Practical observations of loss-of-mains nuisance tripping of fast acting energy storage

Fast acting battery energy storage systems are able to swing power very quickly between maximum import and maximum export in less than 50ms based on operational experience of a 2MW energy storage system. However, this can result in nuisance tripping of the unit through the operation of the loss-of-mains protection (LoM). This paper looks at data captured during power swings of up to 4MW during typical operation and discusses the potential for nuisance tripping, and suggests potential settings for improved operation

Using power factor to limit the impact of energy storage on distribution network voltage

The introduction of embedded renewable generation and energy storage into the electricity grid may result in increased complexity to the Distribution Network Operator (DNO) in managing the voltage within statutory limits. This paper investigates how the voltage at the point of common coupling between the grid and an energy storage system could be adapted such that the charging and discharging of a battery energy storage system has a neutral impact on the voltage at that point. The paper uses measured results from the Willenhall Energy Storage System to show that a “seagull” shape curve of Power and corresponding Var setting could be used to mitigate against voltage rise or fall on the Network caused by the Energy Storage System

Network meta-analysis of food and drug administration-approved treatment options for adults with aquaporin-4 immunoglobulin G-positive neuromyelitis optica spectrum disorder

INTRODUCTION: Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease defined by attacks on the central nervous system that cause irreversible damage. Recent approval of NMOSD therapies warrants investigations of comparative efficacy to inform treatment decisions. METHODS: A network meta-analysis (NMA) of all U.S. Food and Drug Administration-approved therapies (eculizumab, inebilizumab, and satralizumab) for adults with aquaporin-4 immunoglobulin G-positive (AQP4+) NMOSD was conducted via a systematic literature review (SLR) using data from randomized controlled trials (RCTs). Database searches of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were executed for the SLR. A fixed-effects proportional hazards Bayesian NMA was used to estimate relative treatment effects based on data extracted from RCTs identified during the SLR (search end date: 11 September 2020). Four unique RCTs (N-MOmentum, PREVENT, SAkuraSky, and SAkuraStar) were identified, and data from 29 publications were extracted for analysis. Network scenarios describing the most comparable patient population groups (such as by treatment settings) were evaluated in our analyses. Relative treatment effects were evaluated based on time-to-first relapse and were expressed as hazard ratios (HRs) with 95% credible intervals (CrIs). RESULTS: In patients treated with a monoclonal antibody only, eculizumab was associated with a lower risk of relapse compared with satralizumab (HR 0.10, 95% CrI 0.01, 0.65) and inebilizumab (HR 0.11, 95% CrI 0.02, 0.68). In patients treated with monoclonal antibody with or without background immunosuppressive therapy (IST), patients treated with eculizumab ± IST were also less likely to relapse than patients treated with satralizumab ± IST (HR 0.24, 95% CrI 0.06, 0.98). CONCLUSION: The NMA results suggest that complement component 5 (C5) inhibition prevents NMOSD relapses more effectively than broader mechanisms of action

Application of rule based methods to predicting storm surge

The accurate forecast of storm surge, the long wavelength sea level response to meteorological forcing, is imperative for flood warning purposes. There remain regions of the world where operational forecast systems have not been developed and in these locations it is worthwhile considering numerically simpler, data-driven techniques to provide operational services. In this paper, we investigate the applicability of a class of data driven methods referred to as rule based models to the problem of forecasting storm surge. The accuracy of the rule based model is found to be comparable to several alternative data-driven techniques, all of which result in marginally worse but acceptable forecasts compared with the UK's operational hydrodynamic forecast model, given the reduction in computational effort. Promisingly, the rule based model is considered to be skillful in forecasting total water levels above a given flood warning threshold, with a Brier Skill Score of 0.58 against a climatological forecast (the operational storm surge system has a Brier Skill Score of up to 0.75 for the same data set). The structure of the model can be interrogated as IF–THEN rules and we find that the model structure in this case is consistent with our understanding of the physical system. Furthermore, the rule based approach provides probabilistic forecasts of storm surge, which is much more informative to flood warning managers than alternative approaches. Therefore, the rule based model provides reasonably skillful forecasts in comparison with the operational forecast model, for a significant reduction in development and run time, and is therefore considered to be an appropriate data driven approach that could be employed to forecast storm surge in regions of the world where a fully fledged hydrodynamic forecast system does not exist, provided a good observational and meteorological forecast can be made

Phosphorus loss by surface runoff in no-till system under mineral and organic fertilization Perda de fósforo via escoamento superficial no sistema plantio direto sob adubação mineral e orgânica

The no-till system has been intensively used in the state of Paraná, Brazil, and it has increased the nutrients level at the soil surface. This has contributed for nutrient losses via runoff and consequently, off-site water pollution. The objective of this study was to evaluate phosphorus loss in surface runoff by simulated rainfall on an Oxisol, under no-till system following application of mineral fertilizer and liquid swine manure. Nitrogen, soil and water losses from the same study are reported in a separated paper. The application of liquid swine manure, compared with mineral fertilization, increased runoff concentration of total P, particulate P and dissolved reactive P by 193%, 111% and 506%, respectively, averaged for all rainfall intensities. Independently on the fertilizer source, the highest rainfall intensity provided the greatest concentration and loads of P in runoff.<br>O sistema plantio direto tem sito intensivamente utilizado no Estado do Paraná Brasil o qual tem aumentado os níveis de nutrientes na superfície do solo. Isto tem contribuído para a perda de nutrientes via escoamento superficial e consequentemente com a poluição não pontual das águas. Avaliou-se a perda de fósforo via escoamento superficial ocasionado por chuva simulada sobre um Latossolo originário de basalto, em sistema plantio direto submetido à aplicação de fertilizante mineral e dejeto líquido de suíno. As perdas de nitrogênio, solo e água deste mesmo estudo foram publicadas em outro artigo. A aplicação de dejeto líquido suíno, comparado com o fertilizante mineral, aumentou a concentração de P total, P particulado e P dissolvido reativo em 193%, 111% e 506%, respectivamente, na média das chuvas. Independentemente da fonte de fertilizante, a chuva de maior intensidade proporcionou maior concentração e quantidade perdida de P no escoamento superficial