CHAPTER -XVI

POWER SUPPLY ARRANGEMENTS

16.1 GENERAL

16.1.1 Power supply arrangements for different types of signalling installations shall be in accordance with policy approved by the Chief Signal and Telecommunication Engineer of the Railway.

16.1.2 Primary cells may be used for signalling circuits where either there is no power supply or it is very unreliable and the current drawn is small. Wherever possible solar panel (s) in conjunction with secondary cells of suitable capacity may be provided.

16.1.3 At all other locations, Secondary Batteries of appropriate capacity shall be provided for signalling circuits.

16.1.4 Normal power supply for signalling installations shall be 230V AC (single phase) 415 AC three phase or any other supply may be used with the specific approval of the Chief Signal and Telecommunication Engineer of the Railway to meet any specific requirements.

16.1.5 Power supply system shall be such that fixed stop signals for approaching train do not become blank when main power supply source fails.

16.2 SOURCES OF POWER SUPPLY

16.2.1 Railway Electrified Area.

16.2.1.1 Electric supply for signalling and telecommunication installations in RE areas shall normally be provided through auxiliary transformers (ATs) of suitable capacity by tapping 25KV OHE.

16.2.1.2 On double/multi line sections, the power supply shall be drawn from 25KV OHE through ATs provided on up and down OHE lines separately. It shall be ensured that supply from at least one AT is available in the event of power block.

16.2.1.3 On single line section where power supply is drawn from a single AT, a DG set of suitable capacity shall be installed.

16.2.1.4 At stations where local power supply is also available, it shall act a stand-by source of power supply.

16.2.1.5 In big yards, DG sets of adequate capacity shall be installed in addition to supply from ATs and local source.

16.2.1.6 The power supply from auxiliary transformers (ATs), local source and DG set (s) shall be brought and terminated at a power supply control panel in ASM's office/cabin or at LC gate as required. The power supply control panel shall be provided with the facilities for automatic change over between two ATs. In addition, manual change over facility shall also be provided in the control panel. The power supply control panel, cable (other than from DG room) and other associated arrangements shall be provided and maintained by Electrical Deptt.

16.2.1.7 The supply from the power supply control panel as provided by Electrical Deptt. shall be taken to various S&T locations by S&T Deptt.

16.2.1.8 The supply from the power supply control panel shall be extended through separate MCBs to cabins, LC gates, telecom installations etc. if these are falling within two kms of power supply control panel. For location beyond two kms, a separate set of ATs and power supply control panel shall be provided.

16.2.1.9 DG sets where installed shall be provided with push button start/stop facility from ASM office/ cabin/LC gate as the case may be.

16.2.2 Non Railway Electrified Area

16.2.2.1 For Colour Light Signalling (CLS) installations, power supply shall be drawn from the station feeder. In addition, two standby diesel generators shall be installed. These generators should be of standard make and of adequate capacity for reliable and trouble free service.

16.2.2.2 The output supply of these generators shall be brought to the ASM office and connected to Auto/manual change-over Panel.

16.2.2.3 Solar panels or other renewable source of energy may also be used as power supply.

16.3 DISTRIBUTION OF POWER SUPPLY

16.3.1 The selected supply from the Auto/manual change-over panel shall be distributed to installations/cabins at the station through underground power cables of approved type. Proper capacity HRC fuses/Miniature circuit breakers (MCBs) shall be provided to protect against overload/short circuits.

16.3.2 Visual Indications showing availability of power supplies from various feeders shall be provided for information of the ASM.

16.3.3 230V power which is derived from the auto/manual change-over panel shall be distributed to various power equipments such as transformer-rectifier sets, battery chargers, transformers etc. through a Distribution Panel. Proper capacity HRC fuses/MCBs shall be provided for protection of the equipment against overload etc.

16.4 POWER SUPPLY EQUIPMENT

16.4.1 All power supply equipment such as battery chargers, transformers, voltage regulators, transformer-rectifier sets, inverters, batteries etc. shall be procured as per approved specifications.

16.4.2 Battery chargers for axle counters shall have in-built filters to maintain ripple content below specified value.

16.4.3 Standby power equipment such as battery chargers, transformers, Voltage regulators, Transformer-Rectifier Sets etc may be provided.

