With the purpose of improving the PD estimation accuracy and the degree of automation of the measurements, the following study is carried out. Initially, a library of different discharge pulses and actual background noise from a selection of cables is established. The library is then used for the estimation of PD-signals from a parametric model leading to reduction of the noise superimposed on the PD-signals and thus to improved PD-detection. The applicability of these methods is discussed in relation to mobile systems for the assessment of cable insulation condition.