HV/EHV class

On-site Diagnostic Testing of the HV/EHV class of Transformers:

 

Our experience spans across power transformers of all voltage class up to1200kV and rating up to 500 MVA.

 

  • Voltage Ratio and Vector group confirmation test,
  • Frequency Response Analysis (FRA),
  • No-load excitation current measurement
  • Capacitance and dissipation factor measurement of the inner insulation
  • Capacitance and dissipation factor measurement of high-voltage bushings
  • Impedance measurements (short-circuit impedance, zero sequence impedance, FRSL method)
  • Analysis of winding damages with the FRA method
  • Partial discharge measurements of power transformers
  • Moisture analysis of paper insulation by dielectric method (PDC+ FDS) .
  • OLTC operation and dynamic contact resistance measurement,
  • Winding Resistance Measurement
  • Thermography , Noise , Vibration Measurement
  • Routine Oil test, DGA, Furan
  • DP test of paper insulation.

 

 

On-site Testing of the HV/EHV class of Current Transformers

It is intended to perform automatic testing by CT Analyser on-site for utilities with very less testing time or by Primary injection test . The following tests can be performed:

 

  • Burden measurement
  • CT winding resistance measurement
  • CT excitation characteristic according to IEC 60044-1, IEC 60044-6 (TPS,TPX,TPY) and IEEE C57.13. for knee-point voltages (up to 15 kV).
  • CT ratio measurement with consideration of a connected burden
  • CT phase and polarity measurement
  • Determination of accuracy limiting factor, instrument security factor,
  • Test of CTs for knee-point voltages (up to 15 kV).
  • Capacitance and dissipation factor measurement of the inner insulation
  • Capacitance and dissipation factor measurement of high-voltage bushings
  • Partial discharge measurements of power transformers
  • Moisture analysis of paper insulation dielectric method (PDC+ FDS)
  • DGA test of oil.

 

On-site Testing of the HV/EHV class of Potential Transformers and CVTs

  • Capacitance and dissipation factor measurement
  • Partial discharge measurements
  • Primary injection test.
  • Moisture analysis of paper insulation by dielectric method (PDC+ FDS) .
  • IR value with Polarization Index (PI) & Absorption Index (AI),
  • DC Resistance measurement

 

On-site Testing of the HV/EHV class Surge Arrestors

  • Leakage Current monitoring , Leakage Current/ Resistive Current
    3rd Harmonic Resistive component  Measurement
  • Capacitance and dissipation factor measurement of the inner insulation on per stack basis
  • IR value with Polarization Index (PI) & Absorption Index (AI),