Figure 5.2-1 Logic diagram of Energy Check function
The main purpose of the Energy Check is to facilitate the controlled reconnection of the
disconnected lines and buses to the energized lines and buses. The energizing function in the
module is defined as a situation where a dead section of the network is connected to an energized
one.
NOTICE!
If Usys < Sync_NOVOL, it means Ua< Sync_NOVOL, Ub< Sync_NOVOL , Uc< Sync_NOVOL.
If Usys > Sync_LINVOL, it means Ua> Sync_LINVOL, Ub> Sync_LINVOL , Uc> Sync_LINVOL.
Check Sync
The Check Sync module measures the conditions across the circuit breaker. The module also
determines the angle change occurring during the closing delay of the circuit breaker from the
value of the measured slip frequency. The output is only given when all the measured conditions
are simultaneously within their set limits. The issue of the output signal is timed to give closure at
the optimal time including the time for the circuit breaker and the closing circuit.
The Check Sync module measures the amplitude, frequency and phase angle of the voltages
on both sides of the circuit breaker and compares them to the threshold limit detectors. The
voltage, frequency and phase angle difference values between the two sides of the circuit breaker
are measured and available for evaluation before the synchronizing. If the available bus voltage is
phase-to-phase and the line voltage is phase-to-neutral (or the opposite), a compensation is
required. This is done with the voltage ratio, which scales up the line voltage to a level equal to the
bus voltage.
SetSN_Sync_PHA is used for selection of measuring phase of the voltage for power system.
The voltages can be single-phase (phase-to-neutral) or two-phase (phase-to-phase) voltage. If the
SetSN_Sync_PHA value is from 0 to 2, the voltage is single-phase voltage (A/B/C) and
SetSN_Sync_PHA value is from 3 to 5, the voltage is phase-to-phase voltage (AB, BC, CA). When
sync phase is AB/BC/CA, bus dead-line condition: Uab/Ubc/Uca< (Sync_Vol /1.732).
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