Measuring arrangement and method of measuring electrical signals

A method of measuring electrical signals, the method comprising:

• acquiring signals of alternating electrical magnitudes by way of at least two measurement inputs of a measuring arrangement;
• sampling at least two of the signals, each signal with its own sampling clock, to form digital sample values with a sampling apparatus of the measuring arrangement that is arranged following the measurement inputs;
• and
• adapting a sampling clock that is used by the sampling apparatus for the sampling with a clock tracking apparatus of the measuring arrangement in regards to a frequency of the signals to be sampled, and thereby adapting the sampling clock simultaneously for each of the at least two signals to be sampled;
• wherein said at least two measurement inputs are divided into different tracking groups;
• wherein respective measurement inputs of such signals whose frequencies, as a result of particular features of the energy supply network, match are grouped into a common tracking group;
• wherein said clock tracking apparatus is configured to perform an adaptation of the sampling clock for each tracking group;
• and
• wherein the measuring arrangement is a part of a device for observing, monitoring and/or protecting an electrical energy supply network.