Expert systems are used for evaluating the actual state and future behavior of insulating systems of high voltage electrical machines and equipment. Several rule-based expert systems have been developed in cooperation with top diagnostic workplaces in the Czech Republic for this purpose. The IZOLEX expert system evaluates diagnostic measurement data from commonly used off-line diagnostic method...

The main operational parameter of a silicon detector is the charge collected at the electrodes when a particle is impinging on the device. The collected charge should reach its maximum when the detector is fully depleted. Thus it is of major importance to determine the full depletion voltage of the detector before and after irradiation with fast hadron fluence (Φ ). The measurement of the full ...

Abstrac t Impedance measurements based on voltage pulse injection and current detection are faster and easier to implement than measurements based on sine waves, but transients produced in the current-to-voltage conversion may lead to large deviations in the measurement result. Because those transients depend on the same impedance being measured, solutions based on specific circuit values fail ...

The resistance in series with the membrane capacitance in the giant axon of the squid Loligo pealei was measured using potentiometric probes that exhibit absorbance changes proportional to the voltage across the plasma membrane proper. The method relies upon the fact that a voltage drop across the series resistance produces a deviation in the true transmembrane voltage from that imposed by a vo...

In this paper, a four-point characterization method is developed for samples that have either capacitive or ohmic contacts. When capacitive contacts are used, capacitive current- and voltage-dividers result in a capacitive scaling factor not present in four-point measurements with only ohmic contacts. From a circuit equivalent of the complete measurement system, one can determine both the measu...

The importance of the electric power quality (PQ) demands new methodologies and measurement tools in the power industry for the analysis and measurement of the basic electric magnitudes necessary. This paper presents a new measurement procedure based on neural networks for the estimation of harmonic amplitudes of current/voltage and respective harmonic powers. The measurement scheme is built wi...

Measurement errors of a capacitive voltage transformer (CVT) are relevant to its equivalent parameters for which its capacitive divider contributes the most. In daily operation, dielectric aging, moisture, dielectric breakdown, etc., it will exert mixing effects on a capacitive divider’s insulation characteristics, leading to fluctuation in equivalent parameters which result in the measurement ...

Very Low Frequency (VLF) tests are often used for after-laying tests of power cables since the reactive power demand is much lower at VLF than at 50 Hz. In order to augment the usefulness of the test, it is often complemented by a measurement of dielectric dissipation factor (tan ), where the acceptance of the tested object is based on this measurement. A traceability chain for dissipation fac...

Recent studies have found electrical coupling to be more ubiquitous than previously thought, and coupling through gap junctions is known to play a crucial role in neuronal function and network output. In particular, current spread through gap junctions may affect the activation of voltage-dependent conductances as well as chemical synaptic release. Using voltage-clamp recordings of two strongly...

The flicker and harmonics generated by electric arc furnaces present a problem that is well known to both the steel industry and electrical utilities. This paper presents a method to compensate for measurement errors introduced by current and voltage transformers and anti-aliasing filters in a power quality measurement system. Dynamic compensation may be performed in real time using digital fil...