Basic Info
Model NO.: IST-11/631
Structure: Three-column Disconnector
Operation: Manual
Movement Mode: Horizontal Rotary Type
Grounding: Single Ground
Run: Turn the Horizontal
Structure of Operating: Manual
Brand: Oei Power
Specification: IEC IEEE
Type: High-voltage
Installation: Outdoor High-voltage
Grounding Mode: Grounding
Number of Poles: Three Pole
Series: Three
Common Model: Ist
Certification: IEC IEEE
Origin: China Zhejiang

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 61694:2112: Common Specifications for High Voltage Switchgear and Controlgear BS 729: Hot dip galvanized coating on iron and steel articles
IEC62271-112
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 2211m above sea level, humidities of up to 91%, average ambient temperature of +31篊 with a minimum of -1篊 and a maximum of +41篊 and heavy saline conditions along the coast.

4.2. DESIGN AND CONSTRUCTION
4.2.1 The Isolator, Solid Link shall be designed and constructed in accordance with IEC 129 and IEC 61694.
4.2.2 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.
4.2.3 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.
4.2.4 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.
4.2.5 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.
4.2.6 All steel parts shall be hot dip galvanized to BS 729. The minimum coating of galvanizing required is 81 microns.
4.2.7 The solid link shall be removable from the mounting by use of operating rod.
4.2.8 All current carrying parts of the isolator shall be made of high conductivity material.
4.2.9 The isolator shall be fitted with clamp connectors for Aluminium (ACSR) conductor of Aluminium (ACSR)conductor of up to 18.2mm diameter.

The rating of the complete isolator shall be as follows: -
Rated voltage
36 kV
Rated frequency
51 Hz
Rated lightning impulse withstand voltage
211 kV
Rated power frequency withstand voltage, dry
95 kV
Rated normal current
411 Amps
Rated short time withstand current for 3 sec, min.
18.1 kA
Minimum creepage distance of insulators
911 mm