Impact of Non-Linear Small Power Receivers on Low Voltage Network Operation Conditions

Author(s):  
Julian Wosik ◽  
Bogdan Miedzinski ◽  
Artur Kozlowski ◽  
Marian Kalus

This study investigated current harmonic distortions emanating from domestic non-linear loads which have adverse deleterious effects on installed low voltage switchgears such as transformers and conductors. The study examined harmonic distortions emanating from dominant domestic nonlinear loads such as microwave, TV set, radio, fridge, video player and compacted fluorescence bulbs (CFLs) using a power quality equipment. From the results obtained, it was noted that there is need to mitigate harmonic distortions generated by domestic loads at point of common coupling (PCC). It is pertinent to mention that the recent study on supplied loads carried out in Kenya power grid shows that above 67% of power end users are domestic consumers. Under current last mile initiative and Global Partnership on Output Based Aid (GPOBA), unprecedented increase of domestic loads connected to the power grid is predicted. It is worth pointing out that most of these domestic loads have switch mode power supplies (SMPS) which have inherent characteristics of distorting current waveform which causes voltage distortions, over-heating of neutral conductors and premature failure of distribution transformers. Further, most of these loads have two modes; standby/sleep mode and operating mode. Results shows that the two modes generate current harmonic distortions which stream back to power utility network through the service cable. Recently, engineers have designed electronic devices that consume less power. These devices draw current in pulses rather than sinusoidal waveform. As a result, the quality of power supplies continues to deteriorate hence adversely affecting the installed low voltage switchgears such as distribution transformers. Although various mitigation measures exist to reduce the effects of harmonic distortions, this paper proposes a single phase active filter as an optimal solution for attenuating the harmonics emanating from domestic non-linear loads.


2019 ◽  
Vol 1 (1) ◽  
pp. 412-418
Author(s):  
Aleksandra Wrzalik ◽  
Matevž Obrecht

AbstractIn recent years heating in Poland has been transformed as a result of the priorities of the country's energy policy implemented within the European Union. The increase in energy security, the development of renewable energy sources and the fulfilment of legal and environmental requirements are very important. Exploitation of district heating systems should ensure reliable and safe heat supplies for industrial and municipal customers with high energy efficiency and reduction of environmental impact. The article discusses the conditions and directions of centralized heating systems development as well as technical and economic issues, which are important for the security of heat supply. The Author describes selected technological innovations used in the technical infrastructure for heat transfer and modern IT systems which are improving the management of heating systems. The article includes the results of simulation research with use of IT tools showing the impact of selected innovations on the improvement of network operation conditions. Directions of modernization of heating systems in the aspect of increasing energy efficiency and security of heat supply have also been indicted here.


Author(s):  
Mikhail A. Sherkunkov ◽  
Stepan G. Tiguntsev

This article explores the method of joint suppression of harmonic currents, balancing currents and partial compensation of the reactive power of a non-linear asymmetric load connected in a triangle using a device installed on the low voltage side of a power transformer


2017 ◽  
Vol 2017 (1) ◽  
pp. 924-928 ◽  
Author(s):  
Jesús García Prado ◽  
Ana González ◽  
Sandra Riaño

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 972 ◽  
Author(s):  
Fermín Barrero-González ◽  
Victor Pires ◽  
José Sousa ◽  
João Martins ◽  
María Milanés-Montero ◽  
...  

The proliferation of residential photovoltaic (PV) prosumers leads to detrimental impacts on the low-voltage (LV) distribution network operation such as reverse power flow, voltage fluctuations and voltage imbalances. This is due to the fact that the strategies for the PV inverters are usually designed to obtain the maximum energy from the panels. The most recent approach to these issues involves new inverter-based solutions. This paper proposes a novel comprehensive control strategy for the power electronic converters associated with PV installations to improve the operational performance of a four-wire LV distribution network. The objectives are to try to balance the currents demanded by consumers and to compensate the reactive power demanded by them at the expense of the remaining converters’ capacity. The strategy is implemented in each consumer installation, constituting a decentralized or distributed control and allowing its practical implementation based on local measurements. The algorithms were tested, in a yearly simulation horizon, on a typical Portuguese LV network to verify the impact of the high integration of the renewable energy sources in the network and the effectiveness and applicability of the proposed approach.


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