Diagnostic Applications for Micro-Synchrophasor Measurements

This report articulates and justifies the preliminary selection of diagnostic applications for data from micro-synchrophasors (µPMUs) in electric power distribution systems that will be further studied and developed within the scope of the three-year ARPA-e award titled Micro-synchrophasors for Distribution Systems

EcoBlock: Grid Impacts, Scaling, and Resilience

Widespread deployment of EcoBlocks has the potential to transform today's electricity system into one that is more resilient, flexible, efficient and sustainable. In this vision, the system will consist of self- su cient, renewable-powered, block-scale entities that can deliberately adjust their net power exchange and can optimize performance, maintain stability, support each other, or disconnect entirely from the grid as needed. This report is intended as an independent analysis of the potential relationships, both constructive and adverse, between EcoBlocks and the grid

Stochastic Model for Power Grid Dynamics

We introduce a stochastic model that describes the quasi-static dynamics of an electric transmission network under perturbations introduced by random load fluctuations, random removing of system components from service, random repair times for the failed components, and random response times to implement optimal system corrections for removing line overloads in a damaged or stressed transmission network. We use a linear approximation to the network flow equations and apply linear programming techniques that optimize the dispatching of generators and loads in order to eliminate the network overloads associated with a damaged system. We also provide a simple model for the operator's response to various contingency events that is not always optimal due to either failure of the state estimation system or due to the incorrect subjective assessment of the severity associated with these events. This further allows us to use a game theoretic framework for casting the optimization of the operator's response into the choice of the optimal strategy which minimizes the operating cost. We use a simple strategy space which is the degree of tolerance to line overloads and which is an automatic control (optimization) parameter that can be adjusted to trade off automatic load shed without propagating cascades versus reduced load shed and an increased risk of propagating cascades. The tolerance parameter is chosen to describes a smooth transition from a risk averse to a risk taken strategy...Comment: framework for a system-level analysis of the power grid from the viewpoint of complex network

A review of microgrid development in the United States – A decade of progress on policies, demonstrations, controls, and software tools

Microgrids have become increasingly popular in the United States. Supported by favorable federal and local policies, microgrid projects can provide greater energy stability and resilience within a project site or community. This paper reviews major federal, state, and utility-level policies driving microgrid development in the United States. Representative U.S. demonstration projects are selected and their technical characteristics and non-technical features are introduced. The paper discusses trends in the technology development of microgrid systems as well as microgrid control methods and interactions within the electricity market. Software tools for microgrid design, planning, and performance analysis are illustrated with each tool's core capability. Finally, the paper summarizes the successes and lessons learned during the recent expansion of the U.S. microgrid industry that may serve as a reference for other countries developing their own microgrid industries

Stochastic Bioeconomics: A Review of Basic Methods and Results

Basic bioeconomic models which incorporate uncertainty are reviewed to show and compare the principal methods used and results reported in the literature. Beginning with a simple linear control model of stock uncertainty, we proceed to discuss more complex models which explicitly recognize risk preferences, firm and industry behavior, and market price effects. The effects of uncertainty on the results of bioeconomic analysis are rarely unambiguous, and in some instances differ little from corresponding deterministic results. This review is presented to enhance readers' appreciation of the papers to follow in this and the next issue of the journal.Environmental Economics and Policy, International Development, Resource /Energy Economics and Policy, Risk and Uncertainty,

Exchange-Rate Dynamics

This paper discusses the dynamic behavior of exchange rates, focusing both on the exchange rate's response to exogenous shocks and the relation between exchange-rate movements and movements in important endogenous variables such as prices, interest rates, output, and the current account. Aspects of exchange-rate dynamics are studied in a variety of models, some of which are based on postulated supply and demand functions for assets and goods, and some of which are based on explicit individual utility-maximizing problems. Section 1 surveys the terrain. Section 2 explores the simplest model in which the relation among the exchange rate, price levels, and the terms of trade can be addressed -- a flexible-price small-country model in which wealth effects are absent and domestic and foreign goods are imperfect substitutes. Section 3 introduces market frictions so that the role of endogenous output fluctuations can be studied. Both sticky-price models and alternative market-friction models are discussed. Section 4 studies the link between the accumulation of foreign assets and domestic capital and the exchange rate.Section 5 examines deterministic and stochastic models in which individual behavior is derived from an explicit intertemporal optimization problem. Finally, section 6 offers concluding remarks.

Smart Microgrids: Overview and Outlook

The idea of changing our energy system from a hierarchical design into a set of nearly independent microgrids becomes feasible with the availability of small renewable energy generators. The smart microgrid concept comes with several challenges in research and engineering targeting load balancing, pricing, consumer integration and home automation. In this paper we first provide an overview on these challenges and present approaches that target the problems identified. While there exist promising algorithms for the particular field, we see a missing integration which specifically targets smart microgrids. Therefore, we propose an architecture that integrates the presented approaches and defines interfaces between the identified components such as generators, storage, smart and \dq{dumb} devices.Comment: presented at the GI Informatik 2012, Braunschweig Germany, Smart Grid Worksho

A Dynamic Model of Economic Growth in a Small Tourism Driven Economy

The paper studies the dynamics of economic growth caused by an increase in the growth rate of tourism demand. We develop a simple dynamic model of a small open economy, which is completely specialized in the production of tourism services (island economy model), populated by a large number of intertemporally optimizing agents, deriving utility from consuming an imported good. Tourism services are produced by means of a simple AK technology by using imported capital, its accumulation associated with adjustment costs. Moreover, the economy can lend or borrow at the international financial markets at the given world interest rate. Adjustments in the relative price of tourism services ensure market clearance for tourism services. The long-run growth rate of the economy is tied to the growth rate in tourism demand. An increase in the latter increases thus the economy’s long-run balanced growth rate. In contrast to the standard one-good small open economy endogenous growth model, where the economy is always on its balanced growth path, we show that there are transitional dynamics after an increase in the growth rate of tourism demand. In particular, the short-run growth rate of output rises gradually towards its higher long-run level, and the market price of tourism increases during transition. Thus, an increase in the growth of tourism demand, say, caused by higher economic growth abroad, leads to a boom in the small open economy and increasing terms of trade. Adjustments of the relative price of tourism services (i. e. the real exchange rate) can therefore not protect the economy from demand disturbances.tourism demand; growth; economic dynamics