1.0 Power Supply, Air-conditioning & Ventilation and Other General Electrical Assets:
1.1. The activities are distributed in four sections:
· Power Supply Distribution and Third Rail.· Air-Conditioning, Ventilation, False Ceiling & Lighting.· Escalators & Lifts
· Pumps and general assets.
1.1.1.Power Supply Distribution and Third Rail:
· 33kV Power Supply is received from CESC at four Receiving Substations (RSS) viz. Shyambazar, Central, Jatin Das Park & Noapara /RSS. 33KV supply is extended from Shyambazar & Jatin Das Park RSS to Masterda Surya Sen (Bansdroni) RSS. The voltage is stepped down to 11 KV and fed to 19 nos. Traction substation and 34 nos. Auxiliary substations located at stations & mid points. All the Receiving Substations are interconnected through 33 kV cable network and all the Traction & Auxiliary Substations are interconnected through 11 kV cable network to maintain power supply in case of failure of power supply at any of the RSS. In the Traction Substations (TSS), 11 kV is stepped down to 604 Volts, rectified to 750 Volts D.C. and fed to 3rd rail for traction purpose. In the Auxiliary Substations (ASS), 11 kV is stepped down to 415 Volts for lighting, Air conditioning and Ventilation, Pumps, Escalators, Signalling and Telecommunication etc.
· In addition to the 33kV sub-stations mentioned above, there are two receiving sub-stations, one at Metro Rail Bhawan and another at Belgachhia, where power from CESC is received at 6 kV, basically for auxiliary loads.
· 3rd rail between Dakshineswar and Kavi Subhash is fed at 19 Traction Substations with average spacing of 1.58 Km. From Traction Substations, 750 Volts D.C. is fed to 3rd rail through DC High Speed Circuit Breakers and cables. Power Supply is controlled through SCADA system from centralised Traction Power Control located at 4th floor of Metro Bhawan.· Routine maintenance of these assets is done departmentally. Major repair/replacement work is carried out by contractual agencies as per requirement.
1.1.2. Air Conditioning, Ventilation and Lighting:
· All 15 underground stations of Kolkata Metro are equipped with ventilation and air-conditioning system. There are 149 no. ventilation fans working as supply or exhaust fans. The supply fans deliver fresh and cool air to station premises and tunnel sections, whereas the exhaust fans remove air from under platform and mid-tunnel points.· The centralised type station air conditioning system consists of water-cooled chillers, cooling tower, cooling coils and associated ducting. The AC plant capacity for each station ranges from 600 TR to 1200 TR.The use of air washery has been discontinued thereby achieving energy saving. In lieu, dry type filters have been installed. · LED tubes are used for station and tunnel illumination. The switching of lighting system is done through SCADA system as per need during commercial & non-commercial hours. All stations are provided with emergency Light. Emergency Lighting system is provided with battery backup. Diesel Generator sets are also available at Dakshineswar and Baranagar. All the 15 underground stations are provided with aluminium false ceiling with perforation for minimising noise level inside the station. Mural lighting has been provided at stations for beautification purpose. · Routine maintenance of Air Conditioning & Ventilation system is done through outsourcing whereas routine maintenance of lighting system is done departmentally1.1.3. Escalators & Lifts:
·Ninety-eight (98) nos. escalators in service have been installed at 26 stations. Of these, 40 nos. are for carrying passengers from platform to mezzanine and 23 nos. from mezzanine to surface. 26 nos are from concourse to platform and vice-versa. 05 nos. at Dum Dum station & 02 nos at Kavi Subhash, are meant for carrying passengers from ground level to platform and vice-versa and 02 escalators are installed at Tollygunge subway. Thirty nine (39) nos of Escalators have been installed including new as well as replacement in the last year two year (2020-2021) & (2021-2022) at different stations of Metro Railway. In the underground section no passenger lift has been provided. In the elevated section (Netaji – Kavi Subhash) 10 nos lifts have been provided between concourse level and platform level for physically challenged and aged person. At Dumdum station 2 lifts have been provided from ground floor to platform in the year 2015 and 2017. At Dakshineswar 3 lifts have been provided between concourse and platform and 1 lift has been provided between surface to concourse. At Baranagar 2 lifts have been provided in between surface to platform. 2 nos lifts have already been provided at MUK station for passenger, which are commissioned on 02.10.2021. There are 4 no lifts (out of which 3 nos are replaced in the year 2021-2022) which are provided at maintenance depots office and eleven (11) no. Service lifts(out of which 6 no are replaced in the year 2021-2022) are provided at Metro Rail Bhavan and residential complexes. Three (3) patient lifts have been provided at TSM Hospital. Routine maintenance of lifts and escalators are outsourced.
2.1.1.Pumps and Other General Service Assets:
·There are 153 nos Dewatering Pumps of different capacities installed in sump pits at different locations to pump out seepage water, effluent of toilet, sanitary effluent etc. and discharged into Municipal sewer. All these pumps are made “ON” and “OFF” automatically by water level controller.
·There are 53 nos Tube well Pumps of different capacities installed at different locations to meet water required for platform cleaning, drinking, fire fighting etc.
·Periodical maintenance and performance checking of pumping system is done for reliable service. Routine maintenance of pump is done departmentally and repair activity is outsourced.
·Other assets include passenger amenity items like water coolers & illuminated signage, approximately 40,000 LED tube light fittings, fans, battery and battery chargers, UPS, window and split air conditioners, are installed at Station premises, service sub stations, colony and service buildings etc.
2.1.2. Power Requirement:
The approximate Contract Demand for the different receiving sub-stations is as under.
| Name of the RSS | Voltage | Contract Demand |
| Shyambazar | 33 kV | 7.5 MVA |
| Central | 33 kV | 10.5 MVA |
| Jatin Das Park | 33 kV | 10 MVA |
| Noapara | 33kV | 2.5 MVA |
| Metro Rail Bhawan | 6 kV | 0.25 MW (commercial) |
| Belgachhia | 6 kV | 0.08 MW (domestic) |
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During winter the demand is reduced.
2.1.3.The Stores Depot at Noapara caters to the material requirement (stock items) for maintenance of power system.
