This paper discusses the effect of load change on the Thevenin equivalent impedance of power systems. In this paper, the Thevenin equivalent impedance influenced by the derivative of active load with respect to reactive load (dP/dQ) is analyzed. The Thevenin equivalent impedance forms a closed curve in a complex plane and shrinks to one point when voltage collapses. The magnitude of the Theveni...

This paper presents dynamic voltage collapse prediction on an actual power system using support vector machines. Dynamic voltage collapse prediction is first determined based on the PTSI calculated from information in dynamic simulation output. Simulations were carried out on a practical 87 bus test system by considering load increase as the contingency. The data collected from the time domain ...

In this paper, the effect of time dependence of control actions used to avoid voltage collapse, such as reactive power compensation and load shedding, is studied. A thorough justification of the phenomena under study is first presented with the help of a simple test system. The time dependence of the control actions is then studied in a real voltage collapse scenario of the Chilean Interconnec...

 This paper is concerned with numerical simulation of plastic modes of tubular structures. The simulation incorporates with finite element limit analysis based on the upper bound method and the minimization technique. The analysis considers sequential deformation of structures with work-hardening effects. The simulation results demonstrate plastic buckling is one of the collapse modes and occu...

Abstruct-When a generator of a heavily loaded electric power system reaches a reactive power limit, the system can become immediately unstable and a dynamic voltage collapse leading to blackout may follow. We study the statics and dynamics of this mechanism for voltage collapse by example and by the generic theory of saddle node and transcritical bifurcations. Load power margin calculations can...

The collapse state of a rigid plastic material with the linearized Mises yield condition is computed. We use an infeasible point variant of the dual aane scaling algorithm for linear programming which is extremely eecient for this large sparse and ill conditioned problem. For a classical test problem we obtain better results than previously, both for the limit load and for the collapse elds, th...

Introduction Albeit defined as an inspiratory muscle, the diaphragm interacts with the respiratory system also during expiration. The expiratory load on the diaphragm derives from lung volume and hence, possibly from lung collapse. We hypothesized that the diaphragm has a braking effect during the whole expiration, preserving lung patency during SB in collapse prone lungs. We investigated this ...

This paper applies the Sobol’ decomposition of a function of many random variables to a problem in structural mechanics, namely the collapse of a two story two bay frame under gravity load. Prior to introduction of this example application, the Sobol’ decomposition itself is reviewed and extended to cover the case in which the input random variables have Gaussian distribution. Then, an illustra...