“Design & Control of Distributed Generations for Micro-Grid Applications”
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IOE Pulchowk Campus
Abstract
Climate change, its influence on the environment, and natural resources scarcity
necessitate scientific research and creative technical solutions for a modern power
system. This research aims to develop scientific and technological approaches to
“green” technologies, which are environmentally beneficial and long-lasting. Energy
and power supply are major priorities. The design and control of distributed power
generation systems for micro grid applications was the prime focus of this thesis. A 20
KW micro grid is designed to operate in both modes, albeit primarily in the isolated
mode, where solar photovoltaic, wind energy, and battery energy storage modules are
included. Maximum Power Point tracking (MPPT) was used to obtain the highest power
production from solar photovoltaic and wind energy sources. We used lithium-ion
batteries of nominal 48V to store energy produced by PV and wind systems. To maintain
a constant voltage of 220V on the DC bus, bi-directional converters were used to control
charging and discharging process. The inverter, which is based on a voltage sourced
inverter (VSI) was used for supplying power to the AC load. Novel control approach
methods were used to maintain power quality and frequency resynchronization.
Synchronous reference frame theory (D-Q) with voltage oriented dual control was
applied as a control algorithm. Bio inspired metaheuristic technique Particle swarm
optimization (PSO) was applied for PID tuning. Islanded mode and grid feeding
conditions of micro grids were analyzed, discussed and presented.
The results reveal that the system performs satisfactorily under varying generation and
load consumption. The PV module consists of total 14 parallel strings and the series
connected module per string was set at 6. The output variations were observed from
13KW to 21KW with variations of irradiance of and temperature. The wind power
output was 6 KW to 2KW with variations of Speed 12- 8m/s. Lithium-ion batteries rated
420Ah with a nominal discharge current of 182.6887A were used with a normal voltage
of 48V. The load variations used were 5KW to 45KW. Higher order filter (LCL filter)
was utilized to enhance power quality and performance of two different micro grid cases
(i) Islanded mode and (ii) Grid feeding mode was analyzed. This research has a
significant impact on the development of micro grids.
Description
During the recent Java blackout, which took place from August 4, 2019 to August 5,
2019, 120 million people in Indonesia were affected, and 140 million people were
affected by the Pakistan blackout of 2015. In India, a massive blackout happened in
2012. It was the world's most severe power outage in recorded history