Abstract:
Series inductive reactance of a given transmission line is a significant governing factor for the
power transmission capability of that line and as the length of line increases beyond a certain
range, this reactance may impose considerable limitations on the amount power that can be
transferred without violating the prudent operational constraints. Transfer beyond that level
can make the system significantly stressed and may even drive into the region of instability.
In many practical cases this transfer limit has been observed to be noticeably lower than the
thermal capability of conductors physically used to construct the line and hence creates a
scope for finding ways to exploit this otherwise unused capacity. In the cases, where the
transmission lines in discussion are interconnections among utilities, urge for maximum
capacity utilization is much stronger due the constraints related to additional line
construction.
This dissertation deals with enhancement of power transmission capability of
interconnections using series capacitive compensation. In most of the real world cases, tielines
among utilities are medium to long high voltage lines, which are usually more
susceptible to the power, transfer limitations imposed by series inductive reactance.
Introducing series capacitive compensation provides with a negative reactance, resulting in a
reduced net transfer reactance between two ends of a transmission line and hence the
electrical length of the line becomes shorter to facilitate loading towards thermal limit.
The Two-Area system and an approximate model of the Western Grid of Bangladesh Power
System network have been used as case study; both old and new East West Interconnection
has been considered. Controlled series compensation has been applied through Thyristor
Controlled Series Capacitor. Improvement of steady state, dynamic and transient performance
by applying series compensation has been presented based on the results obtain by standard
static and dynamic analyses, i.e., Load Flow, Continuation Power Flow, Modal Analysis and
Transient Analysis. Comparison of loading margins, corresponding to Saddle-Node and Hopf
Bifurcation of the system, with and without compensation has been performed to reveal the
effect of Series compensation' on transmission capability. Financial feasibility of series
compensation project for these interconnections has been performed in a simplified manner
arid findings are presented in the thesis.
