Power flows on the transmission network following the path of least resistance. Diversity in demand and supply, and in transmission facility characteristics result in some transmission facilities carrying more flow than others, not necessarily in proportion to their capacities. Thus, frequently there are a few congested transmission facilities, and most of the system has spare capacity.
Transmission topology control algorithms quickly identify possible network reconfigurations that can route power away from and around congested facilities to uncongested parts of the system. This relieves congestion and increases system reliability in an overflow or contingency situation. The reconfigurations are implemented by opening or closing existing circuit breakers, which remove or put facilities back in service.
While transmission topology control has been known to be effective for a long time, and is in fact used by some system operators, such as PJM, there are currently no tools that systematically identify efficient, reliable and implementable reconfigurations under real-time conditions. Thus, topology control use today is very limited. The TCA project is working to provide the first suite of operations-grade transmission topology control tools. With the TCA tools, system operators and transmission operators will be able to take full advantage of the flexibility offered by the transmission system.