With/without gap:without gap,equipped disconnectorMaximum continuous operating voltage (MCOV):6.6KVApplicable Codes and Standards:
Service Conditions:1) Surge arrester shall be suitable for operation under the service conditions as per SPI latest of General Specification.2) The surge arresters and its fittings shall withstand the effect of direct solar radiation at their installed locations. The temperature of exposed surfaces shall be regarded as 75ºC plus the effect of internal heating.3) All locations are subject to sand storms and arresters shall therefore be designed to preventingress/deposit of sand over the outer and inner surface of surge arresters.Design and Construction:1) This SPI covers one type surge arrester namely Metal oxide non line arrestor type gapless, designedfor outdoor service and shall be housed in sealed casing to prevent ingress of moisture and dust.
|ANSI C62.1||Standard specification for surge arrester for AC|
|NEMA LA1||Standard specification for Surge Arresters.|
|IEC 60099-4||Standard specification for non-linear resistor|
Type arrester for A.C. system.
|IEC TC37- Part-3|
|Standard specification for metal oxide type arrester without spark gaps.|
2)Metal oxide non-linear resistor type gapless: An arrester having one or more non-linear metal oxideresistors, connected in series and/or parallel but having no integrated series or parallel spark gaps.
3) Duty Class :Surge arrester distribution classes shall be as defined in IEC 60099-4
IEC 60099-45KA Arrester-light duty class.10KA Arrester-heavy duty class.5KA,10KA
4) Over Pressure Relief Device :Arrester shall be provided with a pressure relief device, a mean for relieving internal pressure in an arrester and preventing explosive shattering of the housing following prolonged passage of flow current or internal flashover of the arrester.
5) Disconnection Feature :Disconnector shall be incorporated. It is a device for disconnecting an arrester from the system in the event of arrester failure to prevent a persistent fault on the system and to give visible indication of thefailed arrester.
6) Insulator Detail :All the insulator shall have the rated withstand voltage given in Technical Specification. Creepage distance is based on nominal line-to-line voltage and shall be 25/40mm/KV minimum for dry and wet areas respectively. Insulator sheds shall be designed to minimize trappingof contamination. It can either be made of polymer or porcelainhaving glazed brown or gray color. The polymer should be "Siliconrubber housing made by direct molding method".7) Mounting Arrangement :
Mounting arrangement shall be vertical or horizontal. NEMA type mounting brackets shall be provided to facilitate mounting of arresters on angle or channel iron type cross arms.8) Corrosion Protection :All metal parts shall be hot dip galvanized in accordance with the standard with exception tostainless steel.