APPLICATION OF LIGHTNING PROTECTION AND SURGE ARRESTRES IN RAILWAY FACILITIES Ranko Pešič Boris Grmovšek 1 September 2011 CONTENT Overvoltages in railway systems Lightning and surge protection of railway stations MO surge arresters for railway networks and locomotives Surge protection of signalling systems Protect the trains! Abstract 2 OVERVOLTAGES IN RAILWAY SYSTEMS The protection of the electrical railways has the task, in case that faults appear, to: Prevent damages at the installation or try to reduce them as much as possible Assure the availability of the railway energy supply as much as possible Prevent or reduce the endangering of life through direct or indirect influence of the fault voltages 3 OVERVOLTAGES IN RAILWAY SYSTEMS Sources (can not be avoided) Lightning: Direct strike to mast, overhed wires, tracks and air terminals of lightning protection systems (buildings); Induced voltages due to indirect strikes. Switching and other surges: Pantograph arcing; Vacum and DC breaker operations; Feeder cable arcing fault (breaking of overhead line); Induced switching surges from AC system Short circuits Insulation flashovers Violence (storm, objects or animals on the supply line, vandalism,…) Damages at the current collector,traction vehicles or in the supply line installation 1 D. Paul, “Light Rail Transit DC Traction Power System Surge Overvoltage Protection”, IEEE Trans. on Industry Appl., Vol.38, No.1, 2002. 4 OVERVOLTAGES IN RAILWAY SYSTEMS Consequences According to Swedish National Rail Administration, about 789 faults in 2001 and 1067 faults in 2003 have occured due to lightning. The consequences of those faults were delays of trains for 336 h in 2001 and 370 h in 2003. Overvoltage protection must be aplied to all power-supply, control and communication circuits and vehicles in railway system. 2 Nelson Theethayi et al., “Measurements of Lightning Transients Entering a Swedish Railway Facility”, ICLP 2004, Avignon, France 13-16. September 2004,. 5 OVERVOLTAGES IN RAILWAY SYSTEMS Standards EN 50 163 – Railway applications – Supply voltages of traction systems IEC 60099 – 4, Ed2.1,2006-7, Part 4: Metal oxide arrestors without gaps for ac systems EN 50 123-5:2003 – Railway applications – Fixed installations – DC switchgear – Part 5 - Surge arresters and LV limiters for specific use in dc systems prEN 50526-1:2009 – Railway applications – Fixed installations – dc surge arresters and voltage limiting devices – Part 1: Surge arresters prTS xx xxx, pn16441: LV surge protective devices – SPD for specific use including dc, Part 11: Selection and application rules – surge arresters for specific use in dc traction systems IEC 62497-2, Ed1.0, 2010-02 – Railway applications – Insulation coordination – Part 2: Overvoltages and relation protection 6 PROTECTION LIGHTNING AND OF RAILWAY SURGE STATIONS PROTECTION OF RAILWAY STATIONS 7 LIGHTNING AND SURGE RAILWAY STATIONS PROTECTION OF RAILWAY STATIONS Lightning protection Air terminal Down-conductors Grounding rod Grounding ring Exothermic welding 8 PROTECTION LIGHTNING AND OF RAILWAY SURGE STATIONS PROTECTION OF RAILWAY STATIONS Overvoltage protection of power-supply system Overvoltage protection at sub-distribution board SAFETEC class II Overvoltage protection at main distribution board SAFETEC class I 9 LIGHTNING PROTECTION AND OF RAILWAY SURGE RAILWAY STATIONS PROTECTION STATIONS OF RAILWAY STATIONS Overvoltage protection of communication and signalling system DISTRIBUTION FRAME WITH STRIPS AND OVERVOLTAGE PROTECTION MODULES FOR TELEPHONE SYSTEM Overvoltage protection for signal lines IM-TD, SMH-TC, VM-RS 10 LIGHTNING AND SURGE RAILWAY STATIONS PROTECTION OF RAILWAY STATIONS Overvoltage protection in the traffic office Power Supply: MPE-MINI: PROFILT D: Data/communic. network: LZ NET, LZ NEZ cat 6: comput. network SMH-TC 12V : signal lines Power cable extention with telecommunication protection ZE6-TEL MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES 13 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Supply voltages of railway networks The supply voltages are defined in European standard EN 50163. Definitions and voltage values, which are important for the surge arrester and the overvoltage protection are given and explained in the same standard and also in IEC 62497-2 (Ed.2.0, 2010-2) Voltage U – the potential at the trains current collector , measured between the supply conductor and the return conductor Un – nominal voltage (designated value for the system) 14 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Important voltages for SPDs Overvoltage –a transient rise of voltage lasting less than 2s Highest permanent voltage Umax1 – the