What is the function of thyristor in HVDC transmission?
High voltage direct current (HVDC) technology transmits very large amounts of electricity over very long distances with low energy losses. The core elements of HVDC transmission are converter stations at either end of the transmission link, where a solid state valve – or thyristor – converts AC and DC current.
Which method is commonly used for HVDC transmission?
1 HVDC. In HVDC systems, two main methods used in the power conversion between AC and DC are line commutated converter (LCC) and voltage source converter (VSC).
What is converter transformer in HVDC?
Spare converter transformer in the switchyard of an HVDC station. The converter transformers are designed to withstand dc voltage stresses and increased eddy current losses due to harmonic currents. One problem that can arise is due to the dc magnetization of the core due to unsymmetrical firing of valves.
What are HVDC cables?
Sumitomo Electric’s HVDC cable technologies enable interconnection of power grids between countries and across continents to secure reliable energy infrastructures.
What are the main components of the HVDC system?
Main components of HVDC system are as under:
- DC line inductors,
- harmonic filters,
- converter transformers,
- a reactive power source,
- ground electrodes,
- a microwave communication link between the converter stations.
What is HVDC transmission?
A high-voltage, direct current (HVDC) electric power transmission system (also called a power superhighway or an electrical superhighway) uses direct current (DC) for the transmission of electrical power, in contrast with the more common alternating current (AC) systems.
What are the main components of HVDC transmission?
How have HVDC thyristors changed over the years?
The exterior of HVDC thyristors is not so different from components of 20 years ago, but the size has increased considerably. Heavy copper electrodes on the top and bottom cope with enormous electrical currents, and the hermetic seal of the ceramic housing repels any corrosion. Nothing special – so has evolution really stalled for three decades?
What is a thyristor and how does it work?
This thyristor, which is a silicon-based power semiconductor device, is the heart of the converter station, and really the heart of HVDC transmissions, because without them, there are no conversions, and no HVDC transmissions.
What is the difference between mercury-arc valves and thyristor valves?
Since, the early 1970’s, the thyristor valves are universally employed in all new HVDC transmission system while earlier mercury-arc valves were used for conversion/inversion purposes. A thyristor valve has a better operating life and higher consistency of performance than those of a mercury-arc valve.
What type of valves are used in HVDC?
The valves used are of indoor design, air-insulated and air/water cooled. Thyristor assemblies are protected from dv/dt and dI/dt protection. Six-pulse or twelve-pulse converters are used in modern HVDC schemes—12-pulse is more preferred as it contains minimum ripple.