Abstract
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A saturated core fault current limiter (FCL) essentially
utilizes the dynamic and nonlinear magnetic behavior of
steel cores to operate as a variable reactor. However, the nonlinear
characteristic of magnetic materials has made modeling this
unique device a difficult task. Hence, experimental measurements
and finite-element method (FEM) analysis are the most common
techniques used to characterize the transient behavior of the
device. Both of these techniques, while accurate, cannot be used
to analyze the transient electrical behaviour of FCLs in complex
power systems, particularly when investigating power system
switchgear behavior during fault events. FEM-based FCL modelling,
despite its usefulness as a design verification tool, cannot
be easily coupled to all electromagnetic transient programs that
are in use today. This paper presents two modeling approaches to
represent the saturated core FCL in transient network simulators:
1) the nonlinear reluctance model and 2) the nonlinear inductance
model. Both models are implemented in PSCAD/EMTDC and are
validated by experimental results of a single-phase prototype
saturated core FCL, where excellent agreement between the
experimental and the modelling approaches is achieved.