Distributed state estimation of hybrid AC/HVDC grids by network decomposition

Abstract

Power system state estimation is traditionally formulated and executed as one integrated problem while considering all the network components and their interactions in the grid simultaneously. Such simultaneous approach presents challenges when the concerned network consists of different types of systems operated by different entities (ISO, TSO or utility). A leading example is provided by hybrid AC/HVDC grids. We propose a method that complements the simultaneous approach, where the system network is decomposed into several subsystems on which the state estimation is executed separately in an iterative way. Hybrid AC/HVDC grids naturally decompose into AC and HVDC subsystems. The method uses LaGrangian relaxation based approach and blockwise Gauss-Seidel solution technique to arrive at a solution. The solution approach is illustrated using hybrid AC/HVDC grids formed by IEEE AC grid networks along with monopole and bipole VSC HVDC grids. The presented technique is capable of handling monopole/bipole converter configurations, parallel converters, converter-less DC buses, wind farm connections and grid contingencies. Although hybrid AC/HVDC grids is considered as a primary application, the method employs a general formulation applicable to address any power grid that can be decomposed into a number of parts.

Multi‐objective manta ray foraging algorithm for efficient operation of hybrid AC/DC power grids with emission minimisation

“…Traditional operational procedures must be updated and adjusted to this advanced aspect of interconnected MTHVDC power grids. These technologies will impact on several optimization problems in the field of power and energy systems like energy hub problem [7–9], scheduling of electrical consumption in multi‐chiller systems [10], electricity load forecasting [11], assessment of renewable energy sources [12], reactive power dispatch [13, 14], state estimation [15], economic load dispatch [16], and OPF [17] etc. Due to the vital role of the OPF in operating the power networks, its extension plans, and the correlated economic studies, it needs technical and performance improvements to manage the hybrid power grids.…”