配电网安全域法的改进及与N-1仿真法的对比验证

配电系统安全域(DSSR)是一种新的配电网安全评价方法,但是现有DSSR方法尚未给出N-1仿真安全评价法能够得到的所有信息,文中对DSSR法进行改进并与仿真法全面对比。首先,分析了两种方法的原理:N-1仿真法逐个模拟元件故障,通过校验是否满足过负荷等静态安全约束来评价是否安全,并用停电范围和容量裕度来分别衡量不安全和安全的程度;DSSR方法预先根据网络结构和参数计算N-1安全边界,不需要仿真,能够通过判断工作点在安全边界内外快速计算电网是否安全,再依据工作点到安全边界的距离来衡量安全或不安全程度。然后,在此基础上提出了DSSR安全评价的改进方法,使其能够得到仿真法的所有结果,包括按严重程度排序的故障集、过负荷元件集和过负荷的大小。最后,通过算例将两种方法进行对比,验证了改进方法的正确性和快速性。所述工作不仅扩展了DSSR方法的功能,还揭示了DSSR方法与仿真法的关系,解释了DSSR法能够不经过仿真准确得到N-1安全分析结果的原理,为DSSR的实际应用奠定了理论基础。

Enhanced DSSR Method and Its Verification by N-1 Simulation

The distribution system security region(DSSR)is a new method of distribution network security evaluation, but this method has not given all the information obtainable from N-1 simulation. The DSSR method is enhanced and compared with N-1 simulation. Firstly, the principles of two methods are analyzed: the N-1 method simulates the components one by one to check whether they satisfy the static security constraints, and the power cut range and residual capacity is used to measure safety degree. The DSSR method calculates N-1 security boundary in terms of network structure and parameters in advance, and judges whether it is secure or not without simulation by judging whether it is inside or outside the DSSR boundary. Then, the safety degree is measured by the security distance. Secondly, an enhanced DSSR method is proposed to obtain all the results of N-1 simulation, including the sorted contingency set, overload element set and the degree of the overload. Finally, a numerical example comparing the two methods is given to illustrate that the enhanced DSSR method is correct and highly efficient. The proposed work not only extends the function of DSSR, but also reveals the relationship between the two methods while explaining why the enhanced DSSR method has made it possible to obtain all the results from the simulation method. This paper helps to use the DSSR method in practical applications.This work is supported by National Natural Science Foundation of China(No. 51477112)and Program for New Century Excellent Talents in University(No. NCET-10-0624).