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