Which principle is primarily affected when voltage drops in a power system?

The correct answer pertains to how voltage drops in a power system can significantly impact torque generation in electric motors. When voltage levels decrease, the voltage supplied to electric motors may also fall below their optimal operating range. This reduction in voltage can lead to a decrease in torque output because motors require a certain level of voltage to produce the necessary electromagnetic force for efficient operation.

As the voltage decreases, the current required to maintain torque also decreases, which can result in inefficient operation. In extreme cases, if the voltage drops too low, the motor may stall or fail to start altogether. This relationship between voltage and torque generation is critical in maintaining the reliability of electric motors and overall system functionality in power systems.

The other principles, such as power factor and frequency stability, are related to the operational efficiency and stability of the electrical system but are not primary direct effects of voltage drops. Line reactance pertains more to the impedance of transmission lines rather than directly affecting motor performance in the context of torque generation.