الفهرس 
Harmonic Analysis TechniquesOnly 14 pages are availabe for public view
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Abstract
Power system networks are subjected to harmonics injection due
to the presence of nonlinear loads and all kinds of static power
converters ( converters, inverters, ...etc.).
Harmonic flow analysis is the first step to be performed in order
to obtain the existing harmonic distortion levels at different locations in
any network. If the harmonic standards are violated, then there should
be a method for controlling harmonics and reduce them to the
acceptable limits.
This work presents a harmonic flow analysis and different
methods for controlling harmonics at different voltage levels of electrical
networks. Some methods for controlling harmonics are based on
filtering techniques and others are based on system loading control.
Different practical examples are used to evaluate the
performance of different proposed methods.
An example of a factory, supplied from subtransmission network,
using arc furnaces is studied. Harmonic measurements and flow
analysis showed that capacitor banks installed for power factor
correction lead to resonance and high harmonic levels. The capacitor
banks suffered from blowing their fuses. Two alternative counter
measures are suggested for overcoming this problem. The first one inserting series inductor with the capacitor bank.
Another method for harmonic control in EHV networks is
proposed. The method uses a certain combination of shunt and series
passive filters to control harmonic current flow in a practical extra high
voltage network. Harmonic flow analysis for this power network showed
that considerable reduction in the background voltage harmonic level, at
all network buses, is achieved.
A new thyristor controlled filter is proposed for harmonic flow
control at the customer location. The filter consists of a shunt passive
filter controlled by a set of back-to-back thyristors or a triac. This filter
overcomes the known disadvantages associated with the use of passive
and active filters.
The proposed filter is used to reduce the harmonic current
distortion resulting from some typical nonlinear loads. The nonlinear
loads under study are a high power 6-pulse converter and a thyristor
controlled reactor. The results showed that considerable reduction in the
total harmonic current distortion is achieved for each of these
applications. Neural network is used to determine filter parameters that
correspond to minimum total harmonic current distortion for each of the
filter applications.