ABB solves 100-year old dc electrical grid puzzle

Zurich, Switzerland, Nov. 7, 2012 – ABB, the leading power and automation technology group, today announced a breakthrough in the ability to interrupt direct current, solving a 100-year-old electrical engineering puzzle and paving the way for a more efficient and reliable electricity supply system.
After years of research, ABB has developed the world’s first circuit breaker for high voltage direct current (HVDC). It combines very fast mechanics with power electronics, and will be capable of ‘interrupting’ power flows equivalent to the output of a large power station within 5milliseconds- that is thirty times faster than the blink of a human eye.

The breakthrough removes a 100-year-old barrier to the development of DC transmission grids, which will enable the efficient integration and exchange of renewable energy. DC grids will also improve grid reliability and enhance the capability of existing AC (alternating current) networks. ABB is in discussions with power utilities to identify pilot projects for the new development.
“ABB has written a new chapter in the history of electrical engineering,” said Joe Hogan, CEO of ABB. “This historical breakthrough will make it possible to build the grid of the future. Overlay DC grids will be able to interconnect countries and continents, balance loads and reinforce the existing AC transmission networks. “

The Hybrid HVDC breaker development has been a flagship research project for ABB, which invests over $1 billion annually in R&D activities. The breadth of ABB’s portfolio and unique combination of in-house manufacturing capability for power semiconductors, converters and high voltage cables (key components of HVDC systems) were distinct advantages in the new development.

HVDC technology is needed to facilitate the long distance transfer of power from hydropower plants, the integration of offshore wind power, the development of visionary solar projects, and the interconnection of different power networks. ABB pioneered HVDC nearly 60 years ago and continues to be a technology driver and market leader with many innovations and developments. With over 70 HVDC projects, ABB accounts for around half the global installed base, representing an installed capacity of more than 60,000 megawatts (MW).

Deployment of HVDC has led to an increasing number of point-to-point connections in different parts of the world. The logical next step is to connect the lines and optimize the network. ABB is already working on the construction of multi-terminal systems and the latest DC breaker innovation is a major step in the evolution of HVDC grids. In parallel to the new hybrid breaker development, ABB has an established HVDC grid simulation center developing solutions for future DC overlay grid operations.

Career Opportunities for Engineers after IES Exam

Indian Engineering Services Exam provides excellent job opportunities for Engineering Graduates. Candidates who have cleared Indian Engineering Services (IES) Exam will be placed as Assistant Executive Engineer in various departments under Central Government in the initial stage. Those who have experience up to 32 years will be promoted as Secretary to Government of India. Indian Railway, Indian Defense Service, Geological Survey of India, Indian Supply Service and Indian Telecommunication Service etc are some of the areas where engineers can look for a career.

Career Opportunities
Candidates who have cleared Indian Engineering Services Exam, conducted by UPSC can seek employment in various departments under Government of India. Recruitment is conducted on the basis of ranks and industrial experience of the candidates. Candidates can seek employment according to the subjects they have specialized in engineering degree.
Candidates are placed as Assistant Executive Engineer in various organizations at the time of selection. After three to four years of service, they can work in the post of Executive Engineer which is equivalent to Under Secretary to Government of India. Those who have 20 years of service will be promoted to the post of Chief Engineer level-1. Engineers having professional experience of 32 years will be posted as Secretary to the Government of India
Career opportunities for Civil Engineers after IES
Candidates who have specialization in Civil Engineering can start their career as Assistant Executive Engineer in following departments.

• Indian Railway Service of Engineers
• Indian Railway Stores Service
• Central Engineering Service
• Indian Defense Service of Engineers
• Indian Ordnance Factories Service (IOFS)
• Central Water Engineering
• Central Engineering Service (Roads)
• Border Roads Engineering Service

Career opportunities for Mechanical Engineers after IES
Engineering Degree holder in Mechanical Engineering can seek employment in Group A (Mechanical Engineering Posts) in following departments.

• Indian Railway Service of Mechanical Engineers
• Central Engineering Service (Roads)
• Central Power Engineering Service
• Indian Naval Armament Service
• Central Electrical & Mechanical Engineering Service
• Electrical and Mechanical Engineers, a branch in the Indian Army
• Indian Navy
• Geological Survey of India
• Indian Supply Service
• Indian Defence Service of Engineers

Career Opportunities for Electrical Engineers after IES
Candidates who have completed Graduation in Electrical Engineering can seek employment as Assistant Executive Electrical Engineer in following departments.

• Indian Railway Service of Signal Engineers
• Central Power Engineering Service
• Indian Inspection Service
• Indian Defence Service of Engineers
• Central Electrical and Mechanical
• Engineering Service (Electrical Engineering Posts)

Career Opportunities after Electronics & Telecommunication Engineering
Those who have completed graduation in Electronics & Telecommunication Engineering can seek employment in following departments as Grade 1 engineers.

