抄録
The symmetrical method is one of the common theory to simulate the faulted state of electric power system even now. However, this symmetrical method has major disadvantage especially for unbalanced fault calculation on multi-parallel routes due to the necessity of complex equivalent zero-sequence network formation. In order to secure the power system including multi-parallel route in it from the disturbance, the method is needed which can solve the faulted state with accuracy and efficiency when the disturbance occurs on that multi-parallel route.
From the point of view described above, this report proposes a newly developed fault calculation method, which can easily incorporate zero-sequence mutually coupling effect among multi-parallel route in it without any topological changes of the symmetrical network. In the proposed method, mutually coupling effect is treated as voltage source inserted each parallel branches to compensate the mutually coupling effects from other circuits. As the voltage source can be equivalently expressed as injection currents of connected nodes, the faulted state can be easily calculated without topological change of the zero-sequence network. The numerical application result for a couple
