A Non-Standard Characteristic Based Protection Scheme for Distribution Networks

Hasan Kılıçkıran,İbrahim Şengör,Bedri Kekezoğlu,Hüseyin Akdemir,Nikolaos Paterakis

doi:10.3390/en11051241

Hasan Kılıçkıran, İbrahim Şengör + Show 3 more

Open Access

https://doi.org/10.3390/en11051241

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Abstract

The increasing number of distributed generation (DG) units in the distribution systems poses a challenge on protection systems in terms of coordination. In addition, the single characteristic based conventional protection causes an increase in the primary operation time of the relays due to the coordination between relay pairs. As a consequence, earlier studies investigated the utilization of non-standard characteristics and protection schemes in order to ease the insufficiencies of the standard approach. However, a commonly accepted protection approach that mitigates the effect of DG while providing lower primary operating time by levering the benefits of the non-standard protection strategy has not been developed so far. In order to overcome the aforementioned drawbacks of traditional protection, this paper firstly introduces a non-standard characteristic and then proffers an unconventional protection strategy, which utilizes a double characteristic. The suggested protection approach is tested on the IEEE 14 Bus distribution system including synchronous generator based DG connection. The results show that the proposed characteristic and protection scheme are able to provide a substantial decrease in the operation time of the relays while meeting the coordination requirements.

Highlights

Considering the integration of distributed generation (DG) units to a meshed distribution system, this paper presents a non-standard relay characteristic that utilizes both current and voltage measurements, and a protection scheme in which relays are operated with the double characteristic consisting of distinct relay characteristics for primary and backup operation
In a classical protection approach, precaution options against the effect of DG are limited because the standard characteristic depends only on the current measurement
Based on the programmable structure of digital relays, the propounded characteristic and protection scheme are devised as an alternative to the classical approach

Summary

Introduction

Protection systems are responsible for detecting and clearing the faulty part of the power system and preventing the spread of fault to the rest of the system. As the thermal stress on power system equipment decreases with the response time of the protective equipment, the operation time is one of the vital issues in protection systems [1]. Increase in reliability of protection systems is provided by coordination between primary and backup protective equipment, which is referred to as protection coordination. Coordination requirements increase the primary response time of protective equipment due to the nature of the traditional protection approach [2]. The growing share of distributed generation (DG) units in distribution systems jeopardizes the ability of protection systems to operate in a coordinated manner [3]. The traditional protection scheme is established by assuming the fault direction

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