Table of Contents
Advertisement
745
Transformer Management Relay
Tap Monitor Failure
THD Level Scheme
7–38
The time delay can be verified with a watch as the delay is normally set in minutes.
c) Aging Factor Limit
The Aging Factor value is also a function of load, ambient temperature, and
transformer ratings. Apply a current to Winding 1 Phase A to represent at least a
100% transformer load. Use the
actual value to observe that the aging factor increases gradually. You may
FACTOR
want to increase the simulated load or the simulated or programmed ambient
temperature to cause a faster increase.
When the aging factor reaches the
FACTOR LIMIT
!"
AGING FACTOR LIMIT PICKUP
operate. Verify all programmed relay operations as per FlexLogic™ settings. Verify
that all the targets and messages are as expected and programmed.
The time delay can be verified with a watch as the delay is normally set in minutes.
d) Loss of Life Limit
Typical settings for the Loss-of-Life Limit element dictate that either the limit be
changed or the initial transformer loss-of-life be changed temporarily. Verification of
this function is recommended by programming an initial loss-of-life above the
element threshold. The element operates instantly as it has no associated time
delay.
The tap monitor failure element operates when the sensed resistance is 150% larger
than the programmed values for the monitor circuit. Connect a resistance to
simulate the tap changer resistance and increase this resistance until the element
operates. Calculate that the resistance at which the element operated is 150% of
the resistance that would be present at the maximum tap position.
Verify all relay, targets and messages for correct operation per programmed values.
Auxiliary Protection and Monitoring Functions
a) Minimum Pickup
1.
Testing of this element uses with the same setup used in testing the harmonic
restraint percent differential elements (see FIGURE 7–1: Test Setup on page 7–
3).
2.
To test the Winding 1 THD element, connect the composite current signal to
terminals H1 and G1. Since the DC component actually consists of a half-wave
rectified signal, it contains all even harmonics which the relay measures and
operates on. Note that the fundamental component is required to prevent
saturation of the input CTs. Monitor the output relays as per the relay
FlexLogic™ assignment.
3.
Set the fundamental component to rated CT secondary (1 or 5 A). Gradually
increase the DC component to produce even harmonics until the THD Level
element operates.
4.
Display the total harmonic content under
THD
W1 THDA (2ND-21ST)
!"
!
took place should be the same as the programmed value.
5.
Check that the Trip, Pickup (and Alarm if selected) LEDs are on and one of the
following is displayed:
LATCHED: W1 THD Level or OPERATED: W1 THD Level
6.
Lower the DC component until the element resets. The reset value should be
approximately 2% less than the operate value. Verify that the Phase, Pickup,
and Alarm LEDs reset if the target function is set to "Self-resetting". The Trip
LED should remain latched.
http://www.GEindustrial.com/multilin
Auxiliary Protection and Monitoring Functions
A2 METERING
!"
LOSS OF LIFE
S4 ELEMENTS
INSULATION AGING
!"
operating level, the element should
A2 METERING
. The displayed value of THD at which operation
!"
INSULATION AGING
AGING
!"
!"
HARMONIC CONTENT
GE Multilin
Advertisement
Table of Contents
