Noel N. Schulz

Remote rural regions without electricity access suffer from energy poverty and reduced opportunities for the population. Microgrid architectures with optimal planning, design, and operation strategies are essential to meet rural inhabitants’ energy demands. DC microgrids based on photovoltaic panels and batteries are used for remote rural electrification. Centralized islanded systems have shortcomings, i.e., high distribution losses, less efficiency, and are comparatively more expensive than distributed microgrids. The distributed systems comprise independent household prosumers that may work independently or integrated. In this paper, the optimal power dispatch and power-sharing among spatially distributed nanogrids are performed to minimize distribution losses and maximize power electronic conversion efficiency in a typical islanded DC microgrid (IDCMG) for rural electrification. A branch flow model is proposed for modeling the power system with DC-DC converters. The optimal power flow is performed by relaxing the original non-convex constraints using second-order conic programming and is implemented on the modified IEEE-14 bus system. This generic framework can be used for optimal energy management in islanded microgrids using the regional solar irradiance information, climate situations, and energy requirements.

Electric vehicles (EVs) are becoming a promising source of grid ancillary services due to the temporal and spatial charging flexibility, quick response and storage capability. Such advantages are increasing with government policy promotion and technology improvement. However, the exploration of EV flexibility requires the coordination of both transmission system operators (TSOs) and distribution system operators (DSOs), to ensure the safe and reliable operation of power network. In this paper, we propose a coordinated evaluation method that determines the optimal utilization of EV temporal flexibility without compromising EV owners’ usage. At the distribution level, DSOs first evaluate EV aggregators’ operational boundaries to exploit distribution level services. At the transmission level, TSOs then determine EV charging schedules and ancillary service capacity simultaneously, taking into account the requirement from DSOs. We validate the model in a case study using the IEEE 123 node test feeder and EV charging sessions obtained from a transportation simulation tool that uses real-world data.

Distribution systems are growing rapidly in size and complexity with increased penetrations of distributed energy resources (DER) and electric vehicles (EVs), leading to operational challenges. Reactive power compensation from photovoltaic (PV) inverters and active power curtailment of PV output are commonly used to mitigate voltage-related problems. However, the charging/discharging flexibility of EVs can be used to avoid PV output curtailment and save energy motivating methods to coordinate EV charging with PVs. Unfortunately, a large number of control variables makes the centralized voltage control computationally expensive. In this work, a decentralized voltage control algorithm which considers the active and reactive power compensation from PV inverters and EVs is presented. The proposed approach helps to solve the voltage issues in a more effective way. The approach involves clustering of the distribution network based on modified modularity, an index that considers EV flexibility and prediction time period. A model predictive control (MPC)-based algorithm is proposed for each cluster to solve the voltage problem using the respective PVs and EVs, while ensuring that the EV charging demand is satisfied while contributing to the voltage regulation. The proposed algorithm is validated using the IEEE 123 node test systems under two PV and EV penetration levels and shown to be effective in solving the voltage regulation problem.

In an active power distribution system, Volt-VAR optimization (VVO) methods are employed to achieve network-level objectives such as minimization of network power losses. The commonly used model-based centralized and distributed VVO algorithms perform poorly in the absence of a communication system and with model and measurement uncertainties. In this paper, we proposed a model-free local Volt-VAR control approach for network-level optimization that does not require communication with other decision-making agents. The proposed algorithm is based on extremum-seeking approach that uses only local measurements to minimize the network power losses. To prove that the proposed extremum-seeking controller converges to the optimum solution, we also derive mathematical conditions for which the loss minimization problem is convex with respect to the control variables. Local controllers pose stability concerns during highly variable scenarios. Thus, the proposed extremum-seeking controller is integrated with an adaptive-droop control module to provide a stable local control response. The proposed approach is validated using IEEE 4-bus and IEEE 123-bus systems and achieves the loss minimization objective while maintaining the voltage within the pre-specific limits even during highly variable DER(distributed energy resources) generation scenarios.

