Power Plant Substation Research Articles

The Impact of Power Swings on the Performance of Power Unit Distance Protection Relays on the Example of a Disturbance in a Power Plant Substation

The paper presents the results of the analysis of a real disturbance that took place in one of the Polish power plant substations. The fault was caused by the short-circuit that occurred near the power plant bus-bars. As a consequence, change in the power grid configuration occurred and one of two generators working in the power plant lost the synchronism. As a result of power swings, the unwanted operation of the unit distance protection occurred. This caused unwanted tripping of that unit. The paper gives a shortened analysis of the impedance trajectories at the time of the disturbance.

Markov Chain Reliability Model of Cogeneration Power Plant Substation

The paper presents a Markov chain reliability model of a cogeneration power plant substation. Stochastic automata networks formalism and functional transition rates were used to specify the reliability behavior of a system. Iterative solution techniques were used to find steady-state solution of Markov models with different sets of randomly generated failure and repair rates. Modeling results were used to perform uncertainty and sensitivity analysis of the reliability model. DOI: http://dx.doi.org/10.5755/j01.eee.19.5.1214

Cometabolic oxidation of polychlorinated biphenyls in soil with a surfactant-based field application vector

Polychlorinated biphenyl (PCB)-degradative genes, under the control of a constitutive promoter, were cloned into a broad-host-range plasmid and a transposon. These constructs were inserted into a surfactant-utilizing strain, Pseudomonas putida IPL5, to create a field application vector (FAV) in which a surfactant-degrading organism cometabolizes PCB. By utilizing a surfactant not readily available to indigenous populations and a constitutive promoter, selective growth and PCB-degradative gene expression are decoupled from biphenyl. Since PCB degradation via the biphenyl degradation pathway is nonadaptive in the absence of biphenyl, there is no selective pressure for PCB gene maintenance. The recombinant strains exhibited degradative activity against 25 of 33 PCB congeners in Aroclor 1248 in the absence of biphenyl. Whole-cell enzyme assays indicated that PCB-degradative activity of a recombinant strain carrying the PCB genes on a plasmid was approximately twice that of the same strain carrying the PCB genes on a transposon. Plasmid loss rates in the absence of antibiotic selection averaged 7.4% per cell division and were highly variable between experiments. Surfactant-amended slurries of PCB-contaminated electric power plant substation soil were inoculated with approximately 10(5) recombinant cells per ml. The populations of the added strains increased to greater than 10(9) cells per ml in 2 days, and cell growth coincided with PCB degradation. By 15 days, 50 to 60% of the indicator congener 2,3,2',5'-tetrachlorobiphenyl was degraded. The effectiveness of PCB degradation by the plasmid-containing strain depended on plasmid stability. The transposon-encoded PCB genes were much more stable, and in surfactant-amended soil slurries, PCB degradation was more consistent between experiments.

Dynamic thermal rating of critical lines-a study of real-time interface requirements

Power system operators need the ability to assess network performance from a thermal capacity standpoint. However, static ratings do not provide the level of information needed and, in fact, can mislead operators. To address this problem, a study that resulted in the instrumentation of a 138000 V line with the necessary equipment to rate the line dynamically was initiated by Wisconsin Power and Light. The line chosen for the project was the X20 line, a 6 mile transmission line that runs from the Columbia Power Plant substation to the Portage substation. The discussion covers the conductor temperature measurement systems; the real-time interface: monitoring and handling of raw data; the rating process; the thermal transient conductor response; suppressed rating during the transient period; thermal transient response display; and alarm processing.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Effects of Future Turbine-Generator Characteristics on Transient Stability

Future turbine-generator unit designs, particularly for the larger ratings, are expected to have greater generator reactances and lower unit inertias. Transient stability limits are determined for the future designs in terms of critical fault clearing times for faults on the high voltage transmission lines at the power plant substation. Transient stability limits of the future designs are compared with representative existing generating unit designs. Stability performance of future turbine-generator designs will be very similar to existing designs when considering their respective breaker failure (backup) relay system capabilities. Approximate gains in transient stability critical fault clearing times are also listed when applying various feasible stability control techniques.