LVRT综合控制策略作用下的风电系统故障特征及保护对策研究

In order to deal with system security and stability issues to large clusters of grid connected wind power, wind turbine must have low voltage ride through capability. It brings enormous challenge to the protection of wind turbine, collector line , outgoing transmission line of wind farm/groups. So the key content of the research is: based on the characteristics of structure and reactive power control mode, study on the relationship between the protection of wind turbine and the mechanism of interaction of the international requirements of LVRT, Building the wind turbine LVRT coordinated control strategy which meet with the wind turbine protection and requirements of wind power grid control technology and take account into various realization methods of wind turbine LVRT and the additional hardware structure; Based on the function of LVRT coordinated control strategy , analysis the wind power system fault feature with multi time scale and multi space , then research the existing protection performance ,and the present research of traveling wave protection, transient based protection and parameter identification of new intelligent protection principle of adaptive protection; Building the improved protection scheme of wind farm collector line and wind farm/group outgoing transmission line based on the adaptive principle. Simulating the example of wind power entered the network in Xinjiang, further verifies the improvement scheme and modified criterion .The research results to solve the ability of LVRT and the protection of wind farm coordination, lay the foundation for the construction of wind power relay protection system.

为了应对集群风电并网带来的系统安全稳定问题，风电机组必须具备低电压穿越能力，对风电机组本体保护、风电场集电线保护、风电场/群送出线保护性能提出了巨大挑战。因此本项目研究关键内容：基于结构特点和无功控制方式特点研究风电机组本体保护与国标要求的LVRT相互关系机理，构建满足风电机组本体保护条件和风电并网技术要求并兼顾各种风电机组LVRT实现方式和附加硬件结构的风电机组LVRT综合协调控制策略；基于LVRT综合协调控制策略作用，分析多空间、多时间尺度风电系统故障特征，研究现有保护动作性能以及目前已有研究的行波保护、暂态量保护和参数识别保护等智能新原理保护适应性；构建基于自适应原理的风电场集电线路和风电场/群送出线保护改进方案及判据。通过新疆风电并入主网算例仿真验证并进一步修正判据及改进方案。其研究成果为解决风电场LVRT能力与保护间的协调配合、为风电系统继电保护体系的构建奠定基础。

本项目针对风电系统故障穿越和继电保护问题，基于不同类型风电机组结构特点和无功控制方式研究风电机组本体保护与国标要求的LVRT相互关系机理，构建了满足风电机组本体保护条件和风电并网技术要求的风电机组LVRT综合协调控制策略；深入研究了LVRT综合协调控制策略作用下和风电机组结构影响下的风电机组、风电场、风电场群故障特征；基于故障特征分析结果，结合新疆地区风电集群式接入特点，研究了集群风电系统现有保护方案在可靠性、灵敏度以及动作时限配合等方面存在的问题，探究现有保护原理和智能保护新原理的适应性问题。在风电场/群保护必须兼顾“系统故障时风电场/群LVRT”和“风电场内故障时快速有效切除”前提下，研究了风电场/群继电保护的改进措施，以保证集群风电接入系统安全可靠运行。项目主要研究成果如下：. 1.探讨直驱、双馈风电机组LVRT拓扑结构、无功控制策略、风电机组本体保护配置三者相互关系机理，构建了直驱、双馈风电机组LVRT综合协调控制策略。研究了基于LVRT综合协调控制策略作用下的风电系统故障特征。. 2.分析了时域全量距离保护在风电系统中的适应性，分别提出了：考虑过渡电阻影响、抗暂态超越的时域方程模型误差修正时域距离保护、基于分布参数模型的风电系统长距离送出线路时域距离保护、基于参数识别的集群风电送出线路时域距离保护原理。. 3.分析了基于模型识别的纵联保护原理在风电系统中的适应性，提出基于时域全量模型相关性判别的集群风电送出线路纵联保护原理。