16.4.4 Secondary cells of prescribed capacities shall be provided for DC circuits. DC-DC converters with isolated outputs may be used to obtain different voltages from a common Battery-bank.

16.4.5 Integrated power supply system of approved type may be used at CLS installations

16.4.6 Maintenance free cells wherever provided shall be used only with charger suitable for charging maintenance free cells as per approved specification

16.4.7 AC supply for signal transformers shall be derived from a voltage regulator of approved type.

16.4.8 Separate transformer shall be used for feeding signals and track feed chargers.

16.4.9 The current rating of battery charger may be derived from the following formula -

 Current rating of charger = Load current     +          AH capacity of cell                                                                                       10

16.4.10 Battery Chargers shall not directly feed the line circuit of Block Instruments.

16.4.11 For operating signal machines of semaphore signals and for their lighting, solar power packs of approved type may be used as far as possible.

16.5 INSTALLATION OF PRIMARY CELLS

16.5.1 Primary cells of approved type may be used in circuits such as those indicated below which do not involve continuous and heavy intermittent discharge:-

a) Electric Key Transmitters;

b) Arm & Light Repeaters;

c) Repeater Circuits;

d) Track/Treadle Circuits (Open type);

e) Single Line Block Instruments - line and local circuits;

f) Double Line Block Instruments - line and local circuits;

g) Tokenless Block Instruments - line circuits;

h) Magneto Phones and annunciators.

16.5.2 Primary cells shall be stored in a cool dry place. The period of storage shall be no longer than absolutely necessary.

16.5.3 When installing primary cells, they shall be located in a dry place which is not subject to extreme heat. For connecting cells, stranded insulated wires of appropriate gauge shall be used. The ends should be skinned and scraped bright to make good connection with cell terminals. Terminals should be firmly tightened. The connected wires shall be neatly dressed.

16.5.4 The date of installation shall be marked on each cell.

16.6 INSTALLATION OF SECONDARY CELLS

16.6.1 Lead acid cells of an approved type shall be used. The cells shall be installed as per approved drawings

16.6.2 The batteries shall be installed in separate room/apparatus case to avoid damage to power equipment due to fumes. The battery room shall be provided with acid proof flooring and acid proof tiles on walls up to a suitable height. The battery room shall be well ventilated and provided with exhaust fan (s).

16.6.3 The batteries shall be so installed that they are away from direct rays of sun and any heat radiating equipment.

16.6.4 The batteries shall be installed on wooden racks /insulated masonry surface of suitable height to permit easy access for maintenance. The racks shall be protected by two or more coats of acid resistant paint of approved type. The racks shall be level and mounted on approved type of insulators. Where batteries are housed in location boxes, these housings shall be painted with acid resistant paint and shall have suitable openings/holes for ventilation.

16.6.5 The batteries shall be kept properly aligned and suitably numbered. An adequate clearance shall be kept between the cells.

16.6.6 Initial charging of the batteries shall be done as per instructions of the manufacturer and the date of charging shall be suitably painted on the batteries, or on a separate board kept near the batteries.

16.6.7 Battery grade dilute sulphuric acid conforming to IS 266 and distilled or de-mineralised water conforming to IS 1069 shall only be used as electrolyte.

16.6.8 A glass, porcelain, rubber or any other acid proof container shall only be used for mixing acid and water. Metal utensils except lead must not be used as these will contaminate the electrolyte.

16.6.9 Always acid shall be added to water. During mixing, the solution must be stirred constantly so that its temperature does not exceed 50� C.

16.6.10 On receipt of charged secondary cells, the vent Plugs shall be removed and the height of the electrolyte shall be noted. If it is below the prescribed level, the loss may be due to spillage during transit. The level of the electrolyte can be restored by adding battery grade acid of recommended specific gravity.

16.6.11 A hydrometer of approved type shall be available in the battery room.

16.6.12 At the time of installation, capacity test shall be done and record shall be maintained.

16.7 INSTALLATION OF POWER SUPPLY EQUIPMENT

16.7.1 The power supply equipment shall be so installed as to facilitate easy replacement of equipment without affecting the other circuits as far as possible. It is desirable to provide ring main type of power supply arrangement at large stations.

