Internal temperature rise on-line monitoring method of traction transformer of V/X connection

Abstract

The invention discloses an internal temperature on-line monitoring method of a traction transformer of V/X connection. The method comprises the following steps of: (1) acquiring the basic parameters of the transformer; (2) monitoring the current of a traction winding, the current of a positive feed winding and the temperature of top oil of the transformer on line and uploading the monitored data to an upper computer; and (3) calculating the on-line monitored data by utilizing an internal temperature rise calculating formula established on the basis of an internal temperature rise thermal circuit model of the traction transformer of V/X connection to obtain the internal temperature rise condition during the running of the traction transformer of V/X connection. The invention particularly aims at the traction transformers of V/X connection, which are widely applied to heavy haul railways and high speed railways in China at present, has the advantages of simple system structure, less data required to be monitored, easy monitoring, simple data processing process and lower requirement for computer performance; and an ordinary industrial personal computer can meet the requirement for operation, thus the calculating precision is higher.

Description

Technical field [0001] The invention relates to an on-line monitoring method for internal temperature rise of a V / X connection traction transformer, which belongs to the field of electric insulation on-line detection and fault diagnosis. Background technique [0002] The traction transformer is one of the most important and critical electrical equipment in the railway power supply system. The safety and reliability of its operation is directly related to the stability and efficiency of the railway transportation system. Economic losses are immeasurable. The operational reliability of a transformer depends largely on its insulation state, and the internal temperature of the transformer is the most critical factor affecting the insulation state. At present, the internal temperature measurement of the transformer is mainly divided into direct measurement method and indirect measurement method. The direct measurement method is to embed a sensor near the wire in the winding, an...

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Problems solved by technology

The direct measurement method is to embed a sensor near the wire in the winding, and measure the temperature directly by a temperature measuring instrument. The measurement result is accurate, but the sensor needs to be pre-embedded in the design and manufacture of the transformer, and the maintenance technology is complex and expensive.

Therefore, indirect measurement methods are often used in engineering, mainly including numerical calculation methods. This method is based on establishing the internal heat transfer model of the transformer, and solves the internal temperature field of the transformer according to the heat transfer theory and boundary conditions. The calculation accuracy is high, and any The temperature at one position, but the calculation process is complex and requires high computer performance; there is another thermal simulation method, which is to superimpose the additional temperature rise generated by the additional current obtained from the current transformer on the electric heating element to the oil on the top layer of the transformer. In terms of temperature, the winding hot spot temperature of the transformer can be obtained, but there are still some errors in the currently used technology; there is also the calculation method recommended by Annex G in IEEE Std C57.91-1995, which uses superposition calculation method and empirical formula, It is mainly applicable to the temperature rise calculation of power transformers. It has certain limitations for traction transformers with large impact loads, and the calculation error is large.

For V / X connection traction transformers widely used in heavy-duty and high-speed railways, there is no report on the online monitoring method of temperature rise

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