Method and System for Time Synchronization of Sensor Units

A method for time synchronization of sensor units in a distributed system, the sensor units each respectively having one internal time unit, and sensor data being captured by the sensor units and transmitted to a central unit via a radio grid, and an identification signal being emitted at regular intervals in the radio grid, the method comprising:

• monitoring receipt of the identification signal in a respective sensor unit;
• storing one up-to-date value respectively of the internal time unit of the respective sensor unit with at least one transmitter identification contained in the identification signal when a characteristic time feature of the identification signal is received;
• storing a further, up-to-date value of the internal time unit of the respective sensor unit when capturing sensor data;
• storing at least a value of the internal time unit when the characteristic time feature of the identification signal is received, an associated transmitter identification of the identification signal, and a further value of the internal time unit stored when capturing the sensor data being assigned to the captured sensor data and being transferred together with the sensor data to the central unit;
• deriving a temporal relationship of the transferred sensor data of the respective sensor unit to the reference time basis, utilizing the transmitter identification, a reference time basis and utilizing the value of the internal time unit of the respective sensor unit stored when the characteristic time feature of the identification signal is received and the further value of the internal time unit of the respective sensor unit stored when capturing the sensor data;
• capturing, by the central unit, voltage values and phase values from at least one of the three phase conductors of a power grid as at least one of voltage pointers and current pointers to more than one fundamental oscillation period of the voltage;
• and
• aggregating the current pointers of the respective sensor unit to form aggregated current pointers, and instead of the sensor data, transferring the aggregated current pointers to the central unit, and calculating in the central unit correct-phase powers from the voltage values and the aggregated current pointers.