Electric traction is the most favourable type of power supply for electric railways from both an ecological and an economic perspective. The book provides students and those embarking on a career in this field with a Railway company professionals and manufacturers of contact line systems will . Contact Lines for Electrical Railways book. Read reviews from world's largest community for readers. Electric traction is the most favourable type of pow.
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Keeping it simple, this book is a how to or child's guide, for electric rail traction power. It's got substations, protection, lots of overhead (contact) line design. SIEMENS - Contact Lines for Electric Railways - Ebook download as PDF File . pdf), Text File .txt) or read book online. SIEMENS - Contact Lines for Electric. Contact Lines for Electric Railways by Friedrich Kießling, , available at Book Depository with free delivery worldwide.
Its reliability depends to a large degree on the contact lines, which have to operate safely under all relevant climatic conditions, needing as little maintenance as possible. The authors have used their world-wide experience to provide a clear and comprehensive description of the configuration, mechanical and electrical design, installation and operation of contact lines for electric railways on local and long-distance transportation systems. The book provides students and those embarking on a career in this field with a detailed description of the subject, including the electromechanical and structural requirements. Railway company professionals and manufacturers of contact line systems will find practical guidance in the planning and implementation of systems, as well as appropriate specifications and the technical data they will need, including standards and regulations. Since large sections of the book are dedicated to the system aspects, consultant engineers can also use it as a basis for designing systems and interfaces to other subsystems of electric railway engineering.
In addition to these requirements, consideration must be given to the fact that, the electrical loads on traction systems differ from the loads on the public energy supply grid because they are not only heavily dependent on time but also continuously varying in location of consumption.
When referring, to electricity, the term electn. To distinguish between the various types of electrical energy supply for electric trac- tion, it is usual to specify the type of current. Originally, direct current was used for electric rail transport.
On a global scale, over half of all electric traction systems still use direct current.
The low voltage used is a disadvantage of existing direct current traction systems as it I I necessitates high currents to transmit the necessary traction power. At the beginning of the twentieth century, efforts were made to combine the traction advantages of the series motor with the transforming capability of alternating current.
At that time, the objective was a single-phase AC series motor as a drive, which was to be fed with single-phase AC at the frequency of the public grids, in Germany and Central Europe that was 50 Hz. Because of the state of technical development at that time several problems arose including: Table 1.
These problems could not be solved satisfactorily at that time. The system was also adopted by Austria, Switzerland, Norway and Sweden. This electricity system using single-phase AC 16,7 Hz has proven to be particularly powerful and effective for the electrical power supply of high-speed and high-capacity traffic. Figure 1. Initial experience with an AC 50 Hz traction power system was gained at the Hollental- bahn in Germany in approximately Due to the enormous progress made in the field of power electronics, AC 25 kV 50 Hz traction power is the type of electricity currently preferred in countries now starting to electrify their railways.
These three, currently adopted frequencies in electric traction have different nominal voltages depending on their intended purposes. These nominal voltages and the per- missible deviations from the nominal values are listed in Table 1. Traction power plant. The AC 15 kV 16,7 Hz systems are supplied from either the AC 16,7 Hz single phase transmission systems or decentralised converter stations are supplied from the public grid, e.
As illustrated i11 Figure 1. Single-phase AC traction systems are usually connected to a kV power grid. The well over one hundred AC kV subnetworks of public power supply in Germany are not interconnected at the llO kV leveL This limits the short-cirrnit currents a11cl simplifies protc! Energy from the Energy from the Energy from the Energy frorn the Energy from public grid or from public grid public grid public grid other traction power trans- substations mission network.
As a result of this supply from the interconnected grid, all kV power networks in Germany are synchronised. This fact is an essential condition for the implemented par- allel operation of the decentralised traction power supply in parts of German Railway's DB supply system. The functions of traction power distribution are to convert electrical energy supplied to substations into voltages and frequencies conforming with the nominal values used for traction power and the supply of this power to consumers.
Substations SS of various types are used to supply traction power directly into the contact line installations. As indicated in Figure 1. SS"B" Coupling post Coupling post. Their function is to secure the supply of electrical energy to all trains passing through the substation supply section. The substation supply section, also known as the feeding section, designates the total of all contact line sections supplied by a sub- station in regular operation mode. A neutral section is a section of contact line which isolates adjacent feeding sections in such a way that they cannot be bridged by the pantographs of electric traction units.
