Measurements of switching overvoltages in transmission network and power plants

  • Measurements of transient overvoltages especially switching overvoltages in power systems with nominal voltage from 6 kV up to 420 kV
    1. by capacitive dividers in frequency spectrum cca 1 Hz - 1 MHz
    2. by electric field sensors in frequency spectrum 10 Hz - 10 MHz
  • Free potential measurements of transient overcurrents 0,2 A - 20 kA by Rogowski coils in frequency spectrum from 10 Hz to 10 kHz
  • Evaluation of measured data and their analysis
  • Modelling of measured transients using EMTP program
  • Analysis of extraordinary power network states - resonance, ferroresonance - measures for their elimination
  • Design, development and tests of HV dividers


  • Switching overvoltage measurements in 6 kV networks in Power Plants Tusimice, Pocerady, Dukovany, Melník - for Czech Power Company (CEZ)
  • Switching overvoltage measurements in 110, 220 and 420 kV transmission network substations - for Czech Power Transmission Company (CEPS)
  • No load line opening of long overhead line 400 kV - circuit breaker stresses (CEPS)
  • Measurement of overvoltage during disconnector switching in substation 420 kV Chrast (CEPS)
  • Unstability of voltage in circuit of tertiary winding of autotransformer 400/110/10,5 kV in substation Nosovice - elimination of VT ferroresonances (CEPS)