We propose an objective formulation of the impulse analysis problem from a signal analysis viewpoint. The winding response is quintessentially that of a deterministic network to a finite energy signal, with breakdown and partial discharge being inherently nonlinear events. A significant improvement to the acquisition of waveforms is demonstrated by a virtual instrument approach. It retains the advantages of the time- and frequency-domain methods. The drawbacks of the transfer function method are highlighted and a new piecewise linear approach is proposed for analysis. Experiments on a discrete lumped parameter model of the winding are used to validate the PXI based instrument.

Virtual Instrument for Lightning Impulse Tests

Several phenomena in transformers are best analyzed in the frequency domain when energized by broadband excitation. These include dielectric behavior to lightning impulse, winding deformation during transport and structural failure during short circuit tests. We propose an adaptive architecture that characterizes all these events in an unifying manner. The developed instrument is based on the PXI hardware with necessary software developed under LABVIEW environment. Experimental results using the developed instrument are reported to demonstrate its versatility.

V. Jayashankar

Papers

An Adaptive High Resolution Measuring System for Charcaterizing Transformers Subjected to Broadband Excitation