Describe the operational protocols for handling a sudden 'wellhead pressure surge' during a geothermal power plant startup.

A sudden wellhead pressure surge during a geothermal power plant startup requires immediate and carefully coordinated operational protocols to prevent equipment damage and ensure personnel safety. The first step is to immediately assess the situation. This involves verifying the pressure readings from multiple sensors to confirm the surge and evaluating other related parameters such as flow rate and temperature. Next, the wellhead control valves should be adjusted to reduce the pressure surge. This may involve partially closing the production valve to restrict flow from the well. It is crucial to avoid abrupt valve closures, as this can create pressure hammer and further stress the system. If the pressure surge continues despite valve adjustments, the next step is to divert the flow to a designated emergency vent or flash tank. This allows the excess pressure to be safely released, preventing it from reaching the turbine or other downstream equipment. The emergency vent should be located in a safe area away from personnel and sensitive equipment. Simultaneously, the turbine should be isolated from the steam supply by closing the turbine inlet valve. This protects the turbine from overpressure and potential damage. The cause of the pressure surge should then be investigated. This may involve checking for blockages in the pipeline, malfunctioning equipment, or unexpected changes in reservoir conditions. After the cause of the surge has been identified and corrected, the startup procedure can be resumed gradually, with close monitoring of wellhead pressure and other parameters. Communication is essential throughout the entire process. All personnel involved in the startup procedure must be kept informed of the situation and the actions being taken. Emergency shutdown procedures must be readily available in case the pressure surge cannot be controlled. Therefore, a rapid and coordinated response is essential to safely manage a wellhead pressure surge during geothermal power plant startup.