What is a potential risk if a system's power factor is overcorrected with capacitors?

What is a potential risk if a system's power factor is overcorrected with capacitors?

• A. It can cause overvoltage or resonance.
• B. It always improves efficiency with no downside.
• C. It has no effect on the power system.
• D. It reduces real power demand.

Answer: (A)

When you add capacitors to correct a lagging power factor, you’re supplying leading reactive power to the system. If you overdo it, the network can become overcorrected, pushing the bus voltage above its normal level. More importantly, the capacitor bank can interact with the system’s inductance (lines, transformers, etc.) to form a resonant LC circuit. That resonance can amplify voltages and circulating currents at certain frequencies, potentially causing overvoltages, equipment stress, and protective actions to trip. These resonance and overvoltage risks are the real downsides of excessive pf correction.

When you add capacitors to correct a lagging power factor, you’re supplying leading reactive power to the system. If you overdo it, the network can become overcorrected, pushing the bus voltage above its normal level. More importantly, the capacitor bank can interact with the system’s inductance (lines, transformers, etc.) to form a resonant LC circuit. That resonance can amplify voltages and circulating currents at certain frequencies, potentially causing overvoltages, equipment stress, and protective actions to trip. These resonance and overvoltage risks are the real downsides of excessive pf correction.