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This invited panel paper discussion will outline a number of aspects of wind energy characteristics relevant to the optimal wind/transmission model formulation task. Optimal placement of wind capacity on a constrained transmission network is a typical example of this type of problem. In particular the relevance of advanced and computationally intensive stochastic unit commitment to the model formulation will be debated. Optimization constraint matrix structure and techniques to exploit it will be shown to be of considerable importance for this type of problem. The relative merits of different model dimensionality reduction schemes, either through multivariate component analysis and probability discretisation or indeed scenario reduction, will be discussed. A pragmatic acceptance of the imprecise impact of long-term power system uncertainties will be maintained throughout, and wherever possible generality to different types of power systems will be considered.

Compared to the conventional grid, the smart grid requires active participation of consumers to improve the quality and reliability of power delivery. Advanced metering infrastructure (AMI), commonly known as the smart meter, which has the capability of supporting various functions beyond that of recording energy usage, will facilitate this expected increase in consumer participation. Another primary benefit of AMI is load and cost management for the utility. AMI requires a reliable communication system between the smart meter and consumer equipment. This paper identifies wireless networking solutions such as ZigBee as the best mode for such communication. Due to the shared nature of the wireless medium, however, these deployments face security challenges and interference issues. These must be addressed, taking into account the interests of both the utility and the consumer. This paper takes a comprehensive look at wireless security in the AMI based home-area network by identifying a wide range of possible vulnerabilities. Countermeasures that can be used by both the utility company as well as the customer are developed.

This paper presents a real time power system transient stability assessment method using synchrophasor data and the catastrophe theory. It is designed to satisfy the requirement of real time stability assessment in the wide area power system. Different from conventional approaches the proposed method does not consider the process of system operation by certain parameter values but by the concept of continuity of system operation. The stability margin is defined by discontinuity boundary. This feature can greatly simplify the complicity of defining the stability margin for different cases. In this paper the discontinuity of the maximum swing angle has been studied for the power system TSA. The operation trajectory of the maximum swing angle is obtained via different fault clearing angles. Then the stability condition is determined by the continuity of maximum swing angle. The value of fault clearing angle, which correlated to the intersection of the operational trajectory and the discontinuity boundary, is equal to the critical clearing angle. The synchrophasor has been applied here to provide the initial condition of the disturbance and to obtain the center of inertia with the rotor angle as a reference.

This paper describes a modeling approach that simulates the impacts of different climate change mitigation technologies on power grids for power system planning purposes. Because the historical data is less credible when new technologies are being deployed to the system, it is then critical to model them to address their impacts. This paper illustrates how to integrate modeling results obtained from different modeling tools to give a reasonable forecast of the future. Building simulation tools, distribution power grid modeling tools, and power system planning tools are used to model and aggregate the impacts from the end-use to the system level. Electricity generation, production cost, emission, and transmission congestions are used to quantify the influence of different mitigation technologies. Modeling results have shown that the cross-discipline modeling approach provided the modeler with the necessary time resolution and input details to address the variables that influence the modeling results. Different modeling issues are also addressed in the paper.

This paper investigates the operation and protection issues on a distribution system with high penetration of residential PV systems. PV systems are smaller scale resources and therefore they have different impact on a distribution circuit than larger scale resources. The paper indeed considers a typical residential feeder and investigates PV system impacts on the system at different penetration levels. Simulations on this system show that the even the high penetration level PV systems can be accommodated as the impact on the system will not be severe.

Many transmission entities around the world are considering the use of modern synchronous condensers as part of their overall transmission solution. This paper explores the performance characteristics of synchronous condensers and provides reasons why this time-proven technology is now again seen as offering many beneficial characteristics to the transmission grid. Of particular interest are applications in small isolated systems with high penetrations of renewable power sources. Such systems magnify the benefits provided by the synchronous condenser. Another common application involves placement of synchronous condensers electrically near HVDC installations to increase the system short circuit MVA. This paper reports on observations from one particular system that has been studied which involves all of the above situations.

This paper presents the second part of the Bibliography of FACTS technology mainly for the year 2000. Papers published/presented in Conferences in later part of 1999, which appeared on search engines only in the year 2000 are also included in this Bibliography. It provides a listing of various journal and conference papers in this area.

