Power Quality Monitoring System Analysis And Design Of Power Distribution Network

With the development of society,more and more complex loads access to power grid such as control systems which not only require stable power supply but also require high level power quality.Since power electrical equipment widely used,harmonic problem has been prominent.Fast establishment of high-speed railway brings power unbalance problem since high-speed train accessing to a single phase power.Power quality problems affect grid safe operation and result in economic losses which require power suppliers and users pay attention to.Monitoring power quality is the precondition of solving it.A kind of online power quality monitoring system of distribution network is necessary.First this paper illustrates background of research.Then shows the parameters of power quality and how to calculate each parameter such as THD.This paper proposes an improvement method of IEC flicking test which filters well,calculates accurately and has simple operation.According to theories of this paper,the hardware and software of the monitoring system was designed.Sampling circuit has 16-bit AD and CPLD.It supports high-speed sampling and makes the monitoring system analysis harmonic up to 50 th order by FFT.The core CPU is Intel Celeron 1037 U which has low power dissipation and satisfies calculation requirements and other functions.Data saving format accords with Power Quality Data Interchange Format(PQDIF)to realize data interchange between different types of equipment.At last,the power quality monitoring system was tested.According to the results of tests,this monitoring system works well in complex environment and calculates parameters of power quality accurately.This power quality monitoring system has simple structure,low cost,high accurate and abundant functions It is good to monitor power quality of distribution network.