Realization and performance analysis of travelling wave based directional protection prototype

Travelling wave based protection is becoming attractive in ultra-high voltage (UHV) transmission systems due to the requirement for high-speed protection. However, the poor transfer characteristics of coupling capacitor voltage transformers (CCVTs) for high-frequency voltage have strictly limited its application. A travelling wave based protection prototype considering the characteristics of CCVTs is developed in this paper. Extensive laboratory tests are performed to assess the performance of the developed prototype. Further, the prototype has been applied in the 750 kV substations in China and an external fault was recorded during the operation period, validating the effectiveness and reliability of the proposed prototype.