The proper rating of the neutral grounding reactor for high-voltage shunt reactors is crucial for several reasons, including:
Reducing recovery voltage and residual fault current (secondary arc current) during a single line-to-ground fault, which accounts for approximately 80% of transient faults.
Minimizing the reclosing time of transmission line circuit breakers, thereby improving system reliability and stability limits.
Mitigating expected over voltages in the transmission line under various conditions, such as line energization and situations where one circuit is energized while the other remains live.
PSCAD/EMTDC studies are performed to determine the need and sizing of the neutral grounding reactor installed in the neutral of line shunt reactors, as well as the requirement for a neutral surge arrester.
The following studies are to be simulated:-
1) Steady-State Analysis: Analyzing the equivalent system to determine initial parameters for the neutral grounding reactor selection.
2) Induced Voltage Computation: Calculating the induced voltages on the de-energized circuit of a double-circuit line.
3) Transient Analysis: Simulating scenarios that include arc modeling and key events, such as line-to-ground fault application, single-pole breaker opening, arc extinction based on ignition voltage, and circuit breaker reclosing, to finalize the neutral grounding reactor parameters
.4) Over voltage Analysis: Assessing over voltages resulting from high energization voltage due to induction from an energized parallel circuit.
