Maintaining a constant voltage quality in medium-voltage networks is of elementary importance, especially for large companies, in order not to disrupt sensitive manufacturing processes. Whereas in the past a consistent quality of the power supply was ensured by a centralized design of the energy supply („top-down approach“) by means of hierarchy formation, considerable problems arise in particular due to the energy turnaround. Due to a decentralized energy supply based on volatile energy sources, it is necessary to switch strong electrical currents appropriately at short intervals in order to continue to meet the high demands on the energy network. However, a necessary prerequisite for this is a corresponding measuring device, which records parameters in the power grid in order to carry out a subsequent control.
Due to the decentralized energy supply, such measuring devices must fulfill the following characteristics:
Time synchronization: Due to the decentralized energy supply, it is necessary to query the status of a network at different points at a defined time. Here, exact time synchronization in the range of 1 μs is required.
Smartness: The devices mentioned should be able to determine corresponding parameters from the raw values themselves. For widespread use, intelligent internal evaluation (without external PC) of the data is necessary.
Costs: Due to the decentralized energy supply and a broad application, the devices must be small, compact and also inexpensive.
Therefore, the goal of the project was to design and realize such a measuring device, especially for the use in decentralized energy networks. Due to the highly accurate synchronization (synchronous phasor) and the local intelligence of the device, the device to be developed was named and implemented as a „Smart-Phasor-Measurement-Unit“. For this purpose, a research institute (Chair of Computer Architecture, Computer Science 3) and an SME (iba AG) combined their respective competences to realize this project.
Our main contribiution was the conception and realization of an embedded hardware architecture, based on FPGA, to determine corresponding power quality parameter in real-time.