Low impedance restricted earth fault protection is one of the protection function to protect the transformer winding with earthed star point. This paper presents a critical comparison of restricted earth fault algorithms among four restricted earth fault (REF) numerical relay algorithms: ABB's, AREVA T&D's, SIEMENS's, and GENERAL ELECTRIC's. Advantages and disadvantages of these algorithms are investigated based on speed, sensitivity and selectivity. Also, magnetizing inrush current, over excitation and CT saturation impression on the restricted earth fault operation is presented. After the algorithms assessment, to confirm the results they are simulated by using MATLAB SIMULINK. The relay operation characteristic curves and restraint currents for each of algorithms are then investigated.
|Number of pages||8|
|Journal||International Review on Modelling and Simulations|
|Publication status||Published - Apr 2011|
- Low impedance restricted earth fault
- Numerical relay
- Transformer protection