| Bushings represent one of the highest failure components on large power transformers. It has become apparent that defects in bushing can occur very quickly and periodic testing of bushings in these cases is ineffective. This combined with the fact that many defects do not show up at offline testing voltages (10kV) and some defects are temperature sensitive, makes this monitor an ideal complement to any transformer monitoring package. Another significant problem is the mechanical stability of the winding and the ability to withstand tremendous mechanical forces due to short circuit currents. If a winding mechanical support system is loose, the next high peak current associated with a short circuit somewhere in the system may cause mechanical winding deformation and causing a major insulation failure. Timely detection of a deformed winding may avoid a catastrophic failure.
The (BHWM) is designed to monitor both the C1 Capacitance and Power Factor of each individual bushing and winding distortion. The BHWM has unique features unlike any other busing monitor that is available today. Measurement of the power factor and capacitance is based on the common "Sum of Currents Method" algorithms. Winding distortion is monitored by estimating the change in transformer leakage reactance. |
