The invention discloses an
internal temperature on-line testing method of a
zinc oxide lightning protector with 6-35 KV high-
voltage capacitors connected in parallel, which uses a
thermistor PTC embedded into the
lightning protector to measure the heating condition of a valve plate inside the
zinc oxide lightning protector, thereby judging the running condition of the
zinc oxide valve plate. The method comprises the improvement on the structure of a sleeve inside the zinc oxide lightning protector and comprises the following steps: making a groove on one side of the sleeve; after installing the valve plate, pouring heat-conducting
potting adhesive into the groove, embedding a PTC
resistor into the surface of the
adhesive, leading the wire of the
resistor out from the bottommost part of thelightning protector, and meanwhile, connecting high-
voltage capacitors in parallel on the exterior of the sleeve and the zinc oxide valve plate to improve the performance of the zinc oxide lightningprotector; and after the
potting adhesive is dried, carrying out
die casting. For the leading-out wire of each PTC
resistor, a 5V / 5V
isolation transformer, a rectification circuit and a light emittingdiode constitute a loop; when the PTC resistor senses a temperature change, the resistance value changes, thus, the current flowing through the loop changes, and the
light intensity of the
light emitting diode changes; the
light signal is transmitted to a central processor through an optical cable and restored into an
electric signal through a photosensitive tube to complete the photoelectric isolation and collect the heating condition inside the lightning protector.