Improved power quality monitoring through phasor measurement unit data interpretation

The observability needs in future power systems will change radically due to the continuing implementation of renewable energy sources at all voltage levels. Especially in distribution grids new observables will be needed in order to monitor the state of the power system sufficiently and to perform the correct actions for operating the system. In future power systems more measuring sensors including phasor measurement units will be available distributed all over the power system. They can and should be utilized to increase the observability of the power system. In this paper the impact of photovoltaic and wind power production on the voltage unbalance was analyzed. PMU data and NTP-synchronized data from two different MV networks were used. It has been found that PV production has only a minor negative impact on the voltage unbalance whereas the wind power production has a great positive impact. The voltage unbalance factor (VUF) could be a `new´ observable for a particular power system condition. Information about the actual injected wind power for a certain grid area could be derived without knowing/measuring the real wind power injection.