--------------------- Explore the Terms "AUXILIAY CONVERTER" and "Electronic Interlocking System" Used in Indian Railways ---------
M/S Medha or Medha Servo Drives Pvt. Ltd is a Company founded in 1984, is focused on Rail Transportation of Our Country. It is also to be noted here that this company manufactures mainly the products which are used in the Diesel Locomotives, Electric Locomotives and Railway Coaches of Indian Railways. Moreover this Company also produces the components of "Electronic Interlocking System" which is used in the "Signalling System" of Indian Railways.
Brief History about Medha Servo...
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Drives Pvt. Ltd please refer the following Link:
click here
Please see the "Products" manufactured by this Company by clicking on the "Products" Tab in the page which will be opened after You click on the above Link.
In this blog I focus on the "Auxiliary Converters" which are produced by this company and are attached with all 3 Phase Locomotives( i.e WAP5,WAP7 & WAG9) of Indian Railways by Chittaranjan Locomotive Works(CLW) presently in the Workshop of CLW(For More Details about this Please refer Entry #1353010)and Components of Electronic Interlocking System produced by this Company which is used in Signalling System of Indian Railways.
What is Auxiliary Converter?
Ans: This System converts single phase power from Locomotive Transformer to three phase 50Hz power to supply to all auxiliary loads of Electric locomotive. It is direct replacement of Single phase to three phases ARNO Converter.
SYSTEM DESCRIPTION
Single Phase to Three Phase 180KVA Static Converter will take Single Phase Supply from the Locomotive main transformer tertiary winding and will use a Rectifier to derive a stable DC link voltage and unity power factor at input stage. The DC Link is unaffected by supply voltage variations. This DC link will be used as input to the three - phase Inverter, which will utilise IGBTs to synthesise a three-phase Sine Weighted PWM waveforms, with a fundamental voltage of 415 Vrms line to line. Since IGBTs are used as switching devices in the inverter, the system reacts fast to any of the fault conditions and protects itself and loads from all fault conditions. A Battery Charger is also built-in to cater to DC loads and to Charge the battery.
Source Link of this info: click here
Features of Auxiliary Converter:
1 Functions with highly fluctuating input voltages and frequency (600 VAC to 1150 VAC, 47 to 55 Hz)
2 Unity input Power factor at all loads and input voltage conditions.
3 Built-in self Protections.
4 Highly Reliable.
5 Forced Air Cooled. No need for liquid coolants.
6 VVVF Inverter output. Selectable either D.O.L starting or VVVF soft starting for Motor loads.
7 Harmonic Filter at output reduces Voltage/Current Harmonics, thereby reducing dv/dt , di/dt stress on induction motors.
8 Earth Leak monitoring ensures safe operation of entire system.
9 Output overload and Short Circuit protected.
Source Link of this Info: click here
Click on the "Features" tab in the page opened after clicking on the above Link to see the above noted features.
Specification of Auxiliary Converter:
INPUT
Input Voltage Range(19.0 KV to 27.5 KV on Catenary) - 700 to 1015 V AC Single PhaseDown to 600 V @ 16.5 kV and up to 1145 V @31.0 kV
Input Voltage Nominal - 760 / 830 V AC Single Phase
Supply source - Tertiary winding of main transformer of a 25 kV Locomotive
Input Frequency - 47 to 55 Hz
Transformer Impedance Voltage - 3 to 5%
Inrush Current - Less than maximum nominal input current
Efficiency - 93%
Power Factor - 0.9
Power required
15 Watts maximum
OUTPUT
Output Voltage Range - 394 to 436 V (line to line)
Nominal Output Voltage - 415 V
Output Continuous Rating of the Inverter - 180 KVA @ 0.8P.F
Short Time Rating - 600 Amps for 10 Seconds
Current Harmonics - less than 5% up to 20th harmonic
Frequency - 50 Hz ±1%
Wave form type - PWM (Sine Weighted)
Regulation - ±5% due to simultaneous variation of 0 to 100% load changes and input voltage variation of the D.C. supplyPower Factor - 0.9
BATTERY CHARGER
Input Voltage Nominal - 830 / 760V AC
Nominal Output Voltage - 110V DC
Output Continuous Current - 20A
Output Current Ripple - 1%
GENERAL
Operating ambient temperature - 0°C to 55°C
Audible noise - 75 dB (A) measured at a distance of 1 metre from the centre of the equipment
Cooling - Forced cooled using high reliability fans
Protection - Input Under Voltage, Input Over Voltage, Converter Phase Fault, Line to Line Short Circuit, Thermal Over Loading, Converter Fuse Failure, Earth Fault and Reverse Polarity for Battery Charger
Weight of Complete Unit - 1470 Kg approx
Outside Dimensions - 1650mm (H) x 1740mm (W) x 680mm (L)
INDICATIONS AND DIAGNOSTICS
Visual Indications - Converter Supply, Input Voltage, Converter Fuse, Earth Leakage, Converter Output, Converter Trip, Charger Supply, Charger Output, Charger Load, Control Supply, Temperature, Fan & Alarm
Volt free contacts - Converter Trip, Converter OK, Battery Charger Fault and Converter Enable
Source Link of this info: click here
Click on the "Specifications" tab in the page opened after clicking on the above Link to see the above noted Specifications.
