DL/T 911-2016 in English

1 Scope

This standard specifies the basic requirements for detecting the winding deformation of transformers with frequency response analysis method.

This standard is applicable to 66kV or above power transformers and other transformers for special purposes.

2 Normative References

The following referenced documents are indispensable for the application of this document. For dated reference, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

DL/T 1093 Guide for Reactance Method to Detect and Diagnose Winding Deformation of Power Transformer

3 Terms and Definitions

For the purposes of this standard, the following terms and definitions apply.

3.1

winding deformation

axial or radial dimensional change, which is generally characterized by the local distortion, bulge or displacement, of the power transformer winding under the action of electrodynamic force or mechanical force when the winding is suffering from short-circuit current rush or is being impacted during transportation process

3.2

bilateral network

network provided with a pair of input ports and a pair of output ports. If this network is composed of linear resistance, inductance (including mutual inductance) and capacitance elements and does not contain any independent power supply, it is referred to as passive linear bilateral network

3.3

transfer function

output-input ratio of passive bilateral network expressed by means of Laplace transformation. The pole and zero distribution of transfer function is closely related to the parameters and connection modes of internal elements and the impedance connected with the ports of bilateral network

3.4

Foreword I
1 Scope
2 Normative References
3 Terms and Definitions
4 Theory of Detection
5 Requirements for Detecting Instrument
7 Analytical Judgment for Winding Deformation
Annex A (Informative) Basic Requirements for the Tester of Transformer Winding Deformation
Annex B (Informative) Data Export Format of Frequency Response Characteristic Curve
Annex C (Normative) Judging Winding Deformation of Transformers with Assistance of Correlation Coefficient R
Annex D (Informative) Examples for Judging Winding Deformation of Transformers by Vertical Comparison Method
Annex E (Informative) Examples for Judging Winding Deformation of Transformers by Lateral Comparison Method
Annex F (Informative) Examples for Judging Winding Deformation of Transformer by Comprehensive Analysis Method
Annex G (Informative) Examples for Typical Interference Waveforms in Winding Deformation of Transformer
Annex H (Informative) Process of Judging Winding Deformation of Transformers with Frequency Response Analysis Method
Annex I (Informative) Typical Amplitude-frequency Response Characteristic Curves in Deformation of Transformer Winding