Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Harmonic analysis

Spectral Analysis of Some Selected Hydrochemical Parameter Of Diyala River

Qusay A. Al-Suhail; Aqeel S. Al-Adili

Engineering and Technology Journal, 2009, Volume 27, Issue 3, Pages 496-512

Some selected hydrochemical parameters of Diyala river including electrical
conductivity (EC), 1
2 1
Ca+2 ,Mg+2 ,SO- ,Cl - ,HCO- , total soluble solids (T.S.S.),
discharge (Q) and total hardness(TH) were analyzed for their periodicities using monthly
measurements for the period 1993-1997, to quantify and qualify surface water and
investigate the periodicity behavior of these parameters. Results showed significant
autocorrelation for all the studied series and therefore they were subjected to the Spectral
(Fourier) analysis to investigate the main periodicities that contribute to the total
variance of the observed data. Most of the selected parameters have strong (less
frequent) semi-annual and biannual cycle, as well as seasonal cycle for, Cl, Mg, Ca, SO4,
HCO3 ,TSS , and EC. These results reveal the variation of the factors affecting the river
water quality including hydrological and meteorological conditions as well as the impact
of human activities through the river catchments river.

Harmonics Distribution in Electrical Power System Containing Static Var Compensator

Mohammed K. Edan

Engineering and Technology Journal, 2009, Volume 27, Issue 3, Pages 559-572

This research presents a harmonic analysis of the power system with static VAR
compensator. The model is formed by parallel combination of Thyristor Control
Reactor (TCR) with a bank of capacitor .This model based on use of harmonic
switching functions and this harmonic model is completely general and can be
interpreted as a harmonic admittance equivalent. It is suitable for direct
incorporation into the harmonic domain frame of reference where it combines
easily with frequency dependent admittances of the transmission network, and
with other linearised component. This approach leads to efficient iterative solution
of power networks containing TCR. The general operating condition corresponds
to a case, when the switching instant of thyristor valve are function of network
nodal voltage conditions, this applies to both thyristor turn-on and turn-off
instants. In such situation the voltage zero crossing points calculated with good
accuracy at each iterative step, are used to update the TCR switching function.
Newton-Raphson technique is used to determine the zero-crossing points.