Effect of Proximity, Burden, and Position on the Power Quality Accuracy Performance of Rogowski Coils

Power quality evaluation is the process of assessing the actual power network parameters with respect to the ideal conditions. However, several new assets and devices among the grid include mining the voltage and current quality. For example, the power converters needed for renewable energy sources’ connection to the grid, electric vehicles, etc., are some of the main sources of disturbances that inject high-frequency components into the grid. Consequently, instrument transformers (ITs) should be capable of measuring distorted currents and voltages with the same level of accuracy guaranteed for the ideal frequency (50–60 Hz). This is not a simple task if one considers that several other influence quantities endlessly act on the ITs. To this purpose, considering the lack of a standard, this work presents a measurement setup and specific tests for testing a commonly used type of low-power current transformer, the Rogowski coil (RC). In particular, the accuracy performance (ratio error and phase displacement) of the RCs was evaluated when measuring distorted signals while other influence quantities affected the RCs. Such quantities included positioning, burden, and magnetic field. The results indicate which quantities (or combination of them) have the greatest effect on the RC’s accuracy performance.

Contribution To The Reduction Of The Ship’s Switchboard By Applying Sensor Technology

The paper discusses the contribution to energy efficiency by reducing the dimensions of the main switchboard (medium voltage or High Voltage – used on ship). Reducing the dimensions of the switchboards can be achieved by reducing the dimensions of the bus bars, while fully satisfying the conditions with regard to thermal and mechanical stresses. The same can be achieved by modifying some other components, such as the application of new technology for measuring current and voltage, using current and voltage sensors that fall into the category of completely new technological solutions. By replacing conventional measuring transformers (IT), compact and efficient sensor technology significantly contributes to reducing the dimensions and mass of switchboards, which ultimately contributes to energy efficiency. Previous applications, the possibility of improving existing solutions, especially in applications in marine power systems, and new technological solutions that contribute to the efficiency of the marine power system using the Rogowski coil sensor and voltage divider voltage sensors are also considered.

Expansion of cylindrical tubular workpieces on high-voltage magnetic-pulse installation with controlled vacuum discharger

Purpose. An experimental verification of the existence of a range of values for the parameters of the capacitive energy storage of the magnetic-pulse installations with controlled vacuum discharger, in which, with a high probability, there is a «cut» of the discharge current pulses and the expansion of cylindrical thin-walled tubular workpieces using an external coil. Methodology. High voltage magnetic-pulse installation of NTU «KhPI» with controlled vacuum discharger, multiturn coil with inside dielectrical die and inside aluminum alloy workpiece are used. The capacitance and charge voltage of capacitive energy storage are changed. Discharge current pulses are measured by Rogowski coil and the oscillograph. Results. Parts of complicated shape are made by expansion of cylindrical tubular workpieces with help of external coil. Pressed metallic tubular part is removable from inner dielectric rod. Originality. The frequency of «cut» pulse is defined by negative magnetic field pressure amplitude. It is shown that we must coordinate this frequency and charge voltage with capacitive storage parameters by high probability of pulse «cut». Practical value. It is shown how to use installations with controlled vacuum dischargers in magnetic forming technology based on «cut» pulses.