Indian Railways Telecom Manual - AC Power Supply Distribution

AC Power Supply Distribution Arrangements

• Existing installations will continue with existing arrangements of AC Power Supply Distribution for Telecom Equipments.
• New installations shall follow the guidelines stipulated in the manual.
• Incoming AC Power Supply from various sources (AT Transformer, Local Power Supply, Diesel Generator Power Supply, Solar Panel Power Supply) shall be terminated in an AC Distribution Board.
• The AC Distribution Board shall have a facility of changeover from one incoming source to another.
• Incoming AC Power Supply on the AC Distribution Board shall be terminated through MCCBs & MCBs of adequate capacity.
• Outgoing Single Phase AC Power Supply for individual Telecom Equipment from the AC Distribution Board shall be through MCBs of adequate capacity.
• Integrated Surge & Transient Protection Devices shall be provided in the AC Distribution Rack for sensitive Telecom Equipments.
• AC Distribution Board shall have sufficient spare capacity to accommodate anticipated future expansion.

DC Power Plant System

• Battery Chargers and Voltage Stabilizers shall be provided in all Telecom installations.
• Charger capacity should be minimum C/10 + load, where C is the AH of the battery.
• DC Distribution Board can be “wall mounted metallic enclosure” or “floor mounted cubicle”.
• Incoming DC Power Supply shall be terminated in the DC Distribution Board.
• Incoming DC Power Supply on the DC Distribution Board shall be terminated through DC MCB of adequate capacity.
• Outgoing DC Power Supply for individual Telecom Equipment from the DC Distribution Board shall be through DC MCBs of adequate capacity.
• DC Distribution Board shall have sufficient spare capacity to accommodate anticipated future expansion.

Requirement of Power Supply Room(s)

• Power Supply Room(s) shall be dry, cool, well lighted, and well ventilated.
• Exhaust fans shall be provided to remove fumes in all Power Supply Rooms where secondary batteries are installed.
• It is desirable that window glasses shall be frosted or painted wherever necessary to prevent direct sun rays falling on the cells.
• Power Supply Room(s) shall have a water sink and universal (5A & 15A) electric power plug for connection to the hand lamp.
• The Power Supply Room(s) where secondary batteries are installed shall be provided with acid-resistant tiles on the floor and the walls up to 1.5 M.
• A thermometer to measure the room temperature should also be kept in the battery room.
• All cable entry points should be rodent-proof.

Maintenance of Secondary Cells

• Cable to connect battery terminals and load should use proper color code of wires.
• The battery room shall be kept well ventilated, free from water, oil, and dust.
• Surroundings of batteries shall be kept clean.
• Acid-proof reusable hand gloves and Hydrometer to be provided.
• Hydrometer should be kept on a Wall Mounted Stand in the Battery Room.
• Connecting cables shall be flexible and sufficiently long to prevent strain on the battery terminals.
• Connecting lugs shall be fitted to battery posts/terminals by using suitable nuts/bolts & tightened by using flat and spring/serrated washers.
• Lugs at the end of conductors, utilized for making connections, shall be crimped and/or brazed.
• The electrical connections shall always be kept tight.
• Check nuts should also be used to maintain firm connections.
• The terminals and connections of battery cells shall be coated with pure vaseline or petroleum jelly to prevent corrosion.

Power Supply Systems for Telecom Installations

• This chapter discusses the power supply requirements for various Telecommunication Equipments.
• All Telecom Equipments shall be provided with a reliable Power Supply.
• Telecom System/Equipments like Public Address System, Passenger Information Display System, Wifi equipment, Video Surveillance System (Close Circuit TeleVision), Centralised Clock System, Voice Logging Equipments, Railnet, Video conference equipment, Datacom Equipment of PRS, FOIS, UTS, etc. operates on 230 V AC Power Supply.
• Telecom System/Equipments like Train Radio System, Optic Fibre Equipment, Multiplexing Equipments, Telephone Exchanges, etc. operates on 48 V DC Power Supply.
• Train Traffic Control Equipment operates on 12/24/48 V DC. VOIP based TTC may work on standard AC power supply (230 V AC) too. Datacom Equipment of SCADA operates on 48/110 V DC or 230V AC.

Diesel Generator Set Maintenance

• Lubricating oil shall be changed periodically as per the manufacturer's data for engine hour run.
• Diesel generator sets shall be overhauled in accordance with the manufacturer's recommendation.
• Checking and cleaning of parts shall be done once in every three months or as the situation warrants.
• It is preferable to have them overhauled by the manufacturer or their authorized representative.
• Automatic Starting Device shall be tested periodically for effective starting during power failures and low voltage conditions.
• The no-load and on-load voltages of the alternator shall be maintained within limits and the Governor adjusted during periodic maintenance to the RPM specified and a steady output of 50Hz.
• The DG set shall run for 5-10 minutes on load to verify its proper working during periodic maintenance check.
• A log book shall be maintained at every location, which shall bear the history of performance and maintenance of Diesel Generator Set together with the signatures of the maintainers and SSE(Telecom).

Maintenance of Power Supply System

• The working of battery charger shall be checked for proper working of switches, fuses, etc.
• Power equipment shall be cleaned by a blower or any other device to remove dust.
• Battery Measurement & Maintenance:
  • Cell Number
  • Date
  • Parameter (Cell Voltage, Specific Gravity)
  • Work done & remarks
  • Signature & Designation

Maintenance Schedule for Power Supply System

• Battery:
  • Cleaning of all connections: Fortnightly
  • Tightening of all connections: Monthly
  • Checking of working: Weekly
  • Measurement of voltages & load current: Weekly
• Chargers:
  • Cleaning of all connections: Fortnightly
  • Tightening of all connections: Monthly
  • Checking of working: Weekly
  • Measurement of voltages & load current: Weekly

Maintenance of Solar Panel

• Cleaning of Solar panel: Fortnightly
• Measurement of terminal voltage of solar panel: Fortnightly
• Measurement of current of solar panel: Fortnightly

Electrolyte Maintenance

• Electrolyte loss due to spillage shall be replenished with proper amount of electrolyte of the same specific gravity as that of remaining electrolyte in the cell.
• Electrolyte shall not be added under any other circumstances.
• Each cell shall be tested as per maintenance schedule so that its voltage and specific gravity are within specified limits.

Records and Reports

• The inspector in-charge of Telecom Installation and remote control centre shall arrange to maintain:
  • Record of interruptions of main power supply and utilisation of the DG set with details of each duration.
  • Record of supply and utilisation of diesel fuel.
  • Prepare monthly interruption reports of mains supply/upkeep/utilisation of DG set and send to Sr.DSTE/Dy.CSTE(Tele).
• Sr.DSTE/Dy.CSTE(Tele) shall analyse the monthly report and take follow-up action with concerned divisional officers as to minimise the interruption of the main power supply.

Remote Monitoring and Control System

• The arrangement shall be approved by PCSTE of the Railway.
• It shall have the following features:
  • Facility of remote monitoring and control of the power plant systems.
  • Provide vital alarms to the remote monitoring system through NMS / Data Logger/ Mobile app/software using mobile communication facilities etc.
  • The control system shall be capable of accepting and reacting to following vital commands from the remote monitoring centre.