Permanent magnet alternators are gaining ground in the wind turbine market due to their low maintenance requirements and suitability for offshore applications. This paper describes the development and testing of a dynamic model for full converter wind turbines employing permanent magnet alternators. The model described here is not proprietary and is a generic, manufacturer-independent model with no restrictions on its use. It can be implemented in any dynamic modeling software. Detailed representations of the wind turbine aerodynamics, mechanical drive-train, permanent magnet alternator, power converters and controllers are employed. This paper also includes details of model testing, as well as a description of the model's response to an event in the dynamic time scale.

This paper presents a new solution method that combines state-space and nodal analysis for the simulation of electrical systems. The presented flexible clustering of state-space-described electrical subsystems into a nodal method offers several advantages for the efficient solution of switched networks, nonlinear functions, and for interfacing with nodal model equations. This paper extends the concept of discrete companion branch equivalent of the nodal approach to state-space described systems and enables natural coupling between them. The presented solution method is simultaneous and enables benefitting from the advantages of two different modeling approaches normally exclusive from one another.

This report is a progress report by the Generator Subcommittee of the Electrical Machinery Committee of the IEEE Power and Energy Society, Working Group No. 8 (“IEEE C50.13 Review & Compare”). The working group is comparing the 2005 revision of the IEEE C50.13 standard for large round rotor synchronous generators with recent revisions of comparable International Electrotechnical Commission (IEC) 60034 standards. In this paper the working group reports progress made since starting in 2007, summarizes completed results, and outlines plans for next steps. Included are highlights of an incrementally improved C50.13 that is to be submitted for balloting in 2013 and highlights of future improvements that will be pursued after 2013. Also included is a synopsis of suggestions provided to the IEC for harmonization of IEC 60034 with IEEE C50.13. Finally, the paper includes an overview of a 2012 PES panel session to discuss grid code impacts on electric machine design and performance.

Identifying harmonic sources in a given power system is an important task for utility power quality management. This paper presents a new class of harmonic source identification problems: how to quantify the harmonic impact of several known harmonic-producing loads on the harmonic levels observed at a network location. The paper first defines the problem and proposes a harmonic impact index to theorize the problem. The paper then presents a statistical-inference-based method to estimate the index. The data required for this analysis are the harmonic voltage and current magnitudes continuously collected by the existing power quality monitors. The characteristics of the proposed method are investigated through case studies. Finally, additional applications and improvements of the proposed method are discussed.

In order to understand how an energy storage system (ESS) based supplementary damping control (stabilizer) suppresses power system inter-area oscillations, this paper proposes a tie-line power variation related ESS linearized dynamic model. This model describes the direct contribution from the ESS control to the small-signal variations (oscillations) of the tie-line power. Based on the model, a general conclusion is established to assess the capability of the ESS based stabilizer to affect the damping of inter-area power oscillations. Analysis based on the general conclusion explains how the effectiveness of the ESS stabilizer changes with the variations of loading conditions of tie line. It is concluded that the ESS based stabilizer is more robust to the variations of tie-line loading conditions when it is implemented by regulating the active power exchange between the ESS and the power system. In the paper, results of computation and simulation of an example power system installed with a battery energy storage system (BESS) are presented.

This paper presents the third part of the Bibliography of FACTS technology for 2011. It provides a listing of various journal and conference papers in this area. This Bibliography includes papers published until November 2011. If this paper is granted revise and resubmit status, the Working Group will update this bibliography to include all papers published till the end of year 2011 and make it more complete.

This paper presents the use of Higher Order Statistics (HOS) and Artificial Neural Networks (ANNs) for distance relaying purposes. The main objective is to design a distance relay prototype. In the current paper, the results of fault detection and classifications using such tools are presented. Preliminary results of fault location are also presented. It can be noticed the reliability as well as high speed in detecting faults. These results are very promising as the method combines a large number of samples of HOS with different features and the capability of ANNs to discriminate different patterns. Furthermore this new distance protection approach under development is based on voltage signals only which represent an innovation in distance relaying.

