Research On Typical Power Quality Problems And Countermeasures Of Isolated Network System

At present,only isolated network systems can be used for power supply in areas where power grid construction is backward and it is difficult to achieve reliable power supply in a short period of time;due to natural disasters,power grid failures,etc.,it may cause the local power grid with distributed power supply to be disconnected from the large power grid,forming an isolated network to operate independently.some industrial enterprises will also use isolated network systems due to the cost of electricity.However,the capacity of the isolated network system is small,and the ability to withstand power quality interference sources such as impact and nonlinearity is weak.When there are many power quality interference sources in the isolated network system,the power quality problem of the isolated network system will deteriorate.Therefore,it is of great significance to study the typical power quality problems and solutions in isolated network systems.Firstly,this paper introduces the definition of isolated network system,and based on the characteristics of high demand for power supply continuity of isolated network system,puts forward a set of calculation method of power quality limit of isolated network system considering the balance between safe continuous power consumption and power quality supervision.This method is used to evaluate the power quality operation level of a isolated network system.It can ensure the power supply of isolated network system,taking into account both the continuity and reliability,with the power quality supervision and management of the isolated network system considered.Secondly,the typical power quality problems of the isolated network system are analyzed.Based on the harmonic transfer law,the high frequency harmonic amplification of the isolated network system is studied,and the voltage flicker transfer law of the isolated network system is studied through the simulation calculation of voltage flicker caused by a single user.Then,based on the above research results on the power problem of the isolated network system,the corresponding countermeasures are put forward to solve the problems of high frequency harmonic amplification and voltage deviation in the isolated network system,and good results have been achieved,which effectively improves the operation level of the power quality of the isolated network system.Finally,aiming at a frequency anomaly event in a isolated network system,this paper studies the influence of frequency abnormality of the isolated network system on the power quality control device through the simulation modeling and analysis of the fault mechanism of the power quality control device.According to the research results,it is pointed out that comprehensive on-line monitoring devices should be installed to ensure the safe and stable operation of the treatment devices in the isolated network system.The limit calculation method studied in this paper,the typical power quality problem control countermeasures and the integrated online monitoring device are of great significance for the continuity,safety and safe operation of the power supply of the isolated network system.