What specific grid code parameter dictates the acceptable range of voltage fluctuations allowed when a tidal energy plant connects to the grid?

The specific grid code parameter that dictates the acceptable range of voltage fluctuations allowed when a tidal energy plant connects to the grid is typically defined by a combination of steady-state voltage limits, voltage variation limits, and flicker limits at the point of connection. Grid codes are sets of technical requirements and standards that govern the connection and operation of power generation facilities to the electricity grid. These codes are designed to ensure the stability and reliability of the grid. Steady-state voltage limits specify the acceptable range of voltage under normal operating conditions. These limits are typically expressed as a percentage of the nominal voltage (e.g., ±5% of the nominal voltage). The tidal energy plant must maintain its voltage within these limits at all times. Voltage variation limits specify the maximum allowable change in voltage over a given period. These limits are designed to prevent voltage sags and swells that can disrupt the operation of sensitive equipment. Flicker limits specify the maximum allowable level of voltage flicker, which is rapid and repetitive voltage fluctuations that can cause noticeable changes in the brightness of incandescent lights. Flicker limits are typically expressed in terms of a flicker severity index, such as Pst (short-term flicker severity) and Plt (long-term flicker severity). The tidal energy plant must not cause flicker levels to exceed these limits. These parameters are interconnected and often defined in different ways depending on the specific grid code. For example, some grid codes specify different voltage limits for different types of disturbances, such as short circuits and load changes. Others may specify different flicker limits for different times of day. Compliance with these voltage fluctuation limits is typically verified through continuous monitoring of the voltage at the point of connection. If the voltage exceeds the acceptable range, the tidal energy plant must take corrective action, such as reducing its power output or adjusting its reactive power injection. Therefore, understanding and adhering to these grid code parameters is essential for ensuring the safe and reliable connection of a tidal energy plant to the electricity grid.