• Junior Telecom officer in Indian Telecommunication Service
• Indian Railway Stores Service (Telecommunication/ Electronics Engineering Posts)
• Central Power Engineering Service
• Assistant Naval Stores Officer Grade- I
• Indian Inspection Service Group
• Indian Telecommunication Service

Recruitment to the posts is carried out on the basis of merit, candidates’ preferences and their medical fitness. Aspirants belonging to reserved categories can have relaxation in age and other benefits as per the norms issued by Government of India.

Stanford announces 16 free online courses for fall quarter

Sixteen courses and two new platforms for interactive learning will highlight Stanford's free online offerings this fall, with more to follow during winter and spring quarters.
From cryptography to science writing, technology entrepreneurship, finance and a crash course in creativity, the courses are open to anyone with a computer, anywhere.
As the number of Stanford online courses has grown, so too has the range of fields, which now include computer science, mathematics, linguistics, science writing, sociology and education.
Stanford is unique among universities in that it is offering its online courses on more than one platform. Each has its own distinct features and capabilities, among them video lectures, discussion forums, peer assessment, problem sets, quizzes and team projects.
Coursera was developed by two Stanford computer scientists who currently are on leave. Students interested in registering should go to the course websites listed below or to the Stanford Online website, where updates will be available as new courses appear.
Here is a list of fall quarter classes, with instructor, course title, start date and platform:
Andrew Ng, Machine Learning, Aug. 20, Coursera
https://www.coursera.org/course/ml
Dan Boneh, Cryptography, Aug. 27, Coursera
https://www.coursera.org/course/crypto
Keith Devlin, Introduction to Mathematical Thinking, Sept. 17, Coursera
https://www.coursera.org/course/maththink
Daphne Koller, Probabilistic Graphical Models, Sept. 24, Coursera
https://www.coursera.org/course/pgm
Scott Klemmer, Human-Computer Interaction, Sept. 24, Coursera
https://www.coursera.org/course/hci
Michael Genesereth, Introduction to Logic, Sept. 24, Coursera
https://www.coursera.org/course/intrologic
Dan McFarland, Organizational Analysis, Sept. 24, Coursera
https://www.coursera.org/course/organalysis
Kristin Sainani, Writing in the Sciences, Sept. 24, Coursera
https://www.coursera.org/course/sciwrite
Tim Roughgarden, Algorithms: Design and Analysis, Part 2, October, Coursera
https://www.coursera.org/course/algo2
Chuck Eesley, Technology Entrepreneurship, Fall, Venture Lab
http://venturelab.stanford.edu/venture
Tina Seelig, A Crash Course on Creativity, Fall, Venture Lab
http://venturelab.stanford.edu/creativity
Paul Kim, Designing a New Learning Environment, Fall, Venture Lab
http://venturelab.stanford.edu/education
Kay Giesecke, Finance, Fall, Venture Lab
http://venturelab.stanford.edu/finance
Clint Korver, Startup Boards: Advanced Entrepreneurship, Fall, Venture Lab
http://venturelab.stanford.edu/advanced_venture
Bruce Clemens, Solar Cells, Fuel Cells and Batteries, Oct. 8, Class2Go
http://solar.class.stanford.edu
Nick McKeown and Philip Levis, An Introduction to Computer Networks, Oct. 8, Class2Go
http://networking.class.stanford.edu

POWERGRID to recruit Graduate Engineers through GATE-2013

Power Grid Corporation of India Limited (PGCIL) is looking for electrical engineers to join in Executive Trainee positions. The recruitment will be done through GATE 2013 score and candidate must satisfy the below mentioned eligibility criteria.

Upper age limit

28 years as on 31.12.2012

Who can apply

1. Full Time B.E./ B.Tech/ B.Sc (Engg) from recognized University/Institute in Electrical/ Electrical (Power)/ Electrical and Electronics/ Power Systems Engineering with a minimum 65% marks or equivalent CGPA.
2. AMIE in Electrical with a minimum 65% with both Sections A & B cleared by 31.03.2013
3. Final Year / Semester students of Sl. No. 1 above who expect their results by 31.07.2013 are also eligible, provided they have obtained minimum 65% marks or equivalent CGPA in aggregate of all semesters/years up to pre-final examination.
4. Relaxation conditions are mentioned for various categories in the detailed advertisement notification

Important

Candidates have to register themselves and appear for GATE -2013 in Electrical Discipline (Code EE).

From 7th January 2013 onwards, Candidates have to register themselves online at POWERGRID website with details of their GATE -2013 Application No., GATE-2013 Registration Number and other required information, which will be made available at CAREER section of www.powergridindia.com.

