What should be the maximum permissible level for frequency in normal operating conditions?

In the context of power systems, the frequency refers to the rate at which the electric power system generates, transmits, and distributes alternating current (AC). In most parts of the world, the standard frequency of the electricity supply is either 50 Hz or 60 Hz, depending on the region. For a power system to operate reliably and efficiently, the frequency needs to be maintained within a very narrow range around these nominal values.

For systems operating at 50 Hz, the normal permissible frequency range is typically ±0.5 Hz (i.e., 49.5 Hz to 50.5 Hz) for many regions, but it can vary slightly depending on specific grid requirements and regulations. Similarly, for systems operating at 60 Hz, the frequency is often maintained within a range of ±0.5 Hz around the nominal value (i.e., 59.5 Hz to 60.5 Hz), though again, the exact tolerance can vary.

It’s important to note that these figures are general guidelines. The actual acceptable frequency range might be narrower or slightly broader in some systems, especially during emergency or unusual conditions. Grid operators employ various control mechanisms to maintain frequency within these permissible levels, including adjusting power generation output and using frequency response services.

For the most accurate and specific standards regarding permissible frequency levels for a particular region or grid, it is best to consult the technical regulations and standards provided by the local grid operator or regulatory authority.