DYNAMIC STABILITY OF PARALLEL CONNECTED SYNCHRONOUS GENERATORS BY THE EIGENVALUE METHOD

Parallel operation of synchronous generators is commonly used in limited independent power stations. This paper introduces an approach to the determination of dynamic stability of such electrical power stations. The role and influence of the automatic voltage regulators in improving the quality of the parallel operation is discussed. A state-space representation of a power system including two synchronous generators connected in parallel and supplying loads has been accomplished. The eigenvalues method is applied for the determination of the system dynamic stability. The method presented here has the advantage that it provides a technique for evaluating the dynamic stability limit of interconnected-synchronous generators systems. The stable loading conditions for the limited independent power station can also be found by defining the stable regions of operation. Stable-regions charts have been derived for the cases of a single generator station and a power station that consists of two parallel-connected generators. These charts are drawn for a typical independent power station supplying the electric loads of a gas plant. The comparison of the charts for a single -and two parallel generators has shown that parallel operation increases the stable regions at the same loading conditions. An induction motor load of a comparable size to that of the generating unit is applied. Its influence on the dynamic stability of the system is investigated.