CERTS Microgrid Laboratory Test Bed Lasseter, R H; Eto, J H; Schenkman, B ...
IEEE transactions on power delivery,
2011-Jan., 2011, 2011-01-00, 20110101, Letnik:
26, Številka:
1
Journal Article
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The CERTS Microgrid concept captures the emerging potential of distributed generation using a system approach. CERTS views generation and associated loads as a subsystem or a "microgrid." The sources ...can operate in parallel to the grid or can operate in island, providing uninterruptible power-supply services. The system can disconnect from the utility during large events (i.e., faults, voltage collapses), but may also intentionally disconnect when the quality of power from the grid falls below certain standards. CERTS Microgrid concepts were demonstrated at a full-scale test bed built near Columbus, OH, and operated by American Electric Power. The testing fully confirmed earlier research that had been conducted initially through analytical simulations, then through laboratory emulations, and finally through factory acceptance testing of individual microgrid components. The islanding and resynchronization method met all Institute of Electrical and Electronics Engineers Standard 1547 and power-quality requirements. The electrical protection system was able to distinguish between normal and faulted operation. The controls were found to be robust under all conditions, including difficult motor starts and high impedance faults.
Objective
To assess the efficacy and tolerability of hydroxychloroquine (HCQ) in patients with cutaneous lupus erythematosus (CLE), in a phase III clinical trial conducted in Japan.
Methods
We ...conducted a double‐blind, randomized, parallel‐group clinical trial. This was a baseline‐controlled study, and the group differences were evaluated in an exploratory analysis. A total of 103 patients with active CLE (according to a Cutaneous Lupus Erythematosus Disease Area and Severity Index CLASI activity score of ≥4) were included. Patients were randomized 3:1 to receive HCQ or placebo during the 16‐week double‐blind period, and all patients were given HCQ during the following 36‐week single‐blind period. The primary efficacy end point was a reduction in the CLASI activity score at week 16. The secondary end points included the central photo evaluation (5‐point scale), patient's global assessment (7‐point scale), the Skindex‐29 score, and investigator's global assessment (7‐point scale, based on the other 3 secondary end points). In patients with systemic lupus erythematosus, fatigue and musculoskeletal pain were assessed. Safety was assessed up to week 55.
Results
The mean CLASI score at week 16 was significantly improved from baseline in both the HCQ group and the placebo group: mean change −4.6 (95% confidence interval 95% CI −6.1, −3.1) (P < 0.0001), and mean change −3.2 (95% CI −5.1, −1.3) (P = 0.002), respectively, without between‐group difference (P = 0.197). The investigator's global assessment demonstrated a greater proportion of “improved” and “remarkably improved” patients in the HCQ group (51.4% versus 8.7% in the placebo group P = 0.0002 between groups). The other secondary end points supported the efficacy of HCQ. Cellulitis, drug eruption, hepatic dysfunction, and Stevens‐Johnson syndrome were shown to be serious adverse events related to HCQ use.
Conclusion
The results of this randomized clinical trial support the efficacy and tolerability of HCQ in patients with CLE.
The penetration of wind and solar generating resources is expected to dramatically increase in the United States over the coming years. It is widely understood that large scale deployment of these ...types of renewable energy sources (e.g., wind, solar) that have variable and less predictable production characteristics than traditional thermal resources poses integration challenges for bulk power system operators. At present, bulk power system operators primarily utilize strategies that rely on existing thermal generation resources and improved wind and solar energy production forecasts to manage this uncertainty; a host of additional options are also envisioned for the near future including demand response (DR). There are well-established bodies of research that examine variable generation integration issues as well as demand response potential; but, the existing literature that provides a comparative assessment of the two neither treats this topic comprehensively nor in a highly integrated fashion. Thus, this paper seeks to address these missing pieces by considering the full range of opportunities and challenges for mass market DR rates and programs to support integration of variable renewable generation.
► Mass market demand response can help manage the integration of renewable resources. ► To be more effective, retail electricity rates must apply contemporaneous prices. ► Demand response programs will require shorter duration and more frequent events. ► Mass market customers will likely need to accept control technology. ► Market rules and regulatory policies must change to expand demand response's role.
Objectives The “tissue oxygen saturation (StO2 ) foot-mapping” method was developed using a non-invasive near-infrared tissue oximeter monitor to classify the foot regions as ischemic and ...non-ischemic areas. The purpose of this study was to evaluate StO2 foot-mapping as a reliable method to detect ischemic areas in the feet of patients with critical limb ischemia (CLI), and to compare the results with assessments from the angiosome model. Methods The foot areas of 20 CLI patients and 20 healthy controls were classified into four regions: (1) 0 ≤ StO2 < 30%, (2) 30 ≤ StO2 < 50%, (3) 50 ≤ StO2 < 70%, and (4) 70 ≤ StO2 ≤ 100% to perform StO2 foot-mapping. Each area occupancy rate was compared between the two groups, and the threshold StO2 value for detecting ischemia was set. Next, the locations of ulcers (in 16 patients) were compared to the predicted ischemic regions by the StO2 foot-mapping and by the angiosome model and angiography. Results In regions (1) and (2) (StO2 < 50%), the area occupancy rate was significantly higher in the CLI group and almost zero in the control group, so that the threshold StO2 value for detecting ischemia was set at 50%. The locations of ulcers were compatible with StO2 foot-mapping in 87.5% of the cases (14/16), while they were compatible with the assessment from the angiosome model in 68.8% of the cases (11/16). Conclusions This study suggests that StO2 foot-mapping can successfully and non-invasively detect ischemic areas in the peripheral tissue of the foot, and also more appropriately than the assessment provided by the angiosome model. StO2 foot-mapping can be used to evaluate the real angiosome: the real distribution of the peripheral tissue perfusion in the CLI patient's foot, which is determined by the peripheral microvascular blood flow, rather than the main arterial blood flow.