This paper discusses new opportunities and challenges of Integrated Voltage and Var Optimization (IVVO) associated with the emerging high penetration of Advanced Metering Infrastructure (AMI), Distributed Energy Resources (DER), Demand Response (DR) and Plug-In Electric Vehicles (PEV) in power distribution systems. The paper addresses the impact of the IVVO application on the operation of other power system domains, the possible objectives and benefits of IVVO, and the specifics of the constraints, controllable variables, and information sources for the IVVO, all based on a holistic approach.

In this paper, a virtual power system simulator (VPSS) using a virtual power plant (VPP) concept is introduced. VPSS efficiently emulates power system operations and electricity transactions in order to protect the access to future electricity markets utilizing the power system interconnections in Northeast Asia (NEA). This paper introduces methods on how to structure and operate the operative mechanism and the simulator design for these proposed inter-regional interconnections in the NEA. The inter-regional power system interconnection structure is expressed by using an interregional scenario performed by the Integrated Inter-Regional Transmission Organization (IIRTO). In these NEA countries, electric power bidding scenarios and price signal scenarios are options that are able to be defined by one VPSS based on the IIRTO parameters.

As oil and coal reserves are being depleted whilst at the same time the energy demand is growing, it is important to consider alternative energy generating techniques. Similarly there is a move from centralized power generation to decentralized power generation. Specifically within rural communities where there is limited access to electricity, it is possible for decentralized renewable energy systems to make a large impact. This paper outlines the design of a hybrid power system consisting of solar photovoltaics (PV) power system, wind power system and battery storage. This system is designed for stand-alone operation. A novel controller links each of these components to ensure that one system is supplying the load dependant on the weather conditions. This system is modeled in Matlab Simulink and tested for various weather conditions and temperatures. The model and results are detailed in this paper.

This paper presents transient voltage stability analysis of an AC system with multi-infeed HVDC links including a traditional LCC HVDC link and a VSC HVDC link. It is found that the voltage supporting capability of the VSC-HVDC link is significantly influenced by the tie-line distance between the two links and the size of loads. In order to improve the transient voltage stability, a voltage adjusting method is proposed in this paper. A voltage increment component has been introduced into the outer voltage control loop under emergency situation caused by severe grid faults. In order to verify the theoretical analysis and the improved control method, real time simulation model of a hybrid multi-infeed HVDC system based on western Danish power system is established in RTDS™. Simulation results show that the enhanced transient voltage stability can be achieved.

This paper presents Function Optimization by Learning Automata (FOLA) for the power flow problem which aims to achieve economic power system dispatch and voltage stability enhancement in dynamic wind power integrated systems. Dividing each dimension into a certain number of cells, FOLA undertakes the dimensional search, and has the ability of memorizing history through the values of cells that have been visited, in contrast to evolutionary algorithms (EAs) which adopt population-based search and aggregate the individuals of a population towards the best one selected in a current population. In this paper, FOLA is compared with improved Particle Swarm Optimization (PSO) and Genetic Algorithm (GA). Simulation studies have been carried out on the modified IEEE 30-bus and 57-bus power systems respectively, which are integrated with time-varying wind power. The experimental results have demonstrated that FOLA outperforms PSO and GA, as it tracks the changing system configuration more rapidly and accurately than the improved PSO and GA.

Smart grids have attracted significant attention lately, and one can even speak of a hype. However, much of the attention is paid to the distribution side and consumer interaction. Nevertheless, also at the transmission level important improvements can be achieved through farsighted and careful intelligent grid design and implementation. This paper identifies different research areas and their respective boundary interactions in order to enable a practical #x201C;Smart Grid #x201D; implementation in the European power system. Emphasis is placed on three essential aspects of the Smart Transmission Grid. First, the necessary evolution of synchrophasor measurement technology is discussed, as well as the limitations towards and its full integration into power system operation and control. An important aspect to achieve this full integration is the necessity to test and integrate any proposed solution in an open and transparent environment. Secondly, the IT, data and communications paradigm is critically discussed. And lastly, the key questions that are open to the transmission system operators are discussed, specifically regarding the coordination within the pan-European power system and its security. Going beyond the purely academic point-of-view, this paper specifically aims to bring a realistic approach towards research for the transmission network. © 2011 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. Qc 20120202

The impact of distributed generation (DG) on losses is of great interest in the smart grid research area. This paper analyses how DG locations, automatic voltage controls, generator types, and the operation modes of DGs impact the losses of distribution system. The topology of the grid is selected from the practical distribution network in Xiamen, which is one of the four pilot smart distribution grid cities in China. Shapley Value method is used to identify each DG's individual impact on these losses. Results show that the losses are reduced most significantly when DGs operate at the constant current mode and voltage control mode; followed by the power factor control mode. The induction machine bus could increase the losses. At last, according to the Shapley Values of the DGs, the individual impacts of DGs on losses are location-dependent. The method proposed in this paper has been employed in Xiamen smart grid.

