| Micro-grid can unified,manage,and control renewable energy,and is in favor of the development and utilization of new clean energy in large-scale.So it is an important part of the future power system.However,intermittently clean energy like solar energy,wind energy,small hydropower and other clean energy are largely constrained by the environment,so their output are highly random.And the load side of the micro-grid fluctuates significantly,so a higher requirement on power quality monitoring was needed.To ensure safe and stable operation of micro-grid,its power quality must be monitored,and appropriate control strategies must be taken.In this paper,we start with building a micro-grid system including solar,wind and hydroelectric power and other distributed power,distributed power and load like photovoltaic systems,wind energy systems,water and electricity systems were connected in order,providing an operating platform for micro-grid information platform and the study of power quality monitor.Then a smart micro-grid power quality monitoring system was designed,hardware systems from data collection,transmission,storage to display were constructed using the internet of things technology.Power quality analysis software was developed using Lab VIEW,providing decision support for the system power quality monitoring.Finally,the entire system is applied to the micro-grid voltage regulator,practicality and intelligence of the entire system were verified through experimentation.In this paper,innovative points and research results are as follows:(1)The internet of things technology was applied in this paper,the hardware system of power quality monitoring system was established,using various instruments,sensors,and Zig Bee wireless sensor network as a data acquisition module;design of pre-intelligent terminal based on S3C2440A;a central control server consists of application services,Web service and database etc.,providing necessary hardware foundation for the power quality monitoring system.(2)A micro-grid monitoring model that moves operation decision-making to field control layer was put forward.ARM + Linux mode was adopted by pre-intelligent terminals of the local control layer,to deal with data generated by the power grid in real-time,and events generated by abnormal data will be submitted to the application layer.It will save upper computing resources and communication resources of the entire system,and will improve autonomy of the equipment in the monitoring system,to move down decision-making.(3)Power quality analysis module such as,real-time power,voltage and current module,harmonic analysis module,phase unbalance and phase analysis module were developed with Lab VIEW,and used in micro-grid monitoring system framework,the micro-grid information platform was established to monitor power quality in real-time,and to generate abnormal events solutions for auxiliary systems.(4)On the power quality control,by detailed analysis of the micro-grid compositing features and principle of hybrid control,control constraints of power quality controller was put forward,power quality control system mathematical model based on hybrid control method was established.The intelligence of the controller was improved through the modification of hierarchical structure in hybrid power system combined with internet of things technology.This fact proves that pre-intelligent terminals can effectively realize the local autonomy and promote the intelligent of micro-grid,besides,it has a good real-time performance and scalability;hybrid power control system which based on Internet of Things technology can monitor and manage the power quality of micro-grid with a fast response speed,it more close to practical engineering,and realize the multi-objective optimization control. |
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