TOP must develop, maintain, and implement formal policies to ensure transmission reliability. Which of the following does NOT need to be addressed in these policies?

In the context of policy development for transmission reliability by a Transmission Operator (TOP), the emphasis is placed on aspects that directly infringe upon transmission system operations and their reliability. While planned outages of generation units can have an impact on the overall electric system, they primarily fall under the purview of generation operators and their respective policies rather than those specifically required by a TOP.

The other elements mentioned, such as system maintenance schedules, load shedding procedures, and voltage control measures, are critical for ensuring operational reliability within the transmission network. System maintenance schedules help uphold the integrity of transmission infrastructure, ensuring that equipment remains functional and reliable. Load shedding procedures are vital for maintaining system stability during emergency conditions, where demand exceeds supply, directly impacting the reliability of the transmission system. Voltage control measures are essential to maintain acceptable voltage levels across the transmission network, preventing fluctuations that could potentially lead to reliability issues.

Thus, while the policies regarding planned outages of generation units are important for the overall stability of the electric grid, they do not fall under the mandatory requirements for TOPs to ensure transmission reliability, making them the correct choice for the aspect that does not need to be addressed in these policies.