Surge arrester allocation for lightning protection of VSC based HVDC prototype

Abstract

High-voltage direct current (HVDC) systems, based on voltage source converters (VSC), enable asynchronous interconnection of grids with different frequencies and contribute to grid stability by controlling power quickly and precisely. Effective protection of these expensive systems, which must be in continuous operation, increases their lifetime. An overvoltage protection study is needed to ensure the proper protection of HVDC systems that contain multiple devices with varying insulation levels. In this study, lightning protection studies on a prototype VSC-based HVDC (VSC-HVDC) system are explained. In line with this, lightning impulses were modeled and applied to various points in the PSCAD model of the prototype VSC-HVDC, and the response of the system combined with the protection equipment was examined. All stages of protective equipment selection were explained step by step. The suitability of the selected protective equipment was verified based on the simulation results. After running dozens of scenarios, the protection coordination was optimized, and the critical points were determined instead of installing surge arresters at each connection point. In this way, a significant cost benefit was obtained for the investment in protective equipment. Finally, the results of the lightning impulse tests performed to verify the insulation of the VSC-HVDC prototype are reported.