Specification for single phase street lighting fuses (cut-outs) for low-voltage public electricity distribution systems. 25 A rating for highway power supplies and street furniture

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.

Download Full-text

Discussion on “Lower-cost urban electricity-distribution systems by automatic control” and “Design of low-voltage distribution networks. Interactive computer method based on the calculus of variations”

Proceedings of the Institution of Electrical Engineers ◽

10.1049/piee.1974.0156 ◽

1974 ◽

Vol 121 (7) ◽

pp. 694

Keyword(s):

Automatic Control ◽

Calculus Of Variations ◽

Distribution Systems ◽

Lower Cost ◽

Low Voltage ◽

Distribution Networks ◽

Computer Method ◽

Electricity Distribution ◽

Voltage Distribution

Download Full-text

Analysis of power distribution systems based on low-voltage DC/DC power supplies for automated guided vehicles (AGV)

10.1109/ee53374.2021.9628366 ◽

2021 ◽

Author(s):

Andreas J. Hanschek ◽

Yann E. Bouvier ◽

Erwin Jesacher ◽

Petar J. Grbovic

Keyword(s):

Power Distribution ◽

Distribution Systems ◽

Low Voltage ◽

Automated Guided Vehicles ◽

Power Supplies ◽

Power Distribution Systems ◽

Dc Power

Download Full-text

Configuration of smart phase-swapping switches in low-voltage distribution systems based on sequenced participation indices

Measurement and Control ◽

10.1177/0020294020920899 ◽

2020 ◽

Vol 53 (7-8) ◽

pp. 1159-1170

Author(s):

Lixia Cao ◽

Guoliang Feng ◽

Xingong Cheng ◽

Luhao Wang

Keyword(s):

Distribution Systems ◽

Single Phase ◽

Low Voltage ◽

Economic Benefits ◽

Voltage Distribution ◽

Practical Applications ◽

Three Phase ◽

Participation Index ◽

Configuration Problem ◽

High Phase

The smart phase-swapping switches are used to rapidly change the phases of single-phase loads online in low-voltage distribution systems. They can reduce the three-phase imbalance indices. However, the effectiveness of phase-swapping operations is determined by not only the control strategy but also by the quantity and locations of smart phase-swapping switches. In this paper, a configuration method is proposed to determine the preferable quantity and locations of smart phase-swapping switches with considerations of economic benefits and operational requirements. Based on historical load information, the active and reactive powers of the loads are used to formulate the current imbalance index. The configuration problem is modeled as a multiobjective optimization that minimizes the current imbalance indices of all nodes and phase-swapping operations. The problem is solved by the particle swarm optimization algorithm to obtain the phase-swapping participation index of each single-phase load. The loads with high phase-swapping participation indices are preferably equipped with smart phase-swapping switches. The simulation results verify that the proposed method is effective and easy to be implemented in practical applications.

Download Full-text

Coordinated single-phase control scheme for voltage unbalance reduction in low voltage network

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2016.0308 ◽

2017 ◽

Vol 375 (2100) ◽

pp. 20160308 ◽

Cited By ~ 2

Author(s):

Deepak Pullaguram ◽

Sukumar Mishra ◽

Nilanjan Senroy

Keyword(s):

Distribution Systems ◽

Single Phase ◽

Reactive Power ◽

Low Voltage ◽

Power Sharing ◽

Voltage Unbalance ◽

Line Configuration ◽

Control Scheme ◽

Multi Agent ◽

Proper Power

Low voltage (LV) distribution systems are typically unbalanced in nature due to unbalanced loading and unsymmetrical line configuration. This situation is further aggravated by single-phase power injections. A coordinated control scheme is proposed for single-phase sources, to reduce voltage unbalance. A consensus-based coordination is achieved using a multi-agent system, where each agent estimates the averaged global voltage and current magnitudes of individual phases in the LV network. These estimated values are used to modify the reference power of individual single-phase sources, to ensure system-wide balanced voltages and proper power sharing among sources connected to the same phase. Further, the high X / R ratio of the filter, used in the inverter of the single-phase source, enables control of reactive power, to minimize voltage unbalance locally. The proposed scheme is validated by simulating a LV distribution network with multiple single-phase sources subjected to various perturbations. This article is part of the themed issue ‘Energy management: flexibility, risk and optimization’.

Download Full-text