16.7.2 Transformers and battery chargers of adequate capacity and of air-cooled type shall be provided.

16.7.3 Power equipment shall be housed in well ventilated locations/rooms.

16.7.4 Wires connecting equipment shall be of adequate size so that there is not more than 0.5% loss in voltage.

16.7.5 Battery leads shall be colour coded and cut to correct length. They shall be crimped/soldered to appropriate terminal.

16.7.6 Installation and Maintenance instructions for self regulating battery charger as per IRS:S:86-2000 are given in Annexure 15. Initial installation shall be done by an official not below the rank of SSE/SE (Signal).

16.8 INSTALLATION OF DG SET

16.8.1 DG sets shall be installed in a separate room of adequate size with proper ventilation.

16.8.2 The diesel generator set shall be mounted on anti-vibration pads.

16.8.3 The exhaust pipe shall be extended outside the generator room and the silencer fixed away from the premises. Exhaust pipe shall be appropriately insulated.

16.8.4 . The starting battery shall be of adequate capacity to meet the starting load. Where automatic
start has been provided, the generator once started should stop only with a time delay after Main supply is resumed.

16.8.5 The connection between the battery and the DG Set shall be through sufficiently thick wire to avoid drop in voltage.

16.8.6 The starting battery shall normally be on trickle charge.

16.9 MAINTENANCE OF PRIMARY CELLS

16.9.1 Each cell shall be tested individually with a load of 10 ohm resistance and if the voltage of cell falls below 0.85V, then the cell shall be discarded. The voltmeter used for this purpose shall have the sensitivity of not less than 1000 ohms per volt.

16.10 MAINTENANCE OF SECONDARY CELLS

16.10.1 Maintenance tests and repair work on the cells, which may interfere with safe operation of trains shall not be started until movements are fully protected. Temporary repairs or adjustments shall be made in such a manner that safety of train operation is not impaired when repairs and or adjustments are made: Tests shall be immediately carried out to ensure that the connected apparatus functions satisfactorily.

16.10.2 The battery room and location boxes shall be kept well ventilated, free from water, oil or dust. Surroundings and batteries shall be kept clean.

16.10.3 Connecting cables shall be flexible and sufficiently long to prevent strain on the battery terminals.

16.10.4 The electrical connection shall always be kept tight.

16.10.5 The terminals and connections shall be coated with pure Vaseline or petroleum jelly to prevent corrosion. Grease shall not be used.

16.10.6 The Electrolyte shall be maintained at the correct level by topping up as often as necessary with distilled or demineralised water.

16.10.7 Electrolyte lost due to spillage shall be replaced with proper amount of electrolyte of the same specific gravity as that of other cells of the battery. Electrolyte shall not be added in any other circumstances.

16.10.8 Each cell shall be tested periodically and its cleaning and charging arranged so that its voltage and specific gravity are within specified limits. Test results and dates of cleaning and charging adjustments shall be recorded on the Battery History Card No. S&T/BCP-Annexure 16. A separate card shall be maintained for each battery set. The voltage of individual cell shall not fall below 1.85 volts.

16.11 MAINTENANCE OF POWER SUPPLY EQUIPMENT

16.11.1 The Change-over panel in ASM office shall be kept in good working condition. Defects, if any, shall be promptly rectified.

16.11.2 The working of standby voltage regulator, transformer, battery charger, rectifier, inverters etc., provided in power equipment room shall be checked including proper working of switches, fuses, MCBs, terminals, meters etc. during scheduled maintenance. Units shall be switched from active to standby as per local instructions.

16.11.3 The power equipment shall be cleaned by blower or any other suitable device to remove dust etc.

16.11.4 The wiring shall be checked to ensure that wires are in good condition and connections are properly tightened.

16.11.5 Record of voltages and load current of all power equipment shall be maintained. Remedial action shall be taken in case any abnormality is observed.

16.11.6 Insulation of transformers shall be meggered at 500V annually.

16.12 MAINTENANCE OF DG SET

16.12.1 Fuel tank shall be cleaned periodically. Fuel shall be filled through a wire gauze filter which shall form part of fuel tank. Before filling up, unused fuel shall be decanted/replaced if the DG set has been idle for a considerable time.

16.12.2 Lubricating oil shall be periodically checked and proper level maintained.

16.12.3 The maintenance of DG set shall be undertaken by qualified and trained Mechanics.

16.12.4 After 1000 hours of run, the diesel generator sets shall be overhauled. It is preferable to have them overhauled by the manufacturer or his authorised representative.

