Disconnector Center Break Isolator and Double Break Isolator Center
DISCONNECTOR TYPE:GW4-72.5DW/5000A , 7
2.5 KV,5000A,SHORT TIME WITHSTAND CURRENT40(KA),,
MODE OF OPERATION:THE MAIN ISOLATION SWITCH: MOTORIZED-THE EARTH SWITCH:MOTORIZED,WEIGHT 700KG
Disconnector for 220kV Substation
Center- breaker disconnectors GW4(up to 550kV)
Introduciton;
These disconnectors are , no load switching devices which physically isolate the lines. They are designed for
horizontal outdoor application and can also be designed for vertical installation. For earthing and closing of
switchyard portions of the installation, the earthing switches are provided on disconnector. If required.
The following documents were referred to during the preparation of this specification. In case of conflict, the
provisions of this specification shall take precedence.
IEC 129:1975: Alternating Current Disconnectors (Isolators) and Earthing Switches
IEC 60694:2002: Common Specifications for High Voltage Switchgear and Controlgear
BS 729: Hot dip galvanized coating on iron and steel articles
IEC62271-102
Isolator (Disconnector) - a mechanical switching device which provides, in the open position, an isolating
distance in accordance with Electrical Safety requirements.
SERVICE CONDITIONS
The isolator shall be suitable for continuous operation outdoors in tropical areas at altitudes of up to 2200m
above sea level, humidities of up to 90%, average ambient temperature of +30ºC with a minimum of -1ºC and a
maximum of +40ºC and heavy saline conditions along the coast.
DESIGN AND CONSTRUCTION
1 The Isolator, Solid Link shall be designed and constructed in accordance with IEC 129 and IEC 60694.
2 The isolating link shall be of the vertical opening, designed for single phase manual operation. It shall be
easily removed and replaced by using a portable operating rod.
3 The isolating link shall incorporate double porcelain insulators to suit voltage requirements and mounted on
hot dipped galvanised steel under base suitable for vertical mounting.
4 The isolating link shall be arranged so that each unit is mounted independently on an angle bracket. It shall
be supplied complete with the angle bracket and accessories suitable for mounting on 'U' type steel channel.
The drawings to be submitted shall indicate all the applicable mounting positions.
5 The isolator shall be designed such that in fully open position, it shall provide adequate electrical isolation
between the contacts on each phase. It shall conform to the requirement as single point isolation for safety.
6 All steel parts shall be hot dip galvanized to BS 729. The minimum coating of galvanizing required is 80
microns.
7 The solid link shall be removable from the mounting by use of operating rod.
8 All current carrying parts of the isolator shall be made of high conductivity material.
9 The isolator shall be fitted with clamp connectors for Aluminium (ACSR) conductor of Aluminium
(ACSR)conductor of up to 18.2mm diameter.
Main Technical Data :
Rated voltage:12-550kV
Rated current: up to 5000A
Rated frequency:50/60Hz
Short time withstand current :up to 63kA
Mechanical endurance:M2
Ice breaking capacity:10-20mm
Rated insulation level:According to the latest IEC 62271-1
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