Apparent Power-Based Anti-Islanding Protection for Distributed Cogeneration Systems

Abstract

In this paper, the performance of a passive antiislanding method is experimentally tested for three phase (3φ) cogeneration systems. The tested method is based on determining the wavelet packet transform (WPT) high frequency sub-bands present in the d − q-axis components of instantaneous 3φ apparent powers (s d and sq), when evaluated at the point of common coupling (PCC). This passive anti-islanding method is founded based on the nature of instantaneous 3φ apparent powers that have components continuously exchanged between both sides of PCC. An islanding condition can be considered as a transient disturbance that creates non-periodic and non-stationary high frequency components in s d and sq. These frequency components can be parameterized by WPT high frequency sub-bands, which can provide accurate detection of the islanding condition. The d − q WPT-based anti-islanding method is tested for a 3φ co-generation system under various loading and power delivery conditions. Performance results reveal accurate, fast, and reliable detection and response to the islanding condition.Index Terms-3φ co-generation systems, anti-islanding protection, d − q-axis reference frame, and the wavelet packet transform.

Performance of Loss-Of-Mains Detection in Multi-Generator Power Islands

“…Hence by continuously monitoring these parameters an LOM condition can be detected. Some of the most popular are the ROCOF and Vector Shift (VS) [3], Rate of Change of Voltage Angle Difference (ROCPAD) [4], Rate of Change of Power (ROCOP) [5], Apparent Power-Based [6] and Peak-Ratio Analysis [7].…”

A Solution to the Parameter Selection and Current Static Error Issues With Frequency Shift Islanding Detection Methods

“…[17] pointed out a misjudgment problem with the irregular current injection methods and proposed a solution. [18] and [19] belonged to the passive methods, which measured the network impedance passively and employed the wavelet theory, respectively. It was noteworthy that due to the maturity of the theory of signal processing and artificial intelligence and widespread use in other fields, substantial passive methods employing them were emerging [20]- [22].…”

Fast and systematic approach for adjusting ROCOF relay used in islanding detection of SDG

“…Unintentional islanding can threaten the personnel's safety and result in unsynchronised reclosing action, which may damage DG. Moreover, loads may be damaged owing to inadequate voltage and frequency control service provided by DG during islanding [1, 2]. To avoid such issues, islanding should be recognised in a short time to either disconnect each DG unit from the islanded system or adapt its control strategy to the islanding condition so that the system power quality can be kept at an acceptable level [3].…”

“…Islanding detection methods can be divided into four categories including passive [1, 5, 7, 8], active [2, 9–11], hybrid [12–14], and communication‐based [15–17] methods. Passive methods detect islanding using variables such as voltage, frequency, active power, and reactive power measured at the terminal of DG [6, 18].…”