Transients (original) (raw)

Influence of line routing and terminations on transient overvoltages in LV power installations

European Transactions on Electrical Power, 2009

IEC 62305-4 gives the rules for the selection and the installation of surge protective devices (SPDs), where the maximum enhancement factor is considered to be equal to 2 in the worst case of open-circuit condition. The objective of the present paper is to check this relation for equipment connected to low-voltage (LV) power system. The LV power system is considered as TN-S system with different routings in three- and six-storey buildings. The terminals of apparatus are substituted by a variety of different loads, namely, resistances, inductances, and capacitances. All Maxwell's equations are solved by the method of moments (MoM) and the voltage is calculated at the apparatus terminals. The SPD itself is simulated by a voltage source at the ground floor. The results reveal that the voltage at the apparatus terminals may overshoot the SPD protection level by a factor of 3 irrespective of the number of floors and loops. Copyright © 2008 John Wiley & Sons, Ltd.

Design of a resilient solar mini grid

It has been noted of late that the off – grid solar PV installations in Zambia, that are installed in rural areas, experience frequent failures that result in increased maintenance costs and prolonged downtime. It has also been observed that the mobile communication systems that are installed in more weather hostile environment tend to perform better and resilient than the PV off- grid installations in Zambia. Energy being a key driver to development specifically electric power around the world, there is high demand for its use. But even with the extension of the renewable energy such as solar PV plants in rural areas, it is very important that these mini grids are reliable and resilient. Rural installations are failing to deliver because of poor practices, installations, sizing, more especially protection from natural sources like lightning. This project investigates the causes of the poor performance and frequent failures of the rural solar installations and make recommendations on how to make these installations resilient and energy efficient.