Low-voltage ride-through characteristic analysis method for photovoltaic power generation system

Abstract

The invention discloses a low-voltage ride-through characteristic analysis method for a photovoltaic power generation system. The method comprises the steps of: constructing a dynamic model of the photovoltaic power generation system based on a set theory; selecting a representing method of a reachability set of the dynamic set model of the photovoltaic power generation system; performing reachability analysis on the dynamic set model of the photovoltaic power generation system; and, determining an example and necessary characteristics, and performing simulated analysis on the example by adopting matlab/simulink software. The method disclosed by the invention can be used for comprehensively analyzing low-voltage failure ride-through characteristics of the photovoltaic power generation system, and also can be used for judging whether a hardware method or a control technology adopted for improving the low-voltage ride-through capability of a photovoltaic grid-connected system is effect or not.

Description

technical field [0001] The invention relates to the field of photovoltaic power generation, in particular to an analysis method combining Zeno polyhedron and an accessibility analysis algorithm, which can realize a comprehensive analysis of low-voltage ride-through characteristics of a photovoltaic power generation system. Background technique [0002] With the increasing number, installed capacity, installed range and parallel operation scale of the current photovoltaic power generation system, its own uncertain characteristics caused by climate and environmental factors affect the safe and stable operation of the power system. When the power grid voltage drops seriously, It is necessary for the system to adopt accurate and timely control methods so that the photovoltaic power generation system can continue to work in grid connection and go through the process of low voltage faults. [0003] In order to solve this problem, many scholars have improved the low voltage ride-th...

AI Technical Summary

Problems solved by technology

However, the above software-based method provides limited voltage support and reactive power compensation when a serious fault occurs in the power grid due to the limitation of the DC side voltage of the inverter, and the software control method cannot effectively deal with serious faults in some cases. grid voltage drop fault condition

Most of the existing literatures aim at certain types of grid voltage faults and propose corresponding hardware methods or software control methods to improve the low voltage ride-through capability of photovoltaic power generation systems. There are few studies on the effectiveness of the improvement method; and the types, occurrence time and severity of various faults in the power grid are largely unpredictable, and the use of existing power electronic equipment and control systems can target a limited set of possible faults. The voltage fault waveform set is simulated and tested by computer

However, in order to predict all possible fault waveforms, the test system will be over-designed, which is difficult to implement and increases the cost. It is difficult to comprehensively analyze the low voltage ride-through characteristics of photovoltaic power generation systems using existing methods.

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