maximum value of the voltage likely to be present indefinetely Highest non-permanent voltage Umax2 – the maximum value of the voltage likely to be present for maximum 5 minutes Long-term overvoltage Umax3 - a transient rise of voltage, lasting typically more than 20ms (due to low impedance phenomena, e.g. a rise of substation primary voltage) Medium term overvoltage – a transient rise of the voltage lasting typically less than 20ms, due to current transfer following switching (e.g. opening a circuit braker) Short term overvoltage – a transient rise of voltage, lasting less than 20us (e.g. lightning strokes) 15 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Important voltages for SPDs 16 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Voltage levels 17 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Frequencies a.c. systems 15kV- network is 16 2/3Hz 25kV- network is 50Hz Applications d.c. systems - 600V – tramline, trolley-bus - 750V – tramline, trolley-bus, underground, surburban railway - 1.5kV – mine railway, underground, long- distance railway - 3kV – surburban and long distance railways 18 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES MOV advantages against spark gaps Spark-gaps and GDTs suffer from the problem of electrical arc extinguishing and can’t be aplied in DC systems. In the spark gap arrester the follow current flows three times longer in 16 2/3 Hz than with 50Hz,which overloads the spark gaps Spark gaps used in 16 2/3Hz network have an inconvenient higher voltage than the arresters of 50Hz, and implicitly a worse protection level. MOV represents resistor with extremely nonlinear V-I characteristic and behave as surge protection device without arc and follow current. Better protection and longer protection distance Higher pollution resistance In paralell use all MOV react 19 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Protection measures for substations The arrester A1 – connected in the substation between the feeder circuit breakers and the return circuit The arrester A2 – between the return circuit and the structure earth is to limit overvoltages of the running rails 20 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Protection measures for substations 21 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Protection measures for substations 22 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Protection measures for locomotives, class 4 23 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES The protection of the traction current supply installation 24 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES The protection of the traction current supply installation 25 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES The protection of the traction current supply installation 26 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Arrester requirements Arresters A1 and A3 may have different characteristics due to different requirements as: indoor or outdoor, arrester class, short circuit duty etc. Uc≥ Umax2 Arrester A2 may be connected in parallel with a voltage limiting device to provide protections of the persons (limiting the touch voltage). Ucmin ≥ Utemax 27 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Arrester classification AC network - according to IEC 60099 -4, Ed2.1, 2006-07, from 3kV above For railway appications classes 3,4,5 are used. 29 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Arrester classification DC network - according to pr TS XX XXX - 30 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Arrester classification – typical applications Also A3 type can be in this class. 31 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Arrester classification – typical applications Depending on the system requirements SPDs of all classes can be principally used as A1,A2 and A3 arresters. If A1/A3 and A2 are installed close together intentionally (in a substation or on a pole) they should be of the same class and have similar characteristics. Application of the arrester classes 1,2,3 in DC networks is corelated with the arrester classes 3,4,5 in AC networks. 