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With the rise of smart grids in distribution level, the new service of automatic network reconfiguration is established. Consequently, the power system topology may experience multiple changes during any day of operation. However, many services and applications require for reliable operation knowledge about the actual topology state which is provided by network control center. Even in case of communication...
The continuing growth of energy from renewable resources demands for structural changes of energy transmission systems. These changes are on the one hand related to the increasing decentralized power generation and on the other to different power flow scenarios due to fluctuation in power generation. For example, offshore wind parks require a high transmission capacity over long distances. In order...
The integration of decentralized renewable energy sources leads to a changed load profile of electrical power engineering utilities such as generators, transformers etc. A decreased application of thermal power plants as primary supply of electrical energy results in progressive energy transition and rising load dynamics. Frequent start-up processes etc. lead to rapid changes in the operation conditions...
The partial discharge diagnosis is an established instrument for the condition assessment of high voltage insulations and equipment. Under AC voltage stress the phase resolved pattern is of great significance in order to become aware of the type of fault. As a result of the inapplicability for DC voltage stress, approaches for alternative interpretation techniques such as the time domain analysis...
To increase the transmittable electrical power without building more transmission lines, a conversion from an AC circuit into a DC circuit seems reasonable. Within the resulting hybrid transmission line system, coupling phenomena have to be considered. This paper concentrates on the measurements concerning the coupling effect induced by the HVDC system, influencing the HVAC systems: the ohmic coupling...
Experimental data of a long term test for accelerated ageing of mineral oil impregnated presspaper insulation systems are presented. Devices under test were thermally or combined thermally and electrically stressed. After a defined ageing period, the insulation systems were analysed to determine the influences of the different stresses on ageing of presspaper and mineral oil. For the evaluation of...
To increase the transmittable electrical power without building more transmission lines, a conversion from an AC circuit into a DC circuit seems feasible. Within the resulting hybrid transmission line system, coupling phenomena have to be considered. This paper concentrates on the measurements concerning the coupling effect induced by the HVDC system, influencing the HVAC systems: the ohmic coupling.
In standard operation, the electrical insulation system of generators, transformers, etc. used by power utilities is highly stressed with multiple simultaneous loads like electrical, thermal, mechanical, environmental or chemical stresses. Single load tests are therefore not able to fully represent the correspondent aging mechanisms. Multi-factor aging tests with electrical, thermal and mechanical...
Due to the rising number of DC transmission systems there is an increasing interest in partial discharge (PD) diagnostics at DC voltage. Under AC stress there are several established instruments to get evidence of the type and the location of the defect, most important the phase angle histogram. Under DC stress there are no such methods available up to now and therefore new interpretation techniques...
Partial Discharge (PD) detection and diagnostics is an established tool to test the condition of the insulation in HV-facilities. One basic question while performing PD measurements is the one concerning the type and location of the defect. Under AC stress there are several instruments to interpret the measured PD, most important the phase angle histogram. At DC voltages this approach is inapplicable...
An important tool for the estimation of the insulation's condition in electrical devices is the partial discharge (PD) measurement. Under AC stress, the PD phase distribution can be used to classify the type and location of different defects. At DC voltage this approach is inapplicable. Therefore, other parameters for the classification of different PD-sources have to be identified. Here the pulse...
Reverberation Chambers are often made of commercialised shielding rooms with dimensions in the meter range. On one hand this is very expensive; on the other hand the maximum amplitude of the E-field decreases with volume for a given input power. In the lower GHz-range small chambers with volumes below 1 m3 provide much higher field strengths at low input power. If small devices need to be tested at...
Silica (SiO2) filled epoxy with a particle size in μm-range has been established during the last decades. Now it has become possible to produce SiO2-filled epoxies, with filler particles in nm-range, which can be located in the polymer homogenously and without agglomerates. A new group of materials with a high percentage of inner boundaries has been designed. Therefore, the effect of this high interface...
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