The Distributed Electronic Load Controller: A New Concept for Voltage Regulation in Microhydro Systems with Transfer of Excess Power to Households

AbstractConstant voltage and frequency can be generated by a stand-alone Self-Excited Induction Generator (SEIG) driven with a fixed-speed low-head hydro-turbine when the electrical load is maintained constant by an Electronic Load Controller (ELC). In a Conventional-ELC (C-ELC), usually a chopper with a dump load is used in parallel with the consumer loads to provide regulation of voltage and control of frequency. However, in the C-ELC configuration excess generated power may be wasted in a dump load. The objective of this research is to design a simplified ELC for each household to transfer the excess power for domestic consumption in addition to providing voltage regulation. Hence, a new ELC topology is proposed. This topology can be split into two parts. The first part is a regular ELC of low rated power, which should be installed at the generator site and it is responsible for precise voltage and frequency regulation and dealing with unexpected failure conditions. The second one is a simplified and inexpensive ELC which is installed in each household to direct excess power to a low wattage household apparatus in addition to participation in voltage regulation by maintaining constancy of the load power. This concept is referred to here as the Distributed ELC (DELC). One significant advantage of the proposed DELC approach is that the excess power can be utilized for domestic hot water purposes, and possibly resulting in health benefits related to improved sanitation. Moreover, the proposed topology shows more reliability compared with the C-ELC. Simulation results demonstrate that even with unbalanced three-phase loads (assisted with bi-directional switches per-phase), the proposed topology has the capability to regulate voltage from no-load to full load. Moreover, in the case of a failure in the power switches or the control circuits, the DELC has more reliable performance than a C-ELC

Wider renewable energy issues for Nepal

The principle of renewable energy for a near bankrupt and developing country like Nepal is well accepted, but its success in filling the needs and aspirations of the development workers and the country is low. The reasons for this include culture, poverty, language, lack of land titles, ancient rights, inadequate education, civil war, civil strife, hunger, greed, business practices, retaliation, infrastructure, bureaucracy and corruption. Examples of how these effects operate are given, together with some possible short term solutions. Possible long term solutions are discussed and the likely ramifications on the society as a whole. Trigger factors are identified which may effect a complete collapse of the intended outcomes, whether via the collapse of the projects, or collapse of the complete society. Given a complete collapse of the renewable energy project or society, a range of possible least worst (or best) outcomes are presented

Sustainable renewable energy development of a remote community in Nepal

This paper describes the process used in the development of two villages in the remote Humla region of Nepal. The process includes both reducing the deforestation and improving the living standard and health of the local people. Specifically, it implements pit latrines, smokeless stoves and electric lighting. The lighting is powered by either pico hydro systems or by solar photovoltaic systems

Improved wind gust stability for wind diesel generator systems

With a sudden wind gust, a wind-diesel system with a large wind turbine penetration can suffer from power system instability, even though it may be stable under steady-state conditions at the same wind speeds. This suggests that the wind-diesel system should be investigated for better frequency and power stability. In this paper, a concept has been presented to improve the stability of the wind-diesel system in high wind gust condition, by placing the wind turbines in such a way that the wind turbines experience the wind gust at different times. A 1.25 MVA Caterpillar diesel generator with six NORDEX 150 turbines has been modelled using MATLAB, and it has been found that when all the wind turbines experience a sufficiently large wind gust simultaneously, frequency and power control is lost. However, if the turbines are located so that they experience the wind gust at staggered times, the power system is found to remain stable for the same gust conditions. The potential stability benefits of this approach have been demonstrated for an area with a known predominant wind front movement direction