IMPROVING PERSONAL SAFETY IN MV-NETWORKS THROUGH NOVEL EARTH-FAULT CURRENT BASED FEEDER PROTECTION

Thumbnail Image

Files

CIRED 2019 - 695.pdf (1.12 MB)

Paper number

695

Working Group Number

Conference name

CIRED 2019

Conference date

3-6 June 2019

Conference location

Madrid, Spain

Peer-reviewed

Yes

Short title

Convener

Authors

Wahlroos, Ari, ABB Oy, Finland
Altonen, Janne, ABB Oy, Finland
Pitkänen, Risto, -, Finland
Kauppinen, Sakari, JE-Siirto Oy Jyväskylän Energiayhtiöt, Finland

Abstract

In this paper a novel method for earth-fault (EF) protection applicable in high-impedance earthed networks, especially in resonant earthed networks, is described. The innovative method is not based on traditional zero-sequence quantities (Uo, Io), but on accurate estimation of EF-current (IF) flowing at the fault location. Estimation of EF-current is done utilizing changes in phase currents measured at the beginning of the feeder due to an earth fault. Thanks to its novel operation principle, the method has several advantages over the traditional state-of-art EF-protection methods such as the wattmetric method. The method enables automatic adaptation of protection operation speed according to the estimated EF-current magnitude, including the harmonic content, which further enhances the accuracy and practicality of the novel protection method. The estimated EF-current magnitude can be converted into corresponding touch voltage magnitude, which enables direct compliance of protection operation to the electrical safety codes, such as EN50522. In this paper, first the theory and operation principle of the new method is described. Then the performance of the suggested protection algorithm is validated using data from a field test in practical 20kV resonant earthed network. The results show that the novel method enables significant improvement on safety and overall dependability of the protection schemes used today.

Table of content

Keywords

Publisher

AIM

Date

2019-06-03

Published in

CIRED 2019 Conference

Permanent link to this record

https://cired-repository.org/handle/20.500.12455/120
http://dx.doi.org/10.34890/245

ISSN

2032-9644

ISBN

978-2-9602415-0-1