The two kinds most commonly used are circuit breaker and vcuum circuit breaker. 

They are introduced respectively as follows: Less -oil high voltage circuit breaker and oil circuit breaker: They can be divided into two kinds of more oil and less oil type. More oil circuit breaker basically is not produced due to the huge volume and inconvenient installation and maintainance. Less oil circuit breaker is used for indoor and outdoor substation of all levels of voltage due to its small volume, large flow-breaking capacity and solid structure. At prestent indoor SN-10 less oil circuit breaker is widely used for 10 kV substation, and the indoor type SN4-35 less oil circuit is used for 35 kV substation, SN4-35 less oil circuit breaker is used for outdoor substation and SW6-110 less oil circuit breaker is used for 110KV substation. Its shell is charged, during installation, the insulation between the shell and ground must be noticed. 

Vacuum circuit breaker: it is a new type of high voltage circuit breaker developed in 1960s, which uses vacuum for arc extinguishing. Its advantage is small volume, light weight, fast action, fire-proof and explosion-proof and little noise, etc. Currently it has a tendency to replace other circuit breaker; it is mainly used for the substation below 35 kv and the places of industrial and mining enterprises where operation is frequently done.