Constrained frequency domain algorithms for determination of parameters of fundamental sinewave of signals

Eichhorn, K.; Łobos, T.; Ruczewski, P.

doi:10.1049/ip-c.1993.0069

“…real part of the phasor [6], [7], [9], [10]. The filter algorithm is described as (4) However, when the frequency changes, the rectangular window inherent in the DFT has some disadvantages.…”

Section: Filteringmentioning

confidence: 99%

Real-time determination of power system frequency

Lobos¹,

Rezmer²

Quality Measurement: The Indispensable Bridge Between Theory and Reality (No Measurements? No Science! Joint Conference - 1996:

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Abstract-The main frequency is an important parameter of an electrical power system. The frequency can change over a small range due to generation-load mismatches. Some power system protection and control applications, e.g., frequency relay for load shedding, load-frequency controller, require accurate and fast estimation of the frequency. Most digital algorithms for measuring frequency have acceptable accuracy if voltage waveforms are not distorted. However, due to nonlinear devices, e.g., semiconductor rectifiers, electric arc furnaces, the voltage waveforms can include higher harmonics. The paper presents a new method of measurement of power system frequency, based on digital filtering and Prony's estimation method. Simulation results confirm, that the proposed method is more accurate than others, e.g., than the method based on the measurement of angular velocity of the rotating voltage phasor.Index Terms-Discrete Fourier transforms, FIR digital filters, frequency measurement, power system parameter estimation, protective relaying.

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Real-time determination of power system frequency

Łobos

¹

,

Rezmer

²

1997

IEEE Trans. Instrum. Meas.

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Abstract-The main frequency is an important parameter of an electrical power system. The frequency can change over a small range due to generation-load mismatches. Some power system protection and control applications, e.g., frequency relay for load shedding, load-frequency controller, require accurate and fast estimation of the frequency. Most digital algorithms for measuring frequency have acceptable accuracy if voltage waveforms are not distorted. However, due to nonlinear devices, e.g., semiconductor rectifiers, electric arc furnaces, the voltage waveforms can include higher harmonics. The paper presents a new method of measurement of power system frequency, based on digital filtering and Prony's estimation method. Simulation results confirm, that the proposed method is more accurate than others, e.g., than the method based on the measurement of angular velocity of the rotating voltage phasor.Index Terms-Discrete Fourier transforms, FIR digital filters, frequency measurement, power system parameter estimation, protective relaying.

show abstract