Improvements to the fracture pipe network model for complex 3D discrete fracture networks

Acknowledgments Chenhui Wang thanks the financial support from China Scholarship Council (CSC) for his Ph.D. study. The authors thank the discussions of the real-world case study with Dr Yu Jing at the University of New South Wales. Open access via Wiley agreementPeer reviewedPublisher PD

Sufficient Conditions for the Exact Relaxation of Complementarity Constraints for Storages in Multi-period ACOPF

Storage-concerned Alternative Current Optimal Power Flow (ACOPF) with complementarity constraints is highly non-convex and intractable. In this letter, we first derive two types of relaxation conditions, which guarantee no simultaneous charging and discharging (SCD) in the relaxed multi-period ACOPF. Moreover, we prove that the regions on LMPs formed by the proposed two conditions both contain the other four typical ones. We also generalize the application premise of sufficient conditions from the positive electricity price requirements to the negative electricity price scenarios. The case studies verify the exactness and advantages of the proposed method

A Spatio-temporal Decomposition Method for the Coordinated Economic Dispatch of Integrated Transmission and Distribution Grids

With numerous distributed energy resources (DERs) integrated into the distribution networks (DNs), the coordinated economic dispatch (C-ED) is essential for the integrated transmission and distribution grids. For large scale power grids, the centralized C-ED meets high computational burden and information privacy issues. To tackle these issues, this paper proposes a spatio-temporal decomposition algorithm to solve the C-ED in a distributed and parallel manner. In the temporal dimension, the multi-period economic dispatch (ED) of transmission grid (TG) is decomposed to several subproblems by introducing auxiliary variables and overlapping time intervals to deal with the temporal coupling constraints. Besides, an accelerated alternative direction method of multipliers (A-ADMM) based temporal decomposition algorithm with the warm-start strategy, is developed to solve the ED subproblems of TG in parallel. In the spatial dimension, a multi-parametric programming projection based spatial decomposition algorithm is developed to coordinate the ED problems of TG and DNs in a distributed manner. To further improve the convergence performance of the spatial decomposition algorithm, the aggregate equivalence approach is used for determining the feasible range of boundary variables of TG and DNs. Moreover, we prove that the proposed spatio-temporal decomposition method can obtain the optimal solution for bilevel convex optimization problems with continuously differentiable objectives and constraints. Numerical tests are conducted on three systems with different scales, demonstrating the high computational efficiency and scalability of the proposed spatio-temporal decomposition method

A Dynamic Equivalent Energy Storage Model of Natural Gas Networks for Joint Optimal Dispatch of Electricity-Gas Systems

The development of energy conversion techniques enhances the coupling between the gas network and power system. However, challenges remain in the joint optimal dispatch of electricity-gas systems. The dynamic model of the gas network, described by partial differential equations, is complex and computationally demanding for power system operators. Furthermore, information privacy concerns and limited accessibility to detailed gas network models by power system operators necessitate quantifying the equivalent energy storage capacity of gas networks. This paper proposes a multi-port energy storage model with time-varying capacity to represent the dynamic gas state transformation and operational constraints in a compact and intuitive form. The model can be easily integrated into the optimal dispatch problem of the power system. Test cases demonstrate that the proposed model ensures feasible control strategies and significantly reduces the computational burden while maintaining high accuracy in the joint optimal dispatch of electricity-gas systems. In contrast, the existing static equivalent model fails to capture the full flexibility of the gas network and may yield infeasible results.Comment: 12 pages, 8 figure

Explicit incorporation of discrete fractures into pore network models

Research Funding China Scholarship Council. Grant Number: 201708060457Peer reviewedPublisher PD