Hugo Gastón Mayer

Perturbation measurements on HV overhead lines using Electric Field Sensors

It is widely known that in most countries there are severe Power Quality rules that Utilities as well as customers have to comply with. Therefore, it is necessary to assess carefully the levels of disturbances. The traditional procedure to determine the origin of such disturbances is to perform field measurements in all the plants containing power electronic equipment, electric arc furnaces, etc., located near the point in which high levels of disturbances have been detected. Nevertheless, in most cases field engineers find it difficult to have access to the plants belonging to Utilities and also to the different industries settled nearby, which are also likely to emit disturbances. In addition, the task of installing the PQ recorder in the electrical cabinets inside the plant demands a considerable time, as well. With the intention of avoiding all the difficulties that can arise when field engineers are searching for a disturbing load, it was considered a great challenge to design a novel device to make the field work simpler. Such a challenge was based on designing a measuring system capable of recording voltage waveforms with no physical contact with the installations and without the assistance of Utilities personnel. In order to achieve this goal an Electric Field Sensor (EFS) was employed in the design of the measuring system. This paper deals with the results of testing an electric field measurement system - completely designed by the authors - for monitoring voltage Flicker and harmonics in overhead power systems [1]-[3]. Some results of field measurements performed in plants containing disturbing loads are shown.

Assessment of Power Quality indices over a decade of control in Argentinian distribution system

The electricity distribution service in the Buenos Aires metropolitan area of Argentina, which was privatized in the early nineties, is carried out by three different Utilities and the control is performed by a Regulatory Agency (ENRE).

Power quality measurements and mitigation of disturbances due to PWM AC drives

Variable speed AC drives are finding their place in all types of industrial and commercial loads. One important application of these drives is in process control, controlling the speed of fans, compressors, pumps and blowers. However, there are many line (source) design parameters frequently overlooked. A pipeline for transporting synthetic crude oil was installed in Argentina and variable frequency drives (VFD) were employed to control the centrifugal pumps, in order to provide flow and pressure control. During the commissioning and start-up program, the IITREE-LAT performed power quality measurements and EMC studies in the petroleum process plants. The first part of the paper deals with the problem of common- mode voltages and its mitigation. In the second part of the paper, the preservation of the reference levels for the supply voltage and emission limits for the petroleum plant as a customer is evaluated by measurements of harmonics content in both voltage and current. An LC resonance problem was found and a practical solution was implemented. The fulfillment of power quality limits for both International and Argentinian standards is assessed. Finally, the behavior of the VFD - in terms of PQ indicators - under different load conditions is analyzed in detail.