Search results for "Reliability engineering"
showing 10 items of 224 documents
Power Grid Integration and Use-Case Study of Acid-Base Flow Battery Technology
2021
There are many different types of energy storage systems (ESS) available and the functionality that they can provide is extensive. However, each of these solutions come with their own set of drawbacks. The acid-base flow battery (ABFB) technology aims to provide a route to a cheap, clean and safe ESS by means of providing a new kind of energy storage technology based on reversible dissociation of water via bipolar electrodialysis. First, the main characteristics of the ABFB technology are described briefly to highlight its main advantages and drawbacks and define the most-competitive use-case scenarios in which the technology could be applied, as well as analyze the particular characteristi…
Calibration and Validation
2016
The aim of this chapter is to summarise the problems incurred during the phases of calibrating and validating the extortion racket models used by the GLODERS project. The chapter starts with the discussion of the data availability and summarises shortly the contents of Sect. 4.3. It continues with a discussion of what parameterisation, calibration, sensitivity analysis and validation have to do with each other and ends up with a discussion of the validity of the GLODERS models.
Uncertainty-Based Internal Quality Control. Harmonization Considerations
2006
Three main quality aspects for analytical laboratories are internal method validation, internal quality control (IQC), and sample result uncertainty. Unfortunately, in the past they have been used in a nonharmonized way. The most universal IQC tool is the mean chart, but some criteria used to fix their control limits do not fit the real nature of analytical results. A new approach for fixing these limits is proposed (the u-approach). The key is the combined uncertainty, u, obtained from the method validation information, also used for estimating the sample result uncertainty. A comparative study on "in-control" simulated, bibliographic, and real laboratory data suggests that the u-approach …
HTLS Conductors: A Way to Optimize RES Generation and to Improve the Competitiveness of the Electrical Market—A Case Study in Sicily
2018
Stringent environmental constraints make more difficult to identify new energy corridors and build new power lines. The increase in the generation of electricity from renewable energy sources (RESs) makes the operation of electrical systems increasingly difficult in some areas. The transmission system operators (TSOs), in Italy Terna, are forced to exploit the existing overhead transmission lines, increasing the possibility of dispatching energy, in particular RES, optimizing the transmission capacity. Therefore, after a brief presentation of the Sicilian electricity system and a brief description of high-temperature low-sag (HTLS) conductors, a case study is presented. It is shown how it i…
A new approach to partial discharge detection under DC voltage
2018
The continuing development of HVDC power transmission systems presents many problems related to evaluation of the reliability of power system assets [1]-[5]. In this context the identification of insulation defects plays a key role in preventing unexpected failures of electrical components. Partial discharge (PD) measurement is a useful approach to assessing the condition of HV power apparatus and cables. Such measurements are also widely employed for HVAC systems. The inception mechanisms of PD in AC systems are well-known, and measurements are usually performed following the IEC 60270 standard [6]. PD measurements under DC voltage present complexities related to the nature of the phenomen…
A framework to determine maximum capacity of interconnecting DGs in distribution networks
2018
Interconnecting Distributed Generation (DG) in the distribution network is considered as an important area of power system planning. When the DG placed inappropriately, the DG can have negative impact on some important and critical characteristics of system performance such as increased power losses, degraded voltage profile, and mis-coordination between protection devices. This paper introduces a framework to determine the maximum capacity limits of interconnecting DG units in radial distribution networks in order to keep protection scheme unchanged, while the voltage profile remains within acceptable range and on the same time having the minimum power losses in the network; applying this …
Effect of Demand Side Management on the Operation of PV-Integrated Distribution Systems
2020
In this new era of high electrical energy dependency, electrical energy must be abundant and reliable, thus smart grids are conducted to deliver load demands. Hence, smart grids are implemented alongside distributed generation of renewable energies to increase the reliability and controllability of the grid, but, with the very volatile nature of the Distributed Generation (DG), Demand Side Management (DSM) helps monitor and control the load shape of the consumed power. The interaction of DSM with the grid provides a wide range of mutual benefits to the user, the utility and the market. DSM methodologies such as Conservation Voltage Reduction (CVR) and Direct Load Control (DLC) collaborate i…
Voltage Rise Issues and Mitigation Techniques Due to High PV Penetration into the Distribution Network
2018
Integration of photovoltaic systems (PV)into the low voltage (LV)grid is seen as a viable and globally accepted optionto meet the ever-increasing energy demands. However, the high PV penetration into the LV distribution grid has raised up many concerns for various stakeholders e.g. distribution company, industry partners, end users etc. The suddenchanges in the voltage level, is one of the main issues due to the reverse power flowfrom distributed energy sources to the grid, has significantly affected the behavior of the traditional LV grid. This paper has reviewed the impacts on voltage profile due to high PV penetration and different techniques used for mitigation these issues such as acti…
Faults identification, location and characterization in electrical systems using an analytical model-based approach
2005
The start of the electrical energy market has encouraged distributors to make new investments at distribution level so as to attain higher quality levels. The service continuity is one of the aspects of greater importance in the definition of the quality of the electrical energy. For this reason, the research in the field of fault diagnostic for distribution systems is spreading ever more. This paper presents a novel methodology to identify, locate and characterize the faulty events in the electrical distribution systems. The methodology can be extended to all types of faulty events and is applicable to reconfigurable systems. After having described the guidelines of the methodology, the Au…
Reducing False Node Failure Predictions in HPC
2019
Future HPC applications must be able to scale to thousands of compute nodes, while running for several days. The increased runtime and node count inconveniently raises the probability of hardware failures that may interrupt computations. Scientists must therefore protect their simulations against hardware failures. This is typically done using frequent checkpoint& restart, which may have significant overheads. Consequently, the frequency in which checkpoints are taken should be minimized. Predicting hardware failures ahead of time is a promising approach to address this problem, but has remaining issues like false alarms at large scales. In this paper, we introduce the probability of unnece…