What are the allowable voltage excursions during System Restoration?

During system restoration, it is critical to maintain voltage within specified limits to ensure the stability and reliability of the electrical grid. The allowable voltage excursions are defined to prevent damage to equipment and to maintain system integrity.

The range of 90% to 110% of the nominal voltage is considered acceptable during restoration activities because it provides a balance between safely energizing the system and allowing for necessary flexibility given the dynamic conditions of restoration. In situations where generation is being brought back online or loads are being reconnected, the system can experience fluctuations in voltage, and this range helps accommodate those variations without compromising system performance.

The narrow range of 90% to 110% helps to avoid excessive voltage changes that could lead to equipment stress or failures, ensuring equipment operates efficiently and safely while the system is in a transitional state. Other ranges, although broader, do not provide the same level of reliability and risk management that this specific range does. Thus, utilizing this defined range during restoration is integral for securing the stability of the power system.