Download or view complete advertisement details of PGCIL recruitment

GAIL to recruit Graduate Engineers through GATE-2013

GAIL India Ltd. is looking for Graduate engineers desirous of joining GAIL as Executive Trainee in 2013 in the disciplines of Mechanical, Electrical, Instrumentation and Chemical through GATE-2013.

GAIL will be utilizing Graduate Aptitude Test in Engineering-2013 scores (GATE 2013-scores) for recruitment of Executive Trainees in the above disciplines during the year 2013.

Eligible candidates who wish to apply for the position of Executive Trainee in the above discipline in GAIL will be required to first apply for appearing in GATE-2013 and thereafter appear in GATE-2013 as per instructions and timelines notified by GATE-2013 organizing institute in one of the following relevant GATE examination papers  Mechanical Engineering (ME); Electrical Engineering (EE); Instrumentation Engineering (IN); Chemical Engineering (CH).

View detailed advertisement from GAIL India Ltd.

HPCL to recruit 250 Graduate Engineers through GATE-2013

HPCL intends to recruit 250 Engineering Graduates through GATE 2013, the positions are available for Engineering Graduates with specializations in Mechanical, Civil, Electrical, Electronics & Telecommunications and Instrumentation Engineering.

Eligibility criteria

Candidates should have passed qualifying degree examinations and awarded bachelor‟s degree in engineering/technology in the above mentioned disciplines (full time regular courses only) from recognized Indian Universities/ Institutes.

Candidates (belonging to General and OBC-NC category) should have secured minimum 60% marks in qualifying degree examinations. It is relaxed to 50% for SC/ST/PWD candidates.

Candidates currently in final year of their engineering studies may also apply. However, if selected, they must be in a position to submit their final mark sheet by 31st August 2013.At the time of applying Candidates (belonging to General and OBC NC category) should have secured minimum 60% aggregate marks upto last semester examinations. It is relaxed to 50% for SC/ST/PWD candidates.

Age limit

Maximum 25 years as on 30th June 2013 for the general category candidates. Age relaxation for OBC (Non Creamy Layer)/SC/ST/PWD candidates will be applicable as per the Presidential Directive.

Relaxation criteria is available please refer the detailed advertisement.

The last date for receiving online application for HPCL is 14th February, 2013.

View HPCL Advertisement for Graduate Engineers through GATE 2013

Understanding Engineers

Understanding Engineers #1 

Two engineering students were biking across a university campus when one said, "Where did you get such a great bike?" The second engineer replied, "Well, I was walking along yesterday, minding my own business, when a beautiful woman rode up on this bike, threw it to the ground, took off all her clothes and said, "Take what you want." The first engineer nodded approvingly and said, "Good choice: The clothes probably wouldn't have fit you anyway." 

Understanding Engineers #2 

To the optimist, the glass is half-full. To the pessimist, the glass is half-empty. To the engineer, the glass is twice as big as it needs to be. 

Understanding Engineers #3 

A priest, a doctor, and an engineer were waiting one morning for a particularly slow group of golfers. The engineer fumed, "What's with those guys? We must have been waiting for fifteen minutes!" The doctor chimed in, "I don't know, but I've never seen such inept golf!" The priest said, "Here comes the greens -keeper. Let's have a word with him." He said, "Hello George, What's wrong with that group ahead of us? They're rather slow, aren'tthey?" The greens-keeper replied, "Oh, yes. That's a group of blind firemen. They lost their sight saving our clubhouse from a fire last year, so we always let them play for free anytime!" The group fell silent for a moment. The priest said, "That's so sad. I think I will say a special prayer for them tonight.." The doctor said, "Good idea. I'm going to contact my ophthalmologist colleague and see if there's anything she can do for them." The engineer said, "Why can't they play at night?" 

Understanding Engineers #4 

What is the difference between mechanical engineers and civil engineers? Mechanical engineers build weapons. Civil engineers build targets. 

Understanding Engineers #5 

The graduate with a science degree asks, "Why does it work?" The graduate with an engineering degree asks, "How does it work?" The graduate with an accounting degree asks, "How much will it cost?" The graduate with an arts degree asks, "Do you want fries with that?" 

Understanding Engineers #6 

Three engineering students were gathered together discussing who must have designed the human body.. One said, "It was a mechanical engineer. Just look at all the joints." Another said, "No, it was an electrical engineer. The nervous system has many thousands of electrical connections." The last one said, "No, actually it had to have been a civil engineer. Who else would run a toxic waste pipeline through a recreational area?" 

Understanding Engineers #7 

Normal people believe that if it ain't broke, don't fix it. Engineers believe that if it ain't broke, it doesn't have enough features yet. 

