08-16-2017, 10:36 PM
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Power System Technology Navigator
Bottlenecks
Constrained transmission paths or interfaces in an interconnected electrical system
The term Bottlenecks is often interchangeable to congested transmission paths or interfaces. A transmission path or interface refers to a specific set of transmission elements between two neighboring control areas or utility systems in an interconnected electrical system. A transmission path or interface becomes congested when the allowed power transfer capability is reached under normal operating conditions or as a result of equipment failures and system disturbance conditions. The key impacts of Bottlenecks are reduction of system reliability, inefficient utilization of transmission capacity and generation resources, and restriction of healthy market competition.The ability of the transmission systems to deliver the energy is dependent on several main factors that are constraining the system, including thermal constraints, voltage constraints, and stability constraints. These transmission limitations are usually determined by performing detailed power flow and stability studies for a range of anticipated system operating conditions. Thermal limitations are the most common constraints, as warming and consequently sagging of the lines is caused by the current flowing in the wires of the lines and other equipment. In some situations, the effective transfer capability of transmission path or interface may have to be reduced from the calculated thermal limit to a level imposed by voltage constraints or stability constraints.