System and method for detecting magnetic properties of silicon steel sheet iron core for power transformer

Abstract

The invention provides a power transformer-used silicon steel sheet iron core magnetic performance detection system and a detection method. The system comprises a to-be-detected excitation iron core, a compressive stress loading and measuring module arranged on the to-be-detected excitation iron core, a variable-frequency excitation power unit, an iron core magnetic performance measurement unit and a DC bias unit. The method comprises steps: the magnetic performance detection type of the to-be-detected excitation iron core is judged; the relationship between each item of magnetic performance and other detection items of the to-be-detected excitation iron core in different conditions is detected; and a detection report is issued. The system and the method provided by the invention is low in cost, flexible in arrangement and simple in structure and realization process; simulation on harmonic excitation conditions of the engineering-used large power transformer iron core, DC magnetic bias operation conditions and iron core compressive stress conditions is effectively and accurately realized; and a reliable and accurate basis is provided for evaluating the no-load excitation performance of the engineering-used large power transformer in different operation working conditions.

Description

technical field [0001] The invention relates to a magnetic performance detection technology of a silicon steel sheet iron core for a transformer, in particular to a magnetic performance detection system and method for a silicon steel sheet iron core for a power transformer. Background technique [0002] In order to test the magnetic properties of silicon steel sheets used in transformers under small samples, GB / T 3655-2008 "Methods for Measuring Magnetic Properties of Electrical Steel Sheets (Strips) Using Epstein Squares" (equivalent to IEC 60404-2:1996) The AC and DC measurement systems and methods for specific total loss and magnetic polarization under a 25cm Epstein square circle consisting of 4 groups of silicon steel sheet samples (length 280-300mm, width 30mm) are specified. GB / T 13789-2008 "Measurement of Magnetic Properties of Electrical Steel Sheet (Strip) with a Single-chip Tester" (equivalent to IEC 60404-3:2002) specifies the specific total loss and magnetic pol...

AI Technical Summary

Problems solved by technology

[0004] 1) The standard small sample is used, and the layout of the excitation silicon steel sheet sample in the winding is far from that of the transformer in engineering applications. The measurement results cannot accurately evaluate the no-load loss and no-load current of the transformer;

[0005] 2) There is no equivalent transformer core excitation model, and a test platform that can comprehensively consider the DC bias effect, current harmonics, and core pressure conditions during transformer operation

However, the large-scale power transformer factory uses two identical actual transformers to test the no-load excitation performance under DC bias. Due to the limitation of the site and equipment, the detection cost is high, the test time is long, and it cannot simulate other conditions except DC bias. Transformer operating conditions

Images