An expanded dalton‐cameron method: DC decay testing method at an arbitrary rotor position

The Dalton-Cameron method is a well-known method for determining direct and quadrature axis subtransient reactance (x′d and x′q) by standstill response testing. This method entails calculating x′d and x′q 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 x′d, x′q and the impedance loci by applying a dc voltage instead of a single-phase voltage. This method was named the expanded Dalton-Cameron method. The method is a small-capacity standstill test, and is carried out by using the following three steps. The first is to short-circuit the U and V terminals while a dc current flows between these terminals, to measure the voltage and current (VDC and IDC) when the dc current flows between these terminals and to record the dc 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 step 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 direct-axis and quadrature-axis impedance loci (Zd(js), Zq(js)). The third step is to calculated the values of x′d and x′q from Zd(js) and Zq(js) and the starting performance on the basis of the two-reaction theory. Experimental and calculated results on starting performance, as well as a comparison with calculated results of x′d and x′q by the Dalton-Cameron method, clearly show that this method is very useful. © 1998 Scripta Technica, Electr Eng Jpn, 123(2): 53–60, 1998