TECHNICAL SPECIFICATION FOR LOW TENSION (FIXED) SHUNT CAPACITOR UNITS (MPP TYPE) FOR DISTRIBUTION TRANSFORMERS Spec. No. MSEDCL/Dist:MSC-III/ LT MPP CAP/11/2009/R0
ELECTRICAL CHARACTERISTICS & FEATURES:
Capacitors of rating 25 & 30 KVAR shall be of three phase having metalized (Silver, Zinc, Aluminum) polypropylene (MPP) type material complying with IS: 13340/1993, IS 13341/1992, or IEC 831-1 (with latest version amendments). Capacitors shall be protected by internal fuses as per IS 12672/1989. Capacitors shall be ISI marked.
The capacitor unit shall be Heavy Duty with modular construction and provided with suitable device per module (inductor coil) to control the inrush current. The capacitor shall have self-healing property & each module shall have the pressure sensitive safety device/ internal fuse elements and shall be suitable for 200 times rated current to take care. The capacitor unit shall be self-cooled totally vermin proof & suitable for outdoor use.
The material used in the capacitor unit shall be of superior quality. Three terminals of the capacitor unit shall be covered with suitable enclosure cover on which MCB of suitable ratings will be clamped/fixed. Connections from the capacitor unit shall be brought out to the MCB. There should be provision for cable entry from bottom for connection of MCB to LT side of the Distribution Transformer. Three Nos. LED indicators shall be provided on the container to be connected between MCB and capacitor for indicating the working status on each phase of the capacitor unit. LED indicators may be provided across a suitable series resistance to indicate failure of capacitor. The capacitor container shall be provided with a clearly marked earth terminal.
The capacitor shall be provided with discharge resistor, which will discharge capacitor when switched off to less than 50V in one minute. In addition a suitable mechanism should be provided for verifying the status/working condition of Capacitor unit. (LED's etc).
General requirement is as follows.
Sr. Particulars No.
1 2 3 4 5
6 7 8 9 10
Rated voltage Rated frequency Rated KVAR Phase & Connections Maximum over voltage
Maximum over current.
Capacity tolerance. Temperature. Loss (Watts/KVAr)
440 Volts 50 Hz 25, 30 KVAR, 440V (poly phase) 3-phase Delta connected. 1.1 times Rated Voltage for Max. duration 12 hrs. in every 24 hrs 1.15 times Rated Voltage for Max. duration 30 min. in every 24 hrs
times Rated Current.
5% to 10%
25° C to 50° C
Max. ambient temperature 50° C
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