基于PSASP的光伏并网系统建模与稳定性研究

在PSASP仿真环境下,开发了光伏并网发电系统中的光伏电池、MPPT控制器、蓄电池组、逆变器及DC-DC升压器的机电暂态模型,研究了光伏并网保护系统中的过/欠电压保护、过/欠频保护、过电流及短路电流保护、电压不平衡保护模型,应用这些模型建立了可用于电力系统稳定性分析的光伏电站仿真模型。最后,以接入光伏电站的某西部孤立电网为例,研究了光伏电源不同容量、不同功率因数接入方式对电网潮流的影响,以及故障扰动下的暂态稳定影响,验证了模型的正确性。

光伏发电系统故障检测与定位方法

随着越来越多的大型光伏电站陆续投产,大型光伏电站的故障检测和诊断将是一个重大的挑战。为维护大型光伏电站的安全性、可靠性,必须开发能够自动检测和定位数量庞大的光伏组件中确定故障的方法。文章提出了一种通过产生称为“残差”的故障指示信号来检测光伏电站故障的方法,并对于每个组串和残差与阀值进行了比较。在此基础上,根据故障电流和辐射水平的测量值来估计故障位置。通过对组串内线路故障的研究,证明了该方法的有效性。

Design of Capacitor Bank in Parallel to Photovoltaic Power Plant

The purpose of the paper is to develop a solution for application of PV （photovoltaic） generators in MV （medium voltage） distribution system without unacceptable voltage changes due to drops of PV power output. The proposed solution includes operation of PV with predetermined leading power factor and addition of a capacitor bank in parallel to PV plant in order to compensate the reactive power absorbed by the PV inverters. The analytical expression of required power factor angle is derived. Adding a capacitor bank in parallel to PV power plant may pose a problem because of space limitations. The dimensions and cost of small MV capacitor banks depend significantly on the capacitor bank protection against internal faults. Application of the developed negative-sequence current difference method for the unbalance protection of the capacitor banks enables to achieve a compact and cost-reduced design of the banks connected in parallel to PV power plants. A real-world example of operation of the PV plant in parallel to the capacitor bank with the novel protection scheme is described.

B型剩余电流保护在新能源发电和电动汽车中的应用

面对日益复杂的剩余电流形式以及需要对剩余电流实时监测的地方增多,传统剩余电流保护显得力不从心。B型剩余电流保护因其可以检测复杂剩余电流并且带有实时监测功能,已经运用到一些特定的保护领域中。文章分别阐述了B型剩余电流保护在三级剩余电流保护、电动汽车充电桩剩余电流保护和光伏发电系统剩余电流保护中的应用,论证了B型剩余电流保护推广的必要性和重要性。