This paper briefly describes Dominion's use of pseudo-measurements for the enhancement of its state estimator solution. Beyond providing a basic definition of pseudo-measurements and their usefulness, this paper highlights the specific integration of pseudo-measurements into Dominion's EMS platform. The paper concludes with a brief caution on the use of pseudo-measurements and highlights possible areas for further integration and treatment of pseudo-measurements.

Power system organization has gone through huge changes in the recent years. Significant increase in distributed generation (DG) and operation in the scope of liberalized markets are two relevant driving forces for these changes. More recently, the smart grid (SG) concept gained increased importance, and is being seen as a paradigm able to support power system requirements for the future. This paper proposes a computational architecture to support day-ahead Virtual Power Player (VPP) bid formation in the smart grid context. This architecture includes a forecasting module, a resource optimization and Locational Marginal Price (LMP) computation module, and a bid formation module. Due to the involved problems characteristics, the implementation of this architecture requires the use of Artificial Intelligence (AI) techniques. Artificial Neural Networks (ANN) are used for resource and load forecasting and Evolutionary Particle Swarm Optimization (EPSO) is used for energy resource scheduling. The paper presents a case study that considers a 33 bus distribution network that includes 67 distributed generators, 32 loads and 9 storage units.

This paper presents the wave energy research, development and demonstration (RD&D) efforts at Oregon State University (OSU), including the activities of the Northwest National Marine Renewable Energy Center (NNMREC) headquartered at OSU. The NNMREC facilities and research thrusts are described, and a full-scale mobile ocean test berth (MOTB) concept is detailed. In addition, a high-precision wave tank testing system established at OSU's O.H. Hinsdale Wave Research Laboratory (HWRL) is presented. The critical wave tank instrumentation, optical motion tracking system, data acquisition and related components are characterized. The paper concludes with example testing of scaled wave energy devices as well as upcoming device array testing.

This paper presents an index set to assess the status and ability of the smart-grid operation. In this paper, the “ability of multi-objective self-approximate-optimal operation” is considered as the most distinctive difference between smart grid and traditional power grid. Since the objectives of grid operation are to satisfy demands from electric system stakeholders, a multilevel set of the key smart-grid objectives is proposed with analysis and summary of these demands. Moreover, an index set that consists of a series of key indices for grid operation is identified around the objective system.

Currently, there are multiple national directives that call for the development of a smarter electrical grid. This includes, but is not limited to, the development of advanced transmission technologies as well as optimizing the use of transmission. Transmission control has been identified as a valuable mechanism for a variety of benefits, from improving the system reliability to improving the market surplus. However, the use of transmission as a controllable asset today is limited. This paper provides a literature review on transmission control and discusses current industry practices involving transmission control; the goal of this paper is to reemphasize the importance of transmission control in order to initiate future research and development in this area so that we are able to truly build and operate a smarter, more flexible transmission grid.

The power output from wind farms is highly volatile, uncertain and hard to be predicted accurately. Then sometimes positive short-run correlation between variations of wind power output and load could bring more and larger disturbances in the system operation, bringing reliability and economic concerns. The integration of wind power generators in power systems poses some challenges, and besides installing extra reserve capacities, transmission reinforcement or other advanced controls may be required to avoid transmission overloads or voltage problem induced by wind power variation. Moreover, a well-developed transmission network may need less reserve capacity for a given reliability level, providing incentives for the research of this paper. In this paper, an optimization & sensitivity method is proposed to identify the vulnerable area of the transmission system with large amount of wind integration. IEEE-57 bus system is used as the test system. Test cases with various objective functions and allocation of reserve capacity are designed and therefore different upgrade schemes are obtained by the method. Monte Carlo simulation is used for the reliability & economic evaluation of the test system with a group of indices, including a new index — entropy. Test results and comparison show the effective of the method, and also the potential of entropy for assessing the robust of the transmission network.

