sensor 3BSE004185R1

sensor 3BSE004185R1

sensor 3BSE004185R1

Application The Mho impedance supervision logic (ZSMGAPC) includes features for fault inception detection and high SIR detection. It also includes the functionality for loss of potential logic as well as for the pilot channel blocking scheme.

One part of ZSMGAPC function identifies a loss of phase potential that is the result of a long term (steady state) condition such as a blown fuse or an open voltage transformer winding or connection.

This will block all trips by the distance protection since they are based on voltage measurement. In the pilot channel blocking scheme a fault inception detected by a fast acting change detector is used to send a block signal to the remote end in order to block an overreaching zone. If the fault is later detected as a forward fault the earlier sent blocking signal is stopped.

The blocking scheme is very dependable because it will operate for faults anywhere on the protected line if the communication channel is out of service. Conversely, it is less secure than permissive schemes because it will trip for external faults within the reach of the tripping function if the communication channel is out of service. Inadequate speed or dependability can cause spurious tripping for external faults. Inadequate security can cause delayed tripping for internal faults.

ZSMGAPC function also includes functionality for blocking the sample based distance protection due to high SIR. SIR directly influences the fault voltage level for a given voltage level, and this is the major factor that affects the severity of CVT transients.