Chapter 16: Power Supply Systems for Signalling Installations PDF

Chapter 16: Power Supply Systems for Signalling Installations Section 1: Power Supply General 16.1.1 Power supply for different types of signalling installations shall be in accordance with policy approved by the Principal Chief Signal and Telecommunication...

Chapter 16: Power Supply Systems for Signalling Installations Section 1: Power Supply General 16.1.1 Power supply for different types of signalling installations shall be in accordance with policy approved by the Principal Chief Signal and Telecommunication Engineer of the Railway, if standard power supply scheme from Railway Board/RDSO is unsuitable for a specific application. (a) At all locations, secondary batteries of appropriate capacity shall be provided for signalling circuits. (b) Normal power supply for signalling installations shall be 230 V AC (single phase) or 415 V AC three phase. Any other supply may be used with the specific approval of the Chief Signal and Telecommunication Engineer incharge of the work. (c) Power supply system shall be such that fixed stop signals for approaching train do not become blank when main power supply source fails. (d) Power supply system with secondary batteries of approved type and adequate capacity shall be used for signalling applications. Section 2: Sources of Power Supply 16.2.1 Railway Electrified Area (a) Electric supply for signalling and telecommunication installations in RE areas shall normally be provided through Auxiliary Transformers (ATs) of suitable capacity by tapping 25 KV OHE. (b) On double/multi line sections, the power supply shall be drawn from 25 KV 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. (c) On single line section where power supply is drawn from a single AT, a DG set of suitable capacity shall be installed. (d) At stations where local power supply is also available, it shall act as a stand-by source of power supply. (e) In big yards, DG sets of adequate capacity shall be installed in addition to supply from ATs and local source. (f) 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 source supplies. In addition, manual change over facility shall also be provided in the control panel. The power supply control panel, in coming cable (other than from DG set) and other associated arrangements shall be provided and maintained by Electrical Dept. Chapter 16: Power Supply Systems for Signalling Installations Page 323 of 530  (g) The supply from the power supply control panel as provided by Electrical Dept. shall be taken to various S&T locations by S&T Dept. 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 km of power supply control panel. For locations which are at two km or beyond, a separate set of ATs and power supply control panel shall be provided. (h) In case of IB Signals, separate set of ATs shall be provided, with Automatic change over switch. Note: Please refer to Para No. 20713 of ACTM, Volume-II, Chapter-VII. (i) DG sets, where installed, shall be provided with push button start/stop facility. As per site requirement and feasibility, it shall also be possible to operate remotely. 16.2.2 Non Railway Electrified Area (a) For Colour Light Signalling (CLS) installations, local power supply shall be used as main source of supply. In addition, two standby diesel generators shall be installed. These generators shall be of standard make and of adequate capacity for reliable and trouble free service. (b) The output supply of these generators, along with local supply, shall be brought to the ASM office and connected to auto/manual change-over panel compatible to RE. (c) Solar Photo Voltaic System/Solar Panels (approved type) may also be used as power supply at wayside stations, LC gates in those areas having sufficient sun light and are not theft prone. (i) A solar panel consists of a number of modules (Typically 12 V each) which are connected in series and parallel configuration to provide a specific voltage and current to charge a battery bank, which in turn supplies necessary power supply to signalling and telecommunication applications. (ii) They may be used to charge battery bank of Integrated Power supplies or may be used in for signal lighting by using invertors. Main components of solar photo voltaic system are;  Solar Array  Battery bank  Solar charge controller  Field junction box  Solar Module Mounting Structure  Earthing Kit  Cables Chapter 16: Power Supply Systems for Signalling Installations Page 324 of 530  The number of solar panels to be installed, shall be decided based on requirement of charging current and voltage. Regular cleaning to be done on the surface solar panels to remove dust. (d) For all new installations even in Non RE area, power supply arrangements shall be designed suitable to RE. Section 3: Distribution of Power Supply 16.3.1 Arrangements (a) 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. (b) Visual Indications showing availability of power supplies from various feeders shall be provided for information of the ASM/Gate man. (c) 230 V power supply which is selected from the auto/manual change-over panel shall be distributed to various power equipments such as IPS, transformer-rectifier sets, battery chargers, transformers etc. through a distribution panel. Proper capacity HRC fuses/MCBs, lightening and surge protection devices shall be provided for protection of the equipment against overload and lightning/surges. (d) Power supply system shall be monitored through Datalogger as required. Section 4: Power Supply Equipment 16.4.1 Equipment General (a) All power supply equipment such as battery chargers, transformers, voltage regulators, transformer-rectifier sets, Inverters, Batteries etc. shall be procured as per approved specifications. (b) Battery chargers for axle counters shall have in-built filters to maintain ripple content below specified value. (c) Standby power equipment such as battery chargers, transformers, Voltage regulators, Transformer-rectifier sets etc. may be provided. (d) Secondary cells of prescribed capacities shall be provided for DC circuits. DC-DC converters of approved type with isolated outputs may be used to obtain different voltages from a common Battery bank. (e) Integrated power supply system of approved type shall be used at CLS installations. (f) Maintenance free cells wherever provided, shall be used only with charger suitable for charging maintenance free cells as per approved specification. Chapter 16: Power Supply Systems for Signalling Installations Page 325 of 530  (g) AC supply for signal transformers shall be derived from a voltage regulator of approved type. (h) Separate Transformer shall be used for feeding signals and track feed chargers. (i) The current rating of battery charger may be derived from the following formula - Current rating of charger = Load current + AH/10 capacity of cell. (j) Battery chargers shall not directly feed the line circuit of Block Instruments. Section 5: Installation of Secondary Cells 16.5.1 Charging & Installation (a) Secondary cells of approved type shall be used. The cells shall be installed as per approved drawings. (b) 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). (c) The batteries shall be so installed that they are away from direct rays of sun and any heat radiating equipment. (d) The batteries shall be installed on wooden racks/insulated masonry surface of suitable height with acid proof tiles 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. (e) The batteries shall be kept properly aligned and suitably numbered. An adequate clearance shall be kept between the cells. (f) 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. (g) Battery grade sulphuric acid conforming to IS 266, diluted with distilled water conforming to IS 1069 shall only be used as electrolyte. (h) 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. Chapter 16: Power Supply Systems for Signalling Installations Page 326 of 530  (i) Always acid shall be added to water. During mixing, the solution must be stirred constantly so that its temperature does not exceed 500C. Suitable protection like goggles, rubber gloves & an apron shall be used while working on electrolyte. (j) On receipt of charged secondary cells, level 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. (k) Hydrometer of approved type shall be available in the battery room. (l) At the time of installation, capacity test shall be done and record shall be maintained, by an official not below the rank of SSE/JE (Signal). Section 6: Installation of Power Supply Equipment 16.6.1 Procedure for Installation (a) 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. (b) Transformers and battery chargers of adequate capacity and of air-cooled type shall be provided. (c) Power equipment shall be housed in well ventilated locations/rooms. (d) Wires connecting equipment shall be of adequate size so that there is not more than 0.5% loss in voltage. (e) Battery leads shall be colour coded (Red for positive, Black for negative and Green for earth terminal) and cut to correct length. They shall be crimped/soldered to appropriate terminal. (f) Maintenance instructions for self-regulating battery charger as per IRS:S: 86-2000 are given in Annexure:16-MS2. Installation shall be done by an official not below the rank of SSE/JE (Signal), as per RDSO specification No. IRS. S86-2000 or latest. (g) All power equipment along with suitable SPDs shall be connected to earthing, having earth resistance