This paper presents a novel proposal for quantifying the influence of Demand Side Management (DSM) objectives on electric energy loss in distribution system. DSM objectives are modeled by VPI model and the testing results prove its suitability, especially for analysis on energy loss in distribution system. This paper uses IEEE's 34 Node Test Feeder as the test system for energy loss calculation and the analysis of DSM's influences. Network modeling is made using PSS/ADEPT 5.0. The research uses typical daily load curves of industrial and residential loads in Vietnam as a case study. Results not only indicate the effectiveness of loss reduction in DSM peak-clipping and load shifting, but also recommend DSM strategies for the best effect on energy loss reduction basing on modeling error testing.

This paper presents the application of FACTS devices for the enhancement of dynamic voltage stability in distribution networks with distributed wind generation. The analysis is carried over a test distribution system representative of the Kumamoto area in Japan. The detailed mathematical modelling of the system is also presented. Firstly, this paper provides simulation results showing the effects of higher and lower penetration of distributed wind generation on the voltage dynamics in a faulted system. Then, a distribution static synchronous compensator (D-STATCOM) is used to improve the voltage profile of the system. This analysis shows that D-STATCOM has significant performance to improve the voltage dynamics of distribution system compared to shunt capacitor.

This panel paper outlines the undergoing research towards the development of a novel smart distribution system at the Future Renewable Electric Energy Delivery and Management (FREEDM) Systems Center. The center's mission is to develop fundamental and enabling technologies necessary for a next generation smart distribution systems which can facilitate seamless integration of distributed recourses. The paper will also highlight center's education programs that are being developed for educating the next generation of power engineers who will be needed for the development and management of such systems.

Solar photovoltaic (PV) energy is becoming an increasingly important part of the world's renewable energy. In order for effective energy extraction from a solar PV system, this paper investigates I-V and P-V characteristics of solar PV cells and modules. The paper focuses particularly on I-V and P-V characteristics of a solar PV system when PV cells operate under uneven shading and dissimilar conditions. The study considers the relationship between semiconductor properties of a solar PV system and the external electric circuit requirements. The paper also examined how different bypass diode arrangements could affect the maximum power extraction characteristics of a solar PV system. It is found in this paper that under uneven shading conditions, solar PV cells may perform very differently and a solar PV system may exhibit multiple peaks in its P-V characteristics, implying that enhanced PV system design approaches and MPPT strategies should be developed to improve efficiency of a solar PV system.

Considering aging power system infrastructures in conjunction with increased electricity trading activities, there is a strong need for future investments in electricity grids. Technological progress has made available a number of different investment alternatives, ranging e.g. from “standard” reinforcements of existing transmission capacities to the installation of Flexible AC Transmission Systems (FACTS). This paper proposes a framework for comparing different investment alternatives. The approach relies on an optimal power flow (OPF), where system security is explicitly considered by means of a novel formulation for a security constrained optimal power flow (SC-OPF). For evaluation purposes several indicators are proposed, such as the loading of transmission lines, the total generation costs and the overall dispatch depending on different consumption levels. In a first case study the installation of shunt and in-series FACTS devices are compared. The paper is concluded with a sample valuation assessing whether to invest in a Thyristor-Controlled Series Capacitor (TCSC) or in a line reinforcement, i.e. additional line capacity.

Modeling of wind speed variation is an essential requirement in the estimation of wind energy potential for a typical site. In this paper, the average wind from April 2007 to March 2008 in Aimangala at central dry zone part of Karnataka, India have been statistically analyzed to determine wind energy potential for electrical power generation by grouping the seasonal observations. We show that the wind speed distribution is represented by the typical two parameter weibull function for prediction of wind energy out put required for preliminary design and assessment of wind power plant. The shape and scale parameters of weibull function have been estimated seasonal basis to calculate the average wind speed and wind power density for the Aimangala station. The maximum power density was found to be 829.73 W/m2 in monsoon season and the minimum power density was found to be 186.15 W/m2 in winter season. The Weibull function using Weibull parameter estimated in this paper shown to provide more accurate prediction of average wind speed and average power density for the selected station. The seasonal variation of wind speed and wind density studied in this paper is useful to ensure optimum selection of wind turbine generator

