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PARALLELING OPERATIONS
MagnaMAX generators come standard with
amortisseur windings die cast as an integral
part of the rotor. This exclusive, Unirotor
construction makes all MagnaMAX
generators suitable for paralleling operations
when the proper control equipment is added.
Paralleling with other generator sets and / or
with the utility power grid offers a number of
advantages. Multiple unit installations
increase power capacity; they can be added or
removed from the line depending on the load
requirements; they can be better maintained
and repaired (since single source breakdown
would mean total loss of power), and they
often provide more reliable, efficient, and
economical operation
.
Successful parallel operation means that the
generators deliver power to the external
system without delivering power to each
other, or accepting power from the load bus or
power grid. Additional equipment is necessary
to insure safe and successful operation.
PRIME MOVER
The prime mover provides the speed and
torque which will be necessary to keep the
machines in synchronized operation. A
governor controls the prime mover's speed.
The governor will directly control the watt or
kW output and frequency of the unit. The
governor must have special paralleling
provisions to permit parallel operation with
the other machines.
VOLTAGE REGULATOR
The voltage regulator controls the generator
output voltage and the reactive power supplied
by the generator. When two or more ac
generators operate in parallel, the voltage regulator
must have paralleling provisions (either internally
or external to the regulator) to control the reactive
or VAR load while it is in parallel operation. A
separate paralleling current transformer is required
TM
,
to sense the reactive current and signal the voltage
regulator. This additional paralleling circuitry is
absolutely necessary to control the reactive current
flowing between the generator sets.
SWITCHGEAR
There are additional relays and breaker controls
that are necessary to insure safe, trouble free
operation of paralleled units. Reverse power relays
monitor the direction of power flow to insure that
the generator is delivering power, not accepting it.
These power relays control breakers, which are a
means of connecting and disconnecting the gen-
erator from the load. The total system can include
over-voltage, over-current protection, under fre-
quency protection, power factor correction provi-
sion and a variety of associated control equipment
from manual switchgear to microprocessors. The
amount of control gear and level of sophistication
will be determined by the needs and requirements
of the particular application.
PARALLELING BASICS
The following points are basic criteria which must
be met before two units can be paralleled. THIS IS
NOT MEANT TO BE SPECIFIC
INSTRUCTIONS FOR PARALLELING
OPERATION.
1. Additional paralleling circuitry
A. Voltage regulator-paralleling provisions
B. Paralleling current transformer(s)
C. Paralleling provisions on governor controls
D. Switchgear
2. The voltage and frequency must be the same for
all sets with voltages in phase.
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