基于风电并网技术规定及运行特征的自适应保护研究

Affected by fuel shortages, environmental degradation, policy incentives, energy consumption quotas, wind power in China is rapid development. But the operating characteristics of wind power is different from the conventional energy，the wind farm output is fluctuating. The grid topology and fault characteristics are changed after wind farm connect to grid. Without considering the impact of wind power will cause protection misoperation，and the scope of protection is difficult to define. Protection schemes are difficult to coordinate with, and protection sensitivity is reduced. Current protection configuration does not meet the technical requirements of the wind power. The following content will be explored in depth。（1）The project intends to build a computational model which is adapted to changing operating characteristics of wind power，and the wind farm is considered as a support power, "Polymorphism" of short-circuit current provided by wind farm will be studied，and the Impact on the protection caused by wind farm will be analyzed.（2）Taking increase current into account provided by the wind turbine ,adaptive current protection for the wind farm collector lines will be studied. (3) Based on the wind power impact on the existing distribution network protection mechanism， the new protection construction method adapt to wind power characteristics will be studied. (4)Against protection problems the wind power output line faced, and based on the wind farm has the fault through ability, adaptive techniques will be studied to improve the protective properties， the efficiency of wind farms and wind power capacity the power system can accept.The results will contribute to rapid development of wind power industry ,and have significant practical value and theoretical significance.

受燃料短缺、环境恶化、政策激励、能源消费量配额等因素驱动，我国风电快速发展。但风电运行特征与常规能源不同，出力波动大。风电接入改变了电网的拓扑结构和故障特征。不考虑风电的影响将导致保护误动、保护范围难界定、配合困难、灵敏度低等问题。目前保护配置与风电并网标准不符。研究内容包括：（1）根据继电保护特性和整定计算要求，将风电场作为支撑电源，构建适应风电场多变运行特征的计算模型，研究其提供的短路电流"多态"性及对保护的影响；（2）计及风电机组提供的助增电流，研究适用于风电场集电线路的自适应电流保护方法（3）在研究风电对原有配网保护影响的机理上，寻求适应风电特点的配网新型保护构建方法；（4）针对风电输出线路保护面临的问题，研究故障穿越运行下，采用自适应技术改进保护性能的途径。旨在保证安全运行的前提下，提高风电场效率和系统对风电的接纳力。研究结果可促进风电行业发展，具有重大的工程实用价值及理论意义。

针对LVRT策略与目前保护配合不协调问题，基于风电并网技术规程，分别提出了应用于直驱、双馈风电场的LVRT的综合控制策略；在研究风电系统短路电流“多态”性的基础上，研究了风电场各部分保护的动作特性及其协调性，提出了改善风电场保护协调性的措施，提出,采用反时限自适应电流保护方案或电流保护I段加一小段延时,解决了电流保护I段与熔断器选择性问题，有效避免了非故障线路风电机组因低压越限保护动作而退出运行的现象；研究了风电场运行参数对测量阻抗的影响，结合风电场侧的阻抗特性，研究了风电场联络线故障电流、电压特性及其对距离保护的影响，提出并实现了应用于风电场联络线的自适应距离保护的方案，所提出的方案有较强的耐受过渡电阻能力，能够适应风电场运行工况多变特性，有效消除双馈风电场侧非工频电流、电压对的保护影响，避免保护误动；推导建立了配电网不同位置故障时的故障电流表达式，研究了风电接入对配网馈线短路电流的影响。基于风电场LVRT并网要求，提出一种可以最大限度地实现风电场LVRT能力的电场联络线多段式低电压保护方案，有效解决了风电场联络线电压保护与风电场LVRT能力要求不协调问题。提出风电场下游线路采用基于背侧阻抗的自适应电流保护方案，避免风电场助增作用对下游线路保护选择性的影响。提出并验证了基于风电场LVRT特性的配电网重合闸保护配合方案。研究了风电场T接对线路保护的影响，提出了风电T接线路保护配置的建议。研究成果可为风电接入系统的保护配置提供理论支撑，保证风电场及其接入系统的稳定运行。