IEEE TECHNICAL TALK

IEEE Delhi Chapter organised a technical talk by Dr. Tapan Manna, IEEE PES Distinguished Lecturer on Applications of HVDC in Energy Generation at IIT Delhi on 28th September 2015. Four Students namely, Praveen Kilhore (16119), Nitin Yadav (16107), Nikhil Sharma (16103) and Saket (17121) from Department of Computer Science & Engineering of Dronacharya College of Engineering, Gurgaon attended the talk.

The Power & Energy Society (PES) is the world's largest forum for sharing the latest in technological developments in the electric power industry, for developing standards that guide the development and construction of equipment and systems, and for educating members of the industry and the general public. Members of the Power & Energy Society are leaders in this field, and they — and their employers — derive substantial benefits from involvement with this unique and outstanding association.

Dr. Tapan Manna discussed the importance of HVDC transmission and designs for several projects along with various conversions like the heart of an HVDC converter station and the equipment which performs the conversion between AC and DC, which is normally referred as converter.

During the talk, Dr. Manna explained that almost all HVDC converters are inherently capable of converting from AC to DC (rectification) and from DC to AC (inversion). He said that although in many HVDC systems, the system as a whole is optimized for power flow in only one direction. All power electronic converters generate some degree of harmonic distortion on the AC and DC systems to which they are connected, and HVDC converters are no exception. With the recently developed Modular Multi-Level Converter (MMC), levels of harmonic distortion may be practically negligible, but with line-commutated converters and simpler types of voltage-source converters, considerable harmonic distortion may be produced on both the AC and DC sides of the converter.

Dr. Manna discussed that the HVDC power flow is fully controllable, fast and accurate. The operator or automatic controller determines power flows via the link. An HVDC link is asynchronous and can adapt to any rated voltage and frequency at reception. He also explained about basic design considerations like Power transmission capacity, Transmission line- OHL, UG or Hybrid, Voltage levels, Current carrying capacity etc. He said that there are many projects in India like (Rihand –Delhi 500 KV-1990) and (Mundra- Haryana 500 KV- 2012), which are very similar to upcoming project “North-east Agra in 2016” .

With the help of presentations, Dr. Manna explained that the direct current equipment often includes a coil, which is normally termed as a reactor that adds inductance in series with the DC line to help smooth the direct current. The inductance typically amounts to between 0.1 H and 1 H. The smoothing reactor can have either an air-core or an iron-core. Iron-core coils look like oil-filled high voltage transformers. Air-core smoothing coils resemble, but are considerably larger than, carrier frequency choke coils in high voltage transmission lines and are supported by insulators. Air coils have the advantage of generating less acoustical noise than iron-core coils, they eliminate the potential environmental hazard of spilled oil, and they do not saturate under transient high current fault conditions. This part of the plant will also contain instruments for measurement of direct current and voltage.

It was an interactive event where the doubts of the participants were cleared by Dr. Manna in a question – answer session. The session was very educational as the participants got a very good opportunity to learn from the session.

Some Glimpses