بررسی حالت گذرای الکترومغناطیسی و وفق پذیری حفاظت دیفرانسیل ترانسفورماتور قدرتUHVبراساس محدودیت هارمونیک دوم
Analysis of Electromagnetic Transient and Adaptability of Second-Harmonic Restraint Based Differential Protection of UHV Power Transformer Abstract—An autotransformer is used as the main type of UHV transformer, but the internal fault model of autotransformer provided by most simulation software is not available. To find out
Analysis of Electromagnetic Transient and Adaptability of Second-Harmonic Restraint Based Differential Protection of UHV Power Transformer
Abstract—An autotransformer is used as the main type of UHV
transformer, but the internal fault model of autotransformer provided
by most simulation software is not available. To find out the
existing problems of the application of the differential protection of
UHVtransformer, a three winding autotransformer model is firstly
built according to the existing Unified Magnetic Equivalent Circuit
transformer model provided by EMTDC software. Furthermore,
the internal fault model of UHV transformer is set up. By virtue of
above models, the energization and internal faults are simulated to
validate the well-applied differential protection using second-harmonic
blocking. It can be proven that the second-harmonic ratios
of three phase inrushes of the UHV power transformer are
all below 10% in some energization scenarios. In this case, the
maloperation of the differential protection by means of 15%
20% second-harmonic restraint ratio cannot be avoided. On the
other hand, the second-harmonic ratio of the fault current is relatively
high in the beginning of fault inception for some light faults,
leading to the short time delay of operation of protection. This discovery
will encourage the research and development of the novel
scheme of the main protection of UHV transformer.
بررسی حالت گذرای الکترومغناطیسی و وفق پذیری حفاظت دیفرانسیل ترانسفورماتور قدرتUHVبراساس محدودیت هارمونیک دوم
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