Circulating MW and Mvar flows in large systems

Circulating power flows are possible in power systems and can lead to unnecessary power losses and voltage drops in the transmission system. The most common example is circulating Mvars caused by transformers with unbalanced tap ratios. This paper presents an algorithm to detect circulating real and reactive flows in a power system and also provides a metric to rank the severity of these circulating flows. Examples and causes of circulating flows are presented from large North American cases. The visualization of circulating flows is discussed, as well as the use of circulating flow information for bad data detection.