Electrical capacitors provide a system for the
supply of a large number of high and low voltage electric motors. The
energy for the start-up of the plant is obtained from the 110kV
switching station. With the general-purpose transformer, the tension is
lowered to the voltage needed by the high-voltage systems depending on
the individual generating unit. This voltage is used to supply the
capacitors, and via the circuit breakers the large motors and
transformers for the lower voltage general-purpose users. The
general-purpose capacitors supply the generating unit capacitors during
start-up, which supplies electricity to the high-voltage motors and
lower voltage transformers. These installations serve exclusively the
generating unit; therefore, their operation must not be affected by
external failures. At a generator power of about 20% of the capacity we
switch the supply to the gen. unit own needs transformer. This mode of
operation is safer and cheaper because the generator provides for the
gen. unit needs.
The general purpose and gen. unit own needs capacitors can be single
or double, depending on the necessary power output. This applies to
high-tension as well as low-tension capacitors. The emergency supply of
alternating power with a voltage of 0.4kV is guaranteed by diesel
engines and direct current motor-generators. This branch also has energy
capacitors and has the option of switching to a reserve power source.
The plant’s control and safety systems are supplied with 24, 48 or
220V direct current. These systems have a doubled basic power supply
system and the possibility to switch between capacitors as they are
vital for the operation of the plant. The direct current capacitors are
supplied parallel from the rectifier and the accumulation batteries.
Each important user is supplied from two distinct capacitors. A complete
discharge of these capacitors is practically impossible or at least
very rare.