ABB’s high power semiconductors are used in HVDC, renewable energies and traction. Yet, they also play a critical role in weather observation. In the U.S., where tornados and severe weather are a threat for areas such as air traffic, shipping and farming, precise weather warning is indispensable. The American observation network is nearly nationwide, thanks to approximately 160 radars.
The emitter of the radar transmits a burst of radio waves in a certain direction. These waves are back-scattered to the receiver after they bounced off an object e.g. a raindrop, bird, dust. The radar’s receiver collects the backscattered energy. Finally, the distance of the object can be calculated by multiplying the speed of light (the travel speed of the radio waves) and the time from transmitted to received, divided by two.
The current radar network across the U.S. was deployed in the mid to late 1990s. The conducted equipment update by the National Oceanic and Atmospheric Administration (NOAA) is part of the next generation weather radar program (NEXRAD) with the goal to achieve faster and more precise data processing and has up to 150 miles reach and one mile resolution, depending on the area. Additionally, future advancement in data quality and collection is expected. Currently, the US government invests approximately 8 million USD a year into this program.
A first prototype for such an application with our power semiconductor switches was built in 2002 for the well-known Massachusetts Institute of Technology (MIT) in the US and tested in operation for several years. During the trial period, ABB’s 4.5 kV Integrated gate-commutated thyristor (IGCT) semiconductor switch-based assembly proved that the new IGCT switch technology has clear advantages regarding lifetime and reliability of the radar installation compared to the current solutions on the market.
The installations are in service for 24 hours, 365 days a year for the weather observation to identify critical weather conditions, like tornados, thunderstorms, or blizzards early on. This information is available through the NOAA weather app for smart phones. Universities use the information to improve their weather forecast models and become more accurate in forecasting. A first large order followed in 2007 as a replacement for the modulator switches in flight radar units at selected locations across the U.S. The implemented semiconductor assemblies are doing their duty to observe the flight traffic until today without any failures.
After the properties of ABB’s fast turn-on IGCT switch technology was proven in the field, NOAA ordered assemblies for the update of their complete weather radar network in the United States. Each semiconductor was tested individually and in the assembly. These tests were carried out with highly specialized test systems for high power semiconductors, which are built by ABB Semiconductors.
More information can be found under http://www.noaa.gov/weather.