Many papers discuss the voltage stability assessment of power system using power flow analysis methods. In this paper, a method for online monitoring of a power system based on measurements is proposed, which is aimed at detection of the voltage instability. Thereby an indicator is derived from the fundamental Kirchoff-Laws. Since in the transient process, at any time point, the electric power ...

In this paper, we discuss a fluid queue driven by an M/M/1 queue with catastrophe and restoration. Using the continued fraction technique, we derive the Laplace transform of the transient state probability distribution of the buffer content, transient solution for this fluid queue and the corresponding steady state results explicitly. Also we analyze the queue when there are no catastrophes and...

Self-excited induction generators (SEIG) offer many advantages as variable-speed generators in renewable energy systems. Small hydro and wind generating systems have constraints on the size of individual machines, and several induction generators must be paralleled in order to access fully the potential of the site. SEIGs connected in parallel may lose excitation momentarily owing to large tran...

Knowledge of the solubility characteristics of an oiVrefrigerant mixture is important when analyzing the lubrication system behavior in refrigerant compressors since the solubility significantly affects the viscosity of the mixture. For an operating compressor, the lubricant is a mixture of oil and refrigerant and the viscosity of the mixture is a strong function of the refrigerant concentratio...

This paper considers stabilization and command following of uncertain dynamical systems and presents a new adaptive control approach with improved system performance. The proposed framework consists of a novel architecture involving modification terms in the adaptive controller and the update law. Specifically, these terms are activated when the system error between an uncertain dynamical syste...

In this study, electromechanical equations of separately excited DC motors are examined and the exact electrical equivalent circuit related to mechanical equations is introduced. The motor has mechanical variables and components in both armature circuit and output circuit related to load. The electrical equivalent circuit having the same equation structure with mechanical system is given. By us...

Stochastic activity networks, which contain only exponentially distributed timed activities, behave as a Markov process, and can hence be solved using known techniques. When deterministically distributed activities are considered together with exponentially distributed activities, solution becomes di cult due to the non-memoryless property of deterministically distributed activity time. Such sy...

Different transformer models have been developed in the past for steady state and transient analysis of power systems. Some of these models have nonlinear components to take into account the magnetic core saturation characteristics so that harmonic generation can be simulated. Case studies based on these models are presented to demonstrate the harmonic generation behaviors of transformers under...

First analysis of Markov Reward Models (MRM) resulted in a double transform expression, whose numerical solution is based on the inverse transformations both in time and reward variable domain. Better numerical methods were proposed based on the time domain properties of these models, such as the set of partial differential equation describes the process evolution in time. This paper introduces...

Direct acting spring loaded pressure relief valve is one of the most important devices to ensure security to pipeline oil transport. However, relief valves’ manufactures generally only provide information on valve characteristics under full opening stage, which is obtained under steady state regime, therefore, valve and flow’s transient behavior are neglected. Understanding the transient behavi...