RECLOSER CONTROL EVRC2A-N6,NT
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7.3. Ground (Fast/Delay) Time Overcurrent (51G)
The EVRC2A has two ground time overcurrent elements. The ground time overcurrent element
in the EVRC2A is set based on CT secondary current as connected to the current inputs. The
ground time overcurrent element is the most commonly used as a protective element for
distribution systems and also used in both down-line and back-up recloser protection. The
ground time overcurrent element provides a time delay versus current for tripping that is used for
an inverse time curve characteristic coordinated with current pickup value, curve type, time dial,
time adder, minimum response time setting and reset type. This inverse characteristic means that
time overcurrent element operates slowly on small values of current above the pickup value and
operates faster when current increases significantly above the pickup value. The ground time
overcurrent element is enabled in the Primary, Alternate settings and both
[PROTECTION
ENABLED]
and
[GROUND ENABLED]
in user interface panel.
Multiple time curves and time dials are available for the ground time overcurrent element to
closely coordinate with other protection elements within the EVRC2A and other external devices
on the distribution system. ANSI, IEC, ESB, USER and non-standard time current curves are
included in the EVRC2A.
A User Programmable curve option is also available allowing the user to create customer time
current curves for more enhanced coordination than the standard curve types.
The Reset type can be either instantaneous or linear. The ground time delay reset mode applies to
the ANSI, IEC, ESB, USER curves. The instantaneous mode is used to coordinate with other
instantaneous reset devices such as a recloser or other protective equipment on the distribution
system. In the instantaneous mode the time overcurrent element will reset instantaneously when
the current level measured by the EVRC2A drops below the pickup setting for one cycle.
If the recloser is closed by pressing the CLOSE button on the front panel, or by an remote
control or via SCADA, the ground time overcurrent element is prevented from tripping for a
period specified by the Cold load pickup scheme.
Summary of Contents for EVRC2A-N6-NT
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