IMPROVED FOURIER ALGORITHM FOR CORRECTING POWER SYSTEM FREQUENCY DEVIATION

On the basis of high precision requirement for input signals in the power system protection and control system,this paper,only for the influence of power system frequency deviation on extracting fundamental harmonic,studies the amplitude error of Fourier algorithm,presents a method of correcting frequency deviation,and further derives the formulas of improved Fourier algorithm.The simulation results verified the effectiveness of the algorithm,it not only can greatly weaken the influence of frequency deviation,but also increase the precision of the power system protection and control.As a result the study in this paper has practical application value.

Fast frequency response of inverter-based resources and its impact on system frequency characteristics

The inertia response and primary frequency regulation capability of synchronous grids are declining owing to the increasing penetration of inverter-based resources. The fast frequency response(FFR) of inverter-based resources is an important mitigation option for maintaining grid security under the conditions of low inertia and insufficient primary frequency response capability. However, the understanding and technical characteristics of the FFR of inverter-based resources are still unclear. Aiming at solving the aforementioned problems, this paper proposes a definition for FFR based on the impact mechanism of FFR on system frequency. The performance requirements of FFR are clarified. Then, the effects of FFR on system frequency characteristics are further analyzed based on steady-state frequency deviation, the initial rate of change of frequency, and the maximum transient frequency deviation. Finally, the system requirements for FFR and its application effects are verified by simulating an actual bulk power grid, providing technical support for subsequent engineering application.

Development approach of a programmable and open software package for power system frequency response calculation

Dynamic behaviour of frequency is crucial for power system operation and control.Several frequency response models have been proposed to reveal frequency dynamics from different aspects.A comprehensive software package incorporating major frequency response models is needed for analysis and control of power system frequency dynamics.In this paper,an approach for developing a programmable and open software package for frequency response studies is proposed.The framework of the package is extendable with reduced frequency response models.Essential models for frequency response study are included,e.g.,generator,load,and under-frequency load shedding(UFLS).The provided application program interfaces(APIs)enable simulation with high-level languages by calling dynamic link library and makes the package programmable.An advanced application module is developed for quantitative assessment of transient frequency deviation.APIs can also be used for model extension and secondary development.To demonstrate the usage of the package,several examples are illustrated to explain how to perform simulations with the package,and to perform advanced applications using scripting with the provided APIs.