This paper summarizes and discusses operational cases where the PSS blocking should be activated and also presents a different scenario in which the PSS should be blocked. More specifically, the paper is concerned with the operation of the PSS of a generator which is part of a power system experiencing a frequency stability problem caused by a severe real power unbalance. The paper discusses in detail the impact of the slow, but large-magnitude system frequency variations on the operation of PSS structures, which use the frequency signal for the synthesis of the stabilizing signal. It is demonstrated that under some circumstances PSS blocking during a frequency instability incident might not be an acceptable option. To address this case, a new PSS operational logic, referred to as ‘PSS de-sensitizing’ is proposed. It is shown that with the PSS de-sensitizing it is possible to operate the PSS during all operational conditions without compromising the small-signal stability of the power system. The discussion is exemplified by realistic examples inspired by field experience.

Security Constrained Unit Commitment (SCUC) is a complex optimization algorithm used for day-ahead planning in restructured electricity markets. There are many existing approaches for implementing SCUC, but this paper will focus on the ones based on General Benders Decomposition (GBD). GBD decomposes the SCUC problem into a master problem, feasibility checks and subproblems. This paper will give a comparison study of different ways how the SCUC problem can be decomposed using variations of the existing GBD framework. Our goal is to show all these possible mappings and determine properties of the algorithms in terms of solution quality and runtime scalability. IEEE test cases will be used to present behavior of the algorithms when applied to networks of different size.

This paper describes the need for on-line decision making in support of reliable, clean and efficient operation of future electric energy systems. This operation will be critically dependent on the systematic dispatch of available resources ranging across real power generation and voltage controllable G&T&D equipment. The emphasis in this paper is on the role of on-line voltage dispatch. An extended AC Optimal Power Flow (AC XOPF) is introduced for computing decisions on-line. It is shown how this software enables optimization of technical and economic decisions in quantifiable ways. Focus then turns to experience with large system studies. It is observed that on-line dispatch of a variety of controllable equipment over the broad range of system conditions is becoming critical during both normal and contingency conditions.

Over the past decade, interconnection authorities have imposed fault ride-through capability requirements for wind farms. Both low voltage ride-through (LVRT) and 9-cycle zero-voltage ride-through requirement are included in FERC Order 661A This paper describes the solution developed by a major manufacturer that helped pioneer the application of type 4 (variable-speed full-converter) wind turbines. The paper will also briefly compare the LVRT characteristics of the type 4 machine with that of the more commonly used type 3 (DFAG) machine.

Total losses in transmission and distribution (T&D) of electrical energy including nontechnical losses (NTL) are huge and are affecting the good interest of utility company and its customers. In this context, importance of customer load profile evaluation for detection of illegal consumers is explained in this paper. Classification of the customers based on load profile evaluation using SVMLIB requires us to choose training function and related parameters. Selecting these parameters would consume a lot of time and is not suggestible evaluation of real time electricity consumption patterns, as, the suspicious profiles are to be predicted instantly. In light of this issue, this paper implements a neural network (NN) model and suggests a hierarchical model for enhanced estimation of the classification efficiency, if that data was classified using support vector machines (SVM). In addition, this paper proposes an encoding technique that can identify illegal consumers with better efficiency and faster classification of data.

Low-frequency inter-area oscillations are threat to secure operation of power systems. Power system stabilizer and Power oscillation damping controllers are used to provide damping to oscillatory modes. Such oscillatory modes, inter-area modes in particular, are significantly affected by change in operating conditions and load characteristics. In this paper, influence of load characteristics on performance of two distinct power oscillation damping controllers is being examined. The interaction between load characteristic and performance of power oscillation damping controller is explored in terms of damping contribution by individual controller on inter-area mode. Eigenvalue analysis approach is used to evaluate the performance of power oscillation controllers, which are designed based on residue compensation technique and H ∞ loop-shaping technique respectively. This paper also addresses the dynamic behaviour of the two controllers under different operating conditions and load characteristics.

