Adaptive Coordination of Distributed Energy Resources in Lossy Power Distribution Systems

This paper is concerned with the problem of coordinating a set of distributed energy resources (DERs) in a lossy power distribution system to provide frequency regulation services to a bulk power grid with the explicit consideration of system losses. To this end, we formulate the problem as an optimization problem, the objective of which is to minimize some cost function subject to a set of constraints. The formulation requires knowledge of incremental total system losses, which we approximate using the so-called loss factors (LFs) that explicitly capture the impacts of both active and reactive power injections on system losses. The LFs are estimated recursively using power injection measurements; thus, they are adaptive to various phenomena that impact the power system operation. Numerical simulation on a 33-bus distribution test feeder validated the effectiveness of the proposed framework

Polarization effects in pion electroproduction from 3He

Inelastic electron scattering from 3He is studied in the kinematic region of pion production. Inclusive processes with polarization of the electron probe and of the 3He target are described in the plane wave impulse approximation. The question to what extent polarized 3He can serve in this kinematic regime as a substitute for unavailable neutron spin targets is discussed

Polarized deep-inelastic lepton scattering from the polarized two- and three-nucleon bound states

A relativistic description of polarized deep-inelastic lepton scattering from polarized nuclei is presented. It is based on front form dynamics. Convolution formulas for the nuclear spin structure functions gA1 and gA2 are derived. They require the front form spin distributions of nuclei and the nucleonic spin structure functions. The description is applied to the deuteron and the trinucleon bound states. The numerical calculations show that relativistic effects arising from the consistent quantum mechanical treatment of spin are small. Simple approximations to the convolution formulas for gA1 and gA2 are justified. The approximative convolution formulas allow the subtraction of nuclear effects from measured spin structure functions and therefore the experimental determination of the neutron spin structure functions. Polarized 3He turns out to be a rather reliable effective neutron spin target for deep-inelastic scattering of polarized leptons. The differences between descriptions based on front form and on instant form dynamics are also discussed

Blue-Box Approach to Power Electronics and Machines Educational Laboratories

Our approach to laboratory education in power electronics and electric machines is presented. The approach centers upon blue-box laboratory components, that aid the student in rapid experiment assembly without disguising important aspects of the hardware. Several example experiments are presented. Schematics and construction techniques for the hardware are publicly available

A Hierarchy of Models for Inverter-Based Microgrids

This chapter develops and presents a time resolution based hierarchy of microgrid models for analysis and control design purposes. The focus is on microgrids with distributed generation interfaced via grid-forming inverters. The process of developing the model hierarchy involves two key stages: the formulation of a microgrid high-order model using circuit and control laws, and the systematic reduction of this high-order model to reduced-order models using singular perturbation techniques. The time-scale based hierarchy of models is comprised of the aforementioned microgrid high-order model (μHOm), along with three reduced-order models (microgrid reduced-order model 1 (μROm1), microgrid reduced-order model 2 (μROm2) and microgrid reduced-order model 3 (μROm3)) which are presented in this chapter.Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, within the NODES program / DE-AR0000695MidAmerica Regional Microgrid Education and Training (MARMET) Consortium, U.S. Department of EnergyOpe

Discrete Laplace Cycles of Period Four

We study discrete conjugate nets whose Laplace sequence is of period four. Corresponding points of opposite nets in this cyclic sequence have equal osculating planes in different net directions, that is, they correspond in an asymptotic transformation. We show that this implies that the connecting lines of corresponding points form a discrete W-congruence. We derive some properties of discrete Laplace cycles of period four and describe two explicit methods for their construction