Wind Farm Maintenance
Wind Farms are relatively new which means in regard to maintenance, the asset owner needs to think outside the square. The nature of the design of the installation basically precludes even more traditional forms of insulation testing. Thus, the customer is particularly vulnerable to unplanned outages.
A wind farm operator experienced random, insulation-based, cable termination failures along with dry transformer faults over a 2 year period.
How to ascertain (while on-line and without loss of productivity) the insulation integrity of the
Dealing with Cable Strings
In wind farms the cables from the main substation are connected in strings where at least 5 wind turbines are connected in series. When a cable fault occurs, it affects that entire string. By using On-Line Partial Discharge it is possible to determine which string and where within the string a potential fault is developing. Once located repairs can be planned at the next outage thus ensuring increased reliability.
Dealing with the Dry Transformer
At the base of each wind turbine a step up Dry type transformer is installed. The problem is that most transformers are located adjacent to the access service door where the transformer is exposed to dust and dirt – a difficult problem to overcome. It was not surprising therefore, to discover that the primary cause of the failures was surface tracking caused by the dirty environment which required a change in maintenance practices.