Current Experience
Technical Support Engineer
- For NCRTC
- Sep 2020 – Present
- 3 yrs 8 mos
Highest Level Of Education
AVCOE ( University of Pune)
- BE ( Eletrical)
- Jul 2013 - Jul 2017
About Me
I have around 4 years of experience working in Railway Metro projects mainly in MEP ( Mechanical, Electrical, and Plumbing/DMRC-NE03 ), Testing, and Commissioning of Rolling stocks (RS10 Project).
Currently, I work as Technical Assistant ( Power, Supply and Traction) at National Capital Region Transport Corporation, assisting in Design, Supply, Installation, Testing, and Commissioning of 5 Receiving Sub Stations [including 25 kV AC Traction cum 33 kV Auxiliary Main Sub Stations] for Complete Corridor of Delhi – Meerut RRTS Corridor of NCRTC.
Along with 25 KV Overhead Equipment (FOCS/ROCS), Auxiliary Power Supply [including Auxiliary Sub Station], and Associated Works on Viaduct & Tunnel.
Experience
For NCRTC
3 yrs 8 mos
Technical Support Engineer
Full-time
Sep 2020 - Present
Roles & Responsibilities ... Read more
Assisting Management of all Contractual Matters of Pkg-19 (P19L1 & P19L2) Contract with GC/PST Contractor. Assisting in modification of Power Supply and Traction System part in Bid Documents of Operation and Maintenance (O&M) of Delhi-Meerut Corridor.
Hyundai Rotem
11 mos
Engineer
Full-time
Jul 2019 - Jun 2020
Roles & Responsibilities ... Read more
Maintaining a record of daily Failure reported and modifications (HECP/SECP/Software Update) in the database. Responsible to demonstrate Contractual reliability, availability, and Maintainability requirements as per RS10 rolling stock contract for Delhi Metro Rail Corporation.
Blue Star Limited
1 yr 11 mos
Engineer
Full-time
Aug 2017 - Jul 2019
Roles & Responsibilities ... Read more
Managed 35 elevated stations in phase III of DMRC for Electrical, Fire Alarm & fire suppression systems worth INR 150 Cr. Supervision in major electrical work installation Such as Slab Conduiting, Cable Tray, Earthing Strip, Light Fixture & Wiring in elevated metro stations at contract NE-03 as per the approved method statement & checklist. End to end material management of various items - Ordering, Tracking, Billing, Handling & Installation.
Education
AVCOE ( University of Pune)
4 yrs
BE ( Eletrical)
Jul 2013 - Jul 2017
BSF Senior Sec School
1 yr 3 mos
HSC
Mar 2012 - Jun 2013Certifications | Licence
Certifications not yet added
Patents | Awards and recognitions | Memberships
Patents or Awards not yet added
Skills
Skills not yet added
Language Proficiency
Languages not yet added
- Posted 2 years ago
Basic of MEP
Basic of MEP MEP, or mechanical, electrical, and plumbing engineering, are the three technical disciplines that encompass the systems that allow stations/building interiors to be suitable for human use and occupancy. MEP construction must require all types of commercial, residential, and industrial purposes where services and facilities are required. MEP consists of installing air conditioning systems, water supply & drainage systems, firefighting systems, electrical power, and lighting systems including transformer substations and emergency power generators, fire protection and alarm systems, voice & data systems, security access, and surveillance systems, UPS, public address systems, Mast antenna TV system, and building management systems. MECHANICAL WORKS IN MEP PROJECT In MEP, major works are to be handled by Mechanical people because of HVAC or air conditioning system and that has piping work for cold and hot water, fabrication works for ducts, dampers and controllers, thermal/cold insulation works, and erection of machines like chiller unit, air handling units, grills, diffusers, etc. along with works of Drinking water, Drainage, and Sewerage systems. Other important Mechanical works are Firefighting works that included piping, sprinklers, and Pumps. ELECTRIC WORKS IN MEP PROJECT Electric works mainly included Electrical Power and Lighting but others like Transformer substations, Emergency power, UPS/Central battery, Voice/Data communication, TV, Security systems like CCTV surveillance system, Access control System, Public address system, Building management system (BMS), Fire alarm system, Surge Protection system, and Lightning protection system. PLUMBING WORKS ON MEP PROJECT Plumbing is a system of pipes and fixtures installed for the distribution and use of potable (drinkable) water, and the removal of waterborne wastes. It is usually distinguished from water and sewage systems that serve a group of buildings or a city.
