This paper deals with the power quality in a distribution grid. It is aimed to analyze active power losses that arises in the distribution grid of 22 kV. The active power losses are influenced by various adverse effects such as the load voltage unbalance, the load power factor, and the higher harmonics. The influence of these adverse effects was analyzed by the simulation model that was created in the simulation program Matlab - Simulink. The simulation was performed for three types of power line cable conductors, their different lengths, different types of active power consumption and different values of adverse effects that are mentioned above. Pursuant to data, obtained from the real measurement on an existing part of the distribution grid, another simulation was performed. Based on the individual analyzes of the real measurement, the financial losses during a certain period were calculated.
Słowa kluczowe: power quality; active power losses; load unbalance; power factor; harmonics.
W artykule analizowano straty mocy czynnej w sieci rozdzielczej 22 kV. Analizowano nierównowagę napięć obciążenia, współczynnik mocy I obecność harmonicznych. Przeprowadzono symulację dla trzech typów linii kablowych o różnej długości I różnych poborów mocy. Inalizowano też koszty.
Keywords: straty mocy, jakość energii, linie kablowe.
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 . 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 . In the ideal case, this current is created by only the active component. The current value can be increased by additional components. The [...]
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