Some traction operators, create neutral section units with a coupling post CP. CP use circuit breakers to facilitate longitudinal and cross-coupling of contact line sections to reduce voltage drops and losses in the contact line network. In overhead contact line networks, CP and switching posts SP connect substation supply sections during normal operations. This facilitates a secured return of the generated braking energy in systems designed for this operational mode.
Switching sections and cirwit groups within the substation supply sections can be electrically separated by air insulated oYerlaps or section insulators, which are bridged by disconnectors during normal operation and may be bridged by the pantographs of the traction vehicles. In mass transit systems, maximum nominal voltages of up to V are used because of the potential danger by higher voltages.
The mu:: Tlw poW! The three-phase voltage supplied from the three-phase public grid is converted at the rectifier substation into direct current at the nominal voltage of the contact line net- work. Previously, six-pulse current transformers were used but now, mainly twelve-pulse transformers are used for rectifiers. The switching components in rectifier substations are turnkey units usually designed for load class VI to EN In the design and operation of direct current railways, special attention has to be paid to the problems of traction current return to minimise the hazard of stray current corrosion.
These problems are addressed separately in clause Single-phase AC with the special frequency of 16, 7 Hz is generated by special single- phase generators. The lowest possible number of pole pairs is 1. Therefore, the highest speed at which a 16, 7 Hz generator can be operated will be n 16,7 s- 1 or luOO min- 1. A 16,7 Hz generator therefore runs at one third the speed of a 50 Hz generator under otherwise equal conditions.
However, the power P and the revolutions n arc linked to the moment M in the following manner: Comparing 50 Hz and lG,7 Hz generators, a moment three times higher would be required to achieve the same power at 16,7 Hz. Three times the moment means three times the size. The generators of the public grid are thre '-phase generators.
The generators used in the Ln-ic-tion power supply with a frequency of lG,7 Hz are single-phase generators. A lG,7 Hz sittglc-p! Practical values lie around 4,5. The largest 16,7 Hz single-phase generator with a nominal power of ,5 MVA therefore corresponds in size to an MVA generator of the 50 Hz three-phase public grid. If 16,7 Hz single-phase generators are driven by motors supplied from the 50 Hz three- phase network, this type of machine combination is designated in the traction power supply as a rotating converter.
Regarding the frequency ratio of 50 Hz to 16, 7 Hz, elastic and rigid converter are discerned. Elastic converters are also designated as asynchronous-synchronous converters.
By using a variable-frequency and, thereby, revolution-variable drive of the single-phase generator driven by an asychronous motor, it is possible to use elastic converters in parallel operation with traction pmver plants.
Elastic converters are used to cover load peaks in centrally supplied networks of the DB. The power of elastic converters lies between 10,7 and 50 MVA.
Rigid converters are synchronous-synchronous converters. Two kinds of lG,7 Hz single-phase power supply have evolved in Europe. HI dc,,11 p Jwer plants n11d drin'n by wa. Design of a decentralised rotating converter station with synchronous-synchronous converters, i.
Hz 15kV converters. Transmission of electrical energy by a or kV overhead line net-work with a nominal frequency of 16,7 Hz from the power plants to the substations. This single-phase network mostly incorporates two circuits and has a feed and return conductor for each system. Distribution of single-phase electricity in railway substations, where the voltage is converted from kV or kV to the nominal voltage of the contact line installation of 15 kV.
Feeding of the single-phase 16,7 Hz energy through section circuit breakers in the substations to the individual feeding sections of the contact line installation. The most significant property of the decentralised traction power supply see Figure 1.
The DRCS embodyies two tasks: Generation of single-phase power with a nominal frequeancy of 16,7 Hz and - Feeding of the single-phase 16, 7 Hz energy through section circuit breakers in the substations to the individual feeding sections of the contact line installation.