This paper is a result of ongoing activity carried out by Understanding, Prediction, Mitigation and Restoration of Cascading Failures Task Force under IEEE Computer Analytical Methods Subcommittee (CAMS). The task force's previous papers [1, 2] are focused on general aspects of cascading outages such as understanding, prediction, prevention and restoration from cascading failures. This is the second of two new papers, which extend this previous work to summarize the state of the art in cascading failure risk analysis methodologies and modeling tools. The first paper reviews the state of the art in methodologies for performing risk assessment of potential cascading outages [3]. This paper describes the state of the art in cascading failure modeling tools, documenting the view of experts representing utilities, universities and consulting companies. The paper is intended to constitute a valid source of information and references about presently available tools that deal with prediction of cascading failure events. This effort involves reviewing published literature and other documentation from vendors, universities and research institutions. The assessment of cascading outages risk evaluation is in continuous evolution. Investigations to gain even better understanding and identification of cascading events are the subject of several research programs underway aimed at solving the complexity of these events that electrical utilities face today. Assessing the risk of cascading failure events in planning and operation for power transmission systems require adequate mathematical tools/software.

A modern power system consists of several control and monitoring loops, both automated and manually operated, to ensure that the system remains within safe operating bounds at all times. The focus of this paper is on data integrity attacks on messages exchanged between the control center and actuators in the voltage control loop. Devices such as the ones belonging to the FACTS family (STATCOM, SVC, TCR, etc.), are connected to the system at designated points for voltage control purposes. An attacker could cause a detrimental impact on the system by performing an attack on the control messages sent to these devices which would manipulate its settings. The aim of this paper is to highlight the impact of an attack targeted at such voltage control deices in the system. This paper presents a template that might be used by an attacker with knowledge of system functionality. The paper also explains the sensitivity analysis technique which will help the attacker identify the device to be compromised. A successful attack would result in abnormal voltage conditions in the system, thus violating NERC reliability standards.

This paper describes the use of Real Time Dynamics Monitoring System (RTDMS®) for use with SynchroPhasor System Technology (SPST). Analysis of some major power blackouts in US and other countries have shown that monitoring power system status and dynamic transient events in real-time can enable the operators to identify deteriorating system conditions early and help them take preventative actions to avoid or reduce likelihood of blackouts. Using RTDMS to monitor the power system with SynchroPhasor technology is expected to improve reliability, provide wide area visibility over multiple control areas, and provide system operators with real-time measurement of key grid metrics, including phase angles, oscillation modes, energy and modal damping. These grid dynamics indicators cannot be obtained in real-time from the existing historic tools such as SCADA or State Estimators. The SPST has great potential for enhancing power system stability and increasing power transmission system capability through high speed response based controls. Given, the proper visualization and analysis tools, this technology can assist operators in avoiding major system disturbances like the North American blackouts that occurred in Western US on August 10, 1996 and in Northeast US and Canada on August 14, 2003. The paper will outline the use of RTDMS with SPST and describes how it enhances the visibility of the power system. The RTDMS is in use at several ISOs and utility locations in North America.

This paper presents the Unit Commitment (UC) problem of thermal units considering Emergency Demand Response Program (EDRP). The optimal schedule minimizes the system production costs during the study period while satisfying load demand, spinning reserve requirements, and the physical as well as operational constraints of each individual unit. Hence, for deriving the best scheduling of generating units, solving such UC problem seems necessary. In this paper, the UC with EDRP problem as a nonlinear and non convex problem is solved using the Simulated Annealing (SA) method. In this regard, the effect of implementing EDRP on decreasing the cost of UC has been studied. It is shown that irrational implementing of EDRP could result in increasing the cost. Numerical studies show a significant improvement in the results of the UC problem.

This paper proposes a novel model of unified power flow controller (UPFC) for enhancing voltage stability margin of the power systems. This model is based upon an innovative approach where, real power exchange of series and shunt elements of UPFC are decoupled with each other. The UPFC model is incorporated into an existing Newton-Raphson load flow algorithm and Jacobian matrix is modified to include the decoupled modes of power exchange of series and shunt elements of UPFC. The modeling approach presented in this paper is tested on standard IEEE 30-bus and IEEE 118-bus systems to validate its feasibility.

