Open conductor analysis and detection

A discussion of the open phase problem in the primary feed of a power plant auxiliary transformer is presented in this publication. The main problem caused by this type of disturbance is the unbalanced voltage and current waveforms that are produced in the secondary terminals of the transformer. An appropriate detection/protection scheme should be available to prevent any potential damage on the auxiliary equipment that can be caused by this abnormal condition. Several techniques can be used to detect this condition and a careful analysis should be performed to consider the benefits and disadvantages of each approach.