Intelligent on-line diagnosis and location method of power transformer winding deformation

Abstract

The invention discloses an intelligent on-line diagnosis and location method of power transformer winding deformation. A winding deformation is called that after the power transformer is lashed by short-circuit or impacted by transportation, characteristics such as distortion and bulging of a local winding can occur under an electrodynamic force or a mechanical force, and buries a huge hidden danger to safe operation of a power network. The common methods of the winding deformation diagnosis are off-line diagnosis, and has the shortcomings of need of transformer shutdown and high requirementsfor professional skills of operators. The invention provides an intelligent on-line diagnosis method of the winding deformation combining information entropy and a support vector machine, the characteristics of current and voltage signals are extracted by using permutation entropy and wavelet entropy, variations of each monitoring index of the power transformer in the aspects of complexity, time-frequency domain and so on are synthesized, and automatic learning of diagnostic logic from fault features is achieved by a machine learning algorithm, the intelligent diagnosis of the winding deformation is achieved, so that the manpower cost is lowered, and the diagnostic efficiency is improved.

Description

technical field [0001] The invention belongs to the field of state monitoring and state diagnosis of power transformers, in particular to a method for intelligent on-line diagnosis and positioning of power transformer winding deformation. Background technique [0002] Transformer is one of the main equipment of the power system, which plays a pivotal role in grid interconnection and power exchange. When the transformer is subjected to short-circuit impact or transportation collision and other factors, the transformer winding may undergo axial or radial dimensional changes under the action of electrodynamic force or mechanical force, which is called winding deformation. Severe winding deformation will lead to insulation breakdown, resulting in power system accidents and huge economic and social losses. The difficulty in the deformation of power transformer windings is that it has the characteristics of concealment and gradual change. If it is not repaired for a long time, it...

AI Technical Summary

Problems solved by technology

Severe winding deformation will lead to insulation breakdown, resulting in power system accidents and huge economic and social losses

The difficulty in the deformation of power transformer windings is that it has the characteristics of concealment and gradual change. If it is not repaired for a long time, it will lead to aggravated deformation, reduced short-circuit resistance, and even complete damage.

[0003] At present, the diagnosis of power transformer winding deformation is based on the results of power failure tests, and there is no complete and scientific online diagnosis method for power transformer winding deformation.

Commonly used diagnostic methods for winding deformation include frequency response method, low-voltage short-circuit impedance test method, and winding dielectric loss capacitance test method. The above three methods are widely used, but the common limitation is that they all require power-off testing, which is an offline diagnostic method.

Off-line diagnostic methods have three disadvantages: First, a power outage is required for testing

In some cases, due to the requirements of system operation, the equipment cannot be powered off, often resulting in missed tests or over-cycle tests, which makes it difficult to diagnose faults and defects in time

Second, the test interval is too long

The period of the test is generally one year, and some faults that develop rapidly can easily develop into accidents within the time between two specified tests.

Finally, the test time is concentrated, the workload is heavy, the professional skills of the operators are high, and a lot of labor costs are required

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