ABSTRACT
This chapter provides an overview of the distance protective relaying system for transmission lines. It provides the basic principle of the distance protection function and analyses the characteristic curve of the impedance, admittance and reactance type relays. Communication-assisted distance protection relaying schemes are analysed for the remote tripping of the circuit breakers connected at both ends of the long transmission line. The case study on distance protection function is analysed using the DigSilent simulation model. The lab-scale test bench setup is implemented to test the performance of the distance protection function of the SEL421 Intelligent Electronic Device (IED). The test bench uses the Omicron CMC356 test set to generate the required current and voltage signals for the considered test case. Solved examples on distance protective relaying system are also provided.
