This chapter gives an extensive overview into the nature of the environment that luminaires and thus LEDs are subjected to during the event of a lightning stroke. Direct lightning stroke almost always results in instant damage for low-voltage connected devices, except in “extraordinary circumstances” where random components may survive. This is usually not a subject for debate and is not the subject of this monograph. Indirect consequences of lightning strokes, however, can be effectively mitigated as described. This chapter also delves into a realistic expected overvoltage levels for two typical systems, overhead lines and insulated cables, as obtained from lightning studies on a power network supplying power to LED devices and thus justifies the recommendations by several standards. In addition, it shows the importance of an often neglected device—MOV in mitigating attendant surges due to lightning to a level that can be withstood by LEDs and associated devices.@en

This paper proposes a new knowledge-based control philosophy for the direct voltage and power control of a multi-terminal voltage source converter based offshore HVDC grid. The limitations of the classical direct voltage droop control
strategy are discussed and mainly the difficulty to reach powerreference set-points is stressed. In that context, a knowledge based intelligent controller (namely Fuzzy) is proposed. It is capable of addressing these weaknesses by combining the advantages of the droop controller such as robustness and exceptional ability to compensate for imbalance during contingencies, and the constant active power controller which has the ability to easily reach power set points. In this context, the power dispatch of the HVDC grid converters is achieved without the need to solve before-hand HVDC grid load flow equations where the droop constant is included in the algorithm. The advantages of the new Fuzzy controller is the reduced computational effort, the high degree of flexibility, and the zero percentage error. The efficacy and robustness of the control strategy is demonstrated by means of time domain simulations for a three terminal voltage source converter based offshore HVDC grid system used for the grid connection of large offshore wind power plants.@en