基于改进FRF估计的电流互感器多频率动态同步测试关键技术研究

The strong promote of the construction of smart grid puts forward the advance-leveled demands to the dynamic test of transfer characteristic of current transducer. However, due to the influence of the noise, harmonics, inter-harmonics and excitation frequency fluctuations, the exist methods of dynamic test of transfer characteristic of current transducer cannot satisfy the requirements of dynamic expression, anti-noise, and real-time simultaneously. This project presents the dynamic test of current transducer with multi-frequency synchronized based on the improved frequency response function (FRF) estimation, which includes: ①The method of gennerating the m sequences for the dynamic test with multi-frequency synchronized will be studied. And the excitation source for the dynamic test of current transducer with multi-frequency synchronized will be presented based on the m pseudo-random sequences. ②By using the Taylor series, the test model of the transfer characteristic of current transducer will be established, which will be able to characterize the dynamic behavior. And the dynamic test of current transducer with multi-frequency synchronized will be proposed based on the improved FRF estimation. ③ The error bounded function of the dynamic test of transfer characteristic of current transducer will be studied, and the noise robustness of the proposed current transducer test method will be presented. ④The test platform of transfer characteristic of current transducer will be designed and built based on the DSP, and the correctness of the theoretic method will be verified by the practical test. The proposed dynamic test method of current transducer with multi-frequency synchronized will feature several significant improvements over the presence method including characterizing dynamic behavior, noise robustness, and real-time implementation, which will provide a new approach for the accurate field test of current transducer. Moreover, the proposed dynamic test method with multi-frequency synchronized will be a new efficient method for test of transfer function.

智能电网建设的强力推进对电流互感器传递特性动态测试提出了更高要求。但受噪声、谐波、间谐波和激励源频率波动等影响，现有电流互感器传递特性测试方法不能兼顾动态表征性、抗噪性和实时性。本项目提出基于改进频率响应函数（FRF）估计的电流互感器多频率动态同步测试方法，包括：①构建基于m伪随机序列的电流互感器多频率动态同步测试激励源；②引入泰勒级数，建立具有动态表征能力的电流互感器传递特性测试模型，构建基于改进FRF估计的电流互感器多频率动态同步测试方法；③研究电流互感器传递特性测试中的随机误差界，确定基于改进FRF估计的电流互感器多频率动态同步测试方法的噪声稳健性；④构建基于DSP的电流互感器传递特性测试平台，验证理论成果的正确性。本项目将大幅改善电流互感器传递特性测试的动态表征性、抗噪性和实时性，为电流互感器现场准确测试提供新的途径；所建立的多频率动态同步测试方法有望成为一种新传递函数测试方法。

电流互感器是智能电网的关键装备，其传递特性直接决定着电能计量装置的整体运行水平。电流互感器运行状况和传递特性测试往往受电网谐波、间谐波、随机噪声干扰等影响，受到了广泛关注。.本项目深入研究改进频率响应函数估计理论，提出电流互感器多频率动态同步测试方法。研究成果如下：1）提出了基于Walsh函数的多频率同步激励信号合成方法，多频率同步信号在时域上仅为二值函数，波形简单，如由7个等幅频率合成的信号在周期内仅有38个间断点，合适于频谱解析；2）提出了噪声稳健的互感器激励与响应功率谱计算方法，构建了基于改进FRF估计的频谱泄漏误差综合等效模型，确定了电流互感器多频率动态同步测试方法的噪声稳健性；3）提出了电流互感器频率响应函数Hn-ave估计算法，构建了移位自相关法计算信号的自相关函数，有效减少了波形衰减，各主频成分的功率相对误差的数量级仅为10^(-14)，提高了频率响应函数估计的准确度；4）研发电流互感器多频率同步测试激励源，各主频率成分的幅值衰减不超过10%，且其能量与整个激励信号能量的比值保持不变，突破电流互感器无法进行多频率动态同步测试的局限。研究成果促进了频率响应函数估计理论和电流互感器测试技术的发展，在电能计量和广域电气参数测量等领域具有重要的应用价值。