Read Full Article- Posted 2 years ago
Earthing works in Railway building/Metro Stations or Substation
MAJOR PARTS OF E&M WORKS IN RAILWAY BUILDING/METRO STATION OR SUBSTATION CONSTRUCTION 1. Earthing 2. Conduiting 3. Light Point wiring, Power Point 4. Installation, testing, commissioning of light fixtures 5. laying of cables, jointing, termination etc. 6. laying of Cable Tray, HDPE pipe. RCC pipe Let’s get a short brief about all one by one EARTHING The earthing protection is an integral part of any electrical system and is required to a. Protect personnel and equipment from electrical hazards. b. Achieve a reduction in potential to the system neutrals. c. Reduce or eliminate the effects of electrostatic and electromagnetic interference on the signaling and Telecom equipment arising from auxiliary electrical systems. The main purpose of earthing in the electrical network is for safety. i) When all metallic parts in electrical equipment are grounded then if the insulation inside the equipment fails there are no dangerous voltages present in the equipment case. ii) To maintain the voltage at any part of an electrical system at a known value to prevent over current or excessive voltage on the appliances or equipment. iii) Lightning, line surges, or unintentional contact with higher voltage lines can cause dangerously high voltages to the electrical distribution system. The earthing is broadly divided as a) System earthing (Connection between a part of a plant in an operating system like LV neutral of a Power Transformer winding and earth). b) Equipment earthing (like motor body, Transformer tank, Switch gearbox, Operating rods of Air brake switches, etc.) to earth. Earthing provides an alternative path around the electrical system to minimize damages in the system. There are several types of earthing systems such as Earth Mat, Plate Earthing & Pipe Earthing which could be used in an elevated station and Substations. The selection of earthing depends upon several factors such as: i) Availability of Land ii) Type of Soil iii) Resistivity of Soil Mainly we follow two Specifications for earthing I. IS:3043 II. IEEE 80 The most commonly used earthing method is Earthmat or Grid Earth Mat or Grid The primary requirement of Earthing is to have a low earth resistance. Substation involves many Earthlings through individual Electrodes, which will have high resistance. But if these individual electrodes are interlinked inside the soil, it increases the area in contact with soil and creates a number of parallel paths. Hence the value of the earth resistance in the inter-linked state which is called combined earth value which will be much lower than the individual value. The interlink is made through a flat or rod conductor which is called an Earth Mat or Grid. It keeps the surface of substation equipment as nearly as absolute earth potential as possible. Picture: Earthmat To achieve the primary requirement of Earthing system, the Earth Mat should be designed properly by considering the safe limit of Step Potential, Touch Potential, and Transfer Potential. The factors which influence the Earth Mat design are: a. Magnitude of Fault Current b. Duration of Fault c. Soil Resistivity d. The resistivity of Surface Material e. Shock Duration f. Material of Earth Mat Conductor g. Earthing Mat Geometry Step Potential It is the potential difference available between the legs while standing on the ground. When a fault occurs at a tower or substation, the current will enter the earth. Based on the distribution of varying resistivity in the soil (typically, a horizontally layered soil is assumed) a corresponding voltage distribution will occur. The voltage drops in the soil surrounding the grounding system can present hazards for personnel standing in the vicinity of the grounding system. Personnel “stepping” in the direction of the voltage, gradient could be subjected to hazardous voltages Touch Potential Touch potential is the voltage between any two points on a person’s body – hand to hand, shoulder to back, elbow to hip, hand to foot, and so on. The touch potential or touch voltage could be nearly the full voltage across the grounded object if that object is grounded at a point remote from the place where the person is in contact with it . The earth resistance shall be as low as possible and shall not exceed the following limits: EHT Substations - 1.0 Ohms 33KV Stations - 2.0 Ohms Metro Stations - < 1.0 Ohms Specification of Earthing Depending on soil resistivity, the earth conductor (flats) shall be buried at the following depths. Soil Resistivity in ohms/metre Economical depth of Burial in metres 1) 50 – 100 0.5 2) 100 – 400 1.0 3) 400 – 1000 1.5 To keep the earth resistance as low as possible to achieve safe step and touch voltages, an earth mat shall be buried at the above depths below ground and the mat shall be provided with grounding rods at suitable points. All non-current carrying parts at the Substation shall be connected to this grid to ensure that under fault conditions, none of these parts are at a higher potential than the grounding grid.
