Detecting measurement error drifts of the capacitor voltage transformer on-line and its field application

With the widespread application of capacitor voltage transformers (CVTs) in relaying, power system control and metering, detecting their measurement error drift has become an important and urgent task. Conventional methods are time-consuming and require the power to be cut, while some novel data-driven methods are impractical given their rigorous preconditions. In this paper, an innovative approach is proposed to detect the measurement error drift of CVTs connected to the same phase. Through principal component analysis, both the ratio error drift and the phase displacement drift of the CVT can be detected on-line. Besides the theoretical analysis, a monitoring system equipped with the proposed approach is installed in a 220 kV thermal power plant. The field application indicates it is not only sensitive to the measurement error drift but also good at locating faults.