A System Based Protection Test Solution for Eskom Sub-Transmission Lines

The failure of protection schemes for subtransmission lines has been a major cause of loss of power supply due to incorrect relay settings, and communication assisted tripping errors. Settings based on testing methods are utilised to verify protection scheme. However, these methods focus mainly on the accuracy of protection relays and the functionality of the scheme. Due to the complexity of protection schemes, verifying the functionality based on future predictions in the actual network is pivotal. The amount of settings and configurations need to be done are tremendous. In this paper the actual network parameters are used to build admittance bus matrix in excel sheet, calculate fault currents and injects them into a protection scheme using the Omicron CMC test set. The results show that relay accuracy test can be performed more effectively and the entire scheme can be tested, monitored and evaluated better; thus improves network reliability.