Read Full Article- Posted 2 years ago
Various Systems of Railway Electrification
Various Systems of Railway Electrification Several different types of Railway Traction Electric Power System configurations have been used all over the World. The choice of the system depends on the train service requirements such as I. Commuter rail -Commuter rail typically includes one to two stops per city/town/suburb along a greater rail corridor II. Freight rail -Rail freight transport is the usage of railroads and trains to transport cargo on land. It can be used for transporting various kinds of goods III. Light rail -The LRT vehicles usually consist of 2–3 cars operating at an average speed of 55–60 km/h on the lines with more dense stops/stations and 65–70 km/h along the lines with less dense stations IV. Train load s V. Electric utility power supply. Railway electrification loads and systems required for light rails, commuter trains, fast high-speed trains, and of course the freight trains are all different. The power demands for these different rail systems are very different. The selection of an appropriate electrification system is therefore very dependent on the Railway system objectives Presently, the following four types of track electrification systems are available: 1. Direct current system—600 V, 750 V, 1500 V, 3000 V 2. Single-phase ac system—15-25 kV, 16 23, 25 and 50 Hz 3. Three-phase ac system—3000-3500 V at 16 2 3 Hz 4. Composite system—involving conversion of single-phase ac into 3-phase ac or dc. Direct Current Traction System In this traction system, electrical motors are operating on DC supply to produce the necessary movement of the vehicle. Mostly DC series motors are used in this system. For tramways, DC compound motors are used where regenerative braking is required. Regenerative braking In this type of braking the motor is not disconnected from the supply but remains connected to it and feeds back the braking energy or its kinetic energy to the supply system. The essential condition for this is that the induced emf should be slightly more than the supply voltage. The various operating voltages of the DC traction system include 600V, 750 V, 1500V, and 3000V. • DC supply at 600-750V is universally employed for tramways and light metros in urban areas and for many suburban areas. This supply is obtained from a third rail or conductor rail, which involves very large currents. • DC supply at 1500- 3000 is used for mainline services such as light and heavy metros. This supply is drawn mostly from an overhead line system that involves small currents. Since in the majority of cases, track (or running) rails are used as the return conductor, only one conductor rail is required. Both these supply voltages are fed from substations which are located 3-5 KM for suburban services and 40 to 50KMs for mainline services. These substations receive power (typically, 110/132 KV, 3 phase) from electric power grids. This three-phase high voltage is stepped-down and converted into single-phase low voltage using Scott-connected three phase transformers. This single-phase low voltage is then converted into DC voltage using suitable converters or rectifiers. The DC supply is then applied to the DC motor via a suitable contact system and additional circuitry. Advantages 1. In the case of heavy trains that require frequent and rapid accelerations, DC traction motors are the better choice as compared to AC motors. 2. DC train consumes less energy compared to AC unit for operating same service conditions. 3. The equipment in the DC traction system is less costly, lighter, and more efficient than the AC traction system. 4. It causes no electrical interference with nearby communication lines. Disadvantages 1. Expensive substations are required at frequent intervals. 2. The overhead wire or third rail must be relatively large and heavy. 3. Voltage goes on decreasing with an increase in length. Single-phase ac system In this type of traction system, AC series motors are used to produce the necessary movement of the vehicle. This supply is taken from a single overhead conductor with the running rails. A pantograph collector is used for this purpose. The supply is transferred to the primary of the transformer through an oil circuit breaker. The secondary of the transformer is connected to the motor through switchgear connected to suitable tapping on the secondary winding of the transformer. The switching equipment may be mechanically operated tapping switch or remote-controlled contractor of group switches. The switching connections are arranged in two groups usually connected to the ends of a double choke coil which lies between the collections to adjacent tapping points on the transformer. Thus, the coil acts as a preventive coil to enable tapping change to be made without short-circuiting sections of the transformer winding and