The authors describe recent developments concerning an improved RF monitoring system on generators. Capacitive coupling has been shown to be much more sensitive than the currently used magnetic coupling through a current transformer (CT). The increase in sensitivity resulted in an improved coupling between the generator's neutral grounding lead and the monitor. An RC high-pass filter was shown to be an effective coupler. This is due to its inherent nature that it will not attenuate the RF noise or create saturation problems as in the case of magnetic coupling through the CT. By selecting the RC filter with a higher value of capacitance than the stray capacitances created by the typical generator grounding transformer, the coupler can detect arcing signals in any generator, regardless of the type of neutral grounding transformer used.
