Branch Point Differential Protection Testing; Backup Overcurrent Time Protection Testing - Siemens 7UT51 Instruction Manual

7UT51 v3
IL1 should display the current you are
applying to the relay's phase A input in % of 5
A.
"Io*-Io**=" displays the angle between the
calculated 3Io (sum of phases) and the 3Io
input.
Io*-Io** should be 0 degrees. If it is 180
degrees, there is a polarity / wiring error to the
relay or the test is set up improperly or the
polarity setting for the ground CT is set wrong
(Address 1108 or 1128).
"Diff =" displays the % of differential current
the relay recognizes between the calculated
3Io (sum of phase currents) and the current
measured at the ground input.
If the test sources being used are accurate, "Diff"
should measure less than 2.0%
Internal Fault Test
∠
Change I2 to 3.62 A
0°
shown in Figure 16.11, Restricted Ground Fault Inside
of Protected Zone.
The relay should trip and LEDs 1 and 7 should light.
Re-enable the differential protection under
Address 1601.
Reset all targets and annunciations.
This validates the configuration of the relay as
connected to your system.
Close Test
1. Close the "Test Results" window.
2. Close the "Commissioning Tests" window.
3. Display "4800 Commissioning Tests Stop".
4. Execute "4801 Stop the CommissioningTests."
5. Confirm by pressing the Yes key.
PRIM-2330C
to emulate the condition
16.5 Branch Point
Differential Protection
Testing
For testing the differential protection, this function
must have been configured as EXIST/ENABLED in
Address 7816 and the protected object in
Address 7801 must be a @ENDS-BRANCH POINT or
a 3ENDS-BRANCH POINT (7UT513 only).
Additionally, it must be parameterized as operative in
Address 1801.
The trip value of the differential protection can be
checked by means of a secondary test set. The test
current can be applied separately for each branch
point terminal, that is, in each case a fault with
single-ended infeed is simulated.
The preset parameter for 87T applies.
Checking the trip value is performed by slowly
increasing the test current. Trip occurs when the trip
value, converted using the matching factor (see
Section 1.2 on page 11), is reached. When the test
current falls below approximately 0.7 times the trip
value, the relay drops off.
16.6 Backup Overcurrent
Time Protection Testing
For testing the backup overcurrent time protection, this
function must be assigned to one side of the protected
object or to the virtual object (Address 7821).
Additionally, this function must be switched On or
BLOCK TRIP REL in Address 2101.
16
Bench Testing
171