Method for testing impedance characteristic of large electrical equipment based on frequency-sweep method

Abstract

The invention relates to a method for testing the impedance characteristic of large electrical equipment based on a frequency-sweep method, which belongs to the field of measurement technique of electrical equipment. The method is suitable for testing the impedance characteristic of the large electrical equipment, through testing the internal resistance of a signal source and the voltage division ratio of the tested equipment, the impedance characteristic of an external circuit is obtained, and the method has the characteristics of wider frequency band, higher precision, small interference and the like. The measurement process of the method comprises four steps of equipment connection, cable parameter calibration, impedance measurement and post-processing calculation; the internal resistance of an instrument and the impedance of a cable are taken into consideration for the measurement, and through the wave process theory, the characteristic impedance of the tested equipment is reversely deduced from the measured impedance; and a measurement system comprises an impedance analyzer, a measurement kit, a coaxial cable and the like. By the method, the testing interference and the generated error are reduced, and the measurement precision of the impedance is improved.

Description

technical field [0001] The invention relates to a method for testing the impedance characteristics of large electric equipment based on a frequency sweep method, and belongs to the technical field of electric equipment measurement. Background technique [0002] In the power system, in addition to generators, passive equipment such as power transformers, high-voltage reactors, and high-voltage capacitors can be equivalently represented by the impedance value of the equipment port. Impedance characteristics are not only important inherent parameters of power equipment itself, but also the basis for establishing equipment models in power system analysis. Accurate measurement of impedance characteristics of power equipment is of great significance for power system simulation analysis, electromagnetic transient calculation, fault recurrence, design evaluation and other work and research. [0003] At present, there are relatively mature methods for measuring the impedance charact...

AI Technical Summary

Problems solved by technology

For the impedance characteristics of large-scale power equipment in EHV and UHV systems, such as transformers and reactors, due to the particularity of their structure, there is currently a lack of fixed testing equipment and practical measurement methods

First of all, large-scale power equipment is bulky (length, width, up to tens of meters), and the distance between the high-voltage end and the low-voltage end to be tested is far away, so the equipment port cannot be directly connected to the test end of the impedance measuring instrument; secondly, during the measurement process, Due to the presence of stray parameters at high frequencies, the introduction of connecting wires and changes in its own parameters will have a certain impact on the measurement results

Images