【作者】 张泽云；

【导师】 黄家栋； 段晓波；

【作者基本信息】 华北电力大学 ， 电力系统及其自动化， 2011， 硕士

【摘要】 随着光伏电源的规模、容量的扩大及其在发电系统中渗透率的提高,使得配电网从传统的单电源放射型网络变为双端甚至多端网络,这可能改变故障电流大小、持续时间及方向,从而导致继电保护误动、拒动及失去选择性;导致熔断器误动作而失去选择性。光伏自身的故障也会对电网运行和其保护产生不利影响。另外,当光伏发电系统反孤岛保护时间与自动重合闸等装置失调配合时,可能产生非同期合闸等问题。因此,有必要深入研究系统故障条件下,光伏电源对配电网保护的影响及其解决方法,协调配网保护和光伏电源自身保护之间的关系。充分发挥光伏电源的积极作用,尽量减小其对电力系统稳定和安全的不利影响,使电力系统更加高效、可靠地运行。本文分析了光伏电源对配电网保护、自动重合闸和配网自动化的影响,在改进的IEEE34节点配电网模型上,利用PSCAD仿真验证了光伏电源的位置和容量对短路电流的影响和贡献,以及对保护装置的影响。运用试探法得出不同接入点的光伏电源准入容量。并提出了一种新的保护方案,在不改变原有保护协调性的情况下,只在光伏电源侧加入阻抗限流器,可以有效地解决光伏电源与配电网保护之间的协调问题。对于光伏电源的并网保护相关问题,分析了并网变压器的联接方式对并网保护的影响,建议最好采用Yn/d变压器。阐述了导致逆变器检测故障失灵的几个方面,分析了光伏并网保护装置对并网联络线保护的影响,介绍了并网保护的孤岛检测原理及方法,并针对光伏并网发电系统中存在的孤岛效应,提出新的孤岛检测方法,该方法通过对功率方向继电器的原理进行改进,在原来的模块上增加了由跳闸信号启动的保持电路模块,这样能可靠地检测出光伏电源的孤岛运行。更多还原

【Abstract】 As the photovoltaic power scale, the expansion capacity in the power generation and the improvement in the proportion, making the distribution network from the traditional radial single supply network into dual-side or multiterminal network, thus changing the size of fault current, duration and its direction, the results may cause that the circuit breaker protection malfunction and refuse to move and lose the selectivity; also make the fuse lead to loss of selectivity. Photovoltaic ’s own fault will affect the operation and protection of the system. In addition, when anti-islanding time of photovoltaic power generation system protection can not be coordinated with automatic reclosing and so on, it will lead to asynchronous closing. Therefore, it is necessary to make an in-depth study for the impact of photovoltaic power on the distribution network protection and solutions, coordinate the relationship between the distribution network protection and photovoltaic power self-protection under the system fault conditions. bring into full play the positive role of photovoltaic power, to minimize its negative impact on the stability and security, make the power system more efficient, reliable operation.This paper analyzes the impact of photovoltaic power on distribution network protection, automatic reclosing and distribution automation. On the modified IEEE34 node distribution network model, using PSCAD simulation shows the impact and contribution of the location and capacity of photovoltaic power on fault currents, as well as the impact of protection devices, the use of heuristics obtained photovoltaic capacity of different access points. Putting forward one new protection approach, that is, without changing the situation of orginal protection, adding impedance current limiter in the photovoltaic power side, effectively addressing the coordination between the photovoltaic power and distribution network protection.For related problems with the interconnection protection of photovoltaic power, analyzing the impact of the interconnection transformer connections on interconnection protection, the adopted proposal should be using the Yn/d transformers. Describing several aspects which will lead to failure of the inverter of fault detection, analyzing of the photovoltaic interconnection protection device on the impact of contact line protection, introducing the islanding detection principles and methods of interconnection protection, and for the photovoltaic power system existing the islanding, a new method of islanding detection is proposed, which improves the principle of power directional relay by adding a hold circuit module initiated by the trip signal module in the original module, thus it can reliably detect the island operation of photovoltaic power.更多还原