Pre-emptive arc fault detection techniques in switchgear and controlgear — Part II

The significant benefits of pre-emptive arc-flash protection and online condition monitoring of electrical equipment are quite well known. Our continuing research focuses on the development of new advanced sensor technologies which are cost effective, reliable and efficient for early detection of faults in order to predict impending arc-flash occurrences in medium voltage and low voltage switchgear and controlgear. More extensive and detailed measurements, regarding significant defects leading to an arc flash event, have been completed since the original work in Part I was completed. A more detailed analysis of the results of this additional testing is presented in this paper. It has been documented that the two major non-contact causes leading to an arc-flash event in switchgear are insulation degradation and thermal stresses. This paper covers the detailed measurement results under both of these conditions. New sensor technologies both for partial discharge (PD) measurement and thermal detection are introduced and evaluated. An effective signal processing technique, needed for extracting the essential indication of a developing fault, is also presented. Finally this paper outlines how a pre-emptive arc detection system can be connected to protection, PLC or SCADA systems.