  An observer based adaptive detection methodology (ADM) is proposed for
estimating frequency and its rate of change (RoCoF) of the voltage and/or
current measurements acquired from an instrument transformer. With guaranteed
convergence and stability, the proposed methodology effectively neutralizes the
effect of the measurement distortions like harmonics, decaying DC components
and outliers by adding its counter negative. It is robust to noise statistics,
performs well while encountering step changes in amplitude/phase and is
demonstrably superior to its precursors as established by test results. A
benchmark IEEE NETS/NYPS 16 machine 68 bus power system has been used for
performance evaluation of robust ADM against its precursors and scaled
laboratory setup based on OP5600 multiprocessors was used for establishing its
real-time applicability.
