ALL YOU NEED TO KNOW ABOUT DISCONNECTORS / ISOLATORS

DISCONNECTOR / ISOLATOR

Fig 1.1 - S&S Power Switchgear Limited 

A disconnector is used in transmission lines and grid substations to disconnect or isolate the power source for maintenance purposes or bus transfer. 

We can operate the disconnector manually or motorize with the help of the operating mechanism. For safety purposes, The disconnectors are paired with earth switches. 

Types of Disconnectors :

Centre Break, Double Break and Pantograph

Centre Break Disconnector

Centre break disconnector provides isolation by breaking at the centre of two insulators mounted parallel to each other

Components of centre break :

1. Disconnector Base
2. Insulators
3. Support structure
4. Rotating hamper assembly
5. Fixed contact assembly
6. Interphase coupling pipes
7. Interlocks
8. Operating mechanism

Fig 1.2 - S&S Power Switchgear Limited
Centre Break Disconnectors at PGCB

Double Break Disconnector

Double break disconnector provides isolation by way of circuit disconnections at the two ends incoming and outgoing. The components of double break are similar to the components of centre break.

For double break disconnector image, please refer to Fig 1.1

Pantograph Disconnector

The pantograph disconnectors provide a connection between busbars positioned at two different vertical levels.

The pantograph isolators are mainly used in substations as well as in railways.

Components of pantograph disconnector :

1. Trapeze contact
2. Scissor assembly
3. Mainframe assembly
4. Support insulators
5. Operating rod insulator
6. Support structure
7. Operating mechanism
8. Interlocks

Fig 1.3-S&S Power switchgear LTD
Pantograph disconnector at Malawi

For better understanding, take a look at the video given below.

In this video, you get to know about the working of all types of disconnectors discussed earlier.