POWER QUALITY IMPROVEMENT IN TRANSMISSION AND DISTRIBUTION SYSTEMS

to hours) (IEEE-CIGRE, 2004). Short-term voltage stability problems are usually associated with therapid response of voltage controllers (e.g., generators’ automatic voltage regulator [AVR]) and powerelectronic converters, such as those encountered in flexible AC transmission sys[r]

j4ÀrðÞruþ xc,NþrÀ xc,rðÞej8ÀrðÞuhi(5:18)With a carefully chosen sampling rate—such as a multiple of three times the nominal power systemfrequency—very efficient symmetrical component calculations can be performed in real time. Equationssimilar to (5.18) hold for negative and zero[r]

The generator speed is decoupled from system frequency and can be controlled as desired, whilethe converter is used to regulate voltage and supply reactive power.Computational models have been developed for each of these technologies, plus the electrical controlsrequired by the[r]

Fig. 14. CVI deviation for load X/R variation whilst line X/R=1 As the X/R ratio of the line increases the index accuracy did not decrease homogeneously. Between the values of 0.3 and 0.5 for load X/R an area of decreased inaccuracy can be observed. This is due to the scaling factor setting b[r]

aspects of obtaining better Lyapunov function, and determining the least conservative estimate ofthe domain of attraction. Gless (1966) applied Lyapunov’s method to the one machine classical modelsystem. El-Abiad and Nagappan (1966) developed a Lyapunov function for multimachine system[r]

ß 2006 by Taylor & Francis Group, LLC.Digital prime mover controls facilitate addition of special features for stability enhancement.Digital boiler controls, often retrofitted on existing equipment, may improve the feasibility offast valving.Fast valving is potentially lower cost than trippin[r]

Make power deregulation work for you
With deregulation, the vast pool of power customers is up for grabs. As a utility, are you ready to compete? As a customer, are you ready to choose? In Power Quality Primer, Barry Kennedy gives you specifically designed, aheadofthecurve methods. Utilities will le[r]

Although many different forms of power system stability have emerged and become problematic inrecent years, transient stability still remains a basic and important consideration in power system designand operation. While it is true that the operation of many pow[r]

Evans and Bergvall, 1924; Wilkins, 1926). The early stability problems were associated with remotepower plants feeding load centers over long transmission lines. With slow exciters and noncontinuouslyacting voltage regulators, power transfer capability was often limited b[r]

C, with B relatively quiescent. However, as already pointed out, the voltages of system B are varying. Ineffect, B is acting as a large synchronous condenser facilitating the transfer of power from A to C, andsuffering voltage fluctuations as a consequence. This situation has occurred several[r]

and the analysis is repeated. This process continues until the level of power transfer reaches a pointwhere the system cannot survive all of the credible contingencies. The maximum allowable transfer levelis then fixed at the last acceptable level, or reduced by some small amount to pro[r]

Papalexopoulos (1996) offers some of the requirements that need to be met so that OPF applications areuseful to, and usable by, the dispatchers in online applications.20.5.1 Speed RequirementsFast OPF programs designed for online application are needed because under normal conditions,[r]

contingency analysis and optimal power flow may be performed. Notice, the state estimation processresults in the state of the system, just as when performing a power flow but without a priori knowledge ofbus injections.19.4 Defining TermsRemote Terminal Unit (RTU)—Hardware t[r]

equipment degradation or damage. Furthermore, overload of transmission lines may be followed byunpredictable line tripping that accelerates the degradation of the voltage profile.Line flows are related to circuit overload (lines and transformers) and should keep below a maximumlim[r]

spatial diversity in multi-user systems with multiple receive antennas. In particular, the performance is evaluated in 3GPP-LTEuplink scenarios.Copyright © 2009 Hanguang Wu et al. This is an open access article distributed under the Creative Commons Attribution License,wh[r]

The UC-GA is run on a small system so that its solution can be easily compared to a solution byexhaustive search. Before running the UC-GA, the GENCO needs to first get an accurate hourly demandand price forecast for the period in question. Developing the forecasted data is an impor tant topic[r]

6Use of OscillographRecords to AnalyzeSystem PerformanceJohn R. BoylePower Sys tem Analys isProtection of present-day power systems is accomplished by a complex system of extremely sensitiverelays that function only during a fault in the power system. Because relays are e[r]

16.5.3 DDSPSO CountermeasureExtensive testing was performed to determine natural modal frequencies for the turbine-generator, thecomponents of armature current, and the arc furnace and SVC stimulus. Once the root cause of theproblem was determined, it was a simple matter to retune the[r]

transmission losses are dependent on the generation pattern and must be considered in obtaining theoptimum pattern.ß 2006 by Taylor & Francis Group, LLC.Certain other factors have to be considered when obtaining the optimum generation pattern. One is thatthe generation p[r]

Research Paper Determinants of improvement in quality of life of alcohol-dependent pa-tients during an inpatient withdrawal programme Pierre Lahmek, Ivan Berlin, Laurent Michel, Chafia Berghout, Nadine Meunier, Henri-Jean Aubin  Centre de Traitement des Addictions, Hôpital Emil[r]