Partial discharge testing of solder fillets on PCBs in a partial vacuum: new experimental results

Abstract

This work investigates the influence on the partial discharge (PD) onset due to the geometry of solder fillets of aerospace and spacecraft component assemblies operating in vacuum and at high voltages. An automatic measuring system has been developed and calibrated to detect PD signals in vacuum (proportional to the apparent charge) which are recorded and displayed in terms of amplitude and temporal distributions. The experimental part of the project is aimed at investigating the influence of the geometry of solder fillets (produced according to the European space industry standard, ECSS-Q-70-08), on the occurrence of PD activity. Stranded terminals of high voltage cables were soldered to circular copper pads on FR4 fiberglass epoxy printed circuit board (PCB). Various copper electrode configurations have been produced and, prior to the test program, they were characterized for dimensional, electrical and optical properties. Two types of solder fillet geometries have been realized for each electrode configuration: round joints with an abundance of solder and sharp pointed joints made with minimal solder. The minimum distance between electrodes for all samples is nominally 5 mm. Paschen-like curves were established from measurements performed where the product of pressure x distance lies in the range of 2 mbar mm-50 mbar mm. Corona inception voltage (CIV) and corona extinction voltage (CEV) values were recorded at different values of pressure x distance. Stable glow discharge triggering voltage and current were also measured. The experimental results indicated that the PD activity for the sharp pointed pads and sharp pointed joints is greater than the other cases, but no significant differences (less than 50 V) of the values of CIV and CEV have been found.Index Terms-High voltage systems, partial discharges, printed circuit board, solder fillets.

Experimental Study of Visual Corona under Aeronautic Pressure Conditions Using Low-Cost Imaging Sensors

“…Therefore, aircraft electrical distribution systems must be highly reliable over a wide pressure range. It is a recognized fact that electrical and electronic assemblies used in aeronautic and aerospace applications are more prone to partial discharge effects due to the low-pressure environments at which they are exposed [3], with corona inception voltages that can be well below those found under normal atmospheric conditions [1]. It is known that at reduced pressure, conductors and electrodes well suited for ground operations can develop corona activity, which is often aggravated by condensation of moisture because of pressure gradients produced during fast airframe ascents and descents.…”

“…Design engineers must take into account the effect of varying the pressure-distance product on the corona inception and extinction voltages during the lifespan of the electrical and electronic components, including the electrical wires. By means of suitable designs, the reliability of such components can increase notably, reducing the aging, unexpected and unscheduled failures, while easing maintenance plans [3]. Many efforts are being made to design aeronautic power systems for operating at higher voltages.…”

Arc Tracking Control in Insulation Systems for Aeronautic Applications: Challenges, Opportunities, and Research Needs

“…Electrical systems well-designed for ground operations can generate partial discharges (PDs) when operating at lower pressures; this effect is frequently intensified due to moisture condensation caused by pressure changes during rapid ascents and descents [1]. Therefore, aeronautic and aerospace insulation systems are more susceptible to PDs because of the low pressure operating environment [7], with inception voltages lower than those found at sea level [2], especially when operating at higher voltage levels [8,9].…”

Effects of atmospheric pressure on tracking failure of gamma-ray irradiated polymer insulating materials

“…Polymers are used on space equipment with the examples of these devices working at high dc voltage on satellites such as ionic propulsion systems, photomultiplier tubes, scientific electronic instruments, communication systems and solar cell power supply systems [16]. Energetic electromagnetic radiation and low pressure are two main factors in the space environment [17].…”