This paper addresses the coordination of the Smart Distribution Grid applications with advanced applications in other power system domains, especially in the transmission operation and customer domains. The paper discusses the holistic approach to the role of Smart Distribution Applications in the support of the wide area situational awareness, dynamic optimization, and self-healing operations of the power system.

This paper studies the Power System Stochastic Storage Problem (PSSSP), a novel application in power restoration which consists of deciding how to store power system components throughout a populated area to maximize the amount of power served after disaster restoration. The paper proposes an exact mixed-integer formulation for the linearized DC power flow model and a general column-generation approach. Both formulations were evaluated experimentally on real-life benchmarks. The results show that the column-generation algorithm produces near-optimal solutions quickly and produces orders of magnitude speedups over the exact formulation for large benchmarks. Moreover, both the exact and the column-generation formulations produce significant improvements over a greedy approach and hence should yield significant benefits in practice.

This paper presents observations and challenges related to integration of renewable resources with respect to frequency control with primary focus on Inertial Frequency Response in ERCOT Interconnection. Frequency Control, in general, can be categorized into Inertial, Primary and Secondary Frequency Responses based on the response time. In ERCOT Interconnection, currently, the primary and secondary frequency response can be achieved by employing adequate control settings and Ancillary Service procurement. The Inertial Frequency Response described in this paper refers to the total synchronous mass connected to the Grid which includes motor loads as well as synchronous generators. Maintaining minimum level of Inertial Frequency Response with unit commitments can be crucial to ensure reliable integration of renewable resources. A trend in decline of Inertial Frequency Response with respect to increasing renewable resources has been observed according to recorded frequency events in the past four years in ERCOT Interconnection. Since Inertial Frequency Response dictates the change in frequency due to supply demand mismatch, it is important to maintain adequate system inertia in real-time operations. Therefore, an on-line tool is developed for the purpose of providing an estimation of system wide Inertial Frequency Response to potentially assist System Operators to maintain adequate system inertia. The unit of the estimated Inertial Frequency Response is MW/0.1 Hz. This unit is recognized to be more practical for System Operator to evaluate the system condition.

This paper uses synchrophasor measurements on a power transfer interface in the US Eastern Interconnection (EI) to develop voltage sensitivities with respect to increases in transfer flow. The disturbance event considered in this analysis involved a sudden loss of generation, resulting in increased flows on lines close to the disturbance location. The increased flow would immediately cause the bus voltages on the transfer path to drop. With high sampling rate synchrophasor data, the voltage and power flow relationship on a power transfer interface would form a segment of the familiar PV-curve. This paper uses phasor measurements from a disturbance event in the EI to develop a Thevenin equivalent circuit and evaluate the voltage sensitivity with respect to power transfer using this reduced model.

Over the next few years, plug-in hybrid electric vehicles (PHEV) and battery electric vehicles (BEV) will become readily-available to consumers. This paper describes the methods, procedures and results from an analysis of the likely near term (10 year) market penetration of electric vehicles (EV) for a large West Coast utility — one of the first markets where these vehicles are expected to be bought in large numbers. The impact of EVs on an electricity system depends heavily on the rates at which PHEVs and BEVs penetrate the market. This study provides realistic projections of the rates of EV market penetration given various types of incentives and utility information programs. It also highlights many of the market barriers that will stand in the way of some of the technologies that have the largest impacts on utility infrastructure costs (e.g., high voltage charging stations at home or in public). The findings from the analysis of the effects of incentives and information programs will be useful to utilities who are interested in encouraging growth in EV market penetration. In addition, the methods and analysis procedures described in this paper can be used by any utility to assess the likely size of the EV market in their jurisdiction in the next 10 years.

This paper investigates the effectiveness of suppression techniques of ferroresonance in nonlinear three-phase three-leg transformers. Previous literature has generally recommended the use of damping resistor loads to suppress ferroresonance. This paper examines the potential pitfalls of this approach and suggests a new simple arrangement which preliminary results indicate to be more effective. A newly developed nonlinear three-phase three-leg transformer model is implemented to accurately model ferroresonance conditions and simulate suppression techniques. The model includes dynamic magnetic hysteresis effects (major and minor loops), flux cross-coupling effects in the legs and asymmetry in the iron-core structure.