Fuel Cell Plant Concept with Dynamic Characteristics of a Rotating Generator

[attachment=17845]
Abstract—Fuel cell plants will be powering future electrical
systems. Fuel cells normally generate direct current (DC) which
must be converted into Alternating Current (AC) for
transmission efficiency and for broader use by numerous loads of
different characteristics. An AC load consists of real power and
reactive power. The real power is generated by fuel cells.
However, the reactive power must be created by other means. It
is possible to create reactive power with DC/AC inverters where
the inverter feeds AC to inductors and capacitors. Usually
inverters have very little overload capability (1-2X for about a
second). On the other hand, if a synchronous condenser is
installed on the AC bus, then the AC system needs to draw only
the real power through the inverter.


INTRODUCTION
fUEL cells are now on the verge of being introduced
commercially, revolutionizing the way power is produced.
Fuel cells can use hydrogen as a fuel, offering the prospect of
supplying the world with clean, sustainable electrical power
[1]. They represent a practical answer to the world's pressing
need for clean and efficient power. A fuel cell produces
electricity by converting the chemical energy of fuel directly
to power in a controlled chemical reaction - without
combustion and without moving parts.



III. CONCEPT DESCRIPTION
A notional fuel cell plant in conjunction with a
synchronous condenser could supply complex AC loads,
including motor loads, as shown in Fig. 1. Fuel cell power
has characteristics of low voltage/high current. For broader
use, the DC power must be converted to AC and raised to
suitable voltage level for transmission and use by various
loads. The power is generally transmitted at 13.8kV at
distribution level and at 138 kV at transmission level. A
transformer requires magnetizing current to support flux level
in its iron core - this current is mostly reactive current with
lagging zero power factor. Induction motor loads also require
lagging power factor currents.