Off-line analysis of the load response during large voltage variations

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


The load response during and after a severe fault is critical for transient stability. This risk increases with the presence of induction motors in the load area. This paper provides analysis of the load voltage characteristic under large voltage variations. Field measurements from a noneffectively earthed system, from phase-to-phase faults at the 50 kV-level in Sweden, have been used. The time-varying load parameters, resistance R(t) and reactance X(t), have been determined from measurements of phase-voltages and currents. Estimates of the active, reactive and apparent power have been calculated. The results show that commonly used models are inaccurate during large voltage variations. The load uncertainty critically increases with the size of the voltage changes since its nonlinear behavior accentuates for more system stressing conditions. This fact is more noticeable for the reactive load characteristic


Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Other Electrical Engineering, Electronic Engineering, Information Engineering


  • apparent power, reactive power, active power, currents measurements, phase-voltages measurements, reactance, resistance, time-varying load parameters, Sweden, phase-to-phase faults, noneffectively earthed system, field measurements, load voltage characteristic, off-line analysis, induction motors, power system dynamic stability, power system transient stability, load modeling, 50 kV, load uncertainty
Original languageEnglish
Title of host publication2004 IEEE/PES Transmision and Distribution Conference and Exposition: Latin America
PublisherIEEE - Institute of Electrical and Electronics Engineers Inc.
ISBN (Print)0-7803-8775-9
Publication statusPublished - 2004
Publication categoryResearch
Event2004 IEEE/PES Transmission and Distribution Conference and Exposition: Latin America - Sao Paulo, Brazil
Duration: 2004 Nov 82004 Nov 11


Conference2004 IEEE/PES Transmission and Distribution Conference and Exposition: Latin America
CitySao Paulo