Dynamic Model Test Of Offshore Substation Platform Under Earthquakes

Wind resources are clean and renewable energy. Wind-power generation plays an important role in alleviating environmental pollution, adjusting wind energy structure and other aspects. Along with the positive development of onshore wind-power generation, offshore wind power has gradually entered the people's view, credit its high quality of offshore wind energy resources.There are two major trends for offshore wind-power generation. The first is that wind turbine capacity is increasing, and the second is the wind energy development in deep sea. In order to reduce electrical energy loss, improve efficiency of power supply, offshore booster station has been an alternative for the construction of large offshore wind farm.Offshore substation platform is a load-bearing structure with lots of electrical equipments arranged on the decks. Substation platform needs to ensure not only the safety under the external environment loads, but also the normal operation of electrical equipments. The substation platform is subjected to wind, waves, currents and sea erosion, as well as earthquakes, ice and other dynamic loads during operation period. The safety of the substation platform and the normal operation of electrical equipment under the complex environmental loads is a key issue in the design of offshore wind farms. At present, there are scarce published research results on the offshore booster station platform in China. This study in the paper will be a significant reference for the design of the offshore booster station platform in the future..Based on a practical substation platform of offshore wind farm, the dynamic experimental model is designed. Then, the dynamic model test under different seismic load conditions is carried out. The main works in this thesis are as follows.1. The similarity theory is derived. Based on the elastic similarity and Froude similarity, and considering section bending stiffness similarity at the same time, the hydro-elastic similarity is suggested.2. The test model is designed and fabricated. Considering the capacity of test facility and the relevant hydrological conditions of substation platform, the geometric scale of the model is determined. According to the similarity laws of parameters, the dimensions of the model substation platform are obtained. Then the test model is manufactured.3. The dynamic model test is carried out. Subjected to white noise excitation, the natural frequency, mode shapes and damping ratio of the substation platform model are obtained. Using the underwater shaking table, dynamic tests are performed under the excitation of actual and synthesized seismic accelerations, and the seismic response characteristics of the offshore substation platform are studied.4. The experimental results and numerical results are compared. Using ANSYS, a finite element model of the substation platform model is established. Then, the dynamic characteristics and response histories of the substation platform model corresponding to the test cases are calculated. Comparing the experimental results with the numerical results, excellent agreement is obtained, which vadidates the finite element model and the reliability of experimental results.