http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Simulation and evaluation of digital protection relay for power transformer applications
xvii, 333 leaves : illustrations ; 28 cm.
The function of protective relaying is to promptly remove
from service any element of the power system that starts to
operate in an abnormal manner due to a fault. Therefore,
protection systems are critical power system components. The
comprehensive testing of a protection system is needed before
the relay is put into service. Combined computer simulation
of power systems and protective relays can be used as a
valuable preliminary step for relay performance testing. In
this dissertation a novel relay simulation scheme, an
automatic pseudo closed loop simulation method, is proposed
to allow for closed loop simulation of the interaction
between power systems and protective relays. The protection
algorithm plays a very important role in a protection scheme.
Computer simulation can provide a tool to evaluate different
algorithms for a specified application. A new algorithm to
eliminate the exponentially decaying component from the
Fourier algorithm is proposed and evaluated using the new
simulation approach. Three simplified methods are proposed
to alleviate the computation burden. The performance of
these algorithms is evaluated both in the ideal and real
power system conditions. A commercial digital power
transformer relay(WBX-500) is selected as the object of this
study. This relay is described by Matlab, a high level
language. The power system in the Electrical Power Dynamic
Laboratory(EPDL), Huazhong University of Science and
Technology, China, is modeled by the Electromagnetic
Transients Program(EMTP). A new method to estimate the RL
parameters which can be used to describe the transient
behavior of the transformer internal winding fault is
proposed in this dissertation. The interaction between the
EMTP and relay modeling program illustrates that this novel
simulation method allows for implementation of the closed
loop simulation, and there is no need to modify the transient
signal generation program itself. The test result in EPDL is
used as the reference to verify if the computer simulation
result presented in this dissertation is consistent with the
laboratory test result. The comparison result is
encouraging. It demonstrates that the computer simulation is
a very good tool for protection system evaluation.
"Major Subject: Electrical Engineering".
Issued also on microfiche from University Microfilms Inc.
Includes bibliographical references: pages 200-214.