基于SOPC的微电网电能质量扰动及谐波检测技术研究

The problem of the power quality for microgrids is a great technological problem related to their survival and development. Compared with the utility grid, a microgrid very easily causes the power quality disturbance and harmonic problems such as voltage drop, surge and interruption because of its small capacity, small inertia, serious nonlinear, and poor ability of resisting the internal and external impact. How to accurately and fast detect these problems so that targeted measures is taken to solve the problems is the key and premise to ensuring the safe and stable operation of microgrid. However, so far the result has not been ideal due to the inherent complexity of these problems and restriction by the methods available. In this research, great efforts will be made to breakthrough the limitation of the past by the method and the hardware architecture. Methodologically,on the basis of the deep investigation of S transform principle, a proposal of an imcomplete improved S-transform method has been made,and an establishment of their unified detection model has been performed ,thus implementing the accurate detection of the power quality disturbance and harmonics,with the emphasis on solving the problems of the “accuracy”. Architecturally, the fast data sampling, an imcomplete improved S-transform operation,data transmission and storage are completed by establishing SOPC real-time detection platform,with the emphasis on solving the problems of the “real-time”. With the research completed, a novel and effective solution will be provided for the microgrid power quality parameters real-time detection, and a good foundation will be laid for the governance of power quality problems.

微电网电能质量问题是关系到其生存和发展的重大技术问题。与公用大电网相比，其容量小、惯性小、非线性严重、抵御外界和内部冲击的能力较低，更容易引起电能质量扰动和谐波问题。如何快速准确检测出这些问题，以便有针对性的采取应对措施解决，是确保微电网安全稳定运行的关键和前提。然而由于这些问题本身固有的复杂性以及受现实方法的限制，迄今为止效果并不理想。本课题试图从算法及硬件上加以突破，构建一种“硬件+算法”的全新协同工作检测体系。在算法上，提出一种不完全改进S变换算法，并构建其统一检测模型，实现对网中各种电能质量扰动及谐波的准确检测，重点解决检测“精确性”问题。在硬件体系上，构建基于SOPC的实时检测平台，完成高速数据采集、不完全改进S变换运算、数据传输及存储等，重点解决检测“实时性”问题。课题完成后，可为电能质量扰动和谐波的检测提供一种全新而有效的解决方案，为治理电能质量问题奠定良好的基础。

微电网建设已经成为智能电网建设的重要内容之一。研究微电网电能质量扰动和谐波检测新技术对于优化微电网系统设计、提高微电网电能质量、保障微电网安全稳定运行、促进微电网技术发展都具有重要意义。本课题针对微电网电能质量的特点，将微电子学的最新成果SOPC技术应用于微电网电能质量扰动和谐波的检测中，从体系结构上深入研究探索了基于SOPC技术并能有效解决微电网电能质量扰动和谐波检测的“实时性”问题实时检测平台的构建方法；从软件算法上研究了一种基于改进不完全S变换实现对微电网各种电能质量扰动（电压骤升、电压骤降、中断）和谐波、间谐波等的快速精确检测的有效算法。提出了一种以改进S变换方法为基础，从硬件体系和软件算法上突破现有方法局限性的新思路和解决方案：通过深入研究微电网电能质量参数扰动和谐波信号的特征，构建起基于这种S变换的信号检测模型；在深入研究S变换基本原理的基础上，探索出一种能有效提高其时频分辨率、从而最大限度地提取短时电能质量扰动信号及谐波信号特征的改进方法。该方法首先利用最大功率谱测度学原理提取扰动信号的主频点，然后，对主频点进行本项目提出的一种改进不完全S变换（该改进不完全S变换通过引入具有两个可调参数的双高斯窗函数代替传统S变换的高斯窗口函数得到），得到包含扰动特征信息的模时频矩阵。然后，利用该矩阵提取出检测电能质量扰动的特征量。最后，根据相关理论和规则得出扰动的幅值、扰动起始时间和结束时间等扰动参数及谐波阶次和幅值。一系列测试结果表明，该系统能够快速、准确地检测出电能质量扰动信号的启动时间、停止时间和幅值,谐波的阶次、大小等，具有运行实时性和强抗干扰能力的特点。成果为微电网电能质量扰动和谐波的实时精确检测提供了一种有效的解决方法，为治理微电网电能质量问题（如减小微电网的谐波危害、治理微电网谐波污染、提高微电网电能质量），优化微电网设计奠定良好基础。