without the necessity of opening the main circuit. Out of various AC systems like 15-25 kV, 16 23, 25, and 50 Hz. Mostly the 25KV voltage is used in railways. The main reason for the 25kV voltage used in the railway is, that 25 kV AC is more economical than a 1.5kV DC voltage system. Since the 25kV voltage system has a higher voltage, the higher voltage reduces the current flow through the conductor; this reflects reducing the conductor size. The cost of the conductor gets less. However, there are other major advantages for using 25kV voltage system in railway are quick availability and generation of AC that can be easily stepped up or down, easy controlling of AC motors, a smaller number of substations requirement, and the presence of light overhead catenaries that transfer low currents at high voltages, and so on. Disadvantages 1. Significant cost of electrification. 2. Increased maintenance cost of lines. 3. Upgrading needs additional cost especially in case there are bridges and tunnels. Composite System As the name suggests this system is classified into two types I single phase to dc system II single phases to 3 phase system Single Phase to DC system The first one single phase to dc system is used where the voltage level is high for transmission and the dc machine is used in the locomotive. This system combines the advantages of high-voltage ac distribution at the industrial frequency with the dc series motors traction. It employs an overhead 25-kV, 50-Hz supply which is stepped down by the transformer installed in the locomotive itself. The low-voltage ac supply is then converted into dc supply by the rectifier which is also carried on the locomotive. This dc supply is finally fed to dc series traction motor fitted between the wheels. Single-phase to 3 phase system Single-phase to 3 phase system is used where 3 phase machine is used in the locomotive and Single-phase track available. In this system, the single-phase 16KV, 50 Hz supply from the sub-station is picked up by the locomotive through the single overhead contact wire. It is then converted into a 3-phase AC supply at the same frequency by means of phase converter equipment carried on the locomotives. This 3-phase supply is then fed to the 3-phase induction motor. References: various EMC Europe IEEE papers, slideshare.net presentations, rail systems, etc.
Read Full Article- Posted 2 years ago
POWER QUALITY ISSUES IN RAILWAY ELECTRIFICATION
POWER QUALITY ISSUES IN RAILWAY ELECTRIFICATION The power quality issues through electric railway development are overviewed as follows : Voltage Unbalance Voltage imbalance (also called voltage unbalance) is defined as the maximum deviation from the average of the three-phase voltages or currents, divided by the average of the three-phase voltages or currents, expressed in percent. The most frequent problems of voltages are associated with their magnitudes. The major problem is unbalanced currents produce unbalanced voltages. Traction motors and other related loads in trains are designed to function properly with reduced voltage amplitude by 24% or increased amplitudes by 10% than the nominal voltage of electric railroad drives. System imbalance System imbalance is the most serious problem in electric railway power quality because most trains are single phase, and a single-phase load produces a current NSC (Negative Sequence Current) as much as a PSC (Positive Sequence Current). A new traction power supply system adopting a single-phase traction transformer and active power flow controller (PFC) is proposed. In the new system, the power quality problems caused by single-phase traction load are solved on the grid side and the continuous power can be Arcing The interaction between the pantograph/catenary of overhead systems or between brushes and the third or fourth rail causes arcs because of dynamic latitudinal tolerance between the wheels and rail. Arcs will occur, which can distort voltages and currents and produce a transient dc component in the ac systems causing a breakdown of dielectrics. Flicker As the train passes between two adjacent substations voltage sag may happen and affect other customers electrical light performance so-called flicker. EMI/EMC The movement of rolling stock along an electrified track produces Electromagnetic interference in the system. EMC covers a wide range of phenomena, including inductive noise in parallel communication lines, impulse noise from lightning and traction transients, the production of hazardous voltage under step and touch conditions, and the appearance of stray currents. EMI and EMC are very complicated for high-speed railway systems. Nowadays, the investigation in EMI/EMC high-speed railway is highly relying on simulation and measurement. Waveform Distortion Waveform distortion is defined as a steady-state deviation from an ideal sine wave of power frequency. There are five primary types of waveform distortion : 1. DC offset The presence of a dc voltage or current in an ac power system is termed dc offset 2. Notching Notching is a periodic voltage disturbance caused by the normal operation of power electronic devices when current is commutated from one phase to another. 