4.27
Date Code 20060320 Instruction Manual SEL-311C Relay
Loss-of-Potential, CCVT Transient Detection, Load-Encroachment, and Directional Element Logic
Directional Control Settings
If configuration setting E32 = Y, settings Z0F and Z0R (zero-sequence
impedance values) are calculated by the user and entered by the user, but
setting Z0R must be greater in value than setting Z0F by 0.1 Ω (5 A nominal)
or 0.5 Ω (1 A nominal).
Z0F and Z0R Set Automatically
If configuration setting E32 = AUTO, settings Z0F and Z0R (zero-sequence
impedance values) are calculated automatically, using the zero-sequence line
impedance magnitude setting Z0MAG as follows:
Z0F = Z0MAG/2 (Ω secondary)
Z0R = Z0MAG/2 + 0.1 (Ω secondary; 5 A nominal)
Z0R = Z0MAG/2 + 0.5 (Ω secondary; 1 A nominal)
E32IV—SELOGIC Control Equation Enable
Refer to Figure 4.7.
SEL
OGIC control equation setting E32IV must be asserted to logical 1 to
enable the zero-sequence voltage-polarized and channel IP current-polarized
directional elements for directional control of ground distance and residual
ground overcurrent elements.
Most often, this setting is set directly to logical 1:
E32IV = 1 (numeral 1)
For situations where zero-sequence source isolation can occur (e.g., by the
opening of a circuit breaker) and result in possible mutual coupling problems
for the zero-sequence voltage-polarized and channel IP current-polarized
directional elements, SEL
OGIC control equation setting E32IV should be
deasserted to logical 0. In this example, this is accomplished by connecting a
circuit breaker auxiliary contact from the identified circuit breaker to the
SEL-311C:
E32IV = IN106 (52a connected to optoisolated input IN106)
Almost any desired control can be set in SEL
OGIC control equation setting
E32IV.
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