This article provides an overview of a monitoring application, its testing and validation process. The application was developed for the detection of sub-synchronous oscillations in power systems, ...utilizing real-time measurements from phasor measurement units (PMUs). It uses two algorithms simultaneously to both detect the frequency at which the oscillatory event occurs and the level of energy in the oscillations. The application has been developed and tested in the framework of SmarTS Lab, an environment capable of hardware-in-the-loop (HIL) simulation. The necessary components of the real-time chain of data acquisition are presented in this paper, as well as testing and validation results, to demonstrate the accuracy of the monitoring tool and the feasibility of fast prototyping for real-time PMU measurements based applications using the SmarTS Lab environment.
The performance of stochastic optimal power control of time varying lognormal fading channels, in which the evolution of the dynamical channel is described by stochastic differential equations ...(SDE's), is determined. Unlike the common random static models, the SDE's essentially capture the spatial-temporal variations of wireless channels. The solution of the stochastic optimal power control is obtained through path-wise optimization, which is solved by linear programming using a predictable power control strategy. The algorithm can be implemented using an iterative numerical scheme. The performance measure is interference or outage probability. Numerical results indicate that the performance of this algorithm is close to the optimal case as long as the channel model does not change significantly.
Insulating liquids have been applied to electrical insulation of transformers, circuit breakers and switch gears and have been investigated in different ways to enhance their performance. Dielectric ...liquids have been used for the transformer insulation and cooling applications since more than a century. Dielectric breakdown tests and the events and processes that affect the breakdown of the transformer insulation have been studied since last 40-50 years. Transformer oil can give a thorough picture of the internal transformer conditions. The fault diagnosis can also be done by investigating the transformer oil. For this reason, oil samples from a transformer that is out of service due to the internal faults are taken and tested to realize the reason behind the faults. Gas Chromatography Mass Spectrometry (GCMS) was employed to investigate the oil condition of the power transformer. GC-MS results show that high molecular weight substances in faulty oil are more than fresh oil. The results are compared with that of the fresh mineral oil supplied by the same manufacturer and presented in detail.
We consider a symmetric five-body problem with three unequal collinear masses on the axis of symmetry. The remaining two masses are symmetrically placed on both sides of the axis of symmetry. Regions ...of possible central configurations are derived for the four- and five-body problems. These regions are determined analytically and explored numerically. The equations of motion are regularized using Levi-Civita type transformations and then the phase space is investigated for chaotic and periodic orbits by means of Poincaré surface of sections.
The objective of this work is to design and implement controlled (weighted round robin matching, WRRM) and sequential iterative schemes for weight based multicast traffic scheduling in input-queued ...(IQ) switches. Motivated by the practical synthesis of a scheduler for a 64-port optical crossbar switch, we demonstrate that limited and sequential iterations in the weight based arbiter (WBA) lead to adjustable clock speeds and configurable designs with flexible control in the performance characteristics close to the conventional WBA. Our FPGA sizing experiments and clock speed evaluations show improvements of upto 46.48% and 19.12%, respectively, over the WBA. In addition, latency-throughput results for the proposed variations, highlight the trade-offs between fairness, throughput, hardware complexity and speed.
Natural gas dew point temperature is a vital quality parameter. The effective control of this specification is important if the natural gas integrity and quality are to be maintained. The present ...work focuses on improving the dew point and condensation production rate of south Dabaa field dew point control unit (DPCU) located in the Egyptian western desert and owned to the South Dabaa Petroleum Company. Influence of the operational variables on outlet gas dew point and produced condensate were investigated. The simulation results illustrated that feed gas inlet temperature, composition and flow rate, Joule Thomson (JT) valve downstream, and upstream pressure and hot bypass flow rate have a great effect on the sales gas dew point as well as the condensate throughput. A field experiments were conducted to validate the simulation results. It is noticed that there is a good agreement between simulation and experimental results, considering the outlet gas dew point at different operating conditions. Lingo optimization software was used to find the plant optimum conditions. Two quadratic equations were developed based on regression analysis for calculating the dew point and plant condensate rate at any operational variables. The impact of replacing the existing JT valve by a turbo expander was studied. The simulation results indicate that the turbo expander is more effective in comparison with JT valve refrigeration system in decreasing the sales gas dew point and increasing the condensate production rate.
•The improvement of dew point and condensation production rate of south Dabaa field dew point control unit (DPCU) – Egyptian western desert - is studied.•A simulation for the above mentioned unit has been developed using HYSYS.•Influence of operating conditions on natural gas dew point and condensation rate is studied.•Two correlations for relating gas dew point and condensate throughput to DPCU operational variables are developed.•An NLP algorithm is developed to find optimum operating conditions of DPCU. The considered operating conditions are gas inlet temperature, inlet gas flow rate, JT valve upstream pressure, JT valve downstream pressure, hot bypass flow rate, and gas composition.•The influence of replacement JT valve by a turbo expander refrigeration technique on the PDCU operation has been investigated.
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