The two types of single-phase 16, 7 Hz traction power networks have different parame- ters which are compared in Table 1. An overall summary slw-ws that both the central and the decentralised traction power supplies are able to supply trains with electricity safely, n"liably and with the required quality parameters. Over eighty years of electric traction transport on 20 km of centrally supplied traction lines and over seventy years of electric traction on 13 line kilometres supplied with 16,7 Hz electrical pavver from decentralised equipment prove the dependability of both types of 16,7 Hz power supply.
Due to the high, short-term load peaks in the DRCS, high demand rates are currently paid in Germany for the energy taken from the AC 50 f-J,1, three-phase net- work.
Comparison of central and decentralised traction power supplies. This single-phase loading of the three-phase network causes unballance in the voltage and current of the three-phase network. The current unballance has only a minor effect on the generators, whereas the voltage unballance has serious effects on the consumers.
The voltage unballance 11,u is inversely proportional to the short-circuit power St of the three-phase network. If the traction power Sc to be drawn from one phase of the three phase network is known, then the voltage unballance in the three-phase network at the point of supply is given with sufficient accuracy by:.
L1 L2 L3 t: With short-circuit power varying between MVA and MVA in the kV three- phase network and powers of the traction power substations up to 40 MVA, high values of voltage unballance are to be expected. Voltage unballance leads to a reduction in the life of three-phase asynchronous motors running on three-phase current.
To minimise the unfavourable effects of voltage unballance, permissible limits of uu are specified. To comply with these stringent requirements, it is necessary to limit or compensate the unballances [1. In practice, the single-phase power is usually connected in a cvdically ehauged manner with the three-phase net,vork, as can be seen in Figme 1. However, this type of feeding leads to a compromise in the single-phase rwtwork with regard Lo optimum operation, which would he the case for thr comwction shown in Figtm!
Phase separations arc necessa. Basic design of the 2 x Un feeding system. The voltage difference at the phase separation is v3 25 kV: Higher voltage drops result in the overhead line network and create unfavourable conditions for electrically regenerating traction units. Feeding as shown in Figure 1. This type of feeding is also used on the high-speed line Madrid-Seville [1.
On this line, the transformers of the individual substations are connected by a 60 connection in such a way that the voltage differences at the phase separations correspond with the nominal voltage of 25 kV [1.
AC 25 kV 50 Hz, transformer connections are used, to partially correct for symmetry see Figure 1. Phase separations are also necessary, however, they can be installed in the vicinity of the substations.
The parallel operation which can be implemented as shown in Figure 1. To improve transmission properties, the 2x25 kV system is used for high-performance traffic in France, Japan and Russia on single phase AC 25 kV 50 Hz railways. This type of feeding is characterised by additional auto-transformers and a return line at a potential of 25 kV.
This return line is often designated as a negative feeder. For this reason, twin-pole switch gear is required in the overhead line network. The basic design of this type of feeding can be seen in Figure 1. The line is supplied by a transformer with a centre tap. The centre tap is connected to the rails. The voltages between the negative feeder and the rails and between the overhead contact line and the rails are both 25 kV.
The potential difference between the overhead contact line and the negative feeder is up to 50 kV. The transmission of power between the substation and the auto-transformer preceding the section on which the traction unit is collecting electric power fr9m the contact line occurs as in a twin-pole 50 kV line. The low currents involved with this transmission of power result in lower voltage drops in the overhead contact line network.
In the section between the substation and auto-transformer, the current flowing in the rails is low due to the a. The interference with adjacent lines is tlwrefore very low. In principle, this type of feeding can be used with an n-fold nominal voltage, e. In this case, the transmission of power to the auto-transformers, between which the power consuming traction unit is located, would be performed with a voltage of 75 kV.
It should be noted that this feeding principle can be used for all single-phase AC systems regardless of their nominal frequencies. The requirements on the design of the insulation increase in systems with n Un. For example, the larger air gaps necessary between parts with multiple nominal voltage differences must be taken into account in the overhead contact line installations. The necessary twin-pole design of switch-gear in the overhead contact line network is a further general disadvantage of feeding systems with multiple nominal voltages.
The largest 16,7 Hz single-phase generator in the joint nuclear power plant at Neckar- westheim which produces ,5! There, the 16,7 Hz energy is generated with synchronous-synchronous trans- formers with a nominal power of 10! At I-Ialtingen and Singcn: Zirl tltl: Line 1: Station C: Station H Line 3. Because it is operated as a resonant-earthed system, 12 arc suppression coils of A each compensate for the line capacitancies.
