This course focuses on protection system building blocks – CT/VT sizing and advanced busbar protection using real case examples. For substations with terminals capable. DEFINITIONS. IV EXECUTIVE. Abstract: This work proposes a busbar protection scheme based on phase changes in positive sequence current of incoming and outgoing line current transformers (CTs). The angle differences of during fault and prefault current signals of incoming and outgoing CTs are the indicators of external or. Schneider Electric support forum about Protection Relays, Substation Controllers & RTUs, Arc Flash Devices & Systems in Medium Voltage and Low Voltage. Last Modified:. Busbars have typically been left without dedicated protection, from the following reasons: It is a fact that the risk of a short circuit happening on modern metal clad equipment is insignificant, but it cannot be completely dismissed. Nevertheless, the damage resulting from one short circuit may be.