Estimation of Quadrature Axis Synchronous Reactance Using the Constant Excitation Test

This paper introduces the constant excitation test to be applied in synchronous machines. The results obtained from this test allow the determination of the quadrature axis synchronous reactance of the salient pole synchronous machines. Despite standard present methods for its determination, the proposed method is suitable for large installed machines. The method basis is described and it is applied to several existent hydrogenerators. The calculated quadrature axis synchronous reactances are compared with the values supplied by the manufacturers, resulting in very good agreement. The appendix shows the quadrature axis location from the previous calculations results to obtain transient parameters from load rejection test.