Phasor correction of coupling capacitor voltage transformers for high-performance protection

The algorithms for the correction of transients in coupling capacitor voltage transformers (CCVTs) are generally designed from processing samples in the time domain. Therefore, they need to be embedded in the measurement, protection, and control devices, because in these instruments only the phasors are available for the development of dedicated applications. In this paper, as an extension of a method originally developed by these authors for the time domain correction of CCVT secondary voltage samples, a mathematical formulation is developed that demonstrates the applicability of the existing method for phasor compensation, regardless of the phasor estimation algorithm used. Three phasor estimation algorithms and two CCVTs with different topologies and voltage levels are used to evaluate the method's performance. ATP (Alternative Transients Program) was used to generate the oscillographic records, while the phasor estimation algorithms and their corrections were implemented in MatLab. From the results, it can be inferred that the evaluated method can be used to correct voltage phasor disturbances, providing more suitable signals for protection algorithms.