基于CPLD的电网过电压变频数据采集卡设计

为了解决过电压信号数据采集的采样长度与存储容量之间的矛盾,提出了一种过电压变频数据采集卡的设计与实现方法,介绍了采集卡的硬件结构、采样原理和软件设计思想。采集卡采用复杂可编程逻辑器件作为控制核心芯片,其预触发变频采样技术可以保证以较小容量存储器记录完整的电力系统暂态信号。现场运行经验表明,该采集卡性能稳定可靠,能够较好的记录电力系统过电压的真实情况。

Data Acquisition Card with Variable Sampling Speed for Monitoring Overvoltage Based on CPLD

Overvoltage is a critical factor which influences the security of the power system.It is necessary to research overvoltage so as to guarantee safe operation of power grid.The data acquisition is one of key techniques in the on-line monitoring system for overvoltage.A remarkable difference between external overvoltage and internal overvoltage in power system sets a higher demand for data acquisition.In order to solve the contradiction of sampling length and storage capacity,an implementation of data acquisition card with variable sampling speed for overvoltage is proposed.Hardware structure,the principle of data sampling and the software design of CPLD is introduced.The data acquisition card employs the complex programmable logic device(CPLD)as the main control chip.With unique pre-trigger acquisition function,the data acquisition card can restore the waveforms before the power grid fault happening.And with variable sampling speed technique,the data acquisition card can sample and record the full transient signals in power system with smaller memory capacity.The field operation experiences show that the data acquisition card features stable and reliable performance and can record the real overvoltage waveform of power system.