Application of Swing Curve with Integration of STATCOM to Assess Transient State Stability in A Multi-Machine Power System

Abstract

Voltage stability is increasingly important in modern power systems due to rising network complexity, higher power demands, widespread integration of large generation units and long distance transmission lines. The bus voltage magnitude tends to decrease continuously due to disturbances and can cause voltage collapse if the network topology and reactive power support are insufficient. This article examines voltage stability on the IEEE 30-bus test system under transient fault conditions. It assesses the role of a Static Synchronous Compensator (STATCOM) in enhancing voltage stability during a three-phase fault. A load-flow analysis was carried out using the Newton-Raphson method. Buses 14 and 24 are identified as weak buses, with highly connected transmission lines and located far from the generator bus. These buses are candidates for the system voltage stability study because they have insufficient reactive power and are likely to collapse under fault conditions. The network was modified by installing STATCOMs on Buses 14 and 24 to improve their reactive power support. The reactive power compensation applied by the STATCOM is done by the injection of reactive power of 0.4760 p.u and 0.5628 p.u at buses 14 and 24 respectively. The behaviour of the system during faults at buses 14 and 24, respectively, was investigated under the same clearing time of 0.1sec and simulation time of 2.0 secs by removing lines 14-15 and 23-24, respectively. The study demonstrates that STATCOM improves the system voltage stability margin in a faulty power system.