Assessment of Passive Islanding Detection Methods for DC Microgrids

Abstract

This paper provides an assessment of passive islanding detection methods in DC microgrids. In order to analyse the response of a DC microgrid to an islanding event, DC voltage and current signatures are captured locally at the terminals of Distributed Energy Resources (DERs). Further analysis on DC voltage and current measurements is carried out to derive the Rate of Change of Voltage (ROCOV) and the Rate of Change of Current (ROCOC), to distinguish between genuine islanding events and other disturbances. A detailed DC microgrid has been developed in MATLAB/Simulink to analyse the response of the DERs within a DC microgrid during intentional or unintentional islanding events. The results show that these approaches cannot be used to classify and characterise between islanding and non-islanding events caused by high resistive faults for DC microgrids, as the response of the DERs are dependent on the technology and associated control systems, which influences post event analysis in distinguishing between events.

A Review on Islanding Detection Schemes for DC Microgrids

“…The islanding situation can be identified when the system parameters deviate from a predefined threshold value. In [27], passive IDSs for DC MGs have been explained. Note that, the implementation of passive detection schemes is simple and easy.…”

Fault analysis in photovoltaic generation based DC microgrid using multifractal detrended fluctuation analysis

“…The major protection issues are islanding phenomenon, faults and nuisance tripping, etc. Among these issues, fault protection is one of the most challenging issues and in order to analyze this, fault detection and classification are primarily necessary for proper operation of the system 3,4 …”

Islanding detection in photovoltaic based DC micro grid using adaptive variational mode decomposition and detrended fluctuation analysis

“…Thus detection of islanding events by simple DC side parameters (no periodic zero crossing/frequency) are proposed in this paper for an effective detection and monitoring (D&M). [5]. These methods work efficiently and are simple to implement as long as a significant difference exists between the power generation and load demand.…”

“…Active techniques are having small NDZ but result in huge impact on power quality. The methods used in active islanding of DC micro grid include harmonic injection, insertion of controllable loads and positive feedback methods [5,6]. Apart from active and passive methods communication links are used in the DC micro grid to monitor the circuit breaker status, voltage and the current signals at the PCC thereby initiating the tripping of breakers when the islanding occurs [5].…”

“…The methods used in active islanding of DC micro grid include harmonic injection, insertion of controllable loads and positive feedback methods [5,6]. Apart from active and passive methods communication links are used in the DC micro grid to monitor the circuit breaker status, voltage and the current signals at the PCC thereby initiating the tripping of breakers when the islanding occurs [5]. Although this remote approach is very effective in reducing the NDZ significantly while producing very accurate islanding detection, it results in high cost by using a high speed communication link that becomes ineffective during communication link failures [7,8].…”