Practical Adaptation of a Low-Cost Voltage Transducer with an Open Feedback Loop for Precise Measurement of Distorted Voltages

Abstract

This paper presents the project proposal of a low-cost transducer with a Hall-effect sensor placed in a ferromagnetic core’s air gap, which enables the measurement of the distorted voltage instantaneous values without the feedback loop used for measurements in electrical machines. The presented transducer allows for electrical separation between the measured voltage and the voltage at the output. Moreover, the influences of frequency, additional resistance, and the reactance of the winding circuit on the voltage phase shift caused by winding inductance with ferrite core and amplitude are discussed. The result of simulating leakage inductance of measuring winding with ferrite core with an air gap is calculated using finite element analysis. Experimental investigations of the voltage phase shift angle and output voltage amplitude drop for the voltage transducers with an open feedback loop are carried out, taking into account the linear core magnetization characteristic.

Low-Frequency Signal Sampling Method Implemented in a PLC Controller Dedicated to Applications in the Monitoring of Selected Electrical Devices

“…Because the current is nonsinusoidal we take 10 consecutive samples to determ the harmonics RMS-value of current with Formulas (16) and (17) and only 3 samples , however, PLC does not hold the same sampling period S T all the time, which is shown in Figure 9.…”

“…Because the current is nonsinusoidal we take 10 consecutive samples to determine the harmonics RMS-value of current with Formulas (16) and (17) and only 3 samples to determine the harmonics and RMS-value of voltage with Formulas (14) and (15) because voltage is almost always sinusoidal (Figure 11). Alternatively, we can use two samples of voltage distanced by four samples (every fourth sample) ( Figure 12).…”

“…The article [17,18] presents a transducer that allows us to measure the instantaneous value of the current with a Hall linear sensor. The advantage of the transducers presented in this paper is their simple design and low cost.…”

Testing Sensitivity of A-Type Residual Current Devices to Earth Fault Currents with Harmonics

“…To detect an insulation fault, especially a line-to-earth fault, which potentially introduces an electric shock hazard or fire hazard, a suitable protective device of a proper sensitivity level should be selected and applied. The type of protective device and its operational algorithm depends on the type of power network (grounded, ungrounded, overhead line, cable line) [4,5], the necessity of detection of an arc fault [6,7], distorted voltages [8], special signals [9], DC currents [10,11], and the necessity of detection of non-sinusoidal alternating earth fault currents. Special attention should be given to the currents comprising very-low-frequency components [12] or high-order harmonics [13][14][15][16][17][18][19], as in circuits with power electronics converters [20].…”

Radial Basis Functions Intended to Determine the Upper Bound of Absolute Dynamic Error at the Output of Voltage-Mode Accelerometers

“…A similar situation occurs when measuring other dynamic quantities (e.g., pressure, temperature, etc.) [5,6,7,8]. For those quantities, no explicit comparative criterion [9] has been developed so far, as is the case with the accuracy class of the instruments intended for static measurements [10,11].…”