This thesis discusses important aspects related to voltage stability indices and their uses in electric power system analysis and operation. Some indices previously studied in the literature are reviewed and implemented in a reduced local network such as Line Stability Index (Lmn), Voltage Collapse Prediction Index (VCPI), and Power Transfer Stability Index (PTSI). In this thesis, a new index, ...

Abstract: Voltage instability is a major threat for security of power systems. Preserving voltage security margin at a certain limit is a vital requirement for today’s power systems. Assessment of voltage security margin is a challenging task demanding sophisticated indices. In this paper, for the purpose of on line voltage security assessment a new index based on the correlation characteristic...

The management of power systems has become more difficult than earlier because power systems are operated closer to security limits, environmental constraints restrict the expansion of transmission network, the need for long distance power transfer has increased and fewer operators are engaged in the supervision and operation of power systems. Voltage stability has become a major concern in man...

In this paper, to enhance voltage stability of distribution systems, a Network Topology based load flow results are used to calculate Voltage Stability Index (VSI). Then an algorithm for capacitor placement (CP) based on this voltage stability index is implemented to determine the optimal locations, number and size of fixed and/or switched shunt capacitors for voltage stability enhancement, in ...

The contingencies contribute to overloading of network branches and unsatisfactory voltages, which may lead to problems of stability/voltage collapse. The most important task in security analysis is the problem of identifying the critical contingencies from a large list of credible contingencies and rank them according to their severity. This paper presents fuzzy approach for ranking the contin...

The paper presents voltage stability analysis of radial distribution networks. A new voltage stability index is proposed for identifying the node, which is most sensitive to voltage collapse. Composite load modelling is considered for the purpose of voltage stability analysis. It is also shown that the load ̄ow solution of radial distribution networks is unique. q 2000 Elsevier Science Ltd. All...

Optimal Location of FACTS devices are very important for the rapid and successful operation because of high cost and circuit complexities. In this paper best location of UPFC (Unified Power Flow Controller) is obtained both for static and transient voltage stability enhancement of an IEEE 14 bus power system. The simulation is done on PSAT (Power System Analysis Tool-box) in MATLAB and optimal ...

A new modified severity function is proposed, based on which the N-2 line contingencies in the IEEE 30 bus system are analyzed and ranked. FACTS devices like Static VAR Compensator (SVC) and Thyristor Controlled Series Capacitor (TCSC) are used for achieving reduction in under voltage severity value and reduction in voltage deviation from the nominal value. A hybrid combination of two heuristic...