An approach for a real time adaption of the dead time for auto-reclosing on high voltage lines was proposed. The objective was the optimal adaption of the dead time of a currently running single-phase auto-reclosing cycle by calculating the secondary arc current based on measurements. The algorithms for optimization were performed for real time application. For this purpose, the fault location plus the load currents of the parallel non-faulty conductors were measured. The measurement and the calculation of the dead time took place during the fault and the dead time period. In this way, an optimized dead time setting with regard to the actual fault location and loading conditions were achieved. This approach results to an on-line determination of a minimum necessary dead time of a successful reclosing under consideration of the fault location and prevailing loading conditions. Analytical calculations and numerical examples as well as high voltage field tests verified the results.

A large-scale testing device for the experimental investigation of soil-structure interactions was developed. It allows an observation of the evolution of deformations and the measurement of the stresses in the soil-structure contact zone under 1 g-conditions. The tests are designed as boundary value problems for benchmark tests of numerical simulations. They can be used to validate contact formulations and constitutive equations for the soil. The dimensions (soil height >1.5 m) provide a sufficiently high stress level for simulations with constitutive models for soil. The major part of the device is an instrumented wall section with modifiable surface roughness representing, e.g., a part of a pile shaft or a steel sheet. This wall can be displaced quasi-statically relative to an adjacent soil body. The distribution of shear and normal stress and the wall displacements are measured. Digital image correlation (DIC) is used to evaluate the soil deformations. The paper focuses on the basic concept, the design, and the instrumentation details of the testing device. Additionally, some selected test results are shown.

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The knowledge of the initial soil state (stress and density distribution) in geotechnical model tests is indispensable, particularly with regard to FE back calculation of experimental results. Usually, so-called K 0 -conditions are assumed, which for many cases do not describe the soil stress state before the experiment begins adequately. Using an exemplary test device we present and discuss different measurement techniques for the interpretation of soil deposition procedures and the evaluation of the initial state. By means of stress and bearing force measurements, the stress state is captured representatively. The soil deformations during the filling of the test device are evaluated with Digital Image Correlation (DIC) methods and the initial density distribution is examined by cone penetration tests (CPT). Afterwards, a simple FE simulation method is presented, which models the soil deposition procedure by a weight increase layer-by-layer. It is shown that the method is suitable to provide a realistic initial soil state. The methods presented can be easily transferred to other geotechnical test devices and can in many cases ensure a better comparability of tests with their simulations.