Indian Railways Electrification PDF

TRACTION DISTRIBUTION 1.0 INTRODUCTION : 1.01 In 1955, French National Railways (SNCF) demonstrated that 25 KV single phase, 50 cycles (Industrial Frequency ) A.C. system is superior to other types of Electric Traction. Initially, in 1957 Indian Railways...

TRACTION DISTRIBUTION 1.0 INTRODUCTION : 1.01 In 1955, French National Railways (SNCF) demonstrated that 25 KV single phase, 50 cycles (Industrial Frequency ) A.C. system is superior to other types of Electric Traction. Initially, in 1957 Indian Railways adopted this system for their Electrification scheme in collaboration with SNFC. After acquiring the know how the Indian Railways are now carrying out the Electrification works independently. PLAN WISE PROGRESS OF ELECTRIFICATION ON I.R. 1. Plan RKM Plan RKM Period Electrified Cumulative Period Electrified Cumulative Pre Indep 388 388 6th 1522 6440 1945-47 1980-85 1st 141 529 7th 2812 9252 1951-56 1985-90 2nd 216 745 Inter Plan 1557 10809 1956-61 1990-92 3rd 1678 2423 8th 2708 13517 1961-66 1992-97 Annual Plan 814 3237 9th 2484 16001 1966-69 1997-2002 4th 935 4190 10th 1810 17811 1969-74 2002-2007 5th 533 4723 11th 1299 19942 1974-78 Upto 31.3.2009 Inter Plan 195 4918 1978-80 First Electric Train BINA to KATNI (C.RLY.) 16.1.1995 On 2 x 25 KV AC Traction 1.2.1 Electrification Progress Year wise in shown in Fig.1. INDIAN RAILWAYS TOTAL TRACK = 63327 RKM ELECTRIFIED upto 31.3.2009 = 18942 RKM % ELECTRIFIED = 29.85% Over Head Equipments Page 4 Over Head Equipments Page 5 1.3 COST OF ELECTRIFICATION The approximate average cost of electrification is as under : PER RKM DOUBLE LINE SINGLE LINE For 25 KV AC TRACTION 1 crore 75 Lakh For 2X25 KV AC TRACTION 94 LAKH (1995) 1.4 DETAILS OF ELECTRIFICATION Total RKM energized on 1500 V DC = BG 258 Total RKM energized on 25 KV AC = BG 18942 Total RKM energized on 2X25 KV AC = BG 627 Electrification work in progress (Dec 09) = 1000 RKM Target for Rly. Electrification during year 2009-10 = 1000 RKM Passenger Train KM Hauled by Electric Traction = 49% BG Freight GTKM Hauled by Electric Traction = 63% Year 2005-06 2006-07 2007-08 Total Traction Charges (Mil. Rs.) 38974 44276 46124 Total Energy Consumed (Mil. KWH)9085 10226 10469 Average Cost/ KWH (PAISA) 4.29 4.32 4.41 1.5 OVER HEAD EQUIPMENT (OHE) 1.5.1 A simple polygonal type of overhead equipment is comprising of a single 65 sq. mm. size Catenary wire of Cadmium Copper and a hard drawn grooved copper Contact wire of 107 sq. mm. size suspended from the Catenary by 5 mm dia copper dropper wire spaced 9 meters apart. The OHE is supported by swiveling type Cantilever bracket assembly. A tension of 1000 kgs is given in each conductors i.e., Catenary and Contact wire. This tension is kept constant, automatically compensating the variations in conductor length due to change in temperature through the regulating equipment erected at the termination of conductors, also known as Automatic Tensioning Device. 1.5.2 The Catenary wire comprises of 19 strands of cadmium copper, each strand of 2.10 mm dia, with overall dia of 10.5 mm having about 80% conductivity and 65 sq. mm cross-sectional area. The contact wire is a solid hard drawn grooved electrolytic copper of 12.24 mm dia and 107 sq. mm cross-sectional area. Total current carrying capacity of both wires is 600 Amps. The condemning size of contact wire is 8.25 mm. 1.5.3 The OHE span varies between 72 Meters and 27 Meters with a step of 4.5 M. The maximum span of 72 M is adopted on section having wind pressure of 112.5 kgs/ M2 and 75 kgs/M2 only. The span is reduced on curvature depending upon the degree of curvature. 1.5.4 As a standard practice, an independent mast is used to support the OHE for each track to obtain mechanical independence Steel masts are of Four types i.e., BFB (Broad Over Head Equipments Page 6  Flanged Beam), RSJ (Rolled Steel Joist) and fabricated rectangular sectional mast of K and B type. 1.5.5 Portals are also used to serve multiple track section where space between two tracks to locate an independent mast is not adequate. There are three types of Portals in use i.e., N, O & R type. P,G and double BFB type uprights are used where track separation is less. All Masts & Portals are galvanized before installation. 1.5.6 Traction Mast / Portals are embedded in the concrete foundation. There are different type of foundations which are used according to soil pressure and location. The five standard types of foundations mostly used are : (a) Side Bearing (b) Side gravity (c) New Pure gravity (d) Wet Black cotton soil (e) Dry Black Cotton soil\ 1.5.7 A presag of 100 mm is provided on the contact wire for the maximum span of 72 meters and proportionately reduced for lesser spans. Regulated OHE with 100 mm presag is considered suitable for 160 Kmph speed operation. 