Method and device for measuring high voltage devices using a correction factor

A method of measuring a characteristic of an electrical insulation system of a high voltage device connectable to an electrical network, the method comprising the following steps:

• a) disconnecting the high voltage device from the electrical network and connecting a measuring equipment to the electrical insulation system, thereby providing a test system,
• b) connecting an inductor to the test system,
• c) determining a reference frequency,
• d) determining an insulation temperature of the electrical insulation system,
• e) determining an equivalent frequency based on the insulation temperature, a reference temperature, a reference frequency, and the activation energy of the electrical insulation system,
• f) determining a measuring frequency of the measuring operation, wherein the step of determining the measuring frequency comprises the following steps:
• determining the capacitance of the test system,
• determining possible inductances connectable to the test system,
• g) based on the capacitance of the test system and possible inductances, determining the measuring frequency at or close to resonance, measuring at least one of capacitance and loss at the measuring frequency (C_m, Loss_m) and at the equivalent frequency (C_e, Loss_e),
• h) providing at least one correction factor (C_corr_C, Loss_corr_C) according to the following formulas:
• C_corr
• ⁢
• _C
• =
• C_e
• /
• C_m
• ⁢
• Loss_corr
• ⁢
• _C
• =
• Loss_e
• /
• Loss_m
• i) and applying at least one correction factor on measurement results at the measuring frequency to obtain corrected measurements results corresponding to the reference frequency and at the reference temperature.