The development of Vacuum SF6 Gas based circuit breakers has begun the end of oil and air blast based circuit breakers which have ruled the medium voltage switchgear for more than Half a Century. With the superior dielectric and arc interruption properties the Vacuum and SF6 Circuit breakers have not only out classed the Oil Circuit Breakers but also improved the user and environment friendliness and opened the door of newer applications like Vacuum Contactors and Auto enclosures. This paper draws up the latest scenario in the field of Medium Voltage Switchgear and assists the user to choose the best from newer technology.

Jyoti Limited has been in the forefront of Switchgear technology for more than three decades. Jyoti's medium voltage Vacuum Circuit Breakers, manufactured in collaboration with the world leaders in vacuum Switchgear technology - TOSHIBA Japan, has created a niche for itself among quality conscious utilities and industries, in India and abroad. Jyoti's Switchboards are custom built to satisfy varying needs of customers such as Power Stations, Fertilizer Plants, Refineries, other large and medium Industries. This paper gives the salient features and the specifications of the medium voltage switchgear in details.

Vacuum Contactor offers most economical and superior alternative for the applications where long switching life and high switching frequency are required i.e. switching of motors. The combination of fuse-backed Vacuum Contactors helps in interrupting the rated load current by Vacuum Contactor, while the higher fault current by fuse. The Thermal rating for the down stream equipments like CTS, cables etc. is considerably reduced due to cut-off characteristics of the fuse. Such devices are working satisfactorily for more than a decade at various installations in India.

The salient features for the Vacuum Contactors are discussed in this paper and the advantages brought about by this combination has been clearly highlighted.

In Medium Voltage Switchgear, installations, Switching surges are unavoidable. The switching surges are generated while switching Circuit Breakers 'ON' and 'OFF'. The magnitude of Switching Surges depends on characteristic of load, as well as the chopping current of the switching devices.

In this article the causes of overvoltages have been described. Various applications and the remedial measures to suppress the surge magnitude as well as to reduce its steepness are discussed.

Minimum Oil Circuit Breakers have ruled the Medium Voltage Switchgear market for nearly fifty years. These Circuit Breakers suffer from two distinct disadvantages. First they require lot of maintenance as the switching life is limited, and second, they are prone to fire hazards. There has been a definite trend to replace Minimum Oil Circuit Breakers with Vacuum Circuit Breakers. In this paper, experience of M/s. Jyoti Limited in retrofitting 12 kV Minimum Oil Circuit Breakers by Vacuum Circuit Breakers has been narrated.