Abstract: A method for detecting, identifying and locating partial discharges occurring in a discharge site along an electric apparatus comprises the following steps: detecting (1) electrical signals in a detection station; attributing (2) to each detected signal a value of a phase parameter; deriving (3) for each signal at least one shape parameter and one amplitude parameter; separating (4) the set of signals detected into sub sets that are homogeneous relative to the shape parameter; identifying (5) sub-sets related to partial discharges and cataloguing them; repeating the above steps in a plurality of detection stations positioned along the apparatus; correlating (7) the sub-sets of signals detected in different detection stations and catalogued similarly; selecting (8) as a function of the amplitude and shape parameters of a sub-set among the correlated ones and locating (9) the partial discharges related to said sub-sets at the detection station of the selected sub-set.

Abstract: A method for monitoring an activity of partial electrical discharges in an electric apparatus powered with direct voltage comprises the following steps, repeated in succession at predetermined time intervals: measuring (1) analogue electrical signals and generating corresponding digital signals representative of the wave form of partial discharge impulses; deriving (2) for each of said digital signals, at least one shape parameter and at least one amplitude parameter; separating (3) the set of the measured data into homogeneous sub-sets with respect to the shape parameter; correlating (4) the sub-sets of signals having similar values of the shape parameter and measured in successive steps; selecting (5) the correlated sub-sets for which the amplitude parameter has a predetermined profile over time and attributing the signals of said subsets to partial discharge activities.

Abstract: A method for measuring and processing data pertaining to an activity of partial electrical discharges taking place in a three-phase electric machine (1) powered with square wave voltage, said data comprising a plurality of discharge signals and a plurality of sets of three values (eu, ev, ew) of power supply voltage of the machine measured in concurrence with a corresponding discharge signal, comprises the following steps: -transforming each set (eu, ev, ew) of three voltage values measured into a corresponding pair (ed, eq) of voltage values; -deriving a phase angle value from each of said pairs (ed, eq) of voltage values; -attributing to each discharge signal the corresponding phase value, to assess the measured discharge signals as a function of corresponding phase values.

Abstract: An instrument (1) and a method for measuring pulses of partial electrical discharges in an electrical system comprise data processing means (5) operatively associated both with an input stage (2), able to receive an analogue signal (3) representing said pulses and to provide a digital representation of the entire wave form of the pulses, to receive said digital representation, extract the value of predetermined parameters relating to the wave form of the pulses and transfer to and output stage (4) a processed digital signal comprising said values, the processing means (5) being able to operate substantially in real time, i.e. with no need for a memory for the intermediate storage of the data.