What happens if we sync high voltage generators in respect of lower grid voltage?

There would be a large voltage difference across the circuit breaker. If the breaker is closed with this large difference it would lead to a arcing which could cause electrical damage and blackout

this means that the internal voltage of the generator is lower than the grid voltage. When it is connected to the grid the generator will be under-excited and it will absorb MVAR.we call it reverse power generator will be as motor MVAR is mega volt amps (reactive) this is another measurement of "power", like W, but it measures the component of power that is reactive, which means the component of power (layman's terms alert) that is flowing in the wires to make magnetic fields, but doesn't actually get turned into work.

Magnitude is the terminal is the one of the matching parameter during synchronization.

 

1. Due to high incoming voltage magnitude, high reactive power will flow through the generator which gives high mechanical shock to the stator and rotor shaft.
2. Due to low incoming voltage magnitude results in weak magnetic flux which may cause reverse current and slip protection of the generator.

When the internal voltage of sync generator is lower than the grid then generator will be under-excited and it will absorb MVAR.

I think synchronizing will never  take place due to difference in voltage.

Sync Generators4 conditions  for synchronizing with Grids are Magnitude of voltage, phase sequence, frequency and phase angle, in this case Generator will be underexcited.

When it is connected to the grid the generator will be under-excited and it will absorb MVAR.

four condition require to sync GEn with the grid.i.e.

 

Phase Sequence

Voltage Magnitude

Frequency

Phase Angle

four condition require to sync GEn with the grid.i.e.

1. Phase Sequence
2. Voltage Magnitude
3. Frequency
4. Phase Angle

When the internal voltage of the gen is more than the grid voltage. When it is connected to the grid the generator will be overexcited and it will put out MVAR.

When internal voltage of the gen is less than the grid voltage. When it is connected to the grid the generator will be under-excited and it will absorb MVAR

VOLTAGE MAGNITUDE SHOULD BE EQUAL FOR SYNCHRONISATION.IN THIS CASE IT LEADS TO AN ARCING AND DAMAGE OF THE CIRCUIT

at the first : In order to synchronize a generator to the grid, four conditions must be met: Phase Sequence Voltage Magnitude Frequency Phase Angle

1/If the generator voltage is higher than the grid voltage, this means that the internal voltage of the generator is higher than the grid voltage. When it is connected to the grid the generator will be overexcited and it will put out MVAR.

2/If the generator voltage is less than the grid voltage, this means that the internal voltage of the generator is lower than the grid voltage. When it is connected to the grid the generator will be under-excited and it will absorb MVAR.