Comprehensive investigation of the voltage relay for anti-islanding protection of synchronous distributed generation

Abstract

Summary Interconnection standards prevent islanding operation of distributed generations (DGs) to keep the safety and avoid the equipment failure. To meet this requirement for synchronous DGs (SDGs), the frequency‐based relays are commonly used in the active distribution networks. This paper shows that in some conditions, a voltage relay has better islanding detection performance than a frequency relay regarding the SDG operating point, power factor of loads, and network characteristics. In this paper, a method is proposed for adjusting and evaluating a voltage relay based on application region and power imbalance application region to satisfy the islanding detection and safe and abnormal voltage variation criteria and to eliminate the false operation for the non‐islanding disturbances including load shedding, load restoration, and 3‐phase short‐circuit fault, as far as possible. The relay false operation is studied for a combination of the control mode of SDG excitation system and the load type that leads to the highest possibility of relay false operation for the non‐islanding disturbances. A number of dynamic simulation case studies are conducted to investigate the characteristics and capabilities of the proposed SDG anti‐islanding protection scheme in both single‐ and multi‐DG systems.

Protective Relaying Coordination in Power Systems Comprising Renewable Sources: Challenges and Future Insights

“…Anti-islanding protection can be categorized into three different types as discussed in [125][126][127][128]. In [127], two-level islanding detection procedures are discussed for DGs in DNs.…”

Design and verification of hardcore reconfigurable relay for islanding detection and subsequent mode adaptation of microgrid

“…Some of the important IDTs in literature are detected by over/under voltage, hybrid IDT based on voltage unbalance (VU) and high‐frequency impedance, rate of change of phase angle difference, frequency based IDTs, etc. In a previous study, hardware‐in‐loop (HIL) validation of frequency‐based IDT using Real Time Digital Simulator (RTDS) and commercial (COM) relay is discribed.…”

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

“…Furthermore, in this reference, the ROCOF relay adjusted by PIAR cannot simultaneously satisfy the islanding detection and false operation criteria. Efficient settings are obtained for the frequency‐based and voltage relays in [23, 24], respectively, utilising both AR and PIAR by trial and error. In these references, the goals of the relays adjustment are to detect islanding in appropriate time, satisfy the safe and abnormal frequency/voltage variation requirements imposed by [4], and not operate for the non‐islanding disturbances mistakenly.…”

“…In these references, the goals of the relays adjustment are to detect islanding in appropriate time, satisfy the safe and abnormal frequency/voltage variation requirements imposed by [4], and not operate for the non‐islanding disturbances mistakenly. However, the approaches adopted by Ahmadzadeh‐Shooshtari et al [23, 24] (as well as [6, 22]) are not optimal. Moreover, adjustment of the relays using such methods can be time‐consuming.…”

“…In this paper, the ROCOF relay of SDG, which is the most widely used device for islanding detection among the frequency‐based relays [2, 5, 26], is adjusted by an approach utilising the particle swarm optimisation (PSO) algorithm as well as AR and PIAR. Unlike [6, 22–24], in which AR and/or PIAR are(is) obtained by conducting numerous dynamic simulations, this paper uses analytical formulas to form AR and PIAR, making the relay adjustment process much faster and more convenient. An algorithm is introduced to determine upper and lower boundaries of the frequency‐based relays NDZs required for evaluation of the performance of the relay using PIAR.…”