2.2.6
Protective Relays, Metering, and Control Devices
2.2.6.1
Relays
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NOTE: The definition and application of device
function numbers used in electrical substations and
switchgear are found in ANSI C37.2, "IEEE Standard
Electrical Power System Device Function Numbers."
For description and application of commonly used
relays, refer to MIL-HDBK-1004/3, "Switchgear and
Relaying." This guide specification does not cover
all possible relay applications. Choose only the
relay types applicable to the specific project.
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Relays shall conform to IEEE C37.90. Protective relays shall be induction
type or solid-state type enclosed in rectangular, semiflush,
switchboard-type drawout cases with indicating targets and provisions for
testing in place by use of manufacturer's standard test blocks or test
switches. One complete set of test blocks or test switches to fit each
type of relay in the equipment shall be provided. Auxiliary and lockout
relays are not required to have drawout cases or test provisions.
Controls, relays, and protective functions shall be provided completely
assembled and wired.
a.
Phase overcurrent relays (device [50/]51): Provide [_____] sets of
three time overcurrent relays responding to phase currents wired to
trip associated circuit breakers upon the occurrence of a current above
the tap setting of the relays. Each relay shall have [very][extremely]
inverse time characteristics with a tap range of [_____] to [_____]
amperes.[ Each relay shall be equipped with an instantaneous
overcurrent unit having a pickup value over the range of [_____] to
[_____] amperes.][ Relays shall be Type [_____].]
b.
Ground overcurrent relays (device [50/]51N): Provide a time
overcurrent relay responding to ground (residual) current, wired to
trip the associated circuit breaker upon occurrence of ground current
above the tap setting of the relay. Relay shall have [very][extremely]
inverse time characteristics with a tap range of [_____] to [_____]
amperes. Relay shall be equipped with an instantaneous overcurrent
unit having a pickup value adjustable over the range of [_____] to
[_____] amperes.[ Relays shall be Type [_____].]
c.
Ground overcurrent relays (device 51N): Provide a time overcurrent
relay responding to ground (residual) current, wired to trip the
associated circuit breaker upon occurrence of ground current above the
tap setting of the relay. Relay shall have [very][extremely] inverse
time characteristics with a tap range of [_____] to [_____] amperes.[
Relay shall be equipped with an instantaneous overcurrent unit having a
pickup value adjustable over the range of [_____] to [_____] amperes.][
Relays shall be Type [_____].]
d.
Directional phase overcurrent relays (device 67): Provide [_____] sets
of three directionally controlled time overcurrent relays sensing phase
current, wired to trip associated circuit breakers upon a current
exceeding the tap setting in the direction indicated. Relays shall
have a voltage polarized directional unit and an inverse time
characteristic overcurrent unit. Overcurrent unit shall have a tap
SECTION 16361N
Page 25
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