微电网建模及其对配电网保护影响研究

发布时间：2018-10-04 22:12

【摘要】：目前,分布式发电(Distributed Generation, DG)大量地引入电网中,有效地减小环境污染、降低能量损耗、提高了电力系统可靠性和灵活性。为了充分发挥分布式发电技术的优势,协调配电网与分布式电源之间的矛盾,将分布式电源、负荷、储能装置及控制装置组成微电网,并合理的接入配电网。然而分布式电源接入将对配电网保护带来较大的影响,传统的故障检测方法和继电保护模式很难满足电网安全运行的需要,因此,研究微电网及其对配电网保护影响和相关保护算法具有重要意义。 论文综述了含分布式电源的配电网保护方法。分析了经逆变器接口分布式电源的特点,结合逆变器在dq旋转坐标系下的数学模型,研究了恒功率控制(PQ控制)和恒压恒频控制(VF控制)的逆变器控制策略,进而构成PQ控制与VF控制相结合的微电网,使其既可运行于并网模式又可运行于孤网模式,且在模式切换时无需改变逆变器的控制策略。 其次,基于Digsilent软件,建立了PQ控制、VF控制分布式电源的仿真模型,并验证了模型的正确性。用PQ控制分布式电源模拟光伏发电,VF控制分布式电源模拟蓄电池,再加入同步发电机和负荷构成微电网,通过仿真验证了微电网建模的正确性。 接着,研究了同步分布式电源接入配电网对电流保护、距离保护和重合闸的影响；研究了经逆变器接口分布式电源(Inverter Interfaced DG,ⅡDG)和微电网接入对配电网电流保护的影响,通过仿真验证了理论分析的正确性。 针对分布式电源接入对电流保护的影响,研究了自适应电流速断保护：对于同步发电机接入的情况采用引入补偿系数的改进自适应电流速断保护方案,对于IIDG接入的情况采用未接入IIDG时的自适应电流速断保护方案仍具有很好的保护性能,并进行仿真验证。
[Abstract]:At present, distributed generation (Distributed Generation, DG) is introduced into the power network, which can effectively reduce environmental pollution, reduce energy loss, and improve the reliability and flexibility of power system. In order to give full play to the advantages of distributed generation technology and coordinate the contradiction between distribution network and distributed generation, the micro-grid is composed of distributed power source, load, energy storage device and control device, and the distribution network is connected reasonably. However, distributed power supply access will have a great impact on distribution network protection. The traditional fault detection method and relay protection mode are difficult to meet the needs of the safe operation of the power network. It is of great significance to study microgrid and its influence on distribution network protection and related protection algorithms. This paper summarizes the method of distribution network protection with distributed generation. The characteristics of distributed power supply via inverter interface are analyzed. Combined with the mathematical model of inverter in dq rotating coordinate system, the inverter control strategies of constant power control (PQ) and constant voltage constant frequency control (VF) are studied. The microgrid, which combines PQ control with VF control, can run in both grid-connected mode and isolated mode, and the control strategy of inverter is not changed when switching mode. Secondly, based on Digsilent software, the simulation model of PQ control VF control distributed power supply is established, and the correctness of the model is verified. PQ is used to control the distributed photovoltaic power generation and VF to control the distributed power simulation battery, and then the synchronous generator and load are added to form the microgrid. The correctness of the modeling of the microgrid is verified by simulation. Then, the influence of synchronous distributed power supply access to distribution network on current protection, distance protection and reclosing is studied, and the influence of (Inverter Interfaced DG, 鈪，

本文编号：2252073