Question

Design a digital relaying algorithm based on the full-cycle Fourier algorithm capable of extracting the magnitude and phase angle of a current signal sampled at 1.92kHz. The signal is posted on URCourses. Implement the algorithm in Octave or MATLAB. Do not use the conv functions, parse the signal with your own code, implementing the operation of the filters at each sample step. Using the returned magnitude and the function provided below in Table 4.20, implement an inverse time overcurrent protective function using the recovered magnitude, such that the relay trips at tp=0.5976 seconds after the fault reaches the value where the fault current to pickup-current ratio reaches M=4. Assume the pickup current is Ip=1.5 p.u. Plot the sampled fault current, the magnitude of the fault current, the phase angle of the fault current, the binary information representing if pickup condition reached, and the binary output of the tripping function at each sample step

Answer 1

The question pertains to designing and implementing a digital relaying algorithm for extracting magnitude and phase angle from a current signal, and applying this to an inverse time overcurrent protective function in an electrical circuit, at a college level of engineering studies.

Step-by-step explanation:

The question involves designing a digital relaying algorithm to extract the magnitude and phase angle of a current signal, and subsequently implementing an inverse time overcurrent protective function. Since the question revolves around electrical engineering concepts, it should be classified under engineering at a college level, as it likely pertains to an advanced course in electrical engineering or signal processing.

By sampling a current signal at 1.92kHz, the implementation of a full-cycle Fourier algorithm would require parsing the signal without the use of built-in convolution functions like conv.

The challenge is to code the operation of filters at each sample step to determine the magnitude and phase angle of the fault current. Then, using an inverse time overcurrent protection function, you would check when the fault current to pickup-current ratio reaches M=4, assuming a pickup current of 1.5 p.u., and cause the relay to trip at tp=0.5976 seconds. The final requirement is to plot various aspects of the signal and the protection response at each sample step in a software tool like Octave or MATLAB.