Disconnectors can be classified into various types based upon their constructional features and mounting arrangement. The major types of disconnectors are: • Centre-break disconnectors • Double-break disconnectors • Pantograph disconnectors • Horizontal break knee disconnectors • Vertical break disconnectors • Coaxial disconnectors These are selected based upon the sub-station layout, clearances available and space constraints.
Switch disconnector A
switch disconnector combines the properties of a disconnector and a load switch, so it provides the safety isolation function while being able to make and break nominal currents.
Integrated disconnecting switch In a
disconnecting circuit breaker the disconnectors are integrated in the breaking chamber, which eliminates the need for separate disconnectors. The intention of this combined device is to decrease maintenance and increase
availability and
reliability. The usage of this device instead of a disconnector is limited due to the fact that the open gap is not clearly visible and many doubts in term of safety arise during maintenance activities. Where it is adopted the earthing switch must be used and the performance must be increased by the typical value. The open-air disconnecting switches typically need maintenance every five years (every two years under very polluted conditions), while circuit breakers have maintenance intervals of 15 years. ==See also==