In a few months, rooftop solar power systems in California are going to start regulating voltage levels and perform other grid-support jobs.
According to the IEEE Spectrum, the added functionality is the result of upgraded solar inverters, which link distributed generators to the grid. The devices can mitigate both excessive voltage and voltage drops caused by fluctuating solar generation, thus preventing potential power quality problems.
If smart inverters are not installed, these voltage swings can potentially damage utility equipment and residents’ home appliances; increase overall cost of maintaining the grid; require continued installation of larger, more expensive alternatives; and could even contribute to distributed outages, according to an article from Transmission & Distribution World.
The California Public Utilities Commission approved the standard for inverter use in December. Solar installers will be encouraged to start using smart inverters within a few months. Meanwhile, efforts are under way to incorporate California’s upgrades into the IEEE 1547 standard governing distributed power devices, which would accelerate smart-inverter use across the United States, the IEEE Spectrum reported.
Frances Cleveland, president of Boulder Creek, Calif.–based Xanthus Consulting International and the CPUC’s technical consultant on smart inverters, said that California’s standard is not mandatory until mid-2016. The idea, she told the Spectrum, is to give utilities time to work out the optimal settings for inverters on their systems. One potential issue they will be watching for is feedback between multiple smart inverters trying to dynamically adjust voltage on the same line—with some inverters absorbing the reactive power that others produce.