Effect of High Harmonics Voltage on Dielectric Properties of Crosslinked
Polyethylene Insulated Cable
Yoshinobu NAKAMICHI, Hiroyasu TODA, Kohji AJIKI, Hiroyuki NOZAWA
In the superconducting MAGLEV system using a linear synchronous motor (LSM),
the power converter for driving LSM is installed on the ground. As one of
the useful power converters, a PWM (pulse width modulation) inverter has been
developed. The output voltage of the PWM inverter contains much harmonics
caused by PWM controller. Crosslinked polyethylene insulated cable (CV cable)
has been adopted as a feeder cable for MAGLEV power supply system, and
accordingly the voltage with much harmonics, which is produced by PWM inverter,
loads on the CV cable.
Therefore, the electric strength of CV cable under the voltage with much
harmonics, which has never been studied so far, has come to be recognized as a
very important thing in developing MAGLEV. Authors have investigated the
electric strength of CV cable under AC voltage of high frequency superimposed
on AC voltage of commercial frequency to simulate the output voltage of PWM
inverter.
This paper gives an outline of specific generator, designed for this purpose,
which can generate a particular high-voltage waveform mentioned above; and
it illustrates the characteristics of CV cable after long-term voltage endurance
test.