PJM Generation Dispatcher Practice Exam 2025 – Complete Preparation Guide

In power systems, inertia is essential because it offers resistance to changes in frequency. Inertia refers to the physical property of rotating masses, typically associated with generators in a power system. When there is a disturbance, such as a sudden increase or decrease in load or generation, the rotational inertia of these generators helps to stabilize the system by resisting immediate changes in frequency.

When a disturbance occurs, the generators’ inertia acts like a buffer, slowing down the rate at which the frequency can change. This characteristic is vital for maintaining the balance between supply and demand in the electrical grid; if the frequency deviation is kept minimal, it allows for more time to deploy emergency measures or to balance the grid effectively.

In contrast, other options involve aspects of the power system that do not directly relate to the inertia of rotating machinery. Changes in temperature, power loss, or energy supply pertain to other operational concerns within the power system, but they do not fundamentally influence the frequency stability in the same way that inertia does. Thus, recognizing the role of inertia in frequency stabilization is critical for understanding the operation and reliability of power systems.