【作者】 刘钢；

【导师】 付志红；

【作者基本信息】 重庆大学 ， 电气工程， 2013， 硕士

【摘要】 随着电力系统以及智能电网的大力发展，电能计量被提到了新的高度。电能计量是发电、供电、用电三者之间用电信息结算的手段，其精度直接关系到三者利益，同时也是智能电网发展的关键。现代电能计量系统，由于计量算法的发展，已经很难实现通过计量算法来提高计量精度，而由器件误差带来的计量误差已不可忽略。电能计量系统中器件误差主要集中在电流互感器的误差，已有研究缺少对电流互感器包括频率特性在内的非线性特性的研究，对由电流互感器带来的电能计量误差不明确。论文以电流互感器的误差理论为基础，对电流互感器的频率特性以及运行工况下外磁场的影响进行了分析，量化了电流互感器非线性特性对电能计量的影响。首先，基于电流互感器的基本原理对电流互感器的误差理论进行了分析，并研究了非周期分量下电流互感器的相位特性，研究表明随着非周期分量的增加，电流互感器的相位误差随之增加，当达到饱和后，相位误差急速增加，最后进入深度饱和，误差稳定在一个极限水平。其次，从电流互感器的等效电路出发推导出了频率特性关系式，并以实际使用的微型电流互感器为实例，进行了理论与实验研究，两者结果基本一致：电流互感器在低频时，其传变特性将产生很大的误差，在工频至300Hz的频率范围内，线性度很好，当超过该频率时，误差开始增大。针对频率特性关系式，提出了电流互感器的频率特性改善以及频带拓宽的建议：通过改善铁芯以及二次绕组参数可有效改善频率特性，拓宽频带。在频率特性的基础上，对经过电流互感器后功率误差的频率特性进行了推导分析，分析发现功率误差与幅值误差两者随频率变化的关系相似；同时对某一锻造厂的谐波电能进行了分析，分析结果表明经过电流互感器后，谐波电能明显减小。再次，针对电流互感器运行中存在外磁场的情况，以永磁铁为场源，分析实际中电流互感器与永磁铁两者的相对位置关系，并推导出了外部恒定磁场对电流互感器传变特性影响的定量关系式，以理论及实验进行了验证，并对电能计量的影响进行了分析，研究结果表明：外部恒定磁场对电流互感器的影响在有恒定交链磁通绕组处与直流偏磁相似，随着外部磁感应强度增加，电流互感器传变误差增大，同时在输出中产生大量谐波，严重影响电能计量的结果。更多还原

【Abstract】 With the vigorous development of the power system and smart grid, energymetering is refered to new heights. Energy metering is power information settlementmeans among power generation、power supply enterprise and power user, its accuracy isdirectly related to the interests of the three, it is also the key to development of smartgrid. In modern energy metering system, it is difficulty to improve the measurementaccuracy though inproving measurement algorithm because of the development of themeasurement algorithm. At the same time, measurement error brought by the deviceerror can not be ignored. Actualy, the main device error of energy metering system isTA’s error, The previous studies are lack of TA’s nonlinear characteristic which containsfrequency characteristic, and the energy metering error brought by the TA is not clear.The paper analyzs TA’s nonlinear characteristic and infuention of externalmagnetic field on operating condition on the basis of TA’s erroe theory, quantify theimpact of the nonlinear characteristics of the TA to energy metering.First of all, the paper anlyzs TA’s erroe theory base on TA’s fundamental, andstudies TA phase characteristics under non-periodic component situation, The researchresult reveals that TA’s phase error will increase with the increasing of non-periodiccomponent. When TA is transient saturated, phase error increased sharply, at last, errorsTableilized at a level of limit when TA is deeply saturated.Secondly, derivating the frequency characteristic relationship base on the TA’sequivalent circuit, and study the frequency characteristic of actual used miniaturecurrent transformer though theory and experiment, obtaining a uniform conclusions, it’sthat there is large error at low-frequency, when frequency is between50Hz-300Hz, TAhas good linearity, error will increase when frequency is greater than300Hz. Gevingadvise to improve the frequency characteristic and widen the band of TA. At the basis offrequency characteristic, analyzing the power’s error change with frequency, it revealsthat power’s error change with frequency is similar to amplitude; at the same time, thepapaer analyzed harmonic energy of a manufactory, the result shows that harmonicenergy will reduce if there is a TA.At last, Alayzing the relative position between TA and permanent magnet whenthere is external magnetic field, deducing the quantitative relationship of externalconstant magnetic field impact on the transfer characteristics of TA, verifing the relationship though theoretically and experimentally, studing the infuence to the energymetering. The research result reveals that there is some similarity between externalconstant magnetic field and DC bias impact on the transfer characteristics of TA, andwith increasing of external magnetic induction, the TA ’s transfer error increases, at thesame time produce a large number of harmonics in output signal, seriously affect theenergy measurement results.更多还原