Testing Differential Setting Of High-Set Element 87Hs - Siemens 7UT51 Instruction Manual

16
Bench Testing
Testing of Other Phases
If testing of the High Set differential element is desired,
follow the 87HS testing instructions before continuing
with this step.
Move the test source to another phase inputs on
Secondary or Tertiary and repeat the above test.
Remember to calculate the new pickup current
dependent upon the Voltage level, CT primary rating,
and correction factor for that winding. The new pickup
current will most likely not be the same for each
winding (W1, W2, or W3).
Note: The functionality of all CT-inputs is verified
during the Through-Fault Testing procedure.
Hence, it is not necessary to test all phase
inputs during this procedure.
16.3.5 Testing Differential Setting
of High
-
Do not exceed the limits as indicated in
the Relay Specifications section!
See Section 2.5 on page 18 or Table 16.1
on page 160.
Never leave high currents on the relay
for an extended period of time.
Thermal damage to the input could result.
166
Set Element 87HS
1. Set 87 Delay, Address 1625, to infinite seconds.
With the current source still connected to the CT
input, switch the single-phase current from 0 A to
120% of I
, calculated from the following
HS
equation:
×
I = I
HS NsecW1
where
I =Nominal current (secondary) of Winding 1
NsecW1
CF =Correction Factor (from Table 16.3)
HS-Setting=Setting in relay Address 1604
Note: If a sufficient current source is not available,
the setting must be lowered to facilitate testing.
2. Change the 87HS setting (Address 1604) to 1.
3. Perform the test as described above.
4. Change the 87HS setting back to its original value.
Expected Results
The pickup current at contact closure should be within
+/- 5% of the calculated 87HS calculated trip value.
Contacts, LEDs, and LCD
All trip contacts should close, Signal Relays 1 and 2
should operate, and LEDs 1, and 3 will light when
87HS trips. When the current is turned off, the
contacts should open, the LEDs should remain
latched, and the LCD should display "87Diff GenFlt"
and "87DiffGenTrip".
7UT51 v3
×
CF HS-Setting
PRIM-2330C