System comprising a power supplying and/or absorbing device connected to a power system and a related method

A method in a system comprising a power supplying and/or absorbing device connected to a power system and configured for selectively supplying power to the power system or absorbing power from the power system, the system further comprising a voltage sensing unit configured to sense at least one voltage of the power supplying and/or absorbing device at successive time instants, and if the sensed at least one voltage of the power supplying and/or absorbing device at a time instant exceeds a threshold voltage value, store values indicative of at least one voltage of the power supplying and/or absorbing device at successive time instants until the sensed at least one voltage of the power supplying and/or absorbing device does not exceed the threshold voltage value, thereby producing one or more pluralities of stored values, each plurality of stored values of the one or more pluralities of stored values representing a transient overvoltage event occurring between two time instants, the method comprising, for each transient overvoltage event:

• obtaining the plurality of stored values corresponding to the transient overvoltage event;
• and
• determining a set of parameters derived from the said plurality of stored values, the set of parameters characterizing the transient overvoltage event, thereby producing one or more sets of parameters, wherein each set of parameters characterizes the corresponding transient overvoltage event;
• the method further comprising:
• based on the one or more sets of parameters, performing at least one of:
• a determination of a point in time when maintenance of at least one part of the power supplying and/or absorbing device is to be carried out, or an analysis related to any subsequent malfunction of the power supplying and/or absorbing device.