Lightning Risk Assessment Method for Important Facilities of New-Type Power System

The Electro-Geometric Model (EGM) is primarily applied to lightning shielding analysis on individual facility but neglects shielding by adjacent objects. Under the background of new-type power system construction, renewable energy plants and dense transmission corridors involve numerous closely spaced facilities. To address this, a unified analytical model and numerical solution to calculation of lightning flashover occurrence is proposed in this paper. All facilities, such as overhead ground wires, conductors, wind turbine blades and photovoltaic arrays, are included in a unified coordinate system, and above area is divided into uniformly sized grids at a certain height, where lightning leader starts from and propagates downward. For each downward step, distances between leader top and each facility are calculated iteratively, and compared with their striking distances to determine whom to be stroke. Finally flashover occurrences of each facility could be obtained through iterations and statistics. Model and numerical solution is also elaborated by assumed cases. Referencing IEC 62305-2 for lightning risk assessment, a risk grade criterion is established. Additionally, a dedicated assessment software is developed, which supports grid meshing, addition of facilities in drag-and-drop way, striking distance ranges visualization and so on. Above work is suitable for practical engineering and provides guidance for accurately obtaining lightning risk and conducting targeted regulation.