基于三端口网络的互感器电压系数测量方法

Voltage Coefficient Measurement Method of Voltage Transformer Based on Three-port Network

为消除电压互感器串联加法中屏蔽泄漏和临近干扰对电压系数测量带来的误差,提出一种基于三端口网络的针对双级互感器串联的电压系数测量方法。首先,通过分析互感器串联加法测量中附加误差的类型和来源,基于双级电压互感器串联建立了考虑附加误差的无源线性三端口网络电压比例量值模型,利用电路理论证明了该三端口网络模型的输出响应具有线性可叠加性;其次,在电压系数求解过程中,在传统电压串联加法的基础上提出新的三步递推测量方法和迭代算法,通过推导证明该方法可以消除屏蔽泄漏和邻近干扰的影响;最后,针对同1台110/√3kV电压互感器,将该文提出的测量方法与德国联邦物理技术研究院开展国际比对,针对同1台220/√3 kV电压互感器将提出的测量方法与传统串联加法进行比对。研究结果表明,国际比对的偏差小于比值误差2×10^(–6)和相位误差2μrad,该文提出的电压系数测量方法比传统加法有较大提升。该研究可为提升中国工频电压比例标准体系量值溯源的准确度提供支撑。

To eliminate the error of voltage coefficient measurement caused by shielding leakage and adjacent interference in the transformer series voltage summation,a measurement method for the voltage coefficient of two-stage transformers in series based on three-port network is proposed.Firstly,the types and sources of additional errors in series voltage summation of transformers are analyzed.The passive linear three-port network voltage proportional-value model in which additional errors are taken into consideration is established based on the series voltage summation of two-stage transformers.The output response of the three-port network model is proved to possess linear superposition by circuit theory.Then,in the process of solving voltage coefficient,the new three-step recursive measurement method and iterative algorithm are proposed based on the traditional series summation.Derivation proves that this method can be adopted to eliminate the influences of shielding leakage and adjacent interference.Finally,for the same 110/√3 kV voltage transformer,the two-stage transformer series method proposed in this paper is compared with the German physikalisch-technische bundesanstalt(PTB).And for the same 220/√23 kV voltage transformer,the method in this paper is compared with the traditional series summation.The results show that the deviation of the international comparison is less than the ratio error of 2×10^(–6) and the phase error of 2μrad,and the two-stage transformer series method proposed in this paper is better than traditional summation method.This research can provide support for improving the accuracy of traceability of power frequency voltage ratio standard system in China.