Study on Application of High-Energy Nonlinear PTC Resistor for Deexcitation of Generating Units

摘要

This article studies the two properties of high-capacity and high voltage withstanding PTC thermistor, namely conductivity and breaking. Through judicious applications, the rotor current could be quickly switched from the main contact of the magnetic blowout to PTC branch circuit with low resistance. After many comparative de-exciting tests, it has been revealed that series & parallel connection of high-power PTC and ZnO components could turn on/off breaker with low-arc or even without arc, improving the residual voltage of non-linear resistor and rapidly absorbing the magnetic energy stored in the exciting winding for an optimum de-excitation, which could meet the de-exciting requirements for various-scale generating units.