This study presents the impact of wind power plant components modelling on harmonics propagation and harmonic small-signal stability studies. Different types of cable and transformer modelling techniques are taken into consideration, e.g. state-of-the-art standard models and latest academic developments. The models are compared based on system-level studies in a real-life large offshore wind power plant. It is shown that the use of detailed cable and transformer models increases the overall damping estimation in the system, and therefore improves the resonance characteristics and small-signal stability margins of the investigated wind power plant.

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<p>Submarine cables used in harsh environmental conditions are often strengthened by means of protective structures, in addition to the armour, for  enhanced mechanical durability. The added exterior protection shields the cable against damage during installation and operation. These, polymeric or<br />metallic protective structures, contribute to the temperature increase in the cables by reducing the natural cooling processes. <br />In this paper are described investigations on the thermal conditions in and outside a three-phased armoured submarine cable equipped with a fully enclosed mechanical protection. The investigations are conducted through a full-scale experiment, including mitigation techniques. <br />In the full-scale experiment, the effects of the protective pipe result in a temperature increase when compared to an experiment using a cable with no protective pipe. The measurements show that the addition of the mechanical protection may result in the phase conductor temperatures to reach and<br />exceed the critical 90 °C limit, even under otherwise normal operating conditions.<br />The effect of measures to mitigate the increase in phase conductor temperature was also investigated. At set intervals a symmetrical distribution of holes<br />were drilled into the protective pipe. This mitigation technique resulted in a temperature decrease of approximately 9 °C in phase conductor temperature.</p>