Military Engineer Services Tender

Supply, Installation, Testing and Commissioning of outdoor type 4 way 12 KV rated Ring Main Unit of and LT fault Level 21 KA , consisiting of 630A 12 kV rated , 02 nos load break switches as incomers & 2 nos motorized type VCB as outgoings with metering modules along with necessary earth switches, battery and battery charger for shunt trip arrangement and motor and other auxiliary circuit operation, HT Copper bus bar as per detailed description as follows:

(Srl Item No. 1.00 Contd...) RMU Construction: The switchgear and busbar shall all be contained in a stainless steel enclosure filled with SF6 at 0.3 bar (300 kPa) relative pressure to ensure the insulation and breaking functions. Sealed for life, the enclosure shall meet the "sealed pressure system" criterion in accordance with the IEC 62271-1 standard (§ 3.6.5.4): "a volume for which no further gas processing is required during its entire expected life”. In addition, manufacturer shall confirm that maximum leakage rate is lower than 0,1 % / year. It shall provide full insulation, making the switchgear insensitive to the environment (temporary flooding, high humidity...), IP67 degrees of protection in accordance with recommendation IEC 60529 § 14.2.7. Thus assembled, the active parts of the switchgear shall be maintenance-free and the switchboard shall be low-maintenance. The switchboards drives shall have an IP2X protection index. The tank shall be made of at least 2mm unpainted stainless steel. SF6 gas is the preferred dielectric medium for MV RMUs. Oil filled switchgear will not be considered. SF6 gas used for the filling of the RMU shall be in accordance with IEC 60376.Any accidental overpressure inside the sealed chamber will be limited by the opening of a pressure limiting device in the lower part of the enclosure. Gas will be released to the rear or the bottom of the switchboard away from the operator. Number of mechanical operations of Circuit breaker 2000 O/C , Number of electrical operations at full loop current for LBS: 100 O/C , Number of electrical operations at full loop current for CB: 2000 O/C,. Manufacturer shall provide type test report to prove compliance with IEC 62271-200 Annex A, Internal arc classification class AFL with 21kA 1s for the SF6 enclosure. Make of the RMU, vaccum intrtupter , relay & meter shall be of same OEM. All the test certificate shall be in the name of the OEM only . If there is any name change / acquisition by other OEM happened for the RMU then test cerificates shall contain the new OEM name only.

(Srl Item No. 1.00 Contd...) HT system : 3 phase -3 wire , HT Fault level 21 kA, Power System earthing - solindly earthed at up stream source, HT Copper Bus with Short Time Curent rating 21 kA for 3Sec, Continuous current rating at least 630 A. Enclosure of RMU must be IAC rated for 21 kA for 1 Sec. Design ambient to be considered as 40 Deg C. HT Circuit Breaker : i) There shall be 2nos.load break switches as incomings and 2 nos 12 kV rated VCB as outgoing ( total 4 nos.) . The circuit breakers shall be horizontal isolation - horinzontal draw out type. All of the switchgear shall be capable of withstanding this current without any damage being caused, in accordance with the recommendations IEC 62271-1 and IEC 62271-200.Loss of service continuity class: LSC2A ii) The Circuit Breaker must be rated for 12 kV ( nominal Voltage), 28 kV/75 kVp , 3 Phase, 50 Hz, Short Circuit Fault Level of 21 kA for 1 secs. iii) No. Of Close Coils - 01 no. operable at 24 V DC (85% - 110%) , No. of Trip Coils - 02 nos. , operabale at 24 V DC ( 70% - 110%) for shunt trip Feature for series trip shall also be enabled.