Lightning impulse test of field-aged PV modules and simulation partial discharge within MATLAB

Impulse voltage withstand test is an important method to identify that the insulating encapsulation of a PV module can withstand overvoltage due to the effects of direct or indirect lightning strikes from atmosphere. In this work, a comparison of testing and simulating on the partial discharge in the PV module produced by lightning impulse voltage source is given. For the experiment, the field aged PV module was applied by 1.2/50 □s impulse voltage generator up to 4 kV between terminal box and frame of PV module. It was found the measured impulse voltage waveform had a number of voltage spikes and oscillations superimposed on the impulse voltage. As to the explanation of this phenomenon, a novel mathematical model of partial discharge inside the void of PV insulation was implemented in MATLAB-Simulink program tool. The simulated result deduced that the ringing oscillations caused by partial discharge in the defects of the deterioration PV modules. In addition, some discussions are given for testing and simulating results.