In the design of static apparatus such as transformers and capacitors, computational analysis is indispensable. Progress of the analysis techniques makes their development more efficient, and makes it possible to identify cause of failure and understand various phenomena. For this reason, computational methods for analysis of power systems and mechanical, heat and electromagnetic fields in static apparatus have been intensively developed. This report describes the-state-of-the-art techniques in these methods and future issues in analysis techniques for static apparatus.
This paper discusses the harmonic distortion occurring at capacitors with 6% series reactor upon energization of parallel connected 3-winding transformer. The harmonic order of resonance between the capacitor and the 6% series reactor is 4.1th harmonic, which is fairly close to the 4th harmonic. Energizing a transformer on the power system can cause sympathetic magnetizing inrush currents to flow in an already energized parallel transformer. Energizing the second transformer causes a voltage drop across the resistance of the source line feeding the transformers. This voltage drop may cause a saturation of the already energized transformer in the negative direction. This saturation causes magnetizing inrush current to supply the flux. This sympathetic inrush current through inductive reactance associated with the source line and leakage reactance of the already energized transformer causes voltage distortion at the load side (capacitor circuit). As the 4th harmonic of the voltage becomes larger, the 4.1th harmonic resonance between the power capacitor and the 6% series reactor occurs, and huge current instantaneously flows. EMTP (Electro Magnetic Transients Program) simulation of the energization of parallel connected transformer (sympathetic inrush) was carried out. As a result, the waveforms simulated by EMTP reproduced the measured waveforms.
In the electric power equipments such as transformers and generators, magnetic shields are placed on the inner side of the tanks to prevent coil leakage fluxes from entering into the tanks. Some of the magnetic shields are constituted of laminated steels and ancillary steels which are welded to the laminated steels for the purpose of holding on the laminated states. In this paper, the eddy current losses of such magnetic shields are analyzed by using the homogenization method and the losses of the shields are measured by using the calorimeter measurement method. The effectiveness of the analysis is shown by comparing with the experiment.
We developed the 550kV disconnectors that strengthened earthquake proofing by the addition of the damper unit and weight reduction of conductive part based on the damage of the 550kV disconnectors by the Great East Japan earthquake (March 11, 2011) and inspected the earthquake proofing performance by shake table test. In shake table test, we performed the test by the artificial seismic wave that varied in phase characteristic in addition to the test by resonance method. And, in a high-level earthquake area, we analyzed it about the influence that a phase characteristic of the artificial seismic wave gave to stress to occur in disconnectors. As a result, it is thought that the stress to occur in disconnectors is decided by a primary natural frequency basically because a bending strain to occur to the disconnectors in the time when the resonance frequency ingredient becomes the big acceleration response value grows big. But, on a particular phase condition, it was confirmed that the bending strain to occur in disconnectors might grow big conspicuously. As for this, the possibility is thought about by influence of higher natural frequency doing superposition.
The operation insulator part of a 550-kV disconnector has a middle universal joint which generates a nonlinear oscillation. Since the nonlinear oscillation characteristic of the middle universal joint was not clear, test device of the operation insulator was created and the nonlinear oscillation characteristic was clarified by the vibration test. Moreover, the Finite Element Method (FEM) model of an operation insulator part is proposed and it calculated in nonlinear analysis. Comparison examination of a measurement result and a calculation result was performed.
In this paper, values of the electric field in the pressboard and oil during the polarity reversal test of the converter transformer were calculated with transient analysis. First, we confirmed the accuracy of the non-linear analysis in the model test. Next, we carried out non-linear transient electric field analysis for polarity reversal test of the converter transformer. In the results, when the applied time of DC voltage before the polarity reversal is 360min, the values of the electric field of oil are the same as when it is 90min. Although, the electric field in the pressboard becomes higher in response to the applied time of DC voltage, it does not cause a problem on the insulation. Because withstand voltage of pressboard is very high. In the results, the correlation between the applied time of DC voltage before the polarity reversal and the withstand voltage of transformer is considered low. This result can be applied to the design of the converter transformer.
In the disconnecting switch of 300kV or less single pole structure, the Great East Japan Earthquake received much damage at the former by the rotation insulator base metal which damage experience had. Conventionally, we carried out a simple desk evaluation about earthquake-proof evaluation of insulator base metal. However, there is deviation with the damage actual condition and it became clear that it was an apparatus weak point part. Then, we worked on the analysis accuracy improvement of insulator base metal, and we built the analysis technology of the single pole structure disconnecting switch.
This paper presents the fundamental seismic response and analytical idealization in the substation steel structures. To obtain realistic response, the seismic observation was conducted on the steel structures which were under operation. The spectral analysis, as well as the dynamic response analysis, was performed in evaluation of the observed records. It was found that the in-plane response in the two-dimensional frame structures was less affected by the electric wires, but the out-plane response became complicated due to the effect of the electric wires such that the detailed model of the wires was required in the analysis. On the other hand, the correlation between observation and simulation in the three-dimensional frame structure could be improved by increasing the damping ratio without modeling of the wires.
In Tohoku Region Pacific Coast Earthquake, many of the power equipment (especially center clamping type bushings for power transformers) were damaged due to the seismic motion that exceeds the design criteria. The problem of the conventional seismic analysis became clear as the actual damage was revealed. Since elaboration of seismic analysis and evaluation technology was called for, the elaboration possibility of seismic analysis was verified by carrying out comparison with various test results and the analysis result by the latest technique.
The parallelization of preconditioned Krylov subspace method is essential for the fast electromagnetic field analysis using edge-based finite element method (FEM). Recently, the parallelization of preconditioned Minimized Residual method based on the Three-term Recurrence formula of the CG-type (MRTR) method by means of multicolor (MC) ordering was demonstrated on the real symmetric linear systems arising in edge-based FEM. Then, this paper investigates the parallelization performance of preconditioned conjugate orthogonal MRTR (COMRTR) method using MC ordering in complex symmetric linear systems. Furthermore, the affinity of two orderings (Reverse Cuthill-McKee and greedy-based MC) on complex symmetric linear systems derived from frequency-domain edge-based FEM is particularly verified.
The Editorial Committee is working in planning and editing of the publication of Power and Energy Society. In this article, activities of the committee of the last term are reported, and recent trend and future problems are also discussed. The process of planning and editing of the publication, and the challenges to reduce the necessary months for reviewing papers and to increase the number of submitted papers are shown.