Voltage measuring apparatus for sheathed power cable

A voltage measuring apparatus for sheathed power cable comprising:

• a first conductive member arranged below the sheathing material for sheathing a power cable conductor,
• a second conductive member arranged below said first conductive member,
• a current voltage converting means for conversion into the voltage signal having a waveform proportional to the current signal flowing between said first conductive member and said second conductive member, and
• a voltage value calculating means for calculating the voltage value applied to said power cable from the voltage signal converted by said current voltage converting means and gain coefficient.

A calibrator for a power cable voltage measuring apparatus comprising;

• a means for calculating the voltage applied to the power cable by multiplying a certain voltage value by a gain count,
• a communications means for communication with the outside, and
• a means for changing said gain count based on the information received by means of said communications means;
• said calibrator further comprising;
• a voltage measuring means for measuring the power cable voltage,
• a means for getting information to change said gain counting based on the measured voltage, and
• a means for sending the obtained information to said power cable voltage measuring apparatus.