作者：李恺, 王海元, 杨茂涛
作者单位：国网湖南省电力有限公司供电服务中心(计量中心) 智能电气量测与应用技术湖南省重点实验室, 湖南 长沙 410001
关键词：直流电能表;纹波影响;调制谐振;计量误差
摘要：
为认识交流调制型直流电能表在纹波背景下的计量性能和特点，对该电能计量模型进行讨论和分析，揭示调制谐振对计量准确性的影响机理，通过仿真计算分析纹波频率、纹波功率、电量计量窗口对准确性的影响规律，通过实测验证仿真分析结论。仿真和实测结果表明，纹波频率越接近电能表调制频率，表计误差震荡趋势越明显，震荡周期越长；调制谐振状态下，纹波功率比越高，表计误差震荡幅度越大；误差震荡幅度存在极限理论峰值，该峰值与纹波视在功率、调制基准信号幅值成正比，与实际功率大小成反比；对于典型技术参数，其误差震荡幅度最大可达纹波含量比的1/2。故该型表计的调制源宜采用单一频率源，且避开典型运用场景的纹波频率，进行误差检测时应充分考虑调制谐振可能带来的影响。
Ripple effects simulation and test of AC modulated DC electric energy meter
LI Kai, WANG Haiyuan, YANG Maotao
Hu'nan Province Key Laboratory of Intelligent Electrical Measurement and Application Technology, State Grid Hu'nan Electric Power Company Power Supply Service Center(Metrology Center), Changsha 410001, China
Abstract: In order to know metrological performance and characteristics of AC modulated DC electric power meter under ripple conditions, the electric energy metering model is discussed and analysed. It reveals the influence mechanism of modulation resonance on measuring accuracy. The influence rule of ripple frequency, ripple power, and measuring window on measuring accuracy are also analysed via simulation calculation and the simulation analysis conclusion is verified by test. The simulation and test results show that the more the ripple frequency closes to modulation frequency of the meter, the oscillation trend of measuring error will be more obvious and the oscillation period will be longer. Under the modulation resonance state, the higher the ripple power ratio is, and the larger oscillation range of measuring error will be. The amplitude of error oscillations has a limit theoretical peak value which is deemed to be directly proportional to apparent power of ripple and modulation reference signal amplitude and be inversely proportional to actual power. Under typical technical parameters conditions, the maximum oscillations amplitude of measuring error can reach 1/2 of ripple content ratio. So single frequency source is suitable for the modulation source of the DC electric power meters, and ripple frequency under typical use scenarios should be avoided. The possible influence of the modulation resonance should be taken into consideration fully when conducting error test.
Keywords: DC electric energy meter;ripple effects;modulation resonance;measuring error
2018, 44(4): 147-152 收稿日期: 2017-07-23;收到修改稿日期: 2017-09-15
基金项目: 国网湖南省电力公司2016年重点科技项目（5216AB50009）
作者简介: 李恺(1985-),男,湖南长沙市人,工程师,硕士,研究方向为电能计量装置的检测和状态评价。
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