A New Time Domain Based Distance Protection for Networks Connected with Inverter Based Unconventional Sources

Although ultra-fast traveling-wave-based protection solutions offer notable improvements in operating speed, they may fail to detect faults near voltage zero crossings and may misclassify non-fault disturbances as faults, restricting their application in systems where security of protection is critical. In comparison, time-domain-based protection offers a promising alternative while providing a balance between speed and reliability. An effective method must operate reliably across diverse systems, including FACTS and renewable-integrated systems, and long underground or subsea export cables. This paper proposes a time-domain distance protection method using a current-based operating quantity and a novel dynamic restraining quantity. The method identifies the fault zone by comparison of the rate of change of current at relay location which is defined as the operating quantity with a novel restraining quantity. The restraining quantity is defined as the rate of change of the relay measured current assuming a fault at zone boundary. The proposed approach mitigates the influence of FACTS devices and renewable integration, enabling fast and reliable protection. Laboratory testing, proof-ofconcept tests, RTDS results, and field data validation confirm that the method can clear the faults within half cycle time (10 ms) without compromising the protection security. It is unaffected by power swing, CT saturation, and remains robust against evolving faults.