开环运行直流配用电系统安全域模型建立与应用

根据直流配用电系统安全性要求,针对一组预想故障,系统应具有对负荷持续供电的能力。N-1校验作为系统故障情况下能否持续带载的评判标准,反映了系统安全性的强弱。当前对直流配用电系统安全性研究较少,为了研究故障后系统的转供机理,对开环运行的直流配电系统进行分析,以此建立简化的安全域模型。首先定义N-1校验所需参数,推导各参数之间的数学关系,以期用较少的参数表示出系统的网络架构。在此基础上分析馈线N-1故障及换流站N-1故障的转供机理,利用已定义的参数描述此转供过程,得到了馈线和换流站的N-1约束条件,建立安全域模型。随后基于安全域模型对系统最大供电能力进行求解,推导分析供电能力与负载均衡度之间的关系,绘制最大供电能力-方差曲线,并利用熵权理想度排序法找到最优解。通过算例与现有安全域模型对比校验,验证了所提模型的可行性,为直流配电系统规划、建设、运行和维护提供理论基础。

Establishment and Application of Security Region Model of DC Distribution System

The security of the DC distribution system requires the system to maintain the ability to supply power in response to a set of expected faults. N-1 check, which reflects the strength of system security, is used as a criterion for judging whether the system can continue to carry load under the condition of system fault. At present, no corresponding evaluation standard are studied on the security of DC distribution system. In order to study the transfer mechanism of fault sysem, open-loop topology is analyzed to establish a simplified security region model. Firstly, the parameters required by N-1 check are defined, and mathematical relationship between these parameters is derived, which is to reveal the network architecture of the system with fewer parameters. Secondly, the transfer mechanism of feederN-1 fault and converter station N-1 fault is analyzed. According to the defined parameters, the transfer process is described, and the N-1 constraint conditions of the feeders and converter stations are obtained. Therefore, the security region model is established. Thirdly, applying the security region model, the total supply capability of the system is calculated. Also, the relationship between power supply capability and load balance, which can be drawn as C_S-s² curve, is deduced. Thereafter, the optimal solution is found by using the entropy order method to analyze the curve. Finally, the feasibility of the model proposed in this paper is verified by comparing with existing security region model in the example.