逆变型分布式电源接入配电网的故障定位方法研究

发布时间：2018-06-18 07:53

本文选题：配电网 + 逆变型分布式电源　；参考：《西安理工大学》2017年硕士论文

【摘要】：随着常规能源的日渐枯竭和环境问题的日益恶化,利用太阳能、风能等可再生能源的逆变型分布式电源(Inverter Interfaced Distributed Generator,IIDG)大规模接入配电网。逆变型分布式电源的并网彻底改变了配电网原有的单电源辐射状网络结构,并导致配电网的潮流分布及故障特性发生改变,给故障的精确定位带来了新的挑战。研究适用于含逆变型分布式电源的配电网故障定位方法对于提高配电网对分布式电源的兼容性及提高配电网的可靠性具有重要意义。本文主要研究内容如下:首先,本文研究了含逆变型分布式电源的配电网故障特性。通过将逆变型分布式电源等效为压控电流源,构建了含逆变型分布式电源的配电网故障等效模型,分析了逆变型分布式电源接入容量和接入位置对配电网故障电流的影响。配电网故障特性的改变将使配电网中故障定位所用启动值难以整定,导致以准确整定值为基础的传统故障定位方法无法直接应用。其次,研究了基于改进阻抗法的故障定位方法。考虑到目前中低压配电网馈线上电压互感器的覆盖率较低,同时为了避免对检测装置开关动作值的整定计算,本文以经济且易于实现的阻抗定位法为基础,提出了基于改进阻抗法的配电网故障定位方法。首先,利用过渡电阻纯阻性的性质,构建故障定位方程,求解得到可能的故障位置,完成粗略故障定位;然后将可能故障点视为虚拟节点,重新形成包含虚拟节点在内的系统节点阻抗矩阵,通过比较变电站出线电压的计算值与测量值,将最接近实测电压值的虚拟节点视为最终故障点。该故障定位方法克服了传统阻抗法在定位之前易产生伪故障点等缺点。在仿真平台上验证了改进阻抗法的有效性,结果表明当过渡电阻较大及故障点距离变电站出线端较远时,该方法仍能保持较高的故障定位精度。最后,研究了计及线路集中电容的含逆变型分布式电源的配电网故障定位方法。由于以往的适用于含分布式电源的配电网故障定位方法需布置较多测量点,且未考虑线路对地电容对故障定位精度的影响,本文在改进阻抗法的基础上,提出了适用于含逆变型分布式电源的配电网故障定位方法,实现了仅利用变电站出线电压、电流及并网点电压测量值对配电网故障进行定位。在仿真平台上对该方法进行验证,分析结果可知该方法受过渡电阻及故障位置的影响较小,定位误差在可接受范围内。
[Abstract]:With the depletion of conventional energy sources and the worsening of environmental problems, Inverter interfaced distributed Generator / IIDG (Inverter Interfaced distributed Generator / IIDG), which uses renewable energy sources such as solar and wind energy, is connected to the distribution network on a large scale. The power flow distribution and fault characteristics of the distribution network have been changed by the grid connection of the inverter distributed generation, which has brought new challenges to the accurate location of the fault. It is of great significance to study the fault location method of distribution network with inverter distributed generation for improving the compatibility of distribution network to distributed generation and improving the reliability of distribution network. The main contents of this paper are as follows: firstly, the fault characteristics of distribution network with inverters are studied. By equivalent inverter distributed power supply to voltage controlled current source, a fault equivalent model of distribution network with inverter distributed power supply is constructed, and the influence of access capacity and location of inverter distributed power supply on fault current of distribution network is analyzed. The change of fault characteristics in distribution network will make it difficult to adjust the starting value of fault location in distribution network, and the traditional fault location method based on accurate setting value can not be directly applied. Secondly, the fault location method based on improved impedance method is studied. Considering that the coverage of voltage transformer on feeder line of medium and low voltage distribution network is low, and in order to avoid the setting calculation of switch action value of detection device, this paper is based on the economical and easy to realize impedance positioning method. A fault location method for distribution network based on improved impedance method is proposed. Firstly, the fault location equation is constructed by using the property of pure resistance of transition resistance, and the possible fault location is solved to complete rough fault location, and then the possible fault point is regarded as a virtual node. The impedance matrix of system nodes including virtual nodes is formed again. By comparing the calculated and measured values of substation outline voltages, the virtual nodes closest to the measured voltage values are regarded as the final fault points. The fault location method overcomes the shortcomings of the traditional impedance method. The effectiveness of the improved impedance method is verified on the simulation platform. The results show that the method can still maintain high fault location accuracy when the transition resistance is large and the fault point is far from the substation outlet. Finally, the fault location method of distribution network with inverter distributed generation is studied. Since the previous fault location methods with distributed power supply need more measuring points, and the influence of line capacitance on fault location accuracy is not considered, the impedance method is improved in this paper. In this paper, a fault location method for distribution network with inverter distributed generation is proposed. The fault location of distribution network is realized only by measuring the output voltage, current and parallel dot voltage of substation. The method is verified on the simulation platform. The analysis results show that the method is less affected by the transition resistance and fault location, and the positioning error is within the acceptable range.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM711

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