Zhang Zhanlong

An Adaptive Fast Multipole Higher Order Boundary Element Method for Power Frequency Electric Field of Substation

An adaptive fast multipole higher order boundary element method combining fast multipole (FM) with a higher order boundary element method is studied to solve the power frequency electric field (PFEF) of substations. In this new technique, the iterative equation solver GMRES is used in the FM, where matrix-vector multiplications are calculated using fast multipole expansions. The coefficients in the preconditioner for GMRES are stored and are used repeatedly in the direct evaluations of the near-field contributions. Then a 500kV outdoor substation is modeled and the PFEF of the substation is analyzed by the novel algorithm and other conventional methods. The results show that, in computational cost and the storages capability aspects, the algorithm proposed in this study has obvious advantages. It is suitable for the calculation of the large-scale PFEF in complex substations and the design of electromagnetic compatibility.

Online detection system for contaminated insulators based on ultra-violet pulse method

In recent years, the contamination extent of insulators gets worse and worse, which leads to heavy pollution flashover of transmission line and power station in China. Based on ultraviolet pulse method, this paper introduces an online pollution monitoring system about its whole structure, hardware and software design. It also illustrates the experiments in the lab and in the field by monitoring continually the insulator strings under 110 kV transmission line. Meanwhile, it analyzes experiment and operation results, which proves that it is possible for this system to online monitor all insulators along the transmission line. Moreover, it can inform the pollution situation of insulators in advance, which is helpful to guarantee security of transmission line and reliable operation of power grid, and avoid large-scale pollution flashover accidents. This system has been using by local Power Supply Bureaus and proving the advantage of low price, high sensitivity and quick response speed.