After experiencing a number of arc flash events at their facilities following an OSHA inspection, a major US utility contracted ENERCON to assess the risk of potential future arc flash events and analyze all major electrical equipment at more than 50 power generating stations, including fossil fuel, wind, and solar. One of the generating stations contained over 150 wind turbines.
Instead of installing new protective devices to limit arc current, ENERCON brought an innovative approach to explore all possible analysis scenarios.
ENERCON completed the arcing current hazard evaluations by generating individual computer models for each power generating station. For each model, ENERCON defined zones of interest – those areas where work could be performed and where electrical properties were unique or bounding.
The project team utilized techniques such as defining bounding conductor lengths for generating sources, bounding the transformer analysis based on size, and carefully considering whether a protective device can provide protection to multiple conductors in a specific zone.
By carefully defining the zones of interest, ENERCON limited the complexity of the computer models and limited the extent of input data.
Using the ENERCON developed results, the utility considered several mitigation strategies in the zones of interest to provide the necessary safety measures:
- What if workers wore personal protective equipment (PPE) in certain areas?
- Special work tools and procedures to limit the exposure
- Modify or upgrade the equipment to limit the risk
- Could certain non-essential equipment be temporarily de-energized?
- Latest IEEE findings to refine the arcing current risks
By evaluating the benefits of multiple solutions and minimizing the zones of interest considering the unique and bounding electrical properties at the power generating facilities, this utility client developed a cost effective arcing current safety mitigation plan.