Dielectric stress, design and validation of MV switchgear

Thumbnail Image

Files

CIRED 2019 - 771.pdf (1.06 MB)

Paper number

771

Working Group Number

Conference name

CIRED 2019

Conference date

3-6 June 2019

Conference location

Madrid, Spain

Peer-reviewed

Yes

Short title

Convener

Authors

Prévé, Christophe, Schneider Electric, France
Maladen, Romain, Schneider Electric, France
DAKIN, Garret, SCHNEIDER-ELECTRIC, United Kingdom
GENTILS, Francois, SCHNEIDER-ELECTRIC, France
Piccoz, Daniel, SASU Daniel PICCOZ, France

Abstract

Medium voltage switchgear is a key component within electrical power distribution networks. It is designed and tested for safe and reliable operation under various operating conditions. Medium voltage air-insulated switchgear (AIS) and gas-insulated switchgear (GIS) have to be validated according to the requirements of international standards like IEC 62271-1 and IEEE C37.100.1 for instance. The dielectric design is optimized with an extensive use of simulation and experimental test validations required by standards, customers specifications or defined by the manufacturers of switchgear for its own quality. That ensures insulation reliability in various applications and operating environments. The first part of this paper concerns dielectric stresses of switchgear during its operational life under real network conditions. The appearance of overvoltages through lightning strokes or switching operations is analysed. The second part of this paper concerns dielectric design and validation of MV AIS switchgear depending of environmental conditions (humidity, salt, dust…) and in particular the impact on insulation ageing and potential degradation. Insulation techniques (GIS and AIS) and testing procedures are discussed. The degradation of the external insulating of AIS is demonstrated and can be mitigated by the choice of an higher value of the dielectric BIL or power frequency withstand (example for 12 kV rating: 95 kV BIL instead of 75 kV BIL or 42 kV instead of 28 kV 50 Hz). On the other hand, no additional margin on the dielectric withstand is necessary for protected insulation (GIS).

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/20.500.12455/146
http://dx.doi.org/10.34890/294

ISSN

2032-9644

ISBN

978-2-9602415-0-1