Research of starting criteria for fault recorder based on CORDIC algorithm
Ning Wang · Power System Protection and Control · 2011
In order to simplify the design of slave computer of fault recorder,the starting criterion modules are integrated into the single FPGA.Two operating modes are used in circular coordinate system of CORDIC algorithm:discrete Fourier transform is realized by rotation model,by which the complex multiplication is transformed into a simple shift and addition and subtraction,avoiding the calculation of cosine value;the real part and imaginary part are transformed into the vector form of amplitude and phase angle by vector model.Using the hardware circuit,through the error analysis of the lowest accuracy of CORDIC algorithm,when the sampling rate is in the range of 1～10 kHz,at the interval of two sampling time the system can calculate the physical quantities of protected object,such as the magnitude and phase of the sequence component,fundamental component and sub-harmonic component for voltage or current.