Online real-time identification method of single-phase transformer short-circuit parameters based on SOGI

Abstract

The invention discloses an online real-time identification method for single-phase transformer short-circuit parameters based on SOGI, establishes a T-type equivalent circuit of a single-phase transformer, and lists the transformer short-circuit impedance parameter equation and T-type equivalent circuit equation; obtains the T-type equivalent circuit equation respectively The d-axis equation and q-axis equation of the circuit in the dq coordinate system; use the SOGI-FLL model to extract the fundamental wave component and the fundamental wave orthogonal component of each input signal, and obtain the d-axis component and q axis of each input signal in the dq coordinate system The axial component is calculated to obtain the short-circuit impedance values ​​Rk and Xk of the single-phase transformer, and the online monitoring of the winding operation status of the single-phase transformer is realized. When the transformer winding is deformed or faulty, the short-circuit impedance of the transformer will also change. By measuring the voltage and current of the primary side and secondary side of the transformer in real time, the short-circuit parameters of the transformer winding can be identified, and the online monitoring of the operating status of the transformer winding can be realized. Discover the hidden dangers of the transformer, remove the fault point in time, avoid the occurrence of operation accidents, and prolong the service life of the transformer.

Description

technical field [0001] The invention relates to an online identification method for a unidirectional transformer, in particular to an online real-time identification method for a single-phase transformer short-circuit parameter based on SOGI. Background technique [0002] The transformer is a very important electrical equipment in the power system, and its safe operation is directly related to the power supply reliability of the power system. In the process of transformer operation, various forms of faults will inevitably occur. Among the many faults of transformers, winding faults have always occurred the largest number. Among the methods for diagnosing transformer windings, frequency response method, impedance analysis method, and low-voltage pulse method are available. They are desirable, but they are all off-line methods, which cannot detect transformer winding faults in time, and are not suitable for on-line measurement. [0003] Chinese Patent No. CN200810011051 discl...

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Problems solved by technology

But when the input matrix |AA identified by the least squares method Τ When |=0, the parameters are not identifiable, causing the identification results to diverge or converge to incorrect values, and the amount of calculation is large, and there is a problem of data saturation in parameter tracking

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