16.12.5 Leakage of fuel oil, lubricating oil and radiator water shall be effectively checked.

16.12.6 Radiator fan shaft shall be grease lubricated and worn out shafts replaced. Radiator hose and fuel oil hose shall be checked for leakage and replaced in time.

16.12.7 Automatic Starting Device, where provided, shall be tested periodically for effective starting during power failures and low voltage condition.

16.12.8 Flexible coupling between the engine and the alternator shall be checked for elongated holes and replaced in time.

16.12.9 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 50 Hz. The DG set shall be run for 5-10 minutes on load to verify its proper working during periodic maintenance check.

16.12.10 A log book shall be maintained at every location which shall bear the history of performance and maintenance of DG set together with the signatures of the Maintainers and SE (Signal).

16.12.11 Wherever auto start is not reliable, the same shall be disconnected and steps taken for manual start/hand cranking of the generator during power failure and also to stop the engine as soon as power supply resumes. Steps shall be taken to rectify the auto start as early as possible.

16.12.12 Adequate number of spares in respect of the following items shall be kept ready with the SE (Signal) for speedy maintenance replacements:

1) Fuel Filter;
2) Oil Filter;
3) Fuel Pipe;
4) Pressure Pipe;
5) Air cleaner;
6) Nozzle;
7) Ring set;
8) Fan Belt;
9) Grease;
10) Lubricating Oil; &
11) Cotton waste 'A' grade

16.12.13 Maintenance of Fuel Account

16.12.13.1 Where standby generators are provided at way side stations for signalling purposes and starting and stopping the standby engine is done by Traffic Staff, suitable instructions for maintenance of fuel account shall be issued locally. The log book shall be maintained by the ASM (Annexure 14).

Annexure 14

Para 16.12.13.1

_________Railway ___________Division

FUEL CONSUMPTION LOG BOOK

Page1

1. Name of Station:

2. Date of commissioning:

3. Location:

4. Description of Generator:

(Make, Capacity in KVA, Voltage, Power Factor, Speed in RPM, Frequency, No. of Phases, Type of Excitation etc.)

5. Description of Engine:

(Make, BHP, Speed in RPM, No. of Cylinders, Capacity of Fuel Tank, Fuel, Standard rate of consumption, Type of start).

Page2

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Annexure 15

Para 16.7.6

INSTALLATION AND MAINTANANCE INSTRUCTIONS FOR SELF REGULATING BATTERY CHARGER AS PER IRS : S 86 - 2000

(A) Output current rating less than 50 A

Various Front panel controls, switches and indications are given in Sketch No. SDO/CH/ 009 enclosed.

1 INITIAL COMMISSIONING

1.1 Auto Mode Working

a) Connect Earth terminal (#8) to earth. After connecting the 230V AC mains to input terminals at the back of the charger, Switch ON the unit by changing the ON/OFF Switch (# 5) to "ON" position. Indication Mains ON (green LED) will glow.

b) Set the Mode selector switch in "Auto" position provided inside the charger.

c) Since there is no battery connected across the battery terminals, the charger will come in Auto Float mode immediately. Indication Auto Float will glow. Adjust the Float voltage to 2.15V/Cell. (25.8V for a 24V charger/12.9V for 12V charger) by adjusting Voltage control pot provided on the Control PCB inside the charger.

d) Current control potentiometer is provided on the control card PCB inside the charger to adjust the output battery current of the battery charger as per actual battery current requirement. The control will permit the continuous variation from 25% to 100% of the rated current. These correspond to 25%, 50%, 75%, and 100% of the rated output current. The current across battery terminals should not exceed 10 % of AH capacity of the battery (i.e. C10 rate of charging). The use of current control pot. is explained by the following, example.

Example
Sometimes a higher current rating battery charger is used at site for charging a lower AH capacity batteries. For example, only 10A rating charger is required for charging 40AH battery set (Clause 1.4, Note 1 of the spec.) However, If 20A rating charger is connected to a 40AH battery set, the Current Control pot. shall be adjusted to "50%" of the rated value therefore the rating of the charger becomes 10A. As long as the Current control pot. remains at 50% position the total output current of the charger ( Load current + Battery current) will not exceed 10A. Therefore overcharging of batteries can be avoided by making use of the Current control pot.

