Wyniki 1-2 spośród 2 dla zapytania: authorDesc:"Alena OTCENASOVA"

Measurement characteristics of voltage in practice and possibilities for improvement of voltage

Czytaj za darmo! »

Worsened quality of supplied as well as demanded electricity causes in reality a large financial loss. The main quality parameters monitored today are voltage dips and interruptions. In this context there are relevant statistics of measurement results and especially the possibility of their improvement by using Dynamic Voltage Restorer, for which we have proposed a possible method of control. The proposed regulation DVR is based on Park transformation of immediate values of voltage in network and its feedback transformation. The method is shown and verified on simulation model. Streszczenie. Pogorszenie jakości dostarczanej jak również zapotrzebowanej energii elektrycznej powoduje powstawanie dużych strat finansowych. Podstawowymi parametrami jakościowymi monitorowanymi obecnie są spadki napięcia i przerwy w zasilaniu. W tym kontekście istnieją adekwatne statystyki pomiarowe, a w szczególności możliwości ich poprawy poprzez użycie dynamicznego układu odtwarzania napięcia (DVR), dla którego zaproponowaliśmy metodę sterowania. Proponowana metoda sterowania układem DVR bazuje na transformacji Parka wartości chwilowych napięcia w sieci i ich transformacji odwrotnej. Metoda została przedstawiona i zweryfikowana na modelu symulacyjnym. (Pomiary parametrów napięcia w praktyce i możliwości poprawy jakości napięcia) Keywords: power quality, electrical network, voltage dips and interruptions, dynamic voltage restorer, controlling of DVR. Słowa kluczowe: jakość energii, sieć elektryczna, spadki napięcia i przerwy w zasilaniu, dynamiczny układ odtwarzania napięcia, sterowanie układem DVR. Introduction Problems with power quality are always hot topic. The quality of electricity is influenced by many factors and to keep the parameters within the required limits is in many cases difficult. Worsened quality of electricity is often caused by customers by the nature of theirs operation. As they are in many cases supplied together with other customers fro[...]

Active Power Losses in Three-Phase Cable Power Lines DOI:10.15199/48.2020.02.46

Czytaj za darmo! »

In modern electrical power systems, electricity is produced at power plants, transmitted through a high voltage network, and finally distributed to consumers. Electricity is one of the key elements of any economy, industrialized society or country [1]. A modern power system should provide reliable and uninterrupted services to its customers at a rated voltage and frequency within constrained variation limits that are defined in standard EN 50160. If the supply quality suffers a reduction and is outside those constrained limits, sensitive equipment might trip, and any motors connected on the system might stall. The electrical system should not only be able to provide cheap, safe and secure energy to the consumer, but also to compensate for the continually changing load demand [1-3]. A number of customer's equipment pollute the supply system as they draw non-sinusoidal current and behave as nonlinear loads. Power quality is quantified in terms of voltage, current or frequency deviation of the supply system. Some power quality problems can be voltage harmonics, sag/dip, swell, fluctuations, unbalance, flickers and so on. Because of for example these problems, power quality has become an important area of study in electrical power systems, especially in electric distribution and utilization systems. It has created a great challenge to both the electric utilities and manufacturers. Utilities must supply consumers with good quality power for operating their equipment satisfactorily, and manufacturers must develop their electric equipment either to be immune to such disturbances or to override them [4-7]. All electrical power systems are connected by transmission power lines and distribution power lines. Voltage drops and power losses occur by the flowing current through these power lines [8]. In the ideal case, this current is created by only the active component. The current value can be increased by additional components. The[...]

 Strona 1