Biodiesel production from Jatropha curcas oil catalyzed by whole cells of Aureobasidium pullulans var. melanogenum SRY 14-3

The main obstacle to using lipase as a catalyst in industrial scale biodiesel production is the cost and availability of the enzyme. To overcome this obstacle, the potential of using a whole cell biocatalyst (for at least partial in situ lipase production) was evaluated as a means to reduce the cost of the lipase. The reaction conditions for biodiesel production via transesterification between Jatropha curcas (physic nut) oil and methanol when catalyzed in the presence of lipase-producing Aureobasidium pullulans yeast cells was investigated. The appropriate conditions for optimal biodiesel production were found to be 1:3 oil:methanol molar ratio at 30°C with constant stirring at 250 rpm. Under these conditions a maximum fatty acid methyl ester (biodiesel) production level of 71.8% was obtained after 72 h.Keywords: Lipase, Aureobasidium pullulans, physic nut oil, biodiesel, green energyAfrican Journal of Biotechnology Vol. 12(27), pp. 4380-438

Application of phasor measurement units for monitoring power system dynamic performance

This Working Group is a sequel to a previous working group on Wide Area Monitoring and Control for Transmission Capability Enhancement, which published the Technical Brochure 330 in 2007. Since then the synchrophasor technology has advanced rapidly and many utilities around the world have installed hundreds of PMUs in their networks. In this Technical Brochure, we look at the current state of the technology and the extent to which it has been used in the industry. As the technology has matured, it is also important to understand the communication protocols used in synchrophasor networks and their relevant cyber-security issues. These concerns are briefly discussed in the brochure. The applications of Phasor Measurement Units (PMU) measurements reported here are divided into three categories: (a) applications already installed in utility networks, (b) applications that are well-tested, but not yet installed, and (c) applications that are beneficial to the industry, but not fully developed yet. The most common and mature applications are wide area monitoring, state estimation, and model validation. Out of these three applications, wide area monitoring is well established in the industry. The protection and control applications are emerging as evident from the reported examples. The experience of using remote synchrophasor measurements as feedback control signals is not widely reported by the industry. In parallel to this Working Group, Study Committee B5 had a Working Group on “Wide area protection and control technologies.” The Technical Brochure 664 published by this Working Group in September 2016 reviews synchrophasor technology and discusses the industry experience with wide area protection and control. The North American synchrophasor Initiative (NASPI) is another technical group that has gathered and reported a wide range of PMU experiences of industry and researchers. In summary, the field-tested applications presented in this Technical Brochure are a testimony to the confidence of utilities in the synchrophasor technology. The progress in state estimation techniques indicates that synchrophasor measurements will become a standard part of energy management and security assessment systems in the near future

Coordination of protection system and VSC-HVDC to mitigate cascading failures

The rapid development of the global economics has made power systems allover the world become large-scale interconnected grids. This increases the capabilityof power grids to transfer power over the long distance to serve the desiredpower demand with the minimum cost of operation. Unfortunately, it alsoenables the propagation of local failures into global networks. In other words,if a blackout happens in a power system, the size and the damage may significantlyincrease. One of the main ways in which blackouts become widespread is cascadingfailures. This type of failure originates after a critical component of the systemhas been removed fromthe service by protective relaying. As a consequence, theload handled by the failed component needs to be redistributed which mightcause an overloading on other components in the system. On the other hand, the high power electronics controllable devices suchas Voltage Source Converters-based High Voltage Direct Current (VSC-HVDC)transmission are recently developed. These electronics devices have the potentialadvantages such as the ability to independently control active and reactivepower, and maintain voltage to be at acceptable level. Therefore, they are consideredto be the promising devices that with an appropriately designed controlstrategy, they can substantially improve the performance and reliability of thepower system. This thesis presents the possibility to consider protection system status inthe control of VSC-HVDC link. A great deal of this research is development ofcoordination between this power electronic device and protection system which normally are considered separately. The derivation of protection system has been selected to determine the operation of VSC-HVDC. The methodology isbased on utilizing the signal created from a logical evaluation of relay and simplificationsof certain parameters. By introducing information from the relays tothe VSC-HVDC link via Central Control Unit (CCU), the modulation of transmitted power is devised in order to reduce the risk of system-wide failures. In turn,this means an avoided blackout.Furthermore, this thesis also includes the preliminary suggestion to selectthe location of VSC-HVDC. The methodology is based on predicting voltage instabilityusing voltage stability indices and related parameterswhich are derivedby using Singular ValueDecomposition method. The solutions indicate an effectivelocation for applying corrective action such as load shedding. This optimallocation is selected to reinforce the control strategy of VSC-HVDC in order toprevent cascading failures in the more encompassing systems.QC2010061

"All-in-one" test system modelling and simulation for multiple instability scenarios

QC 2011121

Power System Protective Relaying : basic concepts, industrial-grade devices, and communication mechanisms

QC 2011121

Power System Protective Relaying : basic concepts, industrial-grade devices, and communication mechanisms

QC 2011121

Modeling Adequacy for Cascading Failure Analysis

This paper describes the mechanisms of cascading failure as the cause of severe blackouts. The severe blackouts that occurred in 2003 affecting large metropolitan areas around the globe are first reviewed. Then the probable root cause of each blackout events is identified in order to seek effective corrective preventive solutions. Several of the well-known techniques for cascading failure analysis and correction are discussed and characterized based on their fundamental features. Thereupon a new model power system component is proposed for simulating cascading failure in actual networks.QC 20111213</p