An Expanded Dalton-Cameron Method. D.C. Decay Testing Method at an Arbitrary Rotor Position.

Abstract

The Dalton-Cameron method is well-known as a method for determining direct and quadrature axis subtransient reactance (xd and xq) by standstill response testing. This method entails calculating xd and xq from the voltage and current measured when a rated-frequency single-phase voltage is applied to each armature winding (U-V, V-W and W-U) in turn. The authors have developed a new method to calculate xd, xq and the impedance loci by means of applying a D. C. voltage instead of a single-phase voltage, and named it the expanded Dalton-Cameron method. This method is a small-capacity standstill test, and is carried out by the following three steps. The first is to short-circuit the U and V terminals while a D. C. current flows between these terminals, to measure the voltage and current (VDC and IDC) when the D. C. current flows between these terminals, and to record the D. C. decay current (i(t)) after these terminals are short-circuited. This same procedure is also performed for the V-W and W-U terminals in turn. The second is to draw the impedance loci from the measured VDC, IDC and i(t) by means of Fourier transformation, and to divide it into the directand quadrature-axis impedance loci (Zd(js), Zq(js)). The third is to calculate from Zd(js) and Zq(js) values of xd and xq and the starting performance on the basis of two-reaction theory. Experimental and calculation results on starting performance as well as a comparison with calculation results of xd and xq by Dalton-Cameron method clearly show that this method is very useful.