From Defense to Degree: Integrating Military Veterans into Engineering ProgramsThis paper addresses curricular issues involved in integrating post-9/11 veterans into theengineering workforce. A 2009 NSF Workshop on Enhancing the Post-9/11 VeteransEducational Benefit indicated that new, more generous veterans’ educational benefits create anopportunity to expand the technical workforce while benefitting those who have served ourcountry. The workshop further indicated that the veterans include a diverse and qualified pool offuture talent for the nation’s engineering and science employers.Based on this opportunity to involve veterans in the workforce, researchers have developed aprogram to help integrate veterans into electrical and computer engineering degrees. The initialtechnical focus will be in the renewable energy and energy distribution systems areas, which hasbeen identified as a critical area where there is a large projected shortage of trained technicalpersonnel. A 2008 NSF Workshop on the Future Power Engineering Workforce indicated “aserious need is emerging for more power and energy engineers.” The IEEE Power and EnergySociety has also indicated that “Immediate action must be taken to avoid letting a growingshortage of well-qualified electric power engineers slow progress in meeting critical nationalobjectives.”This paper will focus on the progress made in developing an accelerated track for militaryveterans into bachelor’s degrees in engineering. It is important to have contact with the militaryveteran prior to their arriving on campus to facilitate their transition to an academic program .This allows an initial thorough evaluation of the veterans’ training, experiences, and expertise tobe conducted with the option of granting academic credit where appropriate. An informationbrochure to inform veterans of engineering workforce opportunities prior to separation from themilitary has been developed.Veterans may have a base of knowledge acquired through the technical nature of their serviceexperience. Assigning them to introductory level courses with traditional freshman andsophomore students does not respect their technical expertise. The development of subject basedon-line tutorials is being used to accelerate the veteran’s entry into the math sequence and thecircuits sequence. These tutorials will include videos of laboratory exercises to ensure thatveterans understand the equipment and terminology used in the introductory courses. We havecreated an informal cohort of veterans to gain feedback and build learning communities. Afuture feature of this project is the inclusion of summer industrial internships for participants.Student success in follow-on courses will be the primary evaluation metric. This evaluation willtake place when a significant number of students are in the program. There are many additionalsupport structures that may or may not be available on any given campus. Key components ofthis program include the development of recruitment activities and coordination with campusmilitary veteran support staff and personnel at nearby military installations.

From Defense to Degree: Accelerating Engineering Degree Opportunities for Military VeteransThis paper addresses curricular issues involved in integrating post-9/11 veterans into theengineering workforce. A recent NSF Workshop on Enhancing the Post-9/11 VeteransEducational Benefit indicates that new, more generous veterans’ educational benefits create anopportunity to expand the technical workforce while benefitting those who have served ourcountry. The workshop further indicates that the veterans include a diverse and qualified pool offuture talent for the nation’s engineering and science employers.There are two main aspects to this project: (1) an accelerated track for veterans into engineeringbachelor’s degrees in engineering for those with no bachelor’s degree or with a non-technicaldegree and (2) bridging to engineering master’s degrees for those with bachelor’s degrees intechnical non-engineering areas. The initial focus will be in the renewable energy and energydistribution systems area. Energy has been identified as a critical area where there is a largeprojected shortage of trained technical personnel. A recent NSF Workshop on the Future PowerEngineering Workforce indicated “a serious need is emerging for more power and energyengineers.” The IEEE Power and Energy Society has also indicated that “Immediate action mustbe taken to avoid letting a growing shortage of well-qualified electric power engineers slowprogress in meeting critical national objectives.”This paper will focus on the accelerated track for military veterans into bachelor’s degrees inengineering. It is important to have contact with the military veteran prior to their arriving oncampus to start school. An initial thorough evaluation of the veterans’ training, experiences, andexpertise will be conducted with the option of granting academic credit where appropriate.Current policies give little credit for military experience or training. The next step will be to usethe initial evaluation to identify areas where the veteran has the technical background but may belacking the necessary mathematics or have not used the mathematics for a long time. Thedevelopment of on-line review courses will be used to accelerate the veterans entry into thetraditional math sequence. The creation of accelerated courses specifically for veterans enrolledin the program will be another aspect used to accelerate degree completion. Veterans may havea base of technical knowledge acquired through the technical nature of their assignments.Assigning them to introductory level courses with traditional freshman and sophomore studentsdoes not respect their technical expertise nor challenge their capabilities and accustomed pace.Another aspect of this project is the inclusion of summer internships for participants.Student success in the accelerated courses and follow-on courses will be the primary evaluationmetric. This evaluation will take place once there are a significant number of students in theprogram.There are many additional support structures that may or may not be available on any givencampus. Key supporting components include the development of strategies to inform veterans ofengineering workforce opportunities and the recruitment activities, and coordination withcampus military veteran support staff and personnel at nearby military installations.Understanding what is available is an important part of the overall success of a program.