Patent ID: 6118187
Filing Date: 2000-09-12
Classification: H02P

Abstract:
Method for controlling a power plant which delivers electrical power to an electrical grid, wherein the grid is an AC grid having a grid frequency which fluctuates around a nominal frequency (f.sub.o), comprising the steps of:controlling a power output of the power plant as a function of a control frequency by a) increasing the power output when the control frequency decreases below the nominal frequency (f.sub.o), and b) decreasing the power output when the control frequency increases above the nominal frequency (f.sub.o);continuously measuring the grid frequency to obtain a measured grid frequency (f.sub.m);averaging the measured grid frequency (f.sub.m) to give as a moving average a slowly varying averaged grid frequency which is characteristic of the long term behavior of the grid frequency;providing a dead band around the averaged grid frequency;using the averaged grid frequency as the control frequency when the measured grid frequency lies within the dead band; andusing the measured grid frequency as the control frequency when the measured grid frequency lies outside the dead band.