A New Method of Recording Generator Dynamics and Its Application to the Derivation of Synchronous Machine Parameters for Power System Stability Studies

Abstract

The proposed algorithm is based on the discrete Fourier transform (DFT) and a software-based synchronous sampling technique that is locked to the power system frequency using reconfigurable field-programmable gate arrays (FPGAs). The main purposes of this paper are to provide a new method of recording the high-resolution rotor angle of a synchronous machine and a practical method for deriving more accurate d-q-axis synchronous machine parameters. An FPGA is used in realizing the rotor-angle transducer and it simultaneously detects the frequency of the generator terminal voltage. The DFT algorithm is combined with an interpolation technique that downsamples the high-frequency sampled data using the measured power system frequency. This paper also describes a practical method for determining synchronous machine model parameters. The proposed algorithm for recording the generator dynamics was implemented in terms of Labview, Real-Time PCI eXtensions for Instrumentation (PXI) target, and the FPGA, and was applied to generator testing of a 1205-MVA thermal power unit. Its synchronous machine parameters were also derived using the recorded rotor angle.