Siemens 7SA511 manual Phase Sequence Check, Directional Test Using Load Current

7SA511 Line Protection Relay Chapter 7

how to correctly set these parameters. The residual current must be fed to the ground current input of the relay for the current summation check to function properly.

If the CT ratio matching factors and the ground current connections are correct, it may be necessary to adjust the current summation parameters (addresses 2905 and 2906). Reference E “Setting Calculations” provides information on how to correctly set these parameters.

Phase Sequence Check

The measurement monitor checks for a clockwise phase rotation (sequence). If the rotation is not correct, the error message Fail.PhaseSeq is logged in the event log. Check the connections in the measurement circuits for correct phase relationship and make any necessary corrections.

If your system normally has counterclockwise rotation, connections for two of the phases must be interchanged. This exchange of phase connections must be taken into account for the following circumstances:

Setting parameters for the treatment of double ground faults in isolated or compensated networks (address 1803)

Setting parameters for the treatment of double ground faults in solidly grounded systems(address 1703)

Assignment of logical functions to the output signal relays (address block 5300) and

￿LED indicators (address block 5400) Displaying event log data

7.3.2Directional Test Using Load Current (4200)

A test to check the direction of the load current flow for each measurement loop and to verify the correct connections of current and voltage transformers is available in address block 4200. You must use the operator panel to run the test. All six measurement loops are tested, and the active and reactive component of the load impedance is calculated for each loop.

The line to which the relay is connected must be energized and carrying at least 10% of the rated current. The load should be either purely resistive or resistive-inductiveand in a known direction. Where there is any doubt about the direction, interconnected or ring networks must be isolated.

July 27, 1995 7-5