Now like to describe in detail the Electronic Interlocking System produced by Medha used in Signalling System of Indian Railways
What is Electronic Interlocking System ?
Medha’s Electronic Interlocking System MEI 633 is a fail-safe, state-of-the-art Distributed Interlocking System. The System has been designed to CENELEC Standards to meet SIL-4 safety specification. It is based on two out of two architecture with a hot standby provision and automatic change-over facility. The System provides all the Interlocking features including Route Setting, Route Release, Point Operation, Track Occupancy Monitoring, Overlap Protection, Crank Handle Operation, Level Crossing Gate Interlocking, and provision for Block working.The Central Interlocking Unit (CIU) uses Two out of Two Architecture with two independent channels computing the Vital Interlocking Logic and a Supervisory Processor monitoring the two Vital computing channels. Hot standby with automatic change-over facility is provided. Redundant communication channels to Object Controller (OC) and Panel Processor (PP) are provided through two Communication Processors. OFC interface with Ring configuration is used for communication between CIU and OC, CIU and PP. Independent Power Supplies are provided for each Processo module for maximizing availability.Object Controllers (OC) control the field gear through Fail-safe Signaling Relays. One CIU can be connected to a maximum of 32 OCs. Each OC is capable of handling 24 Vital Outputs and 40 Vital Inputs. Two Communication Modules are included in each OC to provide redundant communication channel with CIU. Each OC consists of 8 Wayside Function Modules (WFMs), with each WFM capable of handling 8 Inputs or 8 Outputs. Each WFM is further based on two out of two architecture with two independent channels handling each Vital I/O. Redundant Power supplies are provided for WFMs for maximum availability.Panel Processor provides the Interface between the Operator’s Control Cum Indication Panel and the CIU. Redundant Processors with Independent Power Supplies are provided for maximum availability. System can be controlled either by Operator Control Panel or Visual Display Unit (LCD Display) based Control Terminal through software.
A Windows based user friendly, graphical Application Generation Tool Suite with high level of automation is provided for generation of Yard specific Application Data. The Tool Suite also provides the facility for Reverse Compilation and Relay Diagram Generation for easy verification of Application Data.The Maintenance Terminal provides the Diagnostic Interface through Online and Off-line Event & Fault and Yard Status Display with Date and Time Stamp. The Maintenance Terminal records all the Events and Faults. The recorded events can be replayed to view the Yard Status at any given time.
Source of this Info: click here
Features of Electronic Interlocking System
1 System capable of handling 2048 vital inputs and outputs
2 Large interlocking capability of the system provides faster response time independent of Yard configuration.
3 Modular system design, scalable to suit any yard size.
4 Complex yard configuration (over 1000 routes) possible cascading of EI systems.
5 100% Hot Standby with automatic change-over
6 Reliable and standardized hardware using SMD components
7 Redundant OFC connections for reliable communication linkages.
8 Individual power supplies for all redundant modules to maximize availability.
9 Relay based boolean interlocking logic provides maximum flexibility to the user to design the interlocking logic to meet any special interlocking requirements for a specific installation.
10 Configurable as a Distributed or Centralized Interlocking System
11 Easy upgrade of application data in case of yard modifications / upgradation, with minimum system down time.
12 Easy maintenance through modular design and extensive built-in fault diagnostics capability.
13 Online fault & event logging, troubleshooting guidance through Maintenance Terminal.
14 Replay of recorded events through MT for offline analysis.
Source of this info :click here
After clicking on the link a page will be opened there click on each feature head you can see the above points discussed under the "Features of Electronic Interlocking System"
Attached Images
1 Auxiliary Converter of 3 Phase Electric Locomotive produced by Medha Servo Drives Pvt. Ltd
Image Link: click here
2 Central Interlocking Unit for Electronic Interlocking System used in the Signalling of Indian Railways(produced by Medha Servo Drives Pvt. Ltd)
3 Visual Display Unit for Electronic Interlocking System used in the Signalling of Indian Railways(produced by Medha Servo Drives Pvt. Ltd)
4 Object Controller for Electronic Interlocking System used in the Signalling of Indian Railways(produced by Medha Servo Drives Pvt. Ltd)
Image Link of Images 2,3 and 4: click here