Research On The Active Power Balance Methodology Of The Power System With Renewable Energy Integrated

The balance of active power is the precondition to ensure that the frequency of thesystem within the specified range. Rely on automatic generation control (AGC) and othertechnical measures, the frequency of power system can be maintained at the vicinity ofrated frequency. However, with large-scale renewable energy, such as wind power and solarpower, etc, integrated into the power system, it will give a huge challenge to the operationof power system, due to the variability and uncertainty of the variable renewableenergy(VRE), the problem of frequency regulation and peak regulation of the power systemshould be solved first. Proceed from the power system frequency control, this paperanalysis the impact to the power system with the integration of VRE, and focus onanalyzing the integration of the wind power as an example. Then, introduce a flexibilityassessment method (FAST) of power system and to analysis the balance condition of theactive power from the flexible capacity point of view of the system in different time frame.Firstly, describe the basic principles of frequency control of power system, elaboratethe characteristics of AGC and the modeling methods of frequency control of power systemfor small perturbation analysis are described in detail. Then, establish the frequency controlmodel for multi-area interconnected power system.Secondly, introduce a variety of frequency controller for multi-area interconnectedpower system briefly. Describe the design method of H∞controller and the PI robustcontroller based on Linear Matrix Inequity (LMI) and Particle Swarm Optimization (PSO).Then, analysis the characteristic of the changes of minute-to-minute wind power output in awind-farm, and integrate the wind-farm into an area of the three interconnected areas, withthe use of the frequency controller described above, the simulation and analysis offrequency control after the wind-farm‘s interconnected was carried out. Draw relevantconclusion of the impacts to the power system, due to the minute-to-minute changes ofwind power output.Thirdly, introduce a flexibility assessment method (FAST) of power system which canhelp to calculate all the possible flexibility capacity of power system, in respond to theflexibility capacity requirement after the integration of VRE. Then, the analysis steps ofFAST were elaborated in detail and give two evaluation index of flexibility of system. Then, use the FAST to analysis the ability of the integration of VRE in Gansu power grid and findthe biggest capacity of VRE which can be integrated into the Gansu grid presently, finally,give some measurements and recommendations to improve the capacity of VREintegration.