DET-882
SecoGear Medium-voltage Switchgear Application and Technical Guide
System and Equipment Protection
©2017 General Electric All Rights Reserved
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SECTION 4.
SYSTEM AND EQUIPMENT PROTECTION
This section covers some basic considerations used when
selecting relays for the protection of medium-voltage
power systems. It is organized by protection packages with
respect to equipment type generally encountered in
medium voltage systems. Feeders, incoming lines, bus,
transformers, motors, generators and metering will be
covered.
Protection considerations can be provided by single-phase
or multifunction three-phase relays, which may include
phase and ground directional, non-directional relays,
overcurrent, differential, directional power, under-
frequency, and under-/overvoltage relaying.
Many benefits are provided by newer multifunctional
digital relays; expanded relay functions, digital metering,
diagnostics, reduction in relay costs per function, reduction
in wiring and increased panel space with the reduction in
the quantity of relays. GE Multilin Relay product reference
guide can be found at www.GEMultilin.com or directly at
www.gegridsolutions.com/multilin/selector/