A part of the kV overhead line runs beside the main lines of the DB to supply the individual substations, which are designed as node-type substations with double bus bars or as simple block-type substations see clause 1. An example of a contact line supply of this kind is shown in Figure 1. With these, it is possible to switch circuits on and off as required and to switch off faulty equipment quickly and selectively or to isolate it for maintenance purposes.
DB's standard substations are unmanned in operation z,,nd consist of standardised com- ponents with standard interfaces, which can be put together and rated in a modular manner according to functional requirements. The standard is used for substations SS with kV equipment and 15 kV equipment, - switching substations with a llO kV equipment only, - switching posts SP with a several 15 kV supply branches and - coupling posts CP with one 15 kV circuit breaker only.
Swdching posts connect the overhead contact lines and feeders of several railway lines and supply overhead contact line sections fed from one end with 15 kV power.
Co'u,pl'ing posts connect two feeding sections and are used especially in cases of long distances between substations or long sections fed from one end to guarantee the correct functioning of protection. The substation design hand book maintained by the DB, forms the hub for planning and errection of the different typs of substations.
The standarized interfaces specified there enable using of and continuous development of functionally equivalent equipment of various manufactures. It consists of numerous design documents and circuit diagrams, on the basis of which all standard substations are planned and constructed.
Standard substations of the first generation still contain pneumatically operated cir- cuit breakers, control, signalling and protection technology with mostly mechanical relays. The 15 kV vac'U'Um circuit breakers introduced at the beginning of the eighties, electronic information processing and protection systems fostered the transition to the second generation of standard switching substations described below. These are typified by a significant reduction in equipment size, installation and maintenance efforts [1.
DB's directive includes standard specifications for the design of the kV system, based on operational requirements. The main features are: Each substation consists of several branches e. A typical general C'tTc'uit diagram of a block-type substation is shown in Figure 1. Whereas substations with single or double bus bars in transformer and traction overhead line branches are equipped with circuit breakers, the block substation of the DB has no circuit breakers in the traction overhead line outlets.
Substations simplified in this way are used as intermediate substatious between fully equipped node-type substations whose circuit breakers in the overhead power line branches switch off faulty ovcrlwacl power lines including those in the vicinity of block- type substations.
E1 E2 E3 Block branch Longitudinal isolation branch Block branch. The cables of the overhead power line are anchored to section supports or over- head power line end supports with vertical suspension.
They are then connected to the line disconnector Q9 designed as double-pole rotary disconnector with attached earthers QS Figure 1. The twin-pole circuit breakers Q0 contain SF6 as a quenching gas and an electrically powered spring or pneumatic drive for actuation.
Single-pole, oil-filled combination instrument transformers T5 are used to measure currents and voltages. A peculiarity of these power transformers are special lift limiting devices. They prevent the loosening of the windings due to the approx. The transformers are insulated against earth and earthed by tank leakage protection tro: They are also equipped with current transformers Tl.
The bus ha,r disconnectors Qll with attached rartbers Ql5. Transformer 2 B- -. The pole arrangement of the disconnectors depends on the system design successively with pole centre distances of mm or mm, adjacently opening in the opposite directions with pole distances of mm or adjacently opening in the same directions with pole distances of mm or mm.
Because the kV network of the German Railway is operated in resonant-earthed condition, arc suppression coils with integrated neutral point are installed at selected substations. The arc suppression coils are designed as solid core coils with step switches or, for frequency control, as plunger coils with an inductive current of 10 A to A.
For telecommunications via traction overhead power lines, carrier frequency tra11smission devices PLCT with chokes and coupling capacitors are used in various substations.
The mesh earth electrodes used consist of tinned copper conductors with a cross section of 9S rnni'2. They are connected by loops with all steel components and with hall type ca. The lightning protection rods attached to the lighting masts and the earth wires above the traction overhead power line branches and bus bars protect against lightning. Transformer branch Overhead contact Longitudinal disconnecting Overhead contact line branch and metering line branch.
In the medium voltage range, the standard indoor equipment consist mainly of the following configurations: The first variant shown in Figure 1.
