基于ATT7022E工频量测量方法研究

Research on Measuring Method of Main Frequency Parameters Based on ATT7022E

针对继电保护数据需要满足快速性和准确性的要求,文中采用基于IIR低通滤波器有效值快速计算的方法来提高ATT7022E工频量测量的快速性,采用读取芯片有效值寄存器来满足上位机监控对测量值准确性的要求,将两者相结合来达到继电保护对快速性和准确性的要求。根据工频电参量特点推导出对一个电流采样值的平方进行低通滤波,然后进行开方即可得到电流有效值。其只需要一个采样值即可得到电流有效值,具有计算简单、快速性好的优点。在LPC1778进行实验验证,结果表明,前者快速性提高了近十倍,后者准确性更高,两种方法相结合能满足多数实际应用中对快速性和准确性的要求。

The data applied in relay protection requires rapidity and accuracy. In this paper,the rapidity of measuring main frequency parameters by ATT7022 E is improved through effective value calculation based on IIR low- pass filter. The accuracy requirement of host computer monitoring is met by reading data from effective value register. Combining the two methods,a practical method of getting electrical data is proposed. In detail,according to the characteristic of main frequency parameters,the square of current sampling value which passed by low- pass filter is equal to the square of the current effective value. It needs only one sampling value,which is very easy and quick to accomplish. The application of the proposed method in LPC1778 demonstrates its validity. The experimental results showthat the former is nearly 10 times faster than the latter which is more accurate. In conclusion,the two method o combined is very significant in practical applications.