INCREASED TRANSMISSION CAPACITY BY FORCED SYMMETRIZATION

Present planning procedures are based on single outages of three-phase circuits which do not take the actual fault pattern into account. The majority of faults are single-phase faults which is motivating the pr esent approach to exploit the remaining conductors for power transmiss ion. A shunt device (FACTS) is conceived which is able to generate a l oading pattern at breaker locations with one or two phases open such t hat the network side always sees a symmetrical loading. The theoretica l background is given and numerical examples illustrate the efficiency of the concept. The circuit affected by a fault may be modelled by a positive sequence impedance which can be inserted in ordinary power fl ow programs for security calculations.