Arrangement of the medium voltage and secondary technology in type KS substations or switching posts. The operating bus bar 0 BB made of 1 or 2 x 80 x 10 mm copper straps is used to couple the individual branches, to distribute the current and to provide the voltage. The overhead contact line and return voltages tests are carried out using the test bus bar TBB made of 50 x 5 mm copper straps as described in clause 1.
Due to double-row arrangement of the equipment, both bus bars are arranged in a U-shape and can be separated for maintenance and repairs by the longitudinal disconnectors Qll, Q12 and Q61, Q62 into several sections with corresponding measuring devices.
Transformer and feeder line branches are arranged at the ends of the operating bus bar. A third transformer or an additional mobile substation can feed into the centre section if necessary.
By the arrangement of the overhead contact line branches, which serve as back-up supply, to different OBB sections, e. The circuit design of the test bus bar is explained in clause 1. The 15 kV branches are arranged according to Figure 1. The designation of the type, e. K8, refers to the num- ber of cubicles and the number of overhead contact line branches see clause 1.
The vacumn circuit breakers QO consisting of the switch gear trnck and one or two vacuum tubes are chosen acc-ording to the locally expected short-circuit current between 20 kA and 50 kA and for a nominal current of A or A.
They arc connected by copper expansion strips to the bus bars. The response time of thr circuit breaker is around 17 ms [1.
Schematic diagram of the auxiliaries' supply of DB's sub- station and switching posts. Sliding-type dis connectors are used as the longitudinal dis connectors Qll, Q 12, Q Q62 and switch-disconnectors as test disconnectors Q6. The earthing disconnectors Q8 are suitable for closing on to a short circuit.
Resin encapsulated current transformers Tl with a nominal voltage of 24 kV are used in transformer, overhead contact line and feeder line branches.
They transform the corresponding currents for protection and meatering. To measure the framework current, the total current of the transformer and the earth current of the mesh earth electrode, low-voltage transformers with pressed resin insulation are usecL These are located in the neutral bar cubicle of the substation Figures 1. Thereby, certain disturbed conditions, as a short circuit between bus bar and structures, can be detected more rapidly.
With their output signals the overhead contact line and bus bar voltages can be monitored. High-voltage fuses fl are installed upstream of the voltage transformers.
To limit the current during overhead contact line testing, a high-voltage resistor Rl is installed in the test bra. The principle of tlw a: The first group consists of eq11ipment which can be foregone for brirf periods, e. DA and the equipment drives are supplied through rectifiers, a buffering battery and the counter cell unit by the DC distribution DC 60 V. Since rectifier control and battery monitoring has been performed by a control cubicle. If it is necessary to supply continuously operating equipment such as transmission de- vice carrier frequency modulators PLCT or disconnect.
A special case is the auxiliaries supply at coupling posts, where. The isolating transformers rated from 10 to 40 k VA depending on the substation size and the circuit group DYN take care of the protections and interference-related isolation from the local AC 50 Hz network. Panel 1 has a connection for an additional stand-by generation unit, which should be available in due time if the local network failed for more than five hours.
As the only type of protection, coupling posts receive overhead contact line protection. In switching posts, the general protection is supplemented. Block substations have ad- ditional transformer protection.
All other substations are equipped as shown in Figure 1. In substations without transformers, only the overhead power line pro- tection is used. The general protection is equipped with three protective functions: The bus bar protection for switching posts and substations 1 which is triggered im- mediately on short-circuit current in the frame work of the 15 kV installation and the frame work current transformer with of more than approx.
Cfrc'IJ,zt br-eaker monitoring, which is triggered by the Off" command for the circuit breakers of the overhead contact line or overhead traction power line prn- f;e.
Total cTent rnon: For 01 General Transformer protection protection. Schematic diagram of the protection design of a DB substation.
This protection unit is equipped with several time and direction distance steps, polygonal triggering zones, directional detection with high sensitivity, rapid activation for switching short-circuited lines, fault localisation, earth contact relays and automatic re-closing. The exchange of information with the power system control is possible through a serial optical glass fibre interface. To detect network faults, the impedance of the circuit is measured.