3. Noise Noise is the unwanted electrical signal with broadband spectral content lower than 200 kHz superimposed upon the power system voltage or current in phase conductors, or found on neutral conductors or signal lines. 4. Interharmonics Voltages or currents having frequency components that are not integer multiples of the frequency at which the supply system is designed to operate (e.g., 50 or 60 Hz) are called inter harmonics. 5. Harmonics Harmonics can be best described as the shape or characteristics of a voltage or current waveform relative to its fundamental frequency. The ideal power source for all power systems is smooth sinusoidal waves. These perfect sinewaves do not contain harmonics. When waveforms deviate from a sinewave shape, they contain harmonics. These current harmonics distort the voltage waveform and create distortion in the power system which can cause many problems. In short (Harmonics are sinusoidal voltages or currents having frequencies that are integer multiples of the frequency at which the supply system is designed to operate.) Types of Harmonics: Odd and Even Order Harmonics: As their names suggest, odd harmonics have odd numbers (e.g., 3, 5, 7, 9, 11) , and even harmonics have even numbers (e.g., 2, 4, 6, 8, 10) . Harmonic number 1 is assigned to the fundamental frequency component of the periodic wave. Harmonic number 0 represents the constant or DC component of the waveform. The DC component is the net difference between the positive and negative halves of one complete waveform cycle. Total Harmonic Distortion (THD) is defined as the measurement of the harmonic distortion present in a waveform. The power quality of a power system is inversely proportional to THD. More harmonic distortion in the system, lower will be the power quality and vice versa. THD is equal to the ratio of the RMS harmonic content to the fundamental: Where Vn-rms is the RMS voltage of nth harmonic in the signal and Vfund-rms is the RMS voltage of the fundamental frequency. The Destructive Effects of Harmonic Distortion A power system’s ability to perform at optimal levels is compromised when harmonic distortion enters the system. It creates inefficiencies in equipment operations due to the increased need for power consumption. The increase of overall current required creates higher installation and utility costs, heating, and decreasing profitability. Harmonics in Electrified Railways It is well known that the rapid spread of power electronics brought along not only great advantages but also some drawbacks as they are the main sources of harmonics and voltage waveform distortion. Harmonic has emerged as a matter of great interest for electrical power system engineering. The electrified railway is one of the main harmonic sources in utility. Because electrified railway is supplied by High Voltage (HV) power system directly, lots of harmonic (mainly including 3rd, 5th, and 7th) produced by electric locomotive penetrate in the whole utility from HV. Compared with normal load, the most characteristics of traction are random time-varying and non-symmetry. So, the harmonic of traction load is very different from the normal load of utility. In an electrified railroad, the traction power is delivered to the catenary by substations, which in turn receive their supply from the utility network. For the electric utility transmission systems, the alternating current catenary is an unfavorable consumer. Two major reasons for this are: i) the catenary is a single-phase load, which power consumption unbalances the main supply three-phase system, ii) the use of power electronics converters to drive traction motors, generates harmonic currents that perturb interconnection busbar voltage. Basically, the power quality issues in railway electrification systems include the studies of the influence of traction loads on three-phase utility systems. Most of the high-speed trains are single-phase loads. Due to a large amount of power electronics application to the motor driving circuits of trains, they contribute to the high harmonic currents flowing to the railway catenary system. Traction load is varying dynamically, and arcs may occur because of pantograph/catenary and switching actions. Modern drive trains rely on power electronic converters combined with transformers, which inject low amounts of current harmonics into the supply system. Therefore, power quality must be considered in all aspects of the design for every system dealing with electric power systems. Some especially connected transformers are widely