Ct Polarity; Check Relay Settings; Protection Timing Checks; Overcurrent Check - GE Agile P50 Series Technical Manual

13 Commissioning Instructions
• Trip Coil contact connection should be as per the given schematic diagram.
• Latching type annunciation contact connection as per requirement of site.
2.1.9.1 Earthing
An earthing terminal is provided at the back of the relay. Ensure that the case earthing connections
are used to connect the IED to a local earth bar using an adequate conductor.
With several relays present, make sure that the copper earth bar is properly installed for solidity
connecting to the earthing terminal of each relay.
2.1.9.2

CT Polarity

Ensure proper CTs are connected as per required maximum load current and their polarity. When all
CTs are connected with proper polarity, unbalance current flowing through earth fault element will be
approximately zero. Otherwise the relay will trip on earth fault when the CB is energized.
2.1.10

Check relay settings

The relay setting check ensures that all of the application-specific settings for the particular installation
have been correctly applied to the relay. Enter all settings manually via the front panel interface or
using P50 Agile configurator tool.
2.1.11

Protection Timing checks

There is no need to check every protection function. Only one protection function needs to be checked
as the purpose is to verify the timing on the processor is functioning correctly.
2.1.11.1

Overcurrent check

If the overcurrent protection function is being used, test the overcurrent protection for stage 1.
1. Check for any possible dependency conditions and simulate as appropriate.
2. In the CONFIGURATION menu, disable all protection elements other than the one being
tested.
3. Make a note of which elements need to be re-enabled after testing.
4. Connect the test circuit
5. Perform the test
6. Check the operating time
2.1.11.2

Connecting the Test circuit

1. Identify the function associated with the overcurrent protection stage 1 trip.
2. Use the output relay RL1 for assigning the overcurrent trip function
3. Use the IO Masking function in the P50 Configurator or IO configuration menu on relay HMI to
map the protection stage under test directly to an output relay.
4. Connect the output relay so that its operation will trip the test set and stop the timer.
5. Connect the current output of the test set to the A-phase current transformer input.
6. Ensure that the timer starts when the current is applied.
2.1.11.3

Performing the Test

1. Ensure that the timer is reset.
13-6
P50 Agile P153
P153/EN M/B