Operational Experience of Load Shedding and new Operational Requirements on Frequency Relays

Research output: Chapter in Book/Report/Conference proceedingPaper in conference proceeding


This paper summarises experience and analysis of under-frequency load shedding and power generator islanding. Most power systems can withstand the loss of a single generating unit or a single transmission line. Simultaneous loss of several power system components may cause a severe deficit in active and reactive power. The action of overexcitation limiters on the remaining generators may further aggravate the situation. Such infrequent events may cause severe drop in system frequency and voltage magnitude. Frequency relays for load shedding and power generator islanding must operate correctly even if the system frequency decays and the voltage magnitude decays rapidly at the same time


  • Sture Lindahl
  • G. Runvik
  • G. Stranne
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Other Electrical Engineering, Electronic Engineering, Information Engineering


  • active power frequency decay frequency relays generating unit operational experience overexcitation limiters power generator islanding power systems reactive power transmission line under-frequency load shedding voltage magnitude decay
Original languageEnglish
Title of host publication[Host publication title missing]
Publication statusPublished - 1997
Publication categoryResearch
Event6th International Conference on Developments in Power System Protection (Conf. Publ. No. 434) - Nottingham, United Kingdom
Duration: 1997 Mar 251997 Mar 27


Conference6th International Conference on Developments in Power System Protection (Conf. Publ. No. 434)
CountryUnited Kingdom