Measuring partial discharges in DC insulation systems. A challenge, but also a must

This paper has the aim of providing possible solutions for PD measurements, noise rejection and PD source identification focusing mainly on extruded cables. PD tests performed on defective cables under DC and AC indicate how PD DC measurements can be done effectively, and show that noise rejection and PD source identification approaches used nowadays for AC might be extended with good potentiality also to DC.