MIL-HDBK-1003/11
Section 8:
GENERATOR CONTROLS AND PROTECTION
8.1 Control Capabilities:
Generator devices provide the following control
features:
a) The generator circuit breaker provides a switching device to
connect or disconnect a generator from the system.
b) The operating control point permits generator switching, voltage
and frequency changing, synchronization of generators and commercial
sources, and a central point for monitoring of system operation.
c) The generator protective devices provide for safe operation. Refer
to the American National Standards Institute (ANSI), C37.2, Electrical Power
System Device Function Numbers, for ANSI device numbering system
assignments.
8.2 Control Locations. The generator circuit breaker and protective
devices are located as appropriate to the installation. The operating
control point may be installed either with or separately from its associated
8.2.1 Definitive Designs 1, 2, 3 and 4. The definitive drawings (refer to
Section 1) utilize a separate control switchboard to provide the operating
control point. No controls are provided on the generator and feeder
switchgear except for operating the bus tie unit. For plants having a
capacity of less than 2,000 kW, consider a need for a control console on the
basis of providing the following features:
a)
Economy, including manpower requirements and operating costs; or,
b) More reliable control, the system requires large and varied load
changes which cause frequent stopping and starting of generating units.
8.2.2 Alternate Definitive Design Control. In some cases it may be
desirable to also provide control at the switchgear. Such a case might one
in which the design configuration requires a significant separation between
the Control Room and the Switchgear Room or if simplicity of operation is
paramount. Safety considerations for maintenance at the switchgear can be
provided as long as the circuit breaker is of the drawout type having a test
position, otherwise some other method of preventing simultaneous local and
remote control is necessary.
8.2.3 Small Low-Voltage Plants. Low-voltage generators quite often have
the generator controls and circuit breaker provided as a part of the
skid-mounted engine-generator used.
8.2.3.1 Automatic Transfer Switch (Single Units Only). Generally, an
automatic transfer switch is used for single low-voltage diesel generator
operation to transfer loads from a normal source to the generator.
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