In recent years, power quality measurements are one of the research topics of the Instrumentation and Measurement Group of Instituto de Telecomunicações. This paper summarizes the latest achievements. The paper describes the proposed algorithms for detection and classification of power quality disturbances and the new measuring instruments that were developed.

Integrating wind power generation into small islands has been one of the demonstration projects in Okinawa Prefecture, Japan. Since such integration could deteriorate power quality, including frequency, in an island grid, a frequency-stabilizing system using flywheels has been integrated into a small island. In order to establish a proper frequency-stabilizing scheme for a small island, an accu...

This effort focus at identifying statistically significant time/frequency domain features with adequate separability and extensive interclass variability to discriminate probable Power Quality (PQ) disturbances such as sag, swell, harmonics, outage, transients etc. Understanding of disturbances is vital to investigate the origin and causes of PQ perturbances, events of equipment failure and for...

Customer loads were linear in nature. When a sinusoidal voltage was supplied to them, they drew a sinusoidal current. They typically fell into the categories of lighting, heating, and motors. In general, they were not very sensitive to momentary variations in the supply voltage, such as transients and voltage sags. The loads were not connected together in networks so grounding issues other than...

The proliferation of non-linear and time-variant loads is causing a number of disturbances on the electric network, from a more and more significant distortion of both currents and voltages, to transient disturbances on the supply voltage. In this respect the electric network behaves as an "healthy carrier" of disturbances, so that a disturbance generated by one customer can be distributed to o...

This paper analyzes necessity of synthesis control of power quality aiming at characteristics of traction power supply system for electrified railway. According to the fact that the existing power quality control, the measure and means were introduced, analyzed and compared in detailed. From reliability, technology and economy point, the project of synthesis Control was put forward on power qua...

For an assessment of the power quality in power distribution systems, classical Fourier series-based power quality indices are normally employed. The classical Fourier series-based power quality indices assume the periodicity of the disturbance so that the applications are limited to the harmonics. Hence, it is necessary for us to redefine power quality indices for the “transient” disturbances....

This paper examines the use of information technology in the electric and gas utilities of Ukraine, Armenia, and Georgia. Data was gathered through the performance of Year 2000 risk assessments, small business visits, document research, and academic visits between 1999 and 2001. Data was analyzed by comparing IT usage in Ukraine, Armenia, and Georgia to that in the United States. Overall IT usa...