HVDC-LIGHT Technology Presented by

What is HVDC LIGHT? The HVDC LIGHT is a technology based on voltage sources converters (VSC’ s) which emphasizing the light weight and compactness features intrinsic to it as well as competitiveness in application in the low end of the power scale.

Introduction HVDC light technology is designed to transmit large quantities of power using underground cables and at the same time adds stability and power quality to the connected networks. These converter stations are compact and by virtue of their control they do not contribute to the short circuit levels. They can meet the demands of competitive power market for transmission up to 1100MW.

Control scheme of HVDC light

Evolution of “HVDC light” Recent development efforts in transmission technology have focused on compact, small weight and cost-effective. By combining the advances made in VSC and DC cables, a new breed of electricity transmission and distribution technology emerges the “HVDC light”.

Installation of HVDC cables The land cables can be installed less costly with plowing technique. The submarine cables can be laid in deeper waters and on rough sea beds. HVDC cables can also be installed as overhead cables. Plastic cable Mass impregnated oil cable

HVDC light converter technology Conventional HVDC converter technology is based on the use of line-commutated or phase-commutated converters (PCC) with high frequency switching of IGBT’s and power full thyristors. IGBT valve Thyristor valve

HVDC light converter

The key part of the HVDC light converter consists of an IGBT valve bridge. HVDC light uses Pulse Width Modulation to generate the fundamental voltage. It controls the magnitude and phase of the voltage freely and allows independent and very fast control of active and reactive power flows. PWM voltage source converter does not contribute to the short-circuit power, as the AC current can be controlled by the converter valve.

Main difference between HVDC light and conventional Single line diagram of conventional HVDC Simplified HVDC light circuit

Applications of HVDC light Delivery of electricity to ISLANDS Feeding electric power to large and rapid growing cities. Feeding electric power to remotely located loads.

Environmental considerations Magnetic fields are eliminated since HVDC light cables are laid in pairs with DC current in opposite directions. It offers no overhead lines, neutral electromagnetic fields, oil-free cables and compact converter stations. The cable insulation is power electronic based are not dangerous.

Conclusion The main advantages of this new technology are short lead times, cost effectiveness, compactness and environmental friendliness. It is anticipated that this technology will quickly become the preferred alternative for transportation of energy, in many application cases where electricity transmission was not considered previously

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