Composite hollow core insulators

Hollow core insulators - dry power frequency voltage test

EGU – HV Laboratory a.s. has been performing electrical and mechanical testing of insulators for decades. As hollow-core insulators represent special design within post insulators other tests are required also to fully qualify those products.
New tests according to IEC 61462 and IEC 62772 have been introduced to the company testing portfolio to cover the majority of the hollow-core testing range.

Testing facility:

  • Composite hollow core insulators


  • Electrical and mechanical design and type testing
  • Thermal-mechanical testing:
    post - 50 kN / 2000 mm
  • Mechanical testing:
    post - 50 kN / 2000 mm
  • Internal Pressure Test (design test):
    Stage 1: Gas leakage test as per IEC 61462, cl.
    Hollow-core insulator samples filled with a gas under required pressure
    Tests done in a special sealed chambre
    Gas leakage detection by means of a special detection device
    On-line monitoring of gas leakage
    Stage 2: Water Leakage Test as per IEC 61462, cl.
    Test samples filled with water by means of a special pump up to SIP
    Water leakage detection
  • Internal Pressure Test (type test):
    Testing as per IEC 61462, cl. 8.4
    Tests done at three stages » related to different maximum service pressures
    Hollow-core samples filled with water by means of a special pump
    Strain condition monitoring before and after the testing » special strain gauges

Housing material testing:

  • salt fog, tracking wheel testing including leakage currents monitoring
  • Housing material testing: fl ammability, UV, X-ray SEM / EDX – in cooperation with other external accredited labs.

Special mechanical testing:

  • cantilever, torsion, compression and special mechanical testing in cooperation with an external accredited testing lab in Prague



Activities at IEC and CIGRE:

  • IEC TC 36/SC36C/PT
  • IEC TC36/MT15
  • CIGRE C4.3.03
  • Cigre D1.44 / CIGRE D1.45