If a network fault impedance was recorded an angular measurement would be made to determine the direction of energy flow during the short-circuit. Depending on the fault impedance and the measured angle and if the low impedance exists in both conductor-earth loops, the activation command is issued to the circuit breakers through a series of timer elements.
In case of a single phase earth fault, the overhead power line and therefore, the supplied substations can continue to operate over a limited period of time approx. Transformer protection, a static protection unit, is installed in standard second gen- eration substations and, since , digital protection units have also been installed.
The digital transformer protection unit also incorporates differential protection, and thermal overload protection and the above mentioned facilities for storing activation data. A detailed description of the overhead contact line protection is contained in clause In node-type substations, central protection data units are used to store and transfer the data of all digital protection relays. The supervisory control and data aquisition system SCADA is a central system for the control, automation, information processing and transfer, which conforms with the traction-specific requirements of the standard AC 15 kV 16,7 Hz switching equipment.
It was used in the middle of the s as a recording and registering system and has been developed since then to a multifunctional substation control centre with data display technology. Its connection to a rail network, i.
All switching equipment and current trans- formers are directly connected and no additional panels or electrical cubicles are used in the 15 kV or kV installations. Local control, Automation components, Signal and measured value processing, Digital meter monitoring and processing DMM , Remote control system, Interlocking and Implementation.
Local control was used until in the form of push buttons on the front panel of the control cubicles. The unit required two-handed operation and was equipped with LED service signals. The data display technology used subsequently, employs a TFT monitor with full graphics in window technology. The switching equipment and the desired switching states are selected in a one-handed operation. The necessary two-handed control for the subsequent command output is ensured by an additional keyboard.
The equipment is displayed in defined colours blinking when changes in the state have been selected. Numerous additional functions such as securing, locking, storing, acknowledging, adop- tion of responsibility, the fault reporting list, the operational reporting journal, general inquires, parameter adjustment facilities allow the dialogue between the operator and the SCADA.
The follmving autornatwn components secure the automatic operation of the 11nm,urned substations and reduce the work of the operating personnel: The automatic overhead contact line testing ACLT verifies that the overhead contact line branches are free from short-circuits before the circuit breaker is switched on and after every activation of an overhead contact line protection unit.
Therefore the test branch is connected temporarily via the test bus bar and the test disconnector Q6 with the overhead contact line see Figure 1. The test criterion is the voltage at the voltage transformer T5 of the test branch. If this is above 7 to 8 kV, the test result is considered good and the circuit breaker QO is re-closed automatically without delay except in cases of activation of the reserve protection unit and in cases of activation of the thermal protection, with an delay until the overhead contact line has cooled down.
A unsatisfactory test result, that means a testing voltage belmv an adjustable threshold of 7 to 8 kV, excludes reclosing of the circuit breaker and is signalled to the master control centre CC.
This automatic procedure excludes repeated short circuit stresses and prevents wearing of the equipment. The entire test procedure for an overhead contact line branch takes less than 10 seconds from the activation of the protection to the re-closing of the circuit breaker and does not affect the railway operation. If several overhead contact line branches are cut off simultaneously, the test is made in an adjustable sequence to allow the voltage to be returned quickly to the most important supply sections.
A 1domatic overhead contact line reverse polarity testing ACLRT checks the reverse voltage of an overhead contact line branch when a command is issued to close the earthing disconnect.
The expression "reverse voltage" means a voltage which might be in the overhead contact line after tripping of the circuit breaker. For this, a self-test of the measuring circuit is performed, after which the bus bar disconnect. If the measured voltage falls below the value previously set, taking account of the induction voltages caused by adjacent overhead or feeder lines, the test is regarded as satisfactory and the earthing disconnect.
By the automatic procedure reclosing of short circuit currents by the earthing disconnector Q8 is avoided. The automatic overhead contact line re-closing ACLR used in standard substations without test branches automatically re-closes the circuit breaker QO after a protection unit has responded.
The operating voltage has then been returned in an pre-set time after a successful test of the overhead contact line by an adjacent substation. The automating of emergency neutral section AENS controls the disconnect. The criterion for the re-closing of the overhead contact line voll. The autornatic synchronising device ASD verifies the synchronising conditions before enabling the on command for the circuit breakers. These include the phase synchro- nization and equal amplitude, taking account of permissible voltage differences caused by different line loads and possible by-pass conditions if voltage is lost at one side.
