Experimental Study on the Effect of Temperature on tan δ Measurement of 110 kV Voltage Transformer

Voltage transformer as a substation important equipment, assuming the role of measurement, control and protection. Equipment in the operation process is susceptible to temperature and other factors that cause insulation defects, need to carry out regular insulation preventive testing. In this paper, we take 110 kV series-type voltage transformer as the research object, and use four different wiring methods to explore the changes of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\tan \delta$</tex> value and capacitance under different ambient temperatures, insulating oil temperatures, and insulating oil moisture conditions, to verify the applicability and reasonableness of the relevant values in the Regulations, and to provide an effective basis for the series-type voltage transformer to determine the insulation faults of the equipment through the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\tan \delta$</tex> value. The results show that the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\tan \delta$</tex> value increases with the rise of temperature under different wiring methods, while the capacitance is basically unchanged; the end shielding method is the most sensitive to the moisture of insulating oil under different temperature conditions; when the insulation is normal, the conventional inverse wiring is more sensitive to the temperature change; when the insulation is faulty, the conventional positive wiring is more sensitive; to determine whether there are insulation defects of voltage transformers should be measured by the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\tan \delta$</tex> value in lower temperature as the main criterion, and the Kegulations” will be used to determine whether there are insulation defects of the series type voltage transformer through the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\tan \delta$</tex> value. Judgment of whether the voltage transformer insulation defects should be measured at lower temperatures <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\tan \delta$</tex> as the main criterion, Kegulations” in the relevant <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\tan \delta$</tex> value criterion should be adjusted in a timely manner.