Swiss supercapacitors drive Chinese 550kV DC meshed grid
The CONDIS supercapacitors from Maxwell Technologies will be the first to market with the largest 550kV DC meshed grid that includes four types of new capacitors for DC high voltage circuit breakers using four lines and four substations. China has been pioneering high voltage DC distribution lines, running a 1100kV system.
The redundant architecture of the Zhangbei Porject will provide more than six times the energy conversion on the grid while allowing the DC circuit breaker to open circuits on the production site should any line get compromised, minimising losses and increasing flexibility to transfer energy on the line. The supercapacitors are rated from 800 kV up to 1100 kV. Customers include ABB, NHVS, PG, XD, NARI and XJ.
“Demand for meshed DC grids is growing and these new developments are opening an increased need for high voltage capacitors,” said Gérard Lopez, vice president and general manager of the high voltage product line. “We have invested substantial time and resources in R&D to follow the evolution of the transmission/distribution grid and to provide our customers with the most secure, reliable and innovative products. Participation in this project is evidence of our proven success with circuit breakers and dividers and reinforces our strategic position in China while paving the way for future worldwide projects of this magnitude.”
The main challenge of this project for OEM partners is the development of DC circuit breakers with a new switching system capable of opening DC currents. To meet this need, Maxwell is in development of four types of supercapacitors for these DC breakers including DC-Fast Circuit Breaker (pure DC-voltage), DC Pole Bus Circuit Breaker (pure DC-voltage), Starting Resistor Bypass Circuit Breaker (composite voltage AC & DC) and Converter AC Side Circuit Breaker (composite voltage AC & DC).
“The CONDIS product line has been regarded as a reliable provider of high voltage capacitors for circuit breakers and dividers for two decades,” said Lijiang Chi, Chief Engineer and Vice GM of XJ, a participant in the ZhangBei DC Grid Project. “The ZhangBei project will supply enough power on the grid to manage the increasing demand for high energy without breakdown of the grid. The technology provided by CONDIS capacitors will aid us in minimizing disruptions by increasing the number of lines and substations.”
The long term stability, temperature control and insulation design of the HV supercapacitors and voltage dividers help handle variable working conditions in high altitude HVDC substations such as Zhangbei.