The signal and measured value processing includes the acquisition and preparation of all standardised operating signals OS , such as circuit breaker position and disturbance signals, the branch currents, bus bar and test voltages, reactive and effective power, which are necessary for the operation and fault analysis of an unmanned substation.
The acquisition of measured values is performed by measuring transformers. Measured value processing includes extensive adjustment facilities for cyclic and dialed measured values, limits, thresholds and windows to compensate measured value fluctuations.
It also includes an algorithm to determine the interfering currents of overhead contact line branches and digital metering monitoring. In the western part of the German Railway, all substations, converter stations and power plants have been equipped with a separate digital metering value transfer.
Because the general technology is no longer capable of extension, installations con- structed since have been equipped with digital metering, value monitoring and pre-processing integrated into the information processing system. This monitors and processes the impulses coming from the effective and reactive power meters according to an algorithm which can be adjusted according to time and values and transfers meter values for the remote control module of the information processing system at transfer intervals of several minutes.
The intelligent remote control system, also integrated in the information processing system, will be described in conjunction with the power system control under clause 1. The interlocking is computer based and software controlled. The circuit breaker and disconnector positions have multi-signal monitoring and in this case use double signals for the associated fault position monitoring.
To avoid interlocking errors, the number of simultaneously controllable types of switch- ing equipment are restricted to one per branch. The automation components at the GO V voltage level, the signal inputs and two-pole command outputs, arc located directly the computer circuit boards since the introduction of data display c-outrnl and a,n c,: To increase the availability, redundant, nmltiple computer systC'ms arc used in the iuformation processing, system.
The reinforcement of all concrete parts including the prefabricated roof, is connected via earthing rods to the foundation earth electrode forming a Faraday cage. The short- circuit current conducting capability of these earth conductors is 40 kA for one second. The foundation earth in switching posts is connected through the main potential com- pensation bar and earthing cables and in substations through the neutral bar cubicle and return conductor cable to the main tracks.
Switching posts and substations use building types K 4 to K 16 with 2 rooms Figure 1. Usually, the GW type is used only for node-type substations. The digit following the K or GW provides information on the number of the 1,40 m wide 15 kV cubicles, which being arranged in two rows determines the length of the 15 kV room [1. The individual rooms are separated by fire walls and fire prevention doors. The 15 kV room is designed for a positive pressure of 0,16 bar and is equipped with ventilation flaps for air pressure compensation and temperature-dependent ventilation for the test resistor of the overhead contact line testing device.
Instead of a cable cellar, tubular openings are used for the entry of the cables. A sandwich floor is used for laying cables within the building. The room for the secondary equipment, known as the auxiliaries room, is equipped with forced ventilation powered by the battery. A further ventilator is installed in the workshop. Switching stations for kV without transformers do not have a 15 kV part. For coupling posts CP , a re-locatable, monolithic post is used due to the small space requirement.
The earthing and ventilation of the buildings are carried out as for switching posts SP.
The minimum permissible room temperature in unmanned units is 5C in the auxiliary power room and -5C in the medium-voltage room. For kV outdoor switching equipment in substations hot dip galvanised dead-end equipment supports is used and installed in sheaths of standardised round or block foundations made of cast in-situ concrete or of prefabricated parts depending on the subsoil conditions. The transformer foundations in the substations, which must bear a mass of over 50 tons, are equipped with an oil drip tray, the level of which is constantly monitored.
They are located at a loading rail or at a substation road suitable for heavy transport. The earthing of all structural steel components and the ball earthing components is carried out by the mesh electrode connected in substations to the neutral bar cubicle.
The power system control of the German Railway encompasses the total of all technical equipment used for the operation of the traction power and overhead contact line networks, the snb.
Its design and principle functions closely related with traction power feeding by overhead contact lines. In the past, the task of the control sy: These were controlled by manned local operating facilities, such as interlockings and control centers, using relay based control, control discrepancy switches, mosaic panels etc. The increasing requirements for safe and economic operation and the introduction of unmanned substations extended the tasks of the control system significantly.
