What must a Balancing Authority do if voltage drops to 200 kV for 3 minutes after a generator trip?

• A. Wait for generator response
• B. Disconnect firm load until voltage is .9 p.u.
• C. Immediately raise voltage without removing load
• D. Close capacitor banks to stabilize voltage

Answer: (C)

When faced with a voltage drop to 200 kV for an extended period, such as three minutes after a generator trip, the priority for a Balancing Authority is to stabilize the voltage without compromising system reliability by removing load.

Option C suggests that the Balancing Authority should immediately raise voltage without removing load, which aligns with the need to maintain system stability and reliability. By focusing on increasing voltage levels while keeping the existing loads connected, the Balancing Authority can ensure that critical services and operations remain functional. This is essential because dropping loads can lead to a cascade of further issues, including more significant system instability and potential blackouts.

In contrast, simply waiting for a generator response could be risky, as there is no guarantee the generator will respond in a timely manner to correct the voltage dip, potentially leading to a prolonged instability period. Disconnecting firm load until voltage stabilizes could also result in unnecessary service interruptions, which can negatively impact consumers and grid reliability. Finally, closing capacitor banks can indeed help in voltage stabilization, yet the immediate action should focus on restoring voltage levels without resorting to removing load, which is why immediately raising voltage is prioritized in this situation.