Abstract: A method of determining the capacitance and loss-factor of each of a plurality of capacitive components of an electrical power device, wherein the method includes: a) obtaining for each capacitive component a respective capacitance value and loss-factor value, and b) processing the capacitance values and the loss-factor values, wherein the processing involves removing a common influence of temperature on the capacitance values from the capacitance values and removing a common influence of temperature on the loss-factor values from the loss-factor values to obtain for each capacitive component a temperature-compensated capacitance value and a temperature-compensated loss-factor value.

Abstract: A method of determining the capacitance and loss-factor of each of a plurality of capacitive components of an electrical power device, wherein the method includes: a) obtaining for each capacitive component a respective capacitance value and loss-factor value, and b) processing the capacitance values and the loss-factor values, wherein the processing involves removing a common influence of temperature on the capacitance values from the capacitance values and removing a common influence of temperature on the loss-factor values from the loss-factor values to obtain for each capacitive component a temperature-compensated capacitance value and a temperature-compensated loss-factor value.

Abstract: A method of determining phasor components of a periodic waveform, wherein the method includes: a) sampling the periodic waveform, b) determining a frequency spectrum of the sampled periodic waveform by means of a frequency transform utilizing a Gaussian window function, wherein a ratio np defined by the duration of the sampling of the periodic waveform divided by the width parameter of the Gaussian window function is at least 5, c) selecting a region of the frequency spectrum containing a frequency peak defined by a group of consecutive frequency bins each being defined by a frequency value and a magnitude value, and d) determining phasor components of the periodic waveform based on the group of consecutive frequency bins.

Abstract: A method of determining phasor components of a periodic waveform, wherein the method includes: a) sampling the periodic waveform, b) determining a frequency spectrum of the sampled periodic waveform by means of a frequency transform utilizing a Gaussian window function, wherein a ratio np defined by the duration of the sampling of the periodic waveform divided by the width parameter of the Gaussian window function is at least 5, c) selecting a region of the frequency spectrum containing a frequency peak defined by a group of consecutive frequency bins each being defined by a frequency value and a magnitude value, and d) determining phasor components of the periodic waveform based on the group of consecutive frequency bins.

Abstract: An arc detector for detecting undesired arcs. The arc detector includes: an antenna for receiving an electromagnetic signal representing an arc; and a discriminator for analyzing a signal from the antenna, the discriminator including a spectrum analyzer arranged to detect whether the signal represents a normal arc or an undesired arc. The discriminator is arranged to detect whether the signal represents a normal arc or an undesired arc by comparing signal levels at frequencies of a spectrum of the signal corresponding to at least one partial reference spectrum, and determining the arc to be a normal arc if a deviation from the reference spectrum is less than a threshold deviation. A corresponding method is also presented.

Abstract: An arc detector for detecting undesired arcs. The arc detector includes: an antenna for receiving an electromagnetic signal representing an arc; and a discriminator for analysing a signal from the antenna, the discriminator including a spectrum analyser arranged to detect whether the signal represents a normal arc or an undesired arc. The discriminator is arranged to detect whether the signal represents a normal arc or an undesired arc by comparing signal levels at frequencies of a spectrum of the signal corresponding to at least one partial reference spectrum, and determining the arc to be a normal arc if a deviation from the reference spectrum is less than a threshold deviation. A corresponding method is also presented.