Photovoltaic power generation system dynamic discrete equivalent model establishment method based on different permeations

Abstract

The invention discloses a photovoltaic power generation system dynamic discrete equivalent model establishment method based on different permeations, and belongs to the technical field of photovoltaic power generation systems. The technical problem to be solved is to provide the photovoltaic power generation system dynamic discrete equivalent model establishment method based on different permeations, wherein the model has good interpolation and extrapolation capabilities and approximates the actual operation condition with a minimum fitting residual error. According to the technical scheme, the photovoltaic power generation system dynamic discrete equivalent model establishment method based on different permeations comprises the following steps: S1) analyzing a photovoltaic power generation system model and a control system; S2) establishing a photovoltaic power generation system dynamic discrete equivalent model; S3) identifying parameters of the photovoltaic power generation system dynamic discrete equivalent model; and S4) carrying out simulation checking calculation and analysis.

Description

technical field [0001] The invention relates to a method for establishing a dynamic discrete equivalent model of a photovoltaic power generation system under different penetrations, belonging to the technical field of photovoltaic power generation systems. Background technique [0002] Renewable energy is changing the power system today, with alternative energy sources such as photovoltaic systems replacing conventional power generation. After the photovoltaic power generation system is connected to the transmission grid, the load characteristics of the system have changed significantly. Due to the unique characteristics of photovoltaic systems different from traditional power generation resources, a high photovoltaic penetration level will have a significant impact on the transient stability of the system. If the power grid fails, the dynamic characteristics of the whole network will change. Existing static load models no longer meet the needs of engineering simulation. ...

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Problems solved by technology

Existing research materials always have certain defects in this aspect of research: ① studied the dynamic behavior of each subsystem of the photovoltaic power generation system, revealed the interaction between the components of the photovoltaic grid-connected power generation system, but did not consider The overall dynamic characteristics of photovoltaics; ② Taking the core device inverter as the center, the overall dynamic model between the inverter DC side and the photovoltaic array, AC measurement and transformer was established, but the relationship between the photovoltaic power station and the grid-connected bus was not studied. Dynamic connection; ③The inverter is equivalent to the controlled current source and voltage source, and the dynamic vector model of the photovoltaic power generation system with better approximation effect is derived, but the control function of the photovoltaic power generation system is ignored; ④Establishment of the inverter control system The third-order differential external characteristics of the photovoltaic power generation system need to be determined, but the initial conditions of the model need to be determined, the model parameters are highly dispersed, and the transient response is insufficient; Good, but it is difficult to identify the parameters, and it is not suitable for the power system simulation requirements of large-scale photovoltaic power plants; ⑥Constructing an equivalent model to describe the generalized comprehensive load is less difficult to identify, and can effectively describe the comprehensive load of the distribution network including photovoltaic power generation systems characteristics, but the comprehensive dynamic response of large power grids with photovoltaic power generation systems under the background of different penetration rates still needs to be studied

[0004] In summary, the photovoltaic power generation system has made great breakthroughs in the dynamic response modeling, but it is more concentrated on the dynamic modeling of the photovoltaic subsystem part, and the research on the fault characteristics of the grid-connected system still has not formed an accurate and uniform equivalent Description: With the continuous increase of photovoltaic grid-connected capacity, the load transient characteristics change rapidly, and the penetration rate of photovoltaics becomes more and more obvious. The detailed physical mechanism modeling of photovoltaic power generation system cannot directly reflect the impact of photovoltaic grid-connected on the whole. The dynamic relationship of the entire power system, the original load model is no longer suitable for grid operation

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