32 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Installation on the overhead line and the rails Surge arrester Tracks are grounded (preferred for AC systems) Exothermic welding Power-supply cable 33 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Installation on the overhead line and the rails Surge arrester Tracks are insulated from the ground (preferred for DC systems due to stray currents) MOV in parallel with thyristor: - lightning protection - touch-voltage protection 34 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Installation on/in the locomotive Surge arrester 3kVDC, class 4 ( Slovenia railway) 35 MO SURGE ARRESTES FOR RAILWAY SURGE PROTECTION DEVICE NETWORKS AND LOCOMOTIVES Where to install SPD? 36 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Where to install SPD? •First place for installation is locomotive, at current collectors on the locomotive roof (to limit overvoltages to propagate into locomotive). •Second SPD may be optionally installed prior main circuit braker •Increased safety due to redundancy 37 MO SURGE ARRESTES FOR RAILWAY NETWORKS AND LOCOMOTIVES Arrester installation on the overhead line, rails and trains - examples AC network 15kV, 16 2/3 Hz Swiss SBB use MO surge arresters of Uc≥18kV on overhead lines (class 3) and locomotives (class 4). German DB install 18kV arrester on the locomotive roof (class 4) and 20kV arrester in the locomotive (lower line discharge class). AC network 25kV, 50HZ MO surge arresters with Uc≥29kV (on the overhead lines class 3 and on the locomotive roof class 4) and 31 kV (in the locomotive in front of the main power braker, lower class than on the roof) are used in the high speed railways. Arresters are installed at both pantographs. DC network 600 and 750V SPDs A1 and A3 with Uc≥ 1kV are recomended on the overhead lines (class 2) and on the locomotive roof (class 3), inside locomotive is recomended class 2 For A2 arrester (class 2) Uc is 350V -500V. SPD has to withstand Ute that may appear during the faults. 38 SURGE PROTECTION OF SIGNALLING SIGNALLING SYSTEMS 39 SURGE PROTECTION OF SIGNALLING SYSTEMS Level crossing - gate Overvoltage protection for the signal – control and communication lines IM-TD, SMH-TC, VM-RS Safetec class I 40 SURGE PROTECTION OF SIGNALLING SYSTEMS -surge protection SAFETEC class I Train detection Surge protection at connections with tracks -touch-voltage protection (voltage limiter – MOV + thyristor) -protection of communication line LZ1 41 SURGE PROTECTION OF SIGNALLING SYSTEMS Surge protection of signal lines IM-TD, SMH-TC, VM-RS Power-supply overvoltage protection SAFETEC class I 42 SURGE PROTECTION OF SIGNALLING SIGNALLING SYSTEMS 43 SURGE PROTECTION OF SIGNALLING SYSTEMS Control room Rack with overvoltage protection for LAN Overvoltage protection at sub-distribution board SAFETEC class II Class III protection for power Supply Profilt D, MPE MINI LZ 24 – NET or LZ NET Cat 6 Protection for communication lines (LPA modules, CCP) 44 PROTECT THE TRAINS! Positioning Display Sensor Voice Dead men controls Various sensors Data aquisition and recording Speed sensors Data transfer Data evaluation 45 PROTECT THE TRAINS! Train BUS Access Node Radio Diagnosis Power electronics Cockpit Doors Motor control Passenger information Breaks Track signals Light Seat reservation Air conditioning Multifunction Vehicle Bus (MVB) -standard communication interface with different equipment in trains -network of various sensors -media: twisted pair cables (RS 485) and optical fiber 46 Power PROTECT THE TRAINS! Train BUS Access Node Radio Cockpit Diagnosis Doors Motor control Power electronics Breaks Track signals Passenger information Light Seat reservation Air conditioning Overvoltage protection for monitoring and control system IM-TD, SMH-TC, SMH2-TC 47 Power PROTECT THE TRAINS! ESD (Electrical Short Distance) RS485: -Connects at distance not longer than 20 m from access node star coupler -Media: twisted pair devices -Interface: Profibus or RS 485 optical links rack sensors twisted wire segment rack VM – RS for RS 485 port, SMH2-TC for Profibus 48 ABSTRACT Lightning and switching overvoltages are a risk for installations and equipment in the electrical railways. Modern surge arresters have been adapted to the special requirements in AC and DC railway systems. The installation of AC and DC MO surge arresters in substations, overhead lines, on locomotives, at equipment connected to the rails and lines, in railway stations, rolling stocks etc is state of the art and worldwide practise. Coordination concepts and developed hybrid voltage limiters alowe new protection concepts, covering the protection of equipment and persons at the same time. During many discussions with the users of surge arresters it was noticed that a thorough information and co-operation is welcomed. Especially with the electrical railways is this very important because there are particular demands to be fulfilled And new application possibilities may appear. An optimal protection concept, taking into concideration the most favourable solution from the economical and technical point of wiev, increases the security and the availability of the alectrical facilities and the personal safety. 49 50