GEK-106310AB F650 Digital Bay Controller 5-67
5 SETTINGS 5.4 PROTECTION ELEMENTS
5
Table 5–60: ISOLATED GROUND IOC ELEMENT SETTINGS
The relay settings for the Isolated Ground IOC elements are as follows:
Function: This setting determines whether the element is operative and can generate pickup
and trip events, which can be configured to close outputs, light up LEDs or trigger
oscillography.
Vh, VL, Ih, IL: Vn and In values that define the points in the operative area.
Operation time (Delay): This is the selectable period between the element pickup and trip, with a range from
0 to 900 seconds in steps of 0,01 seconds.
Deviation time to Instantaneous (Time to inst): Time after the trip during which the elements become instantaneous. It
must be set to zero if the functionality is not required.
Snapshot Events: The snapshot event setting enables or disables the snapshot event generation for
this element.
OPERATION PRINCIPLES:
Operation of the isolated Ground element is based on the detection of a current that exceeds the setting, with neutral
voltage supervision (3V0). This allows to set the element very sensitive, with a very low current level, ensuring that small
angle or ratio errors in the current transformers will not cause the relay to operate, as the neutral voltage verified is higher
than the one set.
Values for Ih, IL, Vh and VL, which define the relay operation area, are configurable. H magnitudes must be higher than L
magnitudes. The 50IG element can be supervised by directional element 67SG.
Using the relay input magnitudes In and Vn, if the point defined by (In, Vn) is inside the operation area and if the directional
element (if directional supervision is set) allows it, the element picks up and the set delay time starts counting down. If a
directional block appears during the countdown, the element is reset. After the set time the element trips. Once tripped, the
relay cannot be blocked by the directional element, and the trip remains while the fault exists.
After the trip, the deviation time to instantaneous starts to run, so that all pickups produced during this time will produce an
Instantaneous trip. This means that, if after a trip the breaker is reclosed and the fault persists or reappears, the trip will be
instantaneous. If the user doesn’t want to use this function, then the Deviation Time to Instantaneous (Time to inst)
setting must be set to zero seconds. Once the time has expired, the element returns to its normal operation.
SETPOINT > PROTECTION ELEMENTS > SENSITIVE GROUND CURRENT > ISOLATED GROUND IOC
ISOLATED GROUND IOC 1> ISOLATED GROUND IOC 2 > ISOLATED GROUND IOC 3
SETTING DESCRIPTION NAME DEFAULT VALUE STEP RANGE
Function Permission Function DISABLED N/A [DISABLED – ENABLED]
High Voltage Vh Level 20 1 V [2 : 70]
Low Current Il LEVEL 0.005 0.001 A [0.005 : 0.400]
Low Voltage Vl LEVEL 2 1 V [2 : 70]
High Current Ih LEVEL 0.025 0.001 A [0.005 : 0.400]
Operation time Delay 0.00 0.01 s [0.00 : 900.00]
Deviation time to instantaneous Time to inst 0.00 0.01 s [0.00 : 900.00]
Snapshot event generation Snapshot Events ENABLED N/A [DISABLED – ENABLED]
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