The invention relates to the technical field of power transformer winding deformation detection, in particular to a linear correlation coefficient calculation method for frequency response winding deformation analysis. The method includes according to the transformer frequency response data measured by the transformer to be diagnosed at different times twice, determining the winding deformation condition by calculating the phase-by-phase longitudinal linear correlation coefficient and calculating the transverse or inter-phase linear correlation coefficient; or calculating the transverse or inter-phase linear correlation coefficient according to the frequency response data measured by the transformer to be diagnosed at this time; converting the relevant coefficient required by the deformation determination, and evaluating the deformation degree of the winding according to the set determination standard. According to the curve data obtained by the frequency response method, the correlation coefficient for determining the deformation degree can be quickly and accurately calculated, the fault type and degree of the winding set can be determined according to the peak change in the curve, and a basis is provided for evaluating the health condition of the transformer.

Linear correlation coefficient calculation method for frequency response winding deformation analysis

The invention discloses an online diagnosis method for a transformer winding deformation position. The method comprises the steps of (1) collecting a transformer with a known winding state, and dividing into a plurality of position sub-samples; (2) performing feature extraction on each position sub-sample by using an information entropy, adding a label of deforming or not, and inputting into a support vector machine for training a diagnostic model; (3) dividing the transformer to be diagnosed into several position sub-samples by the method in step (1), adopting the feature extraction method ofstep (2), and inputting to the trained diagnostic model in step (2); (4) outputting the diagnostic result of the support vector machine about whether the sub-samples of each position of the transformer to be diagnosed are deformed. The method can comprehensively analyze the variation of each monitoring index of the transformer in the complexity, the time-frequency domain and the like, automatically learn a diagnosis logic from the fault feature through a machine learning algorithm, achieve the intelligent diagnosis of the winding deformation, reduce the labor cost and improve the diagnosis effectiveness.

Online diagnosis method for transformer winding deformation position

The present invention discloses a transformer winding deformation detection method. The method comprises the steps of: constructing a transformer self-oscillation circuit, wherein the transformer self-oscillation circuit comprises a direct-current high voltage generator, a first control switch, a second control switch, a detected transformer and a detection device; closing the first control switchto allow the direct-current high voltage generator to allow a direct-current high voltage generator to charge a ground equivalent capacitor; disconnecting the first control switch, rapidly closing the second control switch to allow the detected transformer winding to discharge the ground equivalent capacitor, and forming a coupling voltage through magnetic coupling and capacity coupling of the detected transformer winding; detecting the detected transformer through the detection device to obtain the coupling voltage; and finally, according to the coupling voltage, determining whether the detected transformer winding generates deformation or not. The transformer winding deformation detection method can accurately and rapidly determine whether the transformer winding generates deformation or not and the deformation degree.

Transformer winding deformation detection method

The invention discloses a method for diagnosing inter-turn insulation faults of dry type electric reactors on the basis of frequency response analysis. By the aid of the method, the problem of incapability of timely detecting inter-turn insulation breakdown and occurred inter-turn short-circuit for existing dry type electric reactors in the prior art can be solved. The method includes applying voltage signals at different frequencies to A-phase windings, B-phase windings and C-phase windings of each three-phase dry type hollow electric reactor (2) by the aid of a frequency response analyzer (9), and acquiring electric reactor impedance amplitude-frequency response characteristic curves under the condition of the various voltage signals at the frequencies; comparing the electric reactor impedance amplitude-frequency response characteristic curves acquired at the second step under the condition of the various voltage signals at the frequencies to electric reactor impedance amplitude-frequency response characteristic curves when the three-phase dry type hollow electric reactor is put into operation, and diagnosing that inter-turn short-circuit faults of the three-phase dry type hollowelectric reactor already occur if correlation coefficients of each electric reactor impedance amplitude-frequency response characteristic curve under the condition of the voltage signals at the frequencies and the corresponding electric reactor impedance amplitude-frequency response characteristic curve are smaller than 1. The frequency ranges of the voltage signals are 0-1000 thousand hertz. Themethod has the advantages that the inter-turn insulation faults are detected in advance and are handled in advance, and accordingly burning loss of the dry type hollow electric reactors can be effectively prevented.

Method for diagnosing inter-turn insulation faults of dry type electric reactors on basis of frequency response analysis

An embodiment of the invention relates to a method for determining transverse deformation of transformer windings. The method comprises the steps of taking every two of an outer winding, a middle winding and an inner winding as a winding pair, and determining interphase reactance voltages between phases A, between phases B and between phases C of the two windings in each winding pair; according tothe interphase reactance voltages, determining change rates of the interphase reactance voltages between the phases A, between the phases B and between the phases C of the two windings in each winding pair; determining whether the middle winding and the inner winding have the transverse deformation or not according to the change rates of the interphase reactance voltages; and when the middle winding and the inner winding have the transverse deformation, determining the degree of the transverse deformation according to the change rates of the interphase reactance voltages. Whether the deformation exists or not is determined firstly, and then the deformation degree is determined, so that the method is simple and feasible; and the deformation is determined by the interphase reactance voltages, so that the accuracy is high.

Method for determining transverse deformation of transformer windings

The present invention discloses a method and a system for on-line diagnosis of transformer winding deformation The method comprises: injecting a sweep signal from a high-voltage lead-out line of a transformer winding by way of magnetic field induction; acquiring an excitation current signal induced on the high-voltage lead-out line of the transformer winding; obtaining the response current signal on the neutral ground line of the transformer winding; obtaining the frequency response curve according to the transfer function relationship, which is constructed by using the excitation current signal and the response current signal, of the transformer winding; based on the diagnosis method in the DLT911-2004 standard, diagnosing the frequency response curve; and determining the deformation of the transformer winding According to the invention, the excitation signal injection and response signal measurement do not need direct electrical connection with the transformer winding, making the high-voltage transformer winding operate in a high-voltage and high-current condition and realizing the real-time detection of the transformer winding deformation online

Method and system for on-line diagnosis of transformer winding deformation

The invention discloses a transformer winding deformation on-line diagnosis method. The method comprises the following steps: injecting a sweep frequency signal to a neutral point grounding wire of atransformer winding, and obtaining a current signal I 1 sensed by the neutral point grounding wire of the transformer winding, obtaining a voltage signal V 1 sensed by the neutral point groundingwire of the transformer winding, and obtaining a current signal I 2 on a high-voltage lead-out wire of the transformer winding; constructing an equation based on the V 1, the I 1 and I 2, anddetermining the trajectory of each vector changing with the frequency f of the sweep frequency signal as a frequency response curve of the transformer winding; comparing the obtained frequency response curves through a longitudinal comparison method and a horizontal comparison approach provided in DL/T911, and determining a maximum canonical correlation coefficient between the vectors corresponding to the frequency response curves according to canonical correlation coefficients between existing mature random vectors; and determining deformation conditions of the transformer winding according to a diagnostic method based on correlation coefficient in the DL/T911.

Zhang Liming

Papers

Method and system for on-line diagnosis of transformer winding deformation

Transformer winding deformation on-line diagnosis method and system