Design Of Intelligent Parameters Monitor Of Power System

In late years, the issues of power quality have captured considerable attention from both power systems and their customers. One of reasons is many precision instruments and devices based on computers are applied, which are sensitive for power quality. The other reason is the wide application of various kinds of electric and electronic converters and other non-linear load, this can make the voltage and current waveform distort and result in the serious depravation of power quality. On the one hand the user is required to improve the quality of electricity, and the contradictions are becoming increasingly acute, on the other hand the quality of electric power has declined. To enhance the quality of electrical energy, first of all the testing and analysis of electrical parameters must be accurate and complete.Though researching the qualification, measure and analytical method of electric parameter, combine with current trend which electric parameter detection equipments is incline to install in the job site as the permanent equipments, considering the special demand of real-time and supporting complicated algorithm, embedded system and digital signal processor were adopted to develop the intelligent parameter detection equipment for the intelligent low voltage distribution system. This equipment is used as the node of bottom layer of whole net of power quality meter and provides data for the parent managing layer. This equipment has the characteristics of on-line and real-time detection, supporting complicated algorithm, long range communication and low cost.In the section of system design, an embedded real-time system solution based on double CPU is presented. In this system, a 51 MCU is used to manage the system and a high-speed digital signal processor is used as calculation unit. The design method of the hardware system is introduced in details, and the layered design method of the software system with the concern of the hardware system architecture and the practical applications of the electric parameter detection equipment also discussed. This paper firstly introduced the characteristic of the DSPLF2407A processor, then, the structure of hardware system is described followed by the descriptions of MCU module, data collect module, power supply module, human-machine interface module and communication module. Hardware design adopts standardized design method that is hardware circuit use standardization module as much as possible, in order to expand easily. An analysis on electromagnetic capability of detection equipment was founded and corresponded anti-interference was present. The software adopts the module design methods, uses the assembler language and C language to realize mix programming, these methods improved the execution efficiency. In debug processing, the software demonstrates efficiency and robust. The paper also discusses the software modules, such as the main procedure, data collect procedure, human-machine interface, and communication procedure. In the section of function implementation, a prototype based on the fundamental monitoring functions is completed, it has the following functions: routine measuring including voltage,current,power measurement and so on, stability harmonic analysis etc. Besides, it has a beautiful and practical human-machine interaction based on menu operation.In the section of the experiment, some measuring precision experiments and some functional experiments have been done. The experiment results prove that the prototype has a good performance and reaches the expecting design requirements successfully. In the error analysis, the sources and the affects of the errors are analyzed in details and some error compensation methods based on hardware or software are also introduced.