The influence of generator loss of excitation on bulk power system reliability

The possibilities of generator damage and/or a cascading system outage due to generator loss of excitation are investigated. Load flow techniques are used to screen large systems for locations where a generator operating without excitation could endanger system reliability. It is shown that automatic protection using relays with up to two zones of protection and having time delays for each zone will reliably guard against the detrimental effects of loss of excitation in the system and synchronous machines.