First post so please go easy on me. Can someone give me a better explanation of GE IV reference. The way I understand it is that once a negative load command is given, the turbine should begin to unload. Eventually the turbine will go to reverse flow and the IV control valves will be supplying the turbine with steam. During this ramp down I noticed IV reference (and IV control valves) swinging pretty bad. I assume its because of reheat pressure swings. At any rate, I thought at a negative load reference the IV control valves would close off in order to take unit off line regardless of Reheat pressure. It seems that reheat pressure being low is driving IV reference to 100% and this is keep turbine online even with a negative load reference.
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