Wei Zhang

This paper proposes an optimal power flow method considering interval uncertainties (OPFIU) to enhance the security and economy of power systems with high renewable energy penetration. The OPFIU incorporates bi-level interval power flow (BIPF) equations, security and operation constraints, and active power balance across two extreme renewable output scenarios. Firstly, a dynamic-balance optimization scenario method (DOSM) is proposed to solve the BIPF within the OPFIU. The BIPF involves multiple generators in dynamically balancing the system’s active power, thus reducing the conservatism prevalent in existing interval power flow methods. Next, based on the BIPF results, an adaptive security limits definition method (ASLDM) is presented to convert the OPFIU model into a deterministic optimal power flow model, making it more tractable for solution. The ASLDM not only improves the solution efficiency and convergence of existing interval optimization methods, but also provides enhanced reliability in maintaining transmission power within operational limits across a broad spectrum of uncertainty scenarios. Moreover, the ASLDM, unlike robust optimization methods that require convexification of nonlinear AC power flow equations, partially avoids potential issues such as accuracy degradation or solution infeasibility resulting from model simplifications. The Simulation results, compared with robust optimization and chance-constrained programming methods, demonstrate that the proposed ASLDM improves both solution efficiency and convergence in solving the OPFIU problem.

This article proposes a novel spatial–temporal resilience assessment scheme for the distribution system (DS) to address the issue of overoptimistic and potentially misleading assessment due to the imprecision of a single typhoon wind speed model and the neglect of the coupled impact of typhoon rainstorm. First, a dynamic weighted iterative algorithm (DWIA) is proposed for accurate modeling of the typhoon wind speed, and a DWIA-based equivalent wind speed (EWS) model is further proposed for improving the accuracy of wind speed calculation under the coupling effect of typhoon rainstorm. Then, EWS-based uncertain failure probability models are developed for passive and active components, such as distribution lines, poles, and photovoltaics, and the adverse impacts of typhoon coupled with rainstorm events (TCREs) on the outputs of active components are considered. Furthermore, a set of normalized resilience metrics is defined, and sequential Monte Carlo simulation is adopted to evaluate the DS resilience against the TCRE as it travels inland. Finally, the modified IEEE 33-bus system and the actual distribution system from Southern China affected by the TCRE are both tested and analyzed to validate the effectiveness of the proposed scheme. The numerical results show that the proposed scheme can effectively quantify the adverse impact of the TCRE on the DS, and provide assistance for the proactive resilience control of the DS.

To improve the resilience of distribution networks (DNs) in the event of extreme natural disasters such as typhoons and rainstorms, it is imperative to efficiently implement distribution service restoration (DSR) to restore loads as soon as possible. In previous studies, DSR has mainly adopted the distributed resource model with droop or PQ control. This inhibits the exploitation of the potential of distributed generators (DGs) in load restoration when the DN loses support from the upstream transmission network. Thus, this paper proposes a multi-resource collaborative service restoration (MRCSR) approach for DNs incorporating local soft open points, DGs, and tie switches. The MRCSR model is developed by integrating a decentralized hierarchical droop control (DHDC) strategy and incorporating the frequency and voltage features of the load demand. A two-stage iterative feedback optimization (TSIFO) algorithm is then developed to analyze the MRCSR model in an accurate and efficient manner. Finally, the proposed model and algorithm are tested on the modified IEEE 33-bus system and a practical distribution system of the Taiwan Power Company to verify their effectiveness and advantages over existing approaches.

In order to solve too long maintenance power line and time-consuming in outdoor of substation, and when many maintenance team are working, wiring is confusion, which is easy to create security risks and other problem, a solar portable maintenance power box which using electric/photoelectric complementary technology, is designed from appearance structure, the grid/solar input module, control circuit of battery and inverter. It is tested by using simulation of Matlab/Simulink. Finally, the contrast test is proved to improve efficiency and reliability of maintenance in the substation.