Remanent magnetism amount calculation method after 750kV autotransformer direct current resistance test
A technology of autotransformer and calculation method, applied in the field of residual magnetism calculation, can solve the problems of complex residual magnetism problem of transformer, difficulty in measuring residual magnetic flux, and no calculation and check method.
Inactive Publication Date: 2018-06-01
MAINTENANCE COMPANY OF STATE GRID XINJIANG ELECTRIC POWER COMPANY +1
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Problems solved by technology
[0003] The problem of transformer residual magnetism is more complicated, and it is difficult to measure accurate residual magnetic flux under normal circumstances. At present, there is no accurate calculation and verification method
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[0052] Such as figure 1 Shown, which shows a specific embodiment of the present invention, such as figure 1 As shown, the method for calculating residual magnetism after the 750kV autotransformer direct resistance test disclosed by the present invention comprises the following steps:
[0053]Step I: Simulate the input voltage of the primary winding of the transformer, causing the iron core of the transformer to saturate, thereby calculating the magnetic flux generated by the voltage on the primary side;
[0054] With 750k V single-phase autotransformer ( figure 1 ) to analyze the mechanism process of transformer core saturation and excitation inrush current;
[0055] u 1 is the input voltage, U 1 =U m cos(ωt+α), the primary side voltage at no load is:
[0056]
[0057] In the formula: U m Is the magnitude of the input voltage; R is the resistance of the primary winding; i 1 is the current flowing through the primary winding; N 1 is the number of turns of the primar...
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The present invention discloses a remanent magnetism amount calculation method after a 750kV autotransformer direct current resistance test. A remanent magnetism state of transformer is simulated, theremanent magnetism amount of the transformer is calculated by employing an inrush current generated by a steady-state flux and a transient flux in different closing states to achieve accurate demagnetization. The calculation method comprises the following steps that: the step I: a voltage input into a primary winding of the transformer is simulated to cause saturation of an iron core of the transformer so as to calculate magnetic flux, generated at the primary side, of the voltage; the step II, a primary current is an exciting current because an open circuit is set in a secondary side in a primary pressing process; after the transformer is subjected to no-load closing, an excitation magnetic flux [Phi]1 is generated in the iron core under the action of the exciting current; and the step III, the iron core saturation magnetic flux is a constant value for a 750kV autotransformer put into operation, and remanent magnetism is solved or a saturation current value is solved according to theremanent magnetism and a closing angle according to the closing angle and a iron core saturation current under the closing angle through an expression of excitation f(is) when the transformers with different closing angles are at the saturation current.
Description
technical field [0001] The invention relates to a method for calculating the residual magnetism, which is specifically used for calculating the residual magnetism after the direct resistance test of a 750kV autotransformer. Background technique [0002] Substations with a voltage level of 750kV are mainly used in the northwestern region of my country. Taking Xinjiang as an example, there are currently 17 750kV substations in operation, which not only undertake the task of power transmission in the vast province, but also undertake the important task of west-to-east power transmission. Every time a power outage maintenance task is carried out, the power grid failure caused by human factors should be avoided. Since there are endless cases where transformer degaussing has not been carried out or degaussing has not been done thoroughly, the influence of iron core remanence accounts for a large proportion, especially in the no-load closing of power transformers, the size of rema...
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IPC IPC(8): G01R33/12
Inventor 苏迪马众董雪莲党园张玉辉乔佳男俞元章王彦荣卢兴睿魏恒
Owner MAINTENANCE COMPANY OF STATE GRID XINJIANG ELECTRIC POWER COMPANY