  Zonal configuration of energy market is often a consequence of political
borders. However there are a few methods developed to help with zonal
delimitation in respect to some measures. This paper presents the approach
aiming at reduction of the loop flow effect - an element of unscheduled flows
which introduces a loss of market efficiency. In order to undertake zonal
partitioning, a detailed decomposition of power flow is performed. Next, we
identify the zone which is a source of the problem and enhance delimitation by
dividing it into two zones. The procedure is illustrated by a study of simple
case.
