N-0安全的城市配电网安全域与供电能力

现有的配电网安全域与供电能力大都基于N-1安全准则,文中提出了N-0安全(即正常运行约束下)的城市配电网安全域模型和供电能力模型。首先,分析了研究N-0下的安全域及供电能力的必要性。然后,分别提出了N-0下配电网安全域和供电能力模型及供电能力曲线的概念和数学模型。最后,通过算例验证了所提模型的有效性,并分析了安全域与供电能力在N-0和N-1下的区别、联系以及在运行和规划中的使用方法。

Distribution management system framework based on security region for future low carbon distribution systems

In this paper,a new Distribution Management System(DMS)framework based on security region is proposed.First,the concept of Distribution System Security Region(DSSR)is introduced.DSSR is capable to describe the N-1 security boundary of the whole distribution network,including the secure output range of DGs.This new theoretic tool provides a chance for the implementation of real-time security analysis and active controls in DMS.Second,this paper proposes and describes five security states for distribution system.Third,an upgraded DMS enhanced with DSSR is proposed,which consists of advanced security functions such as preventive and predictive control of the trajectory of operating points.Finally,a practical case is presented to simulate the proposed DSSR-enhanced DMS,in which both the security region of network and the output range of DGs are calculated.Typical security functions are also demonstrated.In conclusion,the new DMS framework aims to help operate the system closed to its security boundary in order to improve the efficiency significantly within same security standard.This work is beneficial for future low carbon distribution systems with high penetration rate of DGs.

Total Quadrant Security Region for Active Distribution Network with High Penetration of Distributed Generation

The region-based method has been applied in transmission systems and traditional passive distribution systems without power sources. This paper proposes the model of total quadrant security region(TQSR) for active distribution networks(ADN) with high penetration of distributed generation(DG). Firstly, TQSR is defined as a closed set of all the N-1 secure operation points in the state space of ADN. Then, the TQSR is modeled considering the constraints of state space,normal operation and N-1 security criterion. Then, the characteristics of TQSR are observed and analyzed on the test systems with different DG penetrations. TQSR can be located in any quadrant of the state space. For different DG penetrations,the shape and security features of TQSR are also different. Finally, the region map is discovered, which summarizes the features of different types of distribution networks.

柔性配电网的安全域模型

提出了柔性配电网(flexible distribution network,FDN)的安全域模型,并与传统配电网(traditional distribution network,TDN)对比分析。首先,介绍了FDN的概念与特点。其次,分析了FDN正常运行N-0和N-1下的安全约束。再次,提出了FDN的安全域模型以及安全边界方程。最后,通过单联络与多联络电缆网算例验证了本文方法的正确性,对FDN和TDN的N-0域、N-1域以及供电能力进行了对比研究。对比发现:1)FDN能扩大N-0/N-1域,提高正常运行情况下带负载的能力与N-1安全性;2)FDN达到不计及N-1和计及N-1下的最大供电能力工作点相比TDN多很多,使其在实际中更容易实现;3)FDN节点负荷能突破馈线容量限制,具有更大的局部带大负荷能力。同时,通过二维视图观察总结FDN安全域的形状特点及形成机理,并揭示其与柔性闭环特征的内在联系,最终从安全和高效角度分析得出多联络更适合发挥FDN作用的结论。

Exploiting Flexibility of Integrated Demand Response to Alleviate Power Flow Violation During Line Tripping Contingency

Multi-energy integrations provide great opportunities for economic and efficient resource utilization. In the meantime, power system operation requires enough flexible resources to deal with contingencies such as transmission line tripping. Besides economic benefits, this paper focuses on the security benefits that can be provided by multi-energy integrations. This paper first proposes an operation scheme to coordinate multiple energy production and local system consumption considering transmission networks. The integrated flexibility model, constructed by the feasible region of integrated demand response(IDR), is then formulated to aggregate and describe local flexibility. Combined with system security constraints, a multi-energy system operation model is formulated to schedule multiple energy production, transmission, and consumption. The effects of local system flexibility on alleviating power flow violations during N-1 line tripping contingencies are then analyzed through a multi-energy system case. The results show that local system flexibility can not only reduce the system operation costs, but also reduce the probability of power flow congestion or violations by approximately 68.8% during N-1 line tripping contingencies.