Testing Differential Protection Functions; Transformer Differential Protection T2Wpdif And T3Wpdif; Verifying The Settings - ABB ret650 Commissioning Manual

Section 6
Testing functionality
6.3
6.3.1
6.3.1.1
40

Testing differential protection functions

Transformer differential protection T2WPDIF and T3WPDIF

Prepare the IED for verification of settings as outlined in
verify settings".
Values of the logical signals for T2WPDIF are available on the local HMI under
Main menu/Tests/Function status/Differential/T2WPDIF(87T,Id)/
1:T2WPDIF. The Signal Monitoring in PCM600 shows the same signals that are
available on the local HMI.
Values of the logical signals for T3WPDIF are available on the local HMI under
Main menu/Tests/Function status/Differential/T3WPDIF(87T,Id)/
1:T3WPDIF. The Signal Monitoring in PCM600 shows the same signals that are
available on the local HMI.

Verifying the settings

1. Go to Main menu/Test/Function test modes/Differential protection and
make sure that the restricted earth fault protection, low impedance function
REFPDIF is set to Off and that the four step residual overcurrent function
EF4PTOC under Main menu/Test/Function test modes/Current protection
is set to Off, since they are configured to the same current transformer inputs
as the transformer differential protection. Make sure that the transformer
differential functions T2WPDIF or T3WPDIF are unblocked.
2. Connect the test set for injection of three-phase currents to the current
terminals of the IED, which are connected to the CTs on the HV side of the
power transformer.
3. Increase the current in phase L1 until the protection function operates and
note the operating current.
4. Check that trip and alarm contacts operate according to the configuration logic.
5. Decrease the current slowly from operate value and note the reset value.
Depending of the power transformer vector group (Yd and so on), the single-
phase injection current will be different for a factor k from the three-phase
start, see step 7. This factor k can have one of the following three values: 1,00
or 1,50 or 1,732.
6. Check in the same way the function by injecting current in phases L2 and L3
respectively. Phase L2 and L3 start shall be the same as for phase L1.
7. Inject a symmetrical three-phase current and note the operate value.
8. Connect the timer and set the current to twice the operate value.
9. Switch on the current and note the operate time.
10. Check in the same way the functioning of the measuring circuits connected to
the CTs on the LV side and other current inputs to the transformer differential
protection.
11. Finally check that trip information is stored in the event menu.
1MRK 504 126-UEN -
5.1 "Preparing the IED to
Commissioning Manual