Numerical phaser estimation algorithms

Continuous development of electrical power systems has resulted in very complex relay protection system with associated numerical protection algorithms. Reliability, selectivity and speed are the basic design requirements for the development of new algorithms. Ideally the amplitude estimation algorithms should determinate the amplitude as fast as possible, theoretically with just one sampled value. Currently there are no algorithms which can do that with a high reliability. Abovementioned requirements are contradictory which makes it impossible to completely fulfil all of them. Current and voltage based phasor estimation algorithms are the core of all numerical protection relays, thus significantly defining protection function performances. A detailed overview of the most common numerical phase estimation algorithms is shown in this paper, including time responses on various input signal combinations. All algorithms are simulated in the LabVIEW development environment.