The Research And The Application Of The Supervising System Of Power Quality Based On Embedded

While a large number of converters based on power electronics techniques and other nonlinear loads are widely used in power systems, the electric workers of many countries have already paid close attention to various kinds of the relevant power quality problems that these equipments bring. The power quality problem is harmful not only to power system itself, but to a large deal of power customers. Thus, it's important for us to measure power quality on line.The paper analyses the definition and harm of power quality and introduces the situation of the power quality measurement. Moreover, it demonstrates the significance of studying a quality measuring device, and shows that the destination of the paper is to develop a device which can measure power quality precisely. This paper explains the development about the theory of digital signal processing, and discusses the application of digital signal processing in electric measurement. It also presents how to build a basic embed system. Accordingly, it puts forward the general design idea in which a ARM controller is used as CPU of the system and CPLD is used as the auxiliary appliance and embed Linux is used as the core of software. The idea can resolve the question which a single-CPU system's calculated capability and a double-CPU system's reliability are not excellent. The idea can raise the system's ratio of performance to value.After analyzing and comparing various power quality analyzing methods, this paper adopts the fast-FFT method, which is fit for embed system. The paper also presents the realization of the method.The paper accomplishes the design of the system's hardware and software. For the hardware, the device is an advanced data acquisition and parallel processing system required specifically by real-time signal monitoring in power system. A multi-channel sampling and retaining circuit, which makes it possible to acquire and transform data synchronously, is designed. To make the application of the device more flexible, two communication methods are offered, i.e. RS-232 communication and Ethernet communication. For the software part, the paper particularly introduces how to the software system of embed system. Meanwhile, the paper accomplishes the partition of all tasks, and the design of each application program.