Browsing by Author "Habyarimana, Mathew."

Now showing 1 - 2 of 2

Automated hybrid solar and mains system for peak time power demand.
(2015) Habyarimana, Mathew.; Venugopal, Chitra.
The power demand during peak period causes large power fluctuations in the commercial grid. The reduction in using grid supply during peak time benefits the supplier and consumer. There are many methods such as monitoring the usage of grid supply, load shedding, using local generators and disconnecting unwanted loads during peak time used to reduce grid dependency during peak time. These methods reduce power demand from grid by either supplying interrupted power to the load or by establishing additional power source. In South Africa, solar energy is abundantly available and it can be utilized to solve the power demand during peak time. In this research, solar and grid power are chosen as two power sources and automatic switching system to select the power source to supply uninterrupted power to the load is designed. The important aspect of using solar system is estimating the system output. The maximum power point tracking system using perturb and observe algorithm is designed. The boost converter and inverter circuits are designed to supply power to the coffee shop loads at Howard College Campus. Battery charger circuit is designed to charge the battery from solar or grid and supply power to the load whenever required. The switching algorithm connects the load to solar or battery during peak time and connects it to grid during off peak time. The switching algorithm is designed to supply uninterrupted power to the load by connecting it to available source when any one of the source failure occurs. The power output from the panel is maximized by automatic panel cleaning system. The panel cleaning starts at the pre-programmed schedule and provision for manual override option to reschedule panel cleaning operation is also provided. The designed system is tested in MATLAB and Proteus simulation software. The results of each section are discussed. It can be seen that designed automatic selection of power sources for supplying 1kW of power during peak time to the selected coffee shop considerably reduces the cost and power demand from the grid during peak time. The designed system is economically feasible and efficient in supplying uninterrupted power to the load.
Methods to reduce the starting current of an induction motor.
(2022) Habyarimana, Mathew.; Carpanen, Rudiren Pillay.; Dorrell, David George.
Power system loads that have high starting currents are a serious source of concern in smaller grids or remote locations on the main grid. This problem is envisaged to be exacerbated by the rollout of smart microgrids. When a high power induction motor is turned on in such a power system, its inrush current can be up to about ten times the full-load current. This transient current can cause problems when attached to weak grids. The increased current is due to the power required to start the load and the increased reactive power demand during the starting process. To protect the grid connection as well as the load, energy storage units can be used to compensate for the increased power requirement. A more pragmatic approach is to reduce the reactive power requirement using tuned compensation capacitors in order to reduce the inrush current. The aim of this research is to address the selection, calculation and switching of the capacitor bank for reactive power compensation. The capacitors are calculated and switched on to compensate the starting transient and disconnected when the machine has run up to speed using a point-on switching approach that reduces the switching transient.