Transformer internal fault online monitoring method

Abstract

The invention relates to a transformer internal fault on-line monitoring method which is characterized by specifically comprising the following steps: (1) establishing a T-shaped equivalent circuit model according to a transformer circuit structure; (2) constructing a target function J shown in the following formula (I), wherein the target function is used for solving a high-voltage side resistorR1, a high-voltage side leakage reactance X1, a low-voltage side resistor reduction value R2', a low-voltage side leakage reactance reduction value X2', an excitation resistor Rm and an excitation reactance Xm; (3) under the normal condition of the transformer, selecting an optimization algorithm to carry out optimization calculation by taking the formula J as the target function to obtain optimalsolutions and corresponding fitness of R1, X1, R2', X2', Rm and Xm, (4) carrying out online monitoring on the transformer, and (5) comparing and judging a fault type. According to the transformer internal fault on-line monitoring method, the equivalent circuit parameters of the transformer, such as winding resistance, leakage reactance and equivalent excitation branch impedance, are judged through on-line calculation and identification, the windings and iron cores can be monitored in real time, the classification monitoring of different internal faults is achieved, and the method has higher sensitivity for slight iron core faults or slight turn-to-turn short circuits.

Description

technical field [0001] The invention belongs to the technical field of transformer operation monitoring, and particularly relates to an on-line monitoring method for internal faults of transformers. Background technique [0002] The operation status of the transformer directly affects the safety and stability of the power equipment and even the entire power grid. In the prior art, the methods for detecting the internal fault of the transformer according to the parameters of the equivalent circuit of the transformer mainly include the short-circuit impedance method and the leakage inductance method, which can detect whether the winding is deformed or short-circuited. The short-circuit impedance of the transformer refers to the equivalent impedance of the transformer when the load impedance is zero and the load current is the rated value, while the leakage inductance is the imaginary part of the short-circuit impedance, that is, the inductance corresponding to the short-circui...

AI Technical Summary

Problems solved by technology

However, although the leakage inductance method can reflect the winding deformation and inter-turn short circuit online, it cannot distinguish the two; and when there is a slight inter-turn short circuit, the change of the leakage inductance is not obvious due to the small number of shorted turns , so the method is not sensitive enough for this case

[0005] In addition, the above-mentioned short-circuit impedance method and leakage inductance method can only monitor the winding, and cannot reflect the fault of the iron core.

Images