基于IEC 61850标准的数字化电能表丢帧误差分析

Frame loss error analysis of digital Watt-hour meter based on IEC 61850

数字化电能表做为数字化电能计量系统中关键设备,其误差大小直接决定了数字化电能计量系统的准确度,数字化电能表在信号输入形式上与传统电能表存在很大的差异,传统电能表的输入信号为三相模拟电压/电流,而数字化电能表的输入信号为遵循IEC 61850协议的数据帧,因此数字化电能表相对传统电能表而言存在一个重要的误差来源—丢帧误差。针对数字化电能表的丢帧误差从理论上进行分析,同时对确定等级的数字化电能表允许最大丢帧率进行了推导,并通过实验仿真验证,发现数字化电能表的丢帧误差在丢帧率一定的情况下随着丢帧序号的变化呈现出正弦变化的规律,且最大丢帧误差与采样频率无关。分析得出要忽略丢帧对数字化电能计量系统造成的误差时,数字化电能表允许的最大丢帧率应该在数字化电能表的准确度等级5%以下,且建立相关的丢帧测试项目对数字化电能表入网运行前进行检测具有重要意义。

As a key device of digital power metering system,the error of digital watt-hour meter directly determines the accuracy of the digital power metering system,the digital Watt-hour meter has a lot of differences from traditional Watt-hour meters in the form of signal input,the input signal of traditional Watt-hour meter is three-phase analog voltage / current and the digital Watt-hour meter is data frame that follows the IEC 61850 protocol,so compared With traditional Watt-hour meter,the digital Watt-hour meter has an important error source-frame loss error. This paper analyzed the frame loss error of digital Watt-hour meter in theory,and derived the maximum allowed frame loss rate to digital Watt-hour meter that determined level,at last,through experiment and simulation verification,it is found that the frame loss error of digital Watt-hour meter changes with the number of lost frame,and the maximum loss error has nothing to do with the sampling frequency. It is concluded that to ignore the digital power metering system loss error,the maximum allowable frame loss rate of digital Watt-hour meter should below 5% of accuracy level,and it has an important significance to set up relevant surveillance project for digital Watt-hour meter.