System Protection Technology

The objective of this module is to review the different bus layouts that are used in power systems and to present the different protection schemes that are installed to protect against bus faults.

After study of this tape and the associated workbook the participant should be able to understand the following overall concepts and apply them to his day-to-day work activities. He will also be able to answer related test questions on these subjects:

• Features of different bus arrangements
• Single breaker – single bus
• Single buses connected with bus tie breaker
• Main and transfer buses with single breaker
• Single breaker – double bus
• Double breaker – double bus
• Ring bus
• Breaker-and-a-half bus
• Special problems of bus protection
• The ground fault bus
• Partial differential protection with overcurrent relays
• Directional comparison schemes
• Residual current differential schemes
• CT saturation problems
• Multi-restraint relays
• Linear coupler
• High impedance relays