Determining Cross-Border Electric Power Transfer Limits: The Case of Zambia and DRC

Increased power transfers on transmission lines may jeopardize safety, stability and reliability of electric power systems. It is thus imperative to determine and enforce power transfer limits on transmission corridors and interconnectors. This paper presents a methodology for determining power transfer limits and applies the methodology to the 220 kV interconnection between Zambia and the Democratic Republic of Congo (DRC) in the Southern African Power Pool (SAPP). Steps of the methodology include simulating the power system in steady state and also in transient time domain. Possibility of occurrence of a contingency in a power system is considered. Also, in determining power transfer limits, the methodology allows for application of a TSO's power supply security criteria, especially concerning voltage collapse and transient stability.