When does the Compressor Discharge Pressure (CDP) switch close and energize the flame out relay?

The correct answer indicates that the Compressor Discharge Pressure (CDP) switch closes and energizes the flame out relay at 70 +/- 5 psig. This pressure threshold is critical for ensuring the proper operation and safety of the gas turbine system.

When the compressor reaches this specific discharge pressure, it signifies that the system is functioning within the designated operational parameters. The flame out relay is an essential safety feature that helps in monitoring and controlling the combustion process within the gas turbine. By closing at this predetermined pressure, the relay contributes to preventing unsafe conditions that could lead to a flame-out situation, thus protecting both the machinery and personnel.

Setting the threshold at 70 +/- 5 psig facilitates a balanced operation of the gas turbine, allowing for safe and efficient combustion while minimizing the risk of operational hazards.