Understanding Engineers #8 

An engineer was crossing a road one day, when a frog called out to him and said, "If you kiss me, I'll turn into a beautiful princess." He bent over, picked up the frog, and put it in his pocket. The frog spoke up again and said, "If you kiss me, I'll turn back into a beautiful princess and stay with you for one week." The engineer took the frog out of his pocket, smiled at it and returned it to the pocket. The frog then cried out, "If you kiss me and turn me back into a princess, I'll stay with you for one week and do anything you want." Again, the engineer took the frog out, smiled at it and put it back into his pocket. Finally, the frog asked, "What is the matter? I've told you I'm a beautiful princess and that I'll stay with you for one week and do anything you want. Why won't you kiss me?" The engineer said, "Look, I'm an engineer. I don't have time for a girlfriend, but a talking frog - now that's cool." 

Electrical Interview Questions and Answers Part 2

Q1. Difference between a four point starter and three point starter?
Q2. Why use the VCB at High Transmission System ? Why can't use ACB?
Q3. What is the difference between surge arrestor and lightning arrestor?
Q4. Explain the working principal of the circuit breaker?
Q5. How many types of colling system it transformers?
Q6. There are a Transformer and an induction machine. Those two have the same supply. For which device the load current will be maximum? And why?
Q7. what is power factor? whether it should be high or low? why?
Q8. What is the difference between Isolator and Circuit Breaker?
Q9. what is boucholz relay and the significance of it in to the transformer?
Q10. What is SF6 Circuit Breaker?
Q11. what is ferrantic effect?
Q12. What is meant by regenerative braking?
Q13. Why is the starting current high in a DC motor?
Q14. What are the advantages of star-delta starter with induction motor?
Q15. Why Delta Star Transformers are used for Lighting Loads?

Download Answers Link 1 Link 2 Link 3

Electrical Interview Questions and Answers Part 1

Q1. What is "pu" in electrical engineering?

Q2. What is the difference between electronic regulator and ordinary electrical rheostat  regulator for fans?

Q3. How tube light circuit is connected and how it works?

Q4. whats is MARX CIRCUIT?

Q5. What are the advantages of speed control using thyristor?

Q6. Why, when birds sit on transmission lines or current wires doesn't get shock?

Q7. what is meant by armature reaction?

Q8. what happen if we give 220 volts dc supply to d bulb r tube light?

Q9. Which motor has high Starting Torque and Staring current DC motor, Induction motor or Synchronous motor?

Q10. Which type of A.C motor is used in the fan (ceiling fan, exhaust fan, padestal fan, bracket fan etc) which are find in the houses ?

Q11. Give two basic speed control scheme of DC shunt motor?

Q12. what is the difference between synchronous generator & asynchronous generator?

Q13. Why syn. generators r used for the production of electricity?

Q14. What is Automatic Voltage regulator(AVR)?

Q15. What is an exciter and how does it work?

 

 Download Answers Link 1 Link 2 Link 3

Principles of Transformers in Parallel Connection

For supplying a load in excess of the rating of an existing transformer, two or more transformers may be connected in parallel with the existing transformer. The transformers are connected in parallel when load on one of the transformers is more than its capacity. The reliability is increased with parallel operation than to have single larger unit. The cost associated with maintaining the spares is less when two transformers are connected in parallel.

It is usually economical to install another transformer in parallel instead of replacing the existing transformer by a single larger unit. The cost of a spare unit in the case of two parallel transformers (of equal rating) is also lower than that of a single large transformer. In addition, it is preferable to have a parallel transformer for the reason of reliability.

With this at least half the load can be supplied with one transformer out of service.

Condition for Parallel Operation of Transformer

For parallel connection of transformers, primary windings of the Transformers are connected to source bus-bars and secondary windings are connected to the load bus-bars.

Various conditions that must be fulfilled for the successful parallel operation of transformers:

1. Same voltage and Turns Ratio (both primary and secondary voltage rating is same)
2. Same Percentage Impedance and X/R ratio
3. Identical Position of Tap changer
4. Same KVA ratings
5. Same Phase angle shift (vector group are same)
6. Same Frequency rating
7. Same Polarity
8. Same Phase sequence

Some of these conditions are convenient and some are mandatory.

The convenient conditions are: Same voltage Ratio and Turns Ratio, Same Percentage Impedance, Same KVA Rating, Same Position of Tap changer.

The mandatory conditions conditions are: Same Phase Angle Shift, Same Polarity, Same Phase Sequence and Same Frequency. When the convenient conditions are not met paralleled operation is possible but not optimal.

For more detailed concept on parallel transformers Download PDF

Contents

• Introduction
• Condition for Parallel Operation of Transformer
• Summary of Parallel Operation of Transformer
• The combinations that will operate in parallel
• The combinations that will not operate in parallel
• How to check Synchronization of Transformers
• Advantages of Transformer Parallel Operation
• Disadvantages of Transformer Parallel Operation
• Conclusions

Download PDF Link 1 Link 2 Link 3