On the basis of the long time change of fundamental component of leakage current on composite insulators, by using several optimal linear equations to simulate wettability process, the authors firstly summarized the mathematic models to describe the wetting process of composite insulators.

A simple method of detecting leakage current to ground;

Technological analysis of measuring leakage current under condition of exerting DC voltage on winding ends for 200MW generator stator windings;

Design of on-line monitoring for leak current of insulating casing;

The average leak current is less than 0.

Adding a appropriate amount of SiO2 to ZnO ceramics leads to incrcase a value and voltage gradient of the varistor, to decrease leakage current and to raise withstanding surge current, that results in making ZnO varistors with excellent performance.

By using DC test,we found that V-I and IdV/dI-I are indicators of current leakage.

Theoretical and experimental results indicate that the BV peak is an indicator of nonlinearity of laser diodes,and it is correlated with the parallel linear current leakage in laser diodes,and the current leakage can result in the right-shifted BV peak.