World’s First Dynamic Grid Control Center
The transition to a new energy mix is making the power grid more dynamic. Siemens coordinated a major research project designed to determine the extent to which existing control center technology can accommodate additional functions, and at which point entirely new structures and architectures will be needed.
by Katrin Nikolaus
The power grid is much more dynamic today than it was 20 years ago due to fluctuating electricity volumes from renewable energy sources and the wide variety of new, highly dynamic utilities, such as HVDC transmission. To control the grid more efficiently, the control centers need new assistance systems. Over the past three years, these systems have been developed and tested in the state-sponsored DynaGridCenter project that Siemens helmed with three universities and two Fraunhofer institutes.
“In this way, we will manage the energy transition,” says a satisfied Rainer Krebs. The head of the consulting unit for the operation and protection of power grids in the Siemens Energy Management Division has no doubts that the research results will contribute significantly to a reliable and efficient electricity grid in Germany in the future. This will also allow the dynamic control center to become a central component of the Power Grid Action Plan presented by the German government in August 2018.
The core problem today is the uneven load distribution in the power grid caused by overcapacities from renewable energy sources, which cannot yet be integrated productively, and by the fluctuations in the feed-in from many smaller electricity producers. Improved control and regulation technology for the control centers that monitor and remotely control the grid is therefore essential. Krebs compares the programs that have now been developed to car assistance systems: “Each system on its own already improves grid reliability but combining the systems will lead to the dynamic control center of the future.” It is planned to introduce the researched systems gradually over the next few years.
Improved power grid monitoring
The technologies for monitoring the grid more closely are already being implemented. So-called phasor measurement units (PMUs) transmit the height and the phase angle of current and voltage every 20 milliseconds. In this way, they supplement the measured data that formerly had been transmitted in the seconds range by adding a highly dynamic component. The PMUs in the grid are synchronized to a common time source, which allows them to be directly compared with each other. This shows up unwanted vibrations and very fast transient effects in the network. The new assistance systems will be tested in a laboratory grid control center at the Technical University of Ilmenau, which is linked to a simulated power grid operated by the Otto-von-Guericke University in Magdeburg.
"Each system on its own already improves grid reliability but combining the systems will lead to the dynamic control center of the future."
“So far, these dangerous, dynamic processes in the grid, which can lead to blackouts, can only be avoided through preventive measures,” explains Krebs. To do this, grid operators intervene in the timetables of power plants to prevent impending bottlenecks. This re-dispatch costs up to a billion euros a year. It is easier and, above all, less expensive to utilize the lines optimally and only intervene to rectify overloads. This is made possible by the new monitoring and control programs, as they firstly make the dangerous situations created by overloads visible, and secondly can initiate the requisite countermeasures much more quickly than humans.
Showroom for the grid of the future
The research project has provided many new insights into the operation of the power grids of the future, explains Krebs. One of the simulated transmission routes is an HVDC line used to transport electricity over long distances, such as from wind farms off the coast of northern Germany to the south. It had already been more difficult than expected to integrate and regulate the HVDC line in the simulated power grid in the laboratory, for example. All new assistance systems developed by the research network can be demonstrated in the control center of the University of Ilmenau as in a showroom. A follow-up project called InnoSys2030 will prove whether or not the systems also work in real power grids. Another follow-up project will be dedicated to the dynamic digital twin of power grids.
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