Research Article

Failure analysis of collector circuits associated with wind farms

School of Engineering, Faculty of Science, Engineering and Built Environment, Deakin University, Geelong Waurn Ponds Campus, Geelong, VIC 3220, Australia

^* e-mail: aclifto@deakin.edu.au

Received: 15 January 2017
Received in final form: 7 July 2017
Accepted: 27 July 2017

Abstract

Wind farm collector circuits generally comprise several wind turbine generators (WTG’s). WTG’s are connected in parallel to a substation. This connection acts as the point-of-connection to the national electricity grid. The electrical load in these circuits is close to component (power cables and accessories) ratings. The objective of this paper is to identify cable joint failure paths; and, develop an understanding of specific contributing factors. All findings presented were established from literature review involving data analysis and discussion with industry experts working across the wind industry. Application of forces, inadequate workmanship, incorrect thermal resistance or other contributing factors, all contribute to high conductor operating temperatures. High conductor operating temperatures highlight issues including insufficient environmental heat transfer due to the use of inadequate cable trenching materials. This in turn results in the imbalanced application of force, experienced at the cable joint, as a direct result of frequent thermal expansion and contraction. For most cable joint failures, the root cause is insulation breakdown due to sustained deterioration of the cross-linked polyethylene insulation. This is a direct result from excessive operating temperatures.