Upgrading the protection and grounding of generators at petroleum and chemical facilities

Significant changes have occurred in the protection of generators in the past 10 years, which impact generators at petroleum refineries and chemical plants. This paper discusses these changes as well as the risks of not addressing them. It specifically addresses the risks in seven functional areas where 20+ year old generator protection is inadequate. These areas include sensitive ground fault protection, unbalanced current protection, field ground fault protection, over excitation protection, inadvertent (accidental) generator energizing protection and high speed loss of field protection. In addition, the paper discusses hybrid grounding of the generator stator windings, which substantially reduces stator ground fault damage - avoiding lengthy generator outages. This new concept in generator grounding was introduced in a series of IAS I&CPS Generator Grounding Working Group papers published in 2002. This paper highlights upgrading generator fault protection using digital technology.