Method for measuring and calculating transformer invading lightning voltage waveforms with transformer bushing

Abstract

The invention provides a method for measuring and calculating transformer invading lightning voltage waveforms with a transformer bushing. The method comprises the following steps: S1, according to the impulse withstand voltage test national standard, exerting lightning impact voltage waves on the transformer bushing same as a measured transformer in type in a testing room, and measuring waveforms i(t) of the current flowing through an end screen ground connection wire of the transformer bushing and lightning impact waveforms u(t) of the voltage exerted on the transformer bushing, S2, obtaining the transfer impedance of the transformer bushing, S3, recording the waveforms il(t) of the current measured by a current sensor and flowing through the end screen ground connection wire of the transformer bushing, and S4, calculating to obtain U1(jomega) according to the formula U1(jomega)=Z(jomega)*I1(jomega), and obtaining the invading lightning voltage waveforms u1(t) of the measured transformer according to the obtained U1(jomega). According to the method for measuring and calculating the transformer invading lightning voltage waveforms with the transformer bushing, the method that a self high-voltage bushing of the transformer is inversely pushed into the invading lightning voltage is used, the operation is simple, the method is easy to implement, the real amplitude and the real waveforms of the invading lightning voltage can be obtained, the accurate lightning prevention parameters are provided for the transformer, and the lightning prevention level of the transformer is improved.

Description

technical field [0001] The invention relates to the field of lightning protection of substations, in particular to a method for measuring the voltage waveform of transformer intrusion by using a transformer bushing. Background technique [0002] After the lightning overvoltage invades the substation, the lightning impulse voltage wave with a very steep rising edge or the clipping wave caused by the action of the arrester will generate a huge potential gradient on the transformer winding, which seriously threatens the longitudinal insulation of the transformer. [0003] At present, the prevention of intrusion lightning waves in transformer substations mostly stays on the overvoltage simulation calculation. There is no device for directly measuring the intrusion lightning voltage waveform on the transformer. Therefore, it is unknown whether the overvoltage simulation calculation is accurate. Transformer lightning protection and The accuracy of insulation coordination is also d...

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Problems solved by technology

[0004] Aiming at the present situation that there is no means of directly measuring the waveform of transformer intrusion lightning in the existing methods for preventing intrusion lightning waves in transformer stations, the present invention proposes a method for measuring and calculating transformer intrusion lightning voltage waveform by using transformer bushings

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