Onboard Energy Storage System in Addis Ababa Light Railway Transit for Energy Efficiency Improvement
No Thumbnail Available
Date
2017-09
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Using onboard Energy storage system for Addis Ababa Light Rail Transit is the main objective
of the thesis. In this thesis for analysis of the efficiency of using onboard energy storage system
in AALRT, North to South line is used for modeling and simulation. Mathematical modeling of
the traction force, Power, and energy consumption has been developed and energy consumption
and regenerative energy have calculated for the lines from station to stations in the line. For
round trip of Menelik II square station to Kality station the generated brake regenerative energy
is 30.01 kWh. This energy is 12.4% of the total energy consumption of the traction for the round
trip of Menelik II square to Kality stations.
Hybrid energy storage system is selected for onboard energy storage system. The HESS design
has been formulated, with energy capacity of 79.78 kWh and mass 2460Kg. HESS/Hybrid
Energy Storage System is used for improving efficiency of energy and power. Super-capacitor is
used for power efficiency and efficient brake regenerative recapturing, and Li-ion battery for
energy saving efficiency.
From the simulation of onboard energy storage system, the hybrid of Super-capacitor and Li-ion
battery with capacity of 79.78kWh is used as per the design. To supply traction energy of
11.28kWh the state of charge of the battery is discharged up to 99.9%, whereas the SoC of the
SC is discharged to 94% and recharged to 99% by the brake regenerative energy. In the
simulation the ESS supply power during acceleration up to 640kW.
Based on the research result, it is concluded onboard energy storage system is an effective
solution for recapturing the brake regenerated energy. The regenerated energy is 12.4% of the
traction consumption energy which is used to increase the energy efficiency. By using the
regenerated energy saved in ESS to supply energy for traction during power shortage and also
for accelerating and up gradient traction. The ESS supply energy for the traction during grid
electric energy supply outage and to minimize energy consumption of the traction.
Description
Keywords
onboard Energy Storage system, Regenerative energy, Hybrid Energy Storage, Energy Consumption, Super-capacitor, Li-ion battery