Patent Document ID: 4770841
Application ID: 06916450
Patent Flag: 1

Claim One:
1. A method of controlling water level in nuclear power plant steam supply systems of the type having steam flow and water flow as inputs to the system and water level as an output of the system, said method comprising: (a) estimating the state variables of said system by applying observer theory to the inputs and the outputs of said system; (b) generating a compensated water level from said estimated state variables, said compensated water level being dynamically related to said steam flow and feed water flow by a compensated transfer function which comprises the integration modes and unstable modes of behavior included in the overall transfer function relating the transforms of said inputs to the transforms of said outputs, said compensated transfer function having no right half plane zeros; (c) displaying said compensated water level and said water level; and (d) controlling said water level by comparing the compensated water level and the water level.