Ac And Dc - Europe PMC

Impact of DC Transient Disturbances on Harmonic Performance of Voltage Transformers for AC Railway Applications.

This paper explores the effect of typical DC transient events in railway grids on instrument transformers' frequency determination, both onboard trains and in AC substations for power quality applications. PQ monitoring in railway systems is a topic of considerable concern, considering that it plays a vital role in energy conservation improvements. The error introduced in harmonic measurements can exceed 100% in some cases, according to two commercial ITs subjected to a wide range of variables regarding amplitude and time length of DC disturbances.

Source link: https://europepmc.org/article/MED/35336441

A High Accuracy AC+DC Current Transducer for Calibration.

Facing a shortage of high-quality current standards in the calibration of AC + DC measurement systems that can both measure DC and AC simultaneously, a measurement technique with high precision is suggested based on a zero-flux self-oscillating fluxgate. The other one of the added windings is used for the AC+DC magnetic potential's feedback, allowing the sensor to operate in a zero-flux state and to measure AC+DC simultaneously. An AC-DC transducer prototype with an AC ranging from 0-500 A to DC 0-300 A is built using the core parameters and an optimized circuit layout. The measurement accuracy in the nominal current range hits class 0. 05, according to the prototype's testing findings. The new transducer has fewer cores and a simpler measuring circuit than the AC+DC current transducer with the same accuracy level.

Source link: https://europepmc.org/article/MED/35336385

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