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  • Analyses of extraordinary network events - failures and damages of HV equipment - investigations to causes of failures

Analyses of extraordinary network events - failures and damages of HV equipment - investigations to causes of failures

(cases connected with some kind of overvoltage or electrical insulation degradation)

These studies generally involve:

  • Analysis of available event records - oscillograms of voltages and currents
  • Inspection of failed equipment
  • Field mesurements with aim to evoke circumstances of the investigated event - if possible - typically measurements of some type of switching
  • Simulation of measured phenomena in EMTP - approximation of computed data by measurement results
  • Extrapolation of simulation to variety of network states that could lead to investigated event
  • Laboratory HV tests of the equipment of the same type - if it is necessary
  • Assesment of failure causes
  • Recommendation of proper corrective measures for equipment or network

References:

  • Failure of circuit breaker 420 kV in line bay V 413 in substation Reporyje - investigation of causes - Study for CEPS
  • Failure of SF6 current transformer 420 kV in bus coupler bay in substation Chrast and Sokolnice - investigation of causes - Study for CEPS
  • Failure of VT 110 kV in line bay V1527 in GIS Vyskov - investigation to causes - Study for North Czech Power Company
  • Field investigations of capacitive voltage transformers with failures in anti-resonance circuit (CEPS)
  • Failure of current transformer 420 kV in substation Slavetice due to lightning