If the AH capacity of the batteries is matching with the charger output current rating (Clause 1.4, Note 1 of the spec), the Current Control pot shall be kept at "100% position"

e) Connect batteries across the battery terminals (#9). With mode selector switch in Auto mode, the charger is in "Auto float mode". But if the current drawn by the batteries changes by more than 8 to 12% of the set current, the charger automatically changes to " Auto Boost Mode" and its output voltage changes to 2.4 V/cell (28.8V in case of 24V charger and 14.4V in case of 12V charger). It comes back to "Auto float mode" when the current drawn across battery terminals drops down to less than 5% of C10 rate and battery voltage builds upto 2.4V/Cell. This happens after the batteries have almost got fully charged.

f) In this mode of working Manual Voltage Selector switch (#4) is ineffective and therefore need not be touched.

1.2 Manual Mode

a) Connect Earth terminal (#8) to earth. After connecting the 230V AC mains to input terminals at the back of the charger, Switch ON the unit by changing the ON/OFF Switch (#5) to "ON" position., Indication Mains ON (green LED) will glow.

b) Change Mode selector switch provided inside the charger to manual position. The charger comes into manual mode and indication amber LED glows.

c) Change manual voltage selector switch (#4) to first, second or third position as per the No. of cells connected to the charger.

d) Connect the load across the load terminal, the output voltage should be 2.25V per cell with the load connected across the load terminal.

e) Initial setting in manual mode is to be done by the SSE/SE (Signal) depending on the load connected. ESM of the station should closely monitor the battery charger as per instructions of the SSE/SE (Signal)

f) Manual mode is to be used when "Auto mode" fails. Manual mode is an unregulated mode where the output voltage changes with change in AC input voltage, and output load. Therefore, the maintainer should keep a watch so that batteries are not overcharged.

2 PROTECTIONS AND INDICATIONS

[ To be checked at the time of initial installation ]

a) Indication Mains ON (green LED) appears as soon as ON/OFF switch is switched "ON".

b) When in auto mode, indications Auto Float or Auto Boost will appear depending on whether the charger is in Auto float or Auto boost mode.

c) Switch ON the charger in Auto mode and short the load terminals. Short circuit indication should glow and charger output becomes zero. If short circuit is removed, the indication extinguishes and the charger gives the required output without any other adjustment. The charger should not trip.

3. ROUTINE OPERATION (BY ESM)

a) Normally the charger will be working in Auto mode. Once it is initially commissioned in "Auto Mode" by the SSE/SE (Signal), no adjustment is required to be done by ESM.

b) Change over to Manual mode

i) When "Auto mode" fails, the Mode Selector Switch provided inside the charger shall be turned to Manual position.

ii) Manual Voltage Selector Switch (#4) may be kept in position 1,2 or 3 depending on load/battery charging requirement.

iii) Failure of Auto mode will be immediately informed to SE (Signal), who in turn will check up the charger as soon as possible.

4. ROUTINE MAINTENANCE

a) During the visit of ESM on duty to the station, he must check the front panel of the battery charger for correctness of the indications. The indications displayed must be in conformity with the mode in which the charger is working. If not so , he must refer to para 3 above, changeover the battery charger to manual mode and report the failure to SE (Signal)

b) The ESM will check the tightness of the connections to battery and load terminals on the front panel and tighten the same if found loose.

c) If everything is normal and indications on the charger front panel are in conformity with the mode of working, the ESM shall not disturb the control switches of the charger.

(B) Output current rating more than 50A

Additional protections and indications are provided for chargers of output ratings 50A and above. These are -

a) Fuses

i) Rectifiers/SCR fuse

ii) Condenser fuse

b) Alarms (Audio & Visual)

i) Main fuse blown

ii) Output fuse blown

iii) SCR/Rectifier fuse blown

iv) Overload/Short circuit

v) Condenser fuse blown

The installation & commissioning procedure is same as that for the charger of current rating less than 50A. There is an additional audio alarm resetting switch/ button on the front panel which is required to be pressed by the ESM on duty to silence the buzzer/hooter. The visual indication will continue till the fuse is replaced or the fault rectified.

Annexure 16