The Role short circuit impedance plays in Power Transformer Assessment

Short Circuit Impedance (SCI) refers to equivalent impedance from one side of Power Transformer (PT) with another side being short-circuited.
The main part of SCI is inductive value, so sometimes it can approximates to leakage inductance.
When testing the SCI, allow one side (ofen secondary) winding be short-circuited, and applies test voltage from another side winding (ofen primary), and then measure the impedance using VA or PQ method.

SCI can be used for frequency response test, with the help of equivalent model, to analyze defect of PT, such as winding deformation, internal insulation and core characteristics.

To analyze the data
Three phase comparision of impedance, periodic comparison and historic comparison are methods usually used to comprehensively characterize structural information of PT.
Also from a point of view to assess PT operation conditions, SCI is an improtant factor that help make medium or long time maintenance decisions.

J.ZH
Notes of Pusala Technology
成都普莎拉科技有限公司
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