Due to the greater distances between the control system and the switching equipment, the tenn remote control technology was coined. This increasingly achieved a central cha.
Remote control also includes telephony, because communication remains necessary be- tween the maintenance personnel or switching requesters and the switchmasters of- ten hundreds of kilometres apart.
The high power of electric locomotives also gives them the ability to pull freight at higher speed over gradients; in mixed traffic conditions this increases capacity when the time between trains can be decreased. The higher power of electric locomotives and an electrification can also be a cheaper alternative to a new and less steep railway if trains weights are to be increased on a system.
On the other hand, electrification may not be suitable for lines with low frequency of traffic, because lower running cost of trains may be outweighed by the high cost of the electrification infrastructure. Therefore, most long-distance lines in developing or sparsely populated countries are not electrified due to relatively low frequency of trains.
Maintenance costs of the lines may be increased by electrification, but many systems claim lower costs due to reduced wear-and-tear from lighter rolling stock. Network effects are a large factor with electrification. Some electrifications have subsequently been removed because of the through traffic to non-electrified lines. This is mostly an issue for long distance trips, but many lines come to be dominated by through traffic from long-haul freight trains usually running coal, ore, or containers to or from ports.
In theory, these trains could enjoy dramatic savings through electrification, but it can be too costly to extend electrification to isolated areas, and unless an entire network is electrified, companies often find that they need to continue use of diesel trains even if sections are electrified.
The increasing demand for container traffic which is more efficient when utilizing the double-stack car also has network effect issues with existing electrifications due to insufficient clearance of overhead electrical lines for these trains, but electrification can be built or modified to have sufficient clearance, at additional cost. A problem specifically related to electrified lines are gaps in the electrification.
Electric vehicles, especially locomotives, lose power when traversing gaps in the supply, such as phase change gaps in overhead systems, and gaps over points in third rail systems. These become a nuisance, if the locomotive stops with its collector on a dead gap, in which case there is no power to restart. Power gaps can be overcome by on-board batteries or motor-flywheel-generator systems. Adding electric catenary to older structures may be an expensive cost of electrification projects Most overhead electrifications do not allow sufficient clearance for a double-stack car.
Electrification cost: electrification requires an entire new infrastructure to be built around the existing tracks at a significant cost. Costs are especially high when tunnels, bridges and other obstructions have to be altered for clearance. Another aspect that can raise the cost of electrification are the alterations or upgrades to railway signalling needed for new traffic characteristics, and to protect signalling circuitry and track circuits from interference by traction current.
Electrification may require line closures while the new equipment is being installed. Appearance: the overhead line structures and cabling can have a significant landscape impact compared with a non-electrified or third rail electrified line that has only occasional signalling equipment above ground level.
Fragility and vulnerability: overhead electrification systems can suffer severe disruption due to minor mechanical faults or the effects of high winds causing the pantograph of a moving train to become entangled with the catenary, ripping the wires from their supports.
Its reliability largely depends on contact lines, which must operate in all climatic conditions with as little maintenance as possible. The authors have used their world-wide experience to provide comprehensive descriptions of configuration, mechanical and electrical design, installation, operation and maintenance of contact lines for electric railways on local and long-distance transportation systems, including high-speed lines.
In this book, railway company professionals and manufacturers of contact line systems, students and those embarking on a career in this field will find practical guidance in the planning and implementation of systems, product descriptions, specifications and the technical data, including standards and other regulations.
Since large sections of the book are dedicated to the system aspects, consultant engineers can also use it as a basis for designing systems and interfaces to other subsystems of electric railway engineering.
The contents of the book are rounded off by examples of running systems from different countries.
Table of contents Power supply systems - Requirements and specifications - Description of contact line systems - Rating overhead contact lines - Currents and voltages - Current return circuit and earthing - Thermal rating - Electromagnetic interferences - Line protection and fault location - Interaction of pantograph and overhead contact line - Components - Contact line design - Cross-span structures, poles and foundations - Design for special applications - Construction, acceptance and commissioning - Examples of running systems from many countries - Management and maintenance show more.
Friedrich Kie? Author of numerous publications on traction power supply systems. Rainer Puschmann: Author of many publications on overhead contact lines and traction power supply systems.