Device for measuring direct current and method

Abstract

The invention provides a device for measuring a direct current and a method. A primary winding passes through a round iron core T1 and a round iron core T2; an excitation coil N1 is wound on the round iron core T1; an excitation coil N2 and a detection coil N3 are wound on the round iron core T2; excitation coils N1 and N2 are in reverse serial connection onto two ends of an AC modulation voltage source by homonymous ends; two ends of the detection coil N3 are respectively connected with two input ends of a buffer amplifier; the output end of the buffer amplifier is respectively connected with the input end of a positive half-wave peak detector, the input end of a negative half-wave peak detector and the input end of a periodic discharge circuit; and two output ends of the periodic discharge circuit are respectively connected with control ends of the positive half-wave peak detector and the negative half-wave peak detector. The proportion of a peak time difference of distorted voltage sensed by the detection coil to a fixed AC power supply period is used for measuring the direct current, the measurement precision can be effectively improved, demands on an excitation power supply are reduced, and the principle is simple and reliable.

Description

technical field [0001] The invention relates to the field of direct current measurement, in particular to a device and method for measuring direct current. Background technique [0002] At present, the most widely used DC transformers in actual DC converter stations are mainly zero-flux transformers and photoelectric transformers. Among them, the zero-flux transformer can adopt a single-core open-loop or closed-loop structure, and can also adopt a double-core open-loop or closed-loop structure. There are excitation coils in both open-loop and closed-loop structures. When the transformer is working normally, the distorted magnetic flux in the iron core will generate a distorted voltage in the excitation circuit, so that the excitation circuit forms a distorted current sine wave, which increases the difficulty of detection. Based on this, it is necessary to invent a new DC current detection device to solve the problem of excitation circuit current distortion and improve detec...

AI Technical Summary

Problems solved by technology

[0003] According to the deficiencies of the prior art, the present invention provides a device and method for measuring DC current, which solves the problems of excitation circuit current distortion and low measurement accuracy in the existing DC current measuring device

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