Purpose/Aim

The dielectric behavior of gas-solid insulating systems is affected to a great extent by surface partial discharges developing at regions of high electric field intensity. Thus, accurate determination of partial discharge inception characteristics is of great importance for an efficient design of insulation systems. The quantification of partial discharge characteristics requires a great number of repetitive withstands tests, allowing for a thorough statistical treatment of data.

Experimental/Modeling methods

Partial discharges (PD) on Polyethylene, Polyoxymethylene, Polyvinyl Chloride, and Polyamide insulating surfaces were investigated by using a non-uniform electric field electrode arrangement stressed by positive ramp high voltages. Measurements of the applied voltage and discharge current were performed using a PC-based control and data acquisition system.

Results/discussion

PD inception voltage is relatively unaffected by successive shots and augments for higher material relative permittivity and discharge current threshold detection value.

Conclusions

Surface partial discharge inception characteristics were investigated by stressing a short sphere-plane gap under positive ramp high voltages. There is a marked dependence of PD inception voltage upon material relative permittivity and discharge threshold current.