used, such as V-V, Scott, Le Blanc, and Modified Woodbridge connection schemes have been utilized in traction substations to compensate for negative sequence current (NSC) of the grid-side. Due to the nature of time-varying traction loads, it is almost impossible to compensate the whole NSC in all loading conditions. Passive filters have been adapted to suppress harmonics in electrical railway systems. Among derivations of filters, a C-type filter (CTF) introduces no power loss at the fundamental. frequency and performs as a first-order high-pass filter at tuned resonance frequency. Accordingly, the CTF is generally used to mitigate high-order harmonics caused by the PWM converters of the traction trains and prevent harmonic resonance. Although passive devices are affordable with a simple configuration, their performance is not satisfactory when operational conditions are varying. Therefore, active devices in AC electric railways have been proposed to resolve this issue. Static VAR compensators (SVC ) and static synchronous compensators (STATCOM) were proposed to compensate the load reactive power of trains dynamically. Since electric locomotives introduce harmonic contents, there is no chance to compensate harmonics by these devices, concurrently. Many other strategies have been also proposed for power quality improvement in electric railways, investigated in a comprehensive historical perspective. Nowadays, power quality improvement strategies have developed to a mature degree for new electric railway systems, among which Railway static Power Conditioners (RPC) and its alternatives (e. g. APQC, HBRPC, HPQC) have the main place. These compensation schemes are connected to the TSS secondary, as shown in Fig. , and theoretically operate based on instantaneous active/reactive power theory, in which the three-phase currents at the TSS primary side are supposed to be: (i) three-phase symmetrical, (ii) fully sinusoidal with no relevant harmonic content (iii) aligned with the three-phase voltage featuring negligible reactive power. Thereafter, the difference between the load currents and the ideal currents must be generated by the compensator, called compensation currents. The compensator operates as an independent three-phase current source, generating the desired compensation currents. The RPC consists of two single-phase back-to-back converters sharing the same DC-link capacitor through which active and reactive power are applied compensates voltage, NSC, total harmonic distortions (THD), and PF simultaneously and each AC side of inverters are connected to the two phases of the secondary side of feeding transformer, main phase, and teaser, respectively. These inverters work as effective power balancers and reactive power compensators. For example, if a load of the main phase is larger than that of the teaser, the RPC transfers effective power from the teaser bus to the main phase bus. This system works to balance the effective power of different phases and compensate for reactive power to reduce voltage unbalance and fluctuation. The various structures of the RPC such as active power quality conditioner (APQC), half-bridge RPC (HBRPC) and Hybrid power quality conditioner (HPQC) were presented. These devices can perform at a full compensating method which results in grid-side power factor unity, zero current unbalance, and harmonics. DIFFERENT COMPENSATORS USED IN SCOTT CO-PHASE SYSTEM Hazards of Poor Power Quality Problems in Railways Impacts on Signaling and Communications: Track circuits are designed to work with a special frequency that must not have any interference with the power frequency. But in presence of harmonics, communication signals may be affected by harmonic frequencies, resulting in erroneous signals and faulty train positioning, which lead to a disaster. Also, high-order harmonics may cause an interference problem between communication and power systems. Malfunction of the protective system: Protection relays may operate incorrectly in the presence of harmonics and NSCs of currents and voltages. Traction load injects many harmonics and NSCs resulting in the malfunction of the protective system. Decreased Utilization Factor: Since the traction load is a large single-phase load, it results in high current NSCs, which will flow in only two phases, and it decreases the utilization factor of the transmission line. Incorrect Operation of Transmission Line Control Systems: Voltages and currents sampling is based on fundamental components of either voltage or current. Every control system in the transmission line would work not appropriately because traction loads inject large amounts of harmonics and NSC current into the transmission lines. References: " IEEE Paper 10.1109/TIE.2014.2386794”, IEEE Paper 10.1109/TVT.2017.2661820, IEEE Std 519-1992
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