Wind storage combined frequency modulation method and system for autonomous microgrid

Abstract

The invention provides an autonomous microgrid wind storage combined frequency modulation method and system. The scheme comprises the following steps: establishing a state space model in which a fan and energy storage equipment participate in micro-grid system frequency modulation; establishing an optimization objective function when the wind storage participates in frequency modulation based on the minimum frequency deviation and the minimum wind curtailment rate; setting a self-adaptive weight coefficient in the optimization objective function; setting a fan constraint condition and an energy storage equipment constraint condition at the kth sampling moment; and carrying out autonomous micro-grid wind storage combined frequency modulation. According to the scheme, a state space model is established by combining operation characteristics of a fan and energy storage equipment, minimum frequency deviation and minimum wind curtailment rate are taken as optimization indexes, a weight coefficient capable of carrying out adaptive adjustment according to frequency change is designed, and the energy storage equipment is optimized according to constraint conditions of dynamic adjustment of the wind speed and the state of charge. Wind energy can be fully converted into electric energy to participate in frequency modulation, the problems of unstable frequency and high wind curtailment rate in an autonomous micro-grid containing wind storage are solved, and energy waste is reduced.

Description

technical field [0001] The present invention relates to the technical field of microgrid coordination control, and more particularly, to a method and system for combined frequency modulation of wind and storage of autonomous microgrid. Background technique [0002] The access of high-penetration renewable energy makes the planning and operation of the power system face great challenges. As a small power system that can effectively integrate various distributed generation (DGs), microgrid has received great attention in recent years. However, when the microgrid operates autonomously, due to the loss of the support of the large power grid, coupled with the randomness of new energy generation such as wind power and photovoltaics, the frequency control of the autonomous microgrid is particularly important for the stable operation of the system; at the same time, renewable energy sources When participating in frequency regulation, how to reduce energy waste is also of great signi...

AI Technical Summary

Problems solved by technology

However, the existing methods such as droop control, virtual synchronous generator control, etc., mostly focus on the improvement of frequency control performance, ignoring the influence of wind speed time-varying characteristics on the active standby power of wind turbines, and the state of charge (State of Charge) of energy storage devices. Charge, SoC) on the charging and discharging power, there is no dynamic constraint on the active output increment when the two participate in frequency regulation, on the one hand, they cannot give full play to their frequency regulation advantages, and on the other hand, it is impossible to guarantee the energy efficiency of wind turbines and energy storage equipment. It may be difficult to obtain the ideal frequency regulation performance; in addition, the dynamic power allocation technology considering the combined frequency regulation of wind storage with the goal of energy efficiency has not been proposed, so it is impossible to maximize the utilization of wind energy and make full use of the energy storage to absorb the active surplus. Advantages of reducing wind curtailment rate and improving system energy efficiency

Images