反时限零序电流保护由于其优越的特性得到越来越广泛的应用，很多学者提出通过优化的方法对其定值进行整定计算。但是，目前常用的保护定值优化算法往往存在迭代过程复杂耗时长、结果不稳定问题，仍存在进一步优化空间。为此，提出了一种超高压电网反时限零序电流保护定值二次型优化方法。首先建立了反时限零序电流保护定值优化模型，分析了在时间整定值T_p一定的情况下，动作时间t与启动电流I_p的关系，然后进行线性拟合，将复杂难以优化求解的非线性非凸优化模型转化为一个二次目标二次约束模型。然后基于MATLAB软件平台，采用建模工具YALMIP对问题进行建模，调用优化求解工具Gurobi进行求解，最后以IEEE 39节点系统为例验证了所提方法的有效性和优越性。

Because of its superior characteristics, inverse-time zero-sequence overcurrent relays have been put into use in more and more areas. Many scholars propose to set its setting value through optimization method. However, the commonly used protection setting optimization algorithms often suffer from complex and time-consuming iterative processes, as well as unstable results, and there is still room for further optimization. Therefore, a quadratic optimization method of inverse-time zero-sequence overcurrent relay settings in extra-high voltage power grid is proposed. Firstly, the inverse-time zero-sequence overcurrent relay setting optimization model is established. When the time setting value T_p is certain, the relationship between action time t and the starting current I_p is analyzed, and then the linear fitting is carried out to transform the complex nonlinear non-convex optimization model that is difficult to optimize into a quadratic objective quadratic constraint model. Then, based on the MATLAB software platform, the problem is modeled according to the modeling tool YALMIP, and the optimization solving tool Gurobi is used to solve it. Finally, the IEEE 39-bus system is taken as an example to verify that the proposed method is effective and superior.