Mitsubishi Electric Substation Division (SSD) provides a high voltage direct current system, which is designed to convert alternating current to direct current or alternating current of one type to alternating current of another type. The HVDC converter valves use Mitsubishi Electric IGBT’s in a Modular Multilevel Converter (MMC) topology to form the rectifiers, converting AC power to DC power, and the inverters that convert DC power back to AC power.
The SSD value of HVDC systems begins in recognition that AC transmission is directly limited in its power transfer capacity over distance. Whereas DC transmission does not have its power transfer capacity limited by distance. Furthermore, the applications for HVDC are point to point, where as DC transmission is attractive in transporting high voltage power over long distances. The second application for HVDC are back to back, where there is a high voltage interconnection between two independent, similar AC power networks, and a demarcation point is required. The third application for HVDC is international, where there is high voltage interconnection between two independent, dissimilar AC power networks, and the demarcation and conversion to different AC formats is required.
The High voltage Diamond system is designed using Melo’s latest IGBT technology and the modular technology employed in STATCOM. It is capable of designed voltages up to 400 kVdc and power transfer capacities up to 1000 MV.
The voltage-source converter devise includes.
- Independent active and reactive power control
- Fault Ride Through (less than 100 microsec.)
- Weak network operation
- Black-start mode
- STATCOM operation
- IEC 62501 compliance