Synchronisation of a Distributed Measurement System

Abstract:
In order to transfer the large amount of energy produced by multiple offshore wind farms to the onshore grid, multi-terminal high voltage direct current grids are proposed. For the evaluation and development of control strategies for such a grid, a demonstrator is currently developed. To analyse the behaviour of the demonstrator voltages and currents, the values have to be measured at multiple locations synchronously. Therefore, a previously developed distributed measurement system is synchronised to assure a simultaneous sampling of all sensor signals. The synchronisation of the components in one measurement system is done by the EtherCAT distributed clock mechanism. A new mechanism is introduced to synchronise the master of the EtherCAT network to the distributed clocks. For the external synchronisation of several measurement systems, two possibilities are presented. The system can be synchronised either by a central oscillator or by a primary EtherCAT network.