A New Non-communication Protection Scheme for Three-terminal Transmission Lines Based on Mathematical Morphology

A New Non-communication Protection Scheme for Three-terminal Transmission Lines Based on Mathematical Morphology

In this paper a new non-communication based scheme is presented for protection of three-terminal transmission lines. Using this scheme, simultaneous operation of CBs at all terminals is provided for at least 92% of internal faults. This scheme can discriminate between external and internal fault using captured transients produced by fault and high-band stop filtering property of stray capacitance of busbars. The presented scheme uses Mathematical Morphology to analyze the captured transients. The presented scheme has been applied on one of three-terminal lines in Iran’s transmission grid. The effects of fault resistance, fault inception angle, internal fault location, type of fault and sampling frequency on the performance of the proposed scheme are evaluated.