the MATLAB/Simulink platform.

Review on islanding detection methods for grid‐connected photovoltaic systems, existing limitations and future insights

“…In addition, the ROCOV and VoI thresholds have been tuned based on the off-line simulations, which depend largely on the studied test system. Elshrief et al adopted the rate of change of active power (ROCOP) and PCC voltage deviation for islanding detection purposes [29]. According to the presented MATLAB/Simulink simulations, this technique fails to detect a well-balanced island as the employed variable hardly deviates in such scenarios.…”

“…As mentioned in the last subsection, standards and system operators have emphasised the importance of providing Maxima of superimposed voltage components [25] CRPH [26] Piecewise P DG vs. V PCC function [27] ROCOV and VoI [28] PR controller feedback [30] PCC voltage ripple [24] ROCOP and ROCOV [29] UVP/OVP [15] PI controller saturation [31] Several cases…”

“…As seen, the thresholds of the mentioned time-domain criteria in [15,16,[23][24][25][26][27][28][29][30][32][33][34] rely highly upon each particular test system. Instead, a smaller threshold mitigates the NDZ notably while the technique's maloperation in non-islanding events rises.…”

A comprehensive fuzzy-based scheme for online detection of operational and topological changes

“…There have been lots of methods to detect the networks' operation mode known as island detection methods. These methods utilized non-phasor measurements of network parameters and characteristics analyses [6]- [15], or phasor measurements data obtained from phasor measurement units (PMUs) [16]- [18].…”

“…Therefore, by offline modeling and online monitoring, the islanding situation is detected. As a recent non-phasor based method, the islanding mode is detected using the rate of change of power technique based on the terminal voltage of the DG [15]. Also, lots of research have been introduced for island detection that are based on phasor measurements.…”