DC transmission possesses many technical and economic advantages over ac transmission. Some of the advantages are given below: Advantage # 1. Cheaper in Cost: Bipolar HVDC transmission lines require two-pole conductors while ac system requires 3 conductors to carry power. HVDC transmission can utilize earth return and, therefore, does not require a double circuit while EHV-AC transmission always requires a [...]
HVDC transmission is a strong alternative to EHV-AC transmission in some of the applications such as long distance high power transmission by overhead lines, under water transmission, transmission by underground cables, system interconnection by means of overhead lines or underground cables or back-to-back HVDC coupling stations, frequency conversion (50/60 Hz) and hence preferred. On the basis of applications, HVDC transmission [...]
The high voltage dc links may be classified into: 1. Monopolar Link 2. Bipolar Link 3. Homopolar Link. Type # 1. Monopolar DC Link: As the name suggests, monopolar link has only one conductor and return path is provided by permanent earth or sea. The line usually operates with negative polarity with respect to ground so as to reduce corona [...]
In this article we will discuss about:- 1. Introduction to HVDC Transmission 2. Principle of HVDC Transmission 3. Power Control 4. Ground Return 5. Earth Electrode and Station Earth 6. Transient Overvoltages and Insulation Coordination 7. Corona 8. Circuit Breaking 9. Comparison with EHV-AC Transmission 10. Limitations. Contents: Introduction to HVDC Transmission Principle of HVDC Transmission Power Control in HVDC [...]
In HVDC transmission system or HVDC back-to-back coupling station, ac is converted into dc by means of a combination of converter-transformers and concerter valves. The conversion of ac into dc is called rectification. At the receiving end of the HVDC transmission line, dc is converted back to ac by means of converter valves and and converter transformers. The conversion of [...]