Occasionally, forced oscillations (FO) may appear in a power system, and it is critical to quickly identify and isolate their sources in order to prevent damage to other assets. These FOs can ...interact with natural oscillation modes and propagate to multiple areas, typically managed by different entities, making the source identification problem very challenging. To aid coordination among regional operators during wide-area oscillations, a phasor measurement unit (PMU)-based platform for detecting FOs and identifying their source region was recently tested in the U.S. Eastern Interconnection (EI). Oscillation notifications generated by this platform included an easily-interpretable confidence score that conveyed how imperfect data might have impacted source localization accuracy. This paper reports: a) how the confidence score was developed, b) how it performed in an interconnection-level field demonstration, and c) how it can be refined for future implementation. It is shown that the proposed confidence assessment strategy helps system operators ascertain the veracity of source localization results, and accordingly formulate response plans.
Summary
Linear IgA bullous dermatosis (LABD) is a rare autoimmune bullous disease, which is defined by the histopathological finding of subepidermal vesicles with neutrophilic infiltration and linear ...IgA deposits in the basement membrane zone, revealed by immunofluorescence study. We present a case of LABD in which vancomycin (VCM) administration triggered LABD, and immunoblot analysis showed IgA antibodies reactive to the 145‐ and 165‐kDa α3 subunits of laminin‐332. This is the first report of VCM‐associated LABD in which the target antigen was laminin‐332. In the present case, we were compelled to continue administration of VCM along with systemic steroids, which eventually led to the attenuation of the symptoms, normalization of the serum IgA level, and negative results on both indirect immunofluorescence of 1 mol L−1 NaCl‐split skin and immunoblot analysis.
What's already known about this topic?
Vancomycin‐induced linear IgA bullous dermatosis (LABD) comprises 46% of drug‐induced LABD cases and involves reactivity to 83‐, 130‐, 180‐, 230‐ and 285‐kDa proteins.
What does this study add?
We present the first case of vancomycin‐associated LABD with IgA antibodies to the α3 subunit of laminin‐332.
The results of serum IgA level measurement, indirect immunofluorescence and immunoblot analysis were useful to determine the treatment.
Distribution grid reliability and resilience has become a major topic of concern for utilities and their regulators. In particular, with the increase in severity of extreme events, utilities are ...considering major investments in distribution grid assets to mitigate the damage of highly impactful outages. Communicating the overall economic and risk-mitigation benefits of these investments to regulators is an important element of the approval process. Today, industry reliability and resilience planning practices are based largely on methods that do not take explicit account of risk. This paper proposes a practical method for identifying optimal combinations of investments in new line segments and storage devices while considering the balance between the risk associated with high impact and low probability (HILP) events and the reliability related to routine failures. We show that this method can be scaled to address large scale networks and demonstrate its benefits using a Target Feeder from the Commonwealth Edison Reliability Program.
There has been a limited amount of peer-reviewed literature on long-term trends in electricity reliability including the underlying factors that impact reliability across the United States. In this ...analysis, we considered up to 16 years of data from 203 U S. utilities—representing about 70% of electricity sales. Annual frequency of interruptions for an average customer—at the regional and U.S. national-level—has generally decreased over this timeframe. But we do not find that there is a statistically significant trend in the annual duration of interruptions for an average customer. We find that more explicit measures of severe weather are correlated with reliability. We are able to explain 7% and 16% of past variation in the reliability metrics system average interruption duration and frequency indices, respectively, is due to severe weather—a significant improvement over earlier studies. We find that current year spending by utilities is correlated with worse reliability and that cumulative spending over the preceding three years is correlated with better reliability. Finally, we demonstrate that using a statistical instrument to represent the annual frequency of interruptions for an average customer can greatly improve analysis of trends in the annual duration of interruptions for an average customer.
•Frequency of power interruptions experienced by U.S. customers is decreasing over time.•Inconclusive trend in total annual duration of power interruptions for typical customer.•Current year utility spending is correlated with worse reliability.•Cumulative spending over preceding three years is correlated with better reliability.
The aim of this study was to evaluate the influence of surface crack on the bending fatigue limit of nitrocarburized steel. Semicircular slits with depths of 0.040, 0.075, and 0.100 mm were ...introduced on the surface of nitrocarburized medium carbon steel specimens to simulate the presence of small cracks. Bending fatigue tests were performed at room temperature in air with the stress ratio R = −1. It was observed that the fatigue limit decreased as the depth of the slit increased. The acceptable crack size was estimated based on fracture mechanics. The predicted acceptable crack size was consistent with the experimental result. Therefore, the acceptable crack size of nitrocarburized carbon steel could be predicted via analysis based on fracture mechanics.
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