1.5.8 The contact wire is staggered at support so that as the pantograph glides along the contact wire, the contact wire sweeps to and fro across the bearing surface of the pantograph pan upto a distance of 200 mm on either side of the centre line of pan on tangent track and 300 mm on curved tracks towards the outer side. This ensures uniform wear of the steel strips of the pantograph. 1.5.9 The electrical clearance between live part, and earthed part i.e. fixed structures or moving load shall be maintained normally as large as possible. The minimum clearance under worst condition of temperature, wind etc are given below: (a) Minimum Vertical distance for Long duration - 250 mm Short duration - 200 mm (b) Minimum horizontal distance for Long duration - 250 mm Short duration - 200 mm 1.5.10 The OHE conductors are terminated at intervals of 1.5 kilometers and suitably anchored. The change over is made by overlapping the conductors, normally on 3 spans. The conductors height at support is so adjusted that the conductors are physically clear from any obstruction under all conditions as well as the pantograph glides over from one conductor to another smoothly without any spark. There are two types of overlap: (a) Uninsulated Overlap In this type of overlap the distance between two conductors is kept 200 mm and the conductors are permanently connected by jumpers to have electrical continuity. Over Head Equipments Page 7  (b) Insulated Overlap In this case, the two OHE conductors are kept apart at a distance of 500 mm. The electrical continuity at the insulated overlap is bridged by Interrupters or Isolating Switches except at Neutral Section (SP). 1.5.11 In regulated OHE, to ensure uniform distribution of the mechanical tension in the OHE conductors, an anticreep point is installed at the midpoint of the tension length of OHE conductor. 1.5.12 Section Insulators are provided to insulate the OHE of one track and another track, such as at turn outs & cross over, and to separate secondary tracks and sidings from the main line or other sidings. 1.5.13 When the pantograph of a locomotive passes from one track to another along a cross over, current collection changes from one OHE to another. The runners do have the overlap so that there may not be any sparking during change over. 1.5.14 Solid core Porcelain Insulators are used to support the OHE as Bracket and Stay arm Insulators. For termination 9 ton insulators are used. 1.6 CONTACT WIRE HEIGHT i) Over Line Structure to permit C class ODC - 4.92 M ii) Electric Loco Shed and Inspection Pits - 5.80 M iii) Level Crossing - 5.50 M iv) Unregulated OHE Temperature 4°C to 65°C - 5.75 M Temperature 15°C to 65°C - 5.65 M v) Regulated OHE with 50 mm Sag - 5.55 M vi) Regulated OHE with 100 mm Sag - 5.60 M vii) Height of the Rail Gauge at level crossing - 4.67 M 1.7 TRACTION SUB STATION (TSS): Every TSS has 2 nos. traction transformer out of which one is working at a time and the second transformer is stand by. The capacity of each traction transformer is sufficient to feed its own feed zone and half of the adjoining feed zone. 1.7.1 Feeding Post (FP): To feed 25 KV traction power to OHE. 1.7.2 The section of OHE normally fed by a traction transformer. 1.7.3 Feed Length : The distance for which a traction transformer will feed power in emergent conditions i.e., the distance between two adjoining FPs. Over Head Equipments Page 8 1.7.4 Over Head equipment (OHE) A system of conductors / equipments carrying traction power from traction sub station to electric locomotive. 1.7.5 Neutral Section (NS) To separate OHE of two adjoining feed posts. A short neutral section (PTFE) type is provided opposite the Traction Sub Station to avoid the need of lowering the pantograph during extended feed conditions. 1.7.6 Sectioning Post (SP) 1. To facilitate the extension of traction power from one feed zone to half of the adjoining feed zone during emergency. 2. Parallel the UP and DN OHE in double the sections. 3. 1.7.7 Sub-sectioning and paralleling post (SSP): 1. To sectionalize OHE. 2. To parallel the UP and DN OHE in double line sections. 1.7.8 Sector: The section of the OHE between the FP & SP is called the sector. 1.7.9 Sub-Sector : The section of the OHE between the FP & SSP, SSP & SP is called sub-sector. This is the shortest section of the OHE which can be isolated through Remote Control by the Traction Power Controller. 1.7.10 Elementary Section (ES) : This is the shortest section of the OHE which can be isolated manually for carrying out OHE maintenance work. Over Head Equipments Page 9