基于改进Karrenbauer变换的有源配电网故障定位新方法

分布式电源DG(distributed generation)并网后,配电网变为两端/多端电源网络,传统基于单向潮流的故障定位方法不再适用,为此提出一种基于改进Karrenbauer变换的有源配电网故障定位新方法。首先针对因配电网不换位造成参数阻抗矩阵中心对称的特点,对阻抗矩阵进行标准Karrenbauer变换增加矩阵的稀疏性;在此基础上,对初步变换矩阵做进一步对角化处理获取修正矩阵,进而得到可实现不换位配电网三相高精度解耦的相模变换矩阵,即改进Karrenbauer矩阵。通过分析相模变换后α模故障附加电流相角差,推导出有源配电网区段故障定位的判据。通过算例分析验证了所提方案可以实现故障区段的准确定位,解决了线路参数不对称对配电网故障定位精度的影响。

Fault location of untransposed double-circuit transmission lines based on an improved Karrenbauer matrix and the QPSO algorithm

Some double-circuit transmission lines are untransposed,which results in complex coupling relations between the parameters of the transmission lines.If the traditional modal transformation matrix is directly used to decouple the parameters,it can lead to large errors in the decoupled modal parameter,errors which will be amplified in the fault location equation.Consequently,it makes the fault location results of the untransposed double-circuit transmission lines less accurate.Therefore,a new modal transformation method is needed to decou-ple the parameter matrix of untransposed double-circuit transmission lines and realize the fault location according to the decoupled modal parameter.By improving the basis of the Karrenbauer matrix,a modal transformation matrix suitable for decoupling parameters of untransposed double-circuit transmission lines is obtained.To address the dif-ficulties in solving the fault location equation of untransposed double-circuit transmission lines,a new fault location method based on an improved Karrenbauer matrix and the quantum-behaved particle swarm optimization(QPSO)algorithm is proposed.Firstly,the line parameter matrix is decomposed into identical and inverse sequence compo-nents using the identical-inverse sequence component transformation.The Karrenbauer matrix is then transformed to obtain the improved Karrenbauer matrix for untransposed double-circuit transmission lines and applied to identi-cal and inverse sequence components to solve the decoupled modal parameter.Secondly,based on the principle that voltage magnitudes at both ends are equal,the fault location equation is expressed using sequence compo-nents at each end,and the QPSO algorithm is introduced to solve the equation.Finally,the feasibility and accuracy of the proposed method are verified by PSCAD simulation.The simulation results fully demonstrate that the innova-tive improvement on the basis of the traditional modal transformation matrix in this paper can realize the modal transformation of the complex coupling parameters of the untransposed double-circuit transmission lines.It causes almost no errors in the decoupling process.The QPSO algorithm can also solve the fault location equation more accu-rately.The new fault location method can realize the accurate fault location of untransposed double-circuit transmis-sion lines.

基于Park变换的线路阻抗参数在线辨识新方法

针对高压微电网或等效线路阻抗呈感性的低压微电网,提出孤岛运行模式下的一种线路阻抗参数在线辨识方法。通过Park变换将电压、电流变换到两相同步旋转坐标系下,利用电压、电流的直流分量求解线路阻抗,从而识别出线路电阻值和电感值。该方法不仅适用于三相平衡系统,更可在三相负荷不平衡情况下,实现对输电线路阻抗参数的在线辨识。仿真和实验中,将提出的Park变换法与Karrenbauer相模变换法进行对比,结果表明所提出的Park变换法易于编程且辨识精度较高。

配网T接架空线路行波故障精确定位

针对现有配网T接架空线路故障暂态行波信号因噪声干扰、线路结构干扰等而导致的定位不准确问题,提出一种基于ICEEMDAN和EDO算子的模量时间差法。首先利用Karrenbauer变换将相量行波分量分解成模分量;再通过ICEEMDAN和EDO算子标定模分量的波头时间,滤除噪声分量,以精确标定故障行波波头;然后通过线模、零模波速以及波头时间计算其故障点的精确位置。所提出的方法经PSCAD/EMTDC仿真分析验证,具有可行性和准确性。