The objective of this work is to study and design a module of super capacitors for recovering the braking
energy in trolleybuses. The module of super capacitors is charged and discharged by Buck-Boost
converter that is reversible in current. The co
ntrol and the smoothing elements of the converter are
designed with taking into account the non-linear nature of super capacitors. To recover quickly the
braking energy, the module is charged with constant current, while the discharging is done with constant
voltage on the DC link of trolleybus. The module of super capacitors in its different operations (starting
up, powering auxiliary equipments, braking) is simulated in the SIMPLORER environment. As a result,
the different operating values (as voltage, current and temperature) are determined for the elements of
the studied module (diodes, IGBTs, capacitor, super capacitors). Finally, the failure rate and the
reliability of the module elements are estimated depending on the different operating factors. The module
faults is analyzed.
Today worldwide distributed generation (DG) takes a very important role in the operation of
distributed electric power systems. However, the existence of distributed generation may have
impacts on different topics, such as fault currents, fault pro
tection, coordination schemes or
fault location. If there is short-circuit in the system, the presence of one or more distributed
generators can affect the fault current levels, the monitoring of voltages and currents at the
substation. The main supply generation will not have to inject as much power to the line because
of the DG and, therefore, voltages and currents at the substation will be different from the ones
that would be measured without DG .
