power system blackouts have become a serious problem for electric utilities especially in recent years. different forms of system instability have emerged in recent blackouts, such as voltage instability and frequency instability. to counteract each form of system instability, special algorithms have been designed in the protection system, e.g. under frequency load shedding (ufls) and under vol...

Yet the audio quality on most devices is inferior. Typical signal-to-noise ratios measure in the 60 to 70 dB range (re –20 dBFS), which is about 5-10 dB worse noise than good portable CD players. They tend to suffer from non-flat frequency responses (bass and treble boost being the biggest offenders) with limited low frequency response (typically rolled off beginning at 60 Hz apparently to comp...

Low-voltage high-speed switched-capacitor (SC) circuit design without using voltage bootstrapper is presented. The basic building block used for low-voltage SC circuit design is the auto-zeroed integrator (AZI), which can work at both low voltage and high sampling frequency. With this method, two low-voltage SC systems were successfully designed and implemented in 1.2m CMOS technology. The firs...

We report on ABB’s fiber-optic current and voltage transducers and their applications in high-voltage substations. We consider bulk-optics and all-fiber current sensors and voltage sensors that exploit the electro-optic effect in BGO and the piezo-electric effect in quartz.

Capacitance between terminals of a power semiconductor device substantially affects on its switching operation. This paper presents a capacitance–voltage (C–V) characterization system for measuring high voltage SiC–JFET and the results. The C–V characterization system enables one to impose high drain-source voltage to the device and extracts the capacitance between two of three terminals in FET...

The National Institute of Standards and Technology (NIST) calibration service for voltage transformers and high-voltage capacitors is described. The service for voltage transformers provides measurements of ratio correction factors and phase angles at primary voltages up to 170 kV and secondary voltages as low as 10 V at 60 Hz. Calibrations at frequencies from 50-400 Hz are available over a mor...