David Lubkeman

A New Professional Science Master Program for Electric Power Systems Engineering

This paper proposes to adopt the emerging Professional Science Master (PSM) program as a model for enriching power engineering education. PSM programs provide comprehensive training in an academic and technical specialty along with the appropriate professional skills needed for a professional career. The paper outlines the new PSM program-MS in Electric Power Systems Engineering. The program encompasses engineering, management, and other professional skills needed for a successful career in the power engineering industry, and includes both in-depth core power engineering topics as wells as new cross-disciplinary technical topics relevant to the clean-energy Smart Grid.

Power electronic components and system installation for plug-and-play residential solar PV

Photovoltaic (PV) system installations in both residential and commercial sectors have increased rapidly throughout the world in the last decade primarily because of the technical advancements and hardware cost reduction. However, challenges remain in the installation and permitting process and the cost is not yet competitive enough for mass adoption. The focus has shifted in recent years to reduce the complexities of PV system installation and streamlining the permitting process. Hardware cost reduction has likely reached limits and only way to reduce cost further is through reduction in soft costs such as installation, permitting and inspection. This paper discusses the barriers in making the PV system Plug-and-Play (PnP) for residential applications, and then, presents a smart interface concept that includes a hardware between the grid and the PV panel and a web portal to bring together all the stake holders for simpler installation and commissioning. A study to evaluate how the commercially available inverters match with the proposed concept is also presented.

Modeling Combined Heat and Power Systems for Microgrid Applications

This paper presents the modeling of combined heat and power (CHP) systems for microgrid applications. When generating electricity, a CHP unit can recycle waste heat to supply building thermal loads to improve the overall efficiency of a traditional generation system. The ramping capability of a CHP unit makes it an ideal resource for load following and frequency regulation in microgrid operation. In this paper, a CHP model built in Simulink is developed. The CHP model includes three key components: generator, turbine, and absorption chiller. A new isochronous governor control strategy is proposed to provide zero-steady-state-error frequency regulation. The supply of building thermal loads is modeled to facilitate the calculation of the overall CHP system efficiency. The impact of ambient temperature on the maximum electrical output is considered. The developed model is implemented on OPAL-RT for testing the microgrid controller performance in a microgrid system.

Improved control of capacitor bank switching to minimize distribution systems losses

The authors review the problem of controlling the switching of capacitor banks to minimize losses on distribution systems. A novel class of controls is available that allows capacitor switching to much more closely follow the actual loading on the distribution feeder. This allows for much better control of reactive loading throughout the distribution system, reduced line losses, improved voltage regulation, and reduced facility loading. The operating characteristics and performance of several of the controls are reviewed and compared. To effectively use the controls, distribution systems engineers must have a methodology to determine appropriate switching set points. The development of an appropriate methodology and its implementation in the form of a computer program called VDXTCAP are described.<<ETX>>

Control strategies for residential microgrids during islanded situation

Microgrids can serve to integrate distributed energy resources (DERs) and controllable loads in a smarter and more reliable fashion. The operation of residential microgrids with DER during islanded situation is of great significance to both customers and utility providers. This paper proposes two control strategies for a residential microgrid that has a shared energy storage (ES) in islanded mode. With ES being the only energy resource, these strategies rationally allocate energy over the islanded time period and also regulate loads to coordinate with ES. A simulation testbed based on household load models for typical residential devices is utilized. Test cases for islanded-situation days using these control strategies are simulated for validation. Finally, simulation results of control signals and resulting load profiles are shown and analyzed. These two control strategies are proved to be effective for the energy management of a residential microgrid during islanded situation.

Transient stability enhancement in multimachine power systems using braking resistors

ABSTRACT In certain situations, it is necessary to consider the use of an alternate control means to enhance and insure power system stability such as an emergency state control. A class of switchable supplementary controls, such as dynamic brakes, shunt reactor or series capacitors could be utilized. The effectiveness of network switching on a one machine system has been well established. However the interaction between closely coupled machines and groups of machines as a result of a control action has not been fully considered. The contribution of the paper is in the area of multimachine control, and, in particular, a power system emergency state control. Topics concerning control models, optimization criteria and characteristics of supplementary controls have been addressed. Dynamic programming is used to derive a switching strategy which takes the form of a closed-loop control. The control strategy is evaluated through the digital simulation of a two machine test system.

Implementation of a distributed microgrid controller on the Resilient Information Architecture Platform for Smart Systems (RIAPS)

Formation of microgrids have been proposed as a solution to improve grid reliability, and enable smoother integration of renewables into the grid. Microgrids are sections of the grid that can operate in isolation from the main power system. Maintaining power balance within an islanded microgrid is a challenging task, due to the low system inertia, which requires complex control to maintain stable and optimized operation. Many studies have demonstrated feasible distributed microgrid controllers that can maintain microgrid stability in grid connected and islanded modes. However, there is little emphasis on how to implement these distributed algorithms on a computational platform that allows for fast and seamless deployment. This paper introduces a decentralized software platform called Resilient Information Architecture Platform for Smart Systems (RIAPS) that runs on processors embedded with the microgrid component. As an example, we describe the implementation of a distributed microgrid secondary control and resynchronization algorithms on RIAPS platform. The controller developed on RIAPS platform is validated on a real-time microgrid testbed.

Continuation power flow analysis for PV integration studies at distribution feeders

This paper presents a method for conducting continuation power flow simulation on high-solar penetration distribution feeders. A load disaggregation method is developed to disaggregate the daily feeder load profiles collected in substations down to each load node, where the electricity consumption of residential houses and commercial buildings are modeled using actual data collected from single family houses and commercial buildings. This allows the modeling of power flow and voltage profile along a distribution feeder on a continuing fashion for a 24-hour period at minute-by-minute resolution. By separating the feeder into load zones based on the distance between the load node and the feeder head, we studied the impact of PV penetration on distribution grid operation in different seasons and under different weather conditions for different PV placements.

A decision support approach for considering reliability criteria in the protective coordination of distribution feeders

Abstract This paper describes an approach for incorporating reliability criteria into the design of protective coordination for distribution feeders. This approach introduces a mechanism for considering the impact of momentary interruptions, caused by excessive switching, upon power quality sensitive loads. The development of a decision support tool for implementing this strategy is also presented. This tool aids the protection engineer by selecting appropriate reclosers and fuses from a component database, checking recloser-to-fuse coordination for all device selections and ranking these selections according to user-selected reliability criteria. An example is included to illustrate the concepts described above.