Kevin P. Schneider

GridLAB-D: An open-source power systems modeling and simulation environment

GridLAB-D is a new power system modeling and simulation environment developed by the US Department of Energy. This paper describes its basic design concept, method of solution, and the initial suite of models that it supports.

Initial review of methods for cascading failure analysis in electric power transmission systems IEEE PES CAMS task force on understanding, prediction, mitigation and restoration of cascading failures

Large blackouts are typically caused by cascading failure propagating through a power system by means of a variety of processes. Because of the wide range of time scales, multiple interacting processes, and the huge number of possible interactions, the simulation and analysis of cascading blackouts is extremely complicated. This paper defines cascading failure for blackouts and gives an initial review of the current understanding, industrial tools, and the challenges and emerging methods of analysis and simulation.

Impact assessment of plug-in hybrid vehicles on pacific northwest distribution systems

The U.S. electric power infrastructure is a significantly underutilized strategic asset which, with the proper shift in operational paradigms could provide a significant portion of the energy requirements for the existing U.S. light duty vehicle (LDV) fleet. This shift would result in reduced emissions, improved economics for utilities, and a reduced dependence on oil. A previous study has shown that the existing generation and transmission assets of the U.S. electric power infrastructure could feasibly supply the electricity for approximately 70% of the U.S. LDV fleet. In the limitations of the distribution system were not explicitly addressed and are more difficult to quantify because of the large diversity of distribution systems topology, design guidelines and load growth. This paper focuses on the impacts of a high penetration of plug-in electric hybrid vehicles (PHEVs) on the distribution systems. Presented are results specific for the Pacific Northwest.

Evaluation of Conservation Voltage Reduction (CVR) on a National Level

Conservation Voltage Reduction (CVR) is a reduction of energy consumption resulting from a reduction of feeder voltage. While there have been numerous CVR systems deployed in North America there has been little substantive analytic analysis of the effect; the majority of the published results are based on empirical field measurements. Since these results are based on empirical measurements it is difficult to extrapolate how this technology will behave on the various types of distribution feeders found throughout the nation. This report has utilized the Taxonomy of Prototypical feeder developed under the Modern Grid Initiative (MGI), now the Modern Grid Strategy (MGS), in order to estimate the benefits of CVR on multiple distribution feeder types. This information will then be used to determine an estimate of the national benefits of a wide scale deployment of CVR.

Distribution System Restoration With Microgrids Using Spanning Tree Search

Distribution system restoration (DSR) is aimed at restoring loads after a fault by altering the topological structure of the distribution network while meeting electrical and operational constraints. The emerging microgrids embedded in distribution systems enhance the self-healing capability and allow distribution systems to recover faster in the event of an outage. This paper presents a graph-theoretic DSR strategy incorporating microgrids that maximizes the restored load and minimizes the number of switching operations. Spanning tree search algorithms are applied to find the candidate restoration strategies by modeling microgrids as virtual feeders and representing the distribution system as a spanning tree. Unbalanced three-phase power flow is performed to ensure that the proposed system topology satisfies all operational constraints. Simulation results based on a modified IEEE 37-node system and a 1069-node distribution system demonstrate the effectiveness of the proposed approach.

Multi-State Load Models for Distribution System Analysis

Recent work in the field of distribution system analysis has shown that the traditional method of peak load analysis is not adequate for the evaluation of emerging distribution system technologies. Voltage optimization, demand response, electric vehicle charging, and energy storage are examples of technologies with characteristics having daily, seasonal, and/or annual variations. In addition to the seasonal variations, emerging technologies such as demand response and plug-in electric vehicle charging have the potential to receive control signals that affects their energy consumption. To support time-series analysis over different time frames and to incorporate potential control signal inputs, detailed end-use load models that accurately represent loads under various conditions, and not just during the peak load period, are necessary. This paper will build on previous end-use load modeling work and outline the methods of general multi-state load models for distribution system analysis.

Controlled Partitioning of a Power Network Considering Real and Reactive Power Balance

In response to disturbances, a self-healing system reconfiguration that splits a power network into self-sufficient islands can stop the propagation of disturbances and avoid cascading events. This paper proposes an area partitioning algorithm that minimizes both real and reactive power imbalance between generation and load within islands. The proposed algorithm is a smart grid technology that applies a highly efficient multilevel multi-objective graph partitioning technique. Thus, it is applicable to very large power grids. The proposed algorithm has been simulated on a 200- and a 22,000-bus test systems. The results indicate that the proposed algorithm improves the voltage profile of an island after the system reconfiguration compared with the algorithm that only considers real power balance. In doing so, the algorithm maintains the computational efficiency.

The Smart Grid: An Estimation of the Energy and CO2 Benefits

This report articulates nine mechanisms by which the smart grid can reduce energy use and carbon impacts associated with electricity generation and delivery. The quantitative estimates of potential reductions in electricity sector energy and associated CO2 emissions presented are based on a survey of published results and simple analyses. This report does not attempt to justify the cost effectiveness of the smart grid, which to date has been based primarily upon the twin pillars of cost-effective operation and improved reliability. Rather, it attempts to quantify the additional energy and CO2 emission benefits inherent in the smart grid’s potential contribution to the nation’s goal of mitigating climate change by reducing the carbon footprint of the electric power system.

Vulnerability assessment for cascading failures in electric power systems

Cascading failures present severe threats to power grid security, and thus vulnerability assessment of power grids is of significant importance. Focusing on analytic methods, this paper reviews the state of the art of vulnerability assessment methods in the context of cascading failures. These methods are based on steady-state power grid modeling or high-level probabilistic modeling. The impact of emerging technologies including phasor technology, high-performance computing techniques, and visualization techniques on the vulnerability assessment of cascading failures is then addressed, and future research directions are presented.

Distribution power flow for smart grid technologies

Smart Grid technologies hold the promise of being able to solve many of the problems currently facing in the electric power industry. However, the large scale deployment of these new technologies has been limited due to an inability to accurately model their effects or to quantify their potential benefits. GridLAB-D is a new open source power system modeling and simulation environment developed by the United States Department of Energy specifically to integrate detailed power systems and end-use models. In order to effectively model the vast array of possible smart grid technologies GridLAB-D was developed as a general simulation environment. This paper describes the basic design concept, the power flow solutions implemented, and a detailed example of the type of analysis that can be performed within the simulation environment in order to support the evaluation of smart grid technologies.