J. C. Smith

National Renewable Energy Laboratory, Golden, Colorado, United States

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Publications (16)1.59 Total impact

  • H. Holttinen · M. O'Malley · M. Milligan · J.C. Smith
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    ABSTRACT: Many wind integration studies have been performed in recent years, with evolving methodologies. Since power systems and data availability vary significantly, the results and methodologies used in these studies have varied accordingly. This paper presents the main findings from the IEA WIND Recommended Practices for Wind Integration studies. An overview of a complete wind integration study is presented as a flow chart. The main simulation steps are presented with recommendations on methodologies: an increase in reserve requirements, estimating impacts on other generation and balancing, capacity value of wind power and transmission expansion due to wind power. The study set-up and the main assumptions are outlined, as they can have a critical impact on the results. The recommendations are applicable for other variable renewable sources, including photovoltaics.
    No preview · Article · Oct 2014
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    ABSTRACT: This Expert Group Report provides recommendations based on more than 8 years of work within International Energy Agency (IEA) Wind Task 25 Design and Operation of Power Systems with Large Amounts of Wind Power. The report is issued as an IEA Wind Recommended Practices document to provide research institutes, consultants, and system operators with the best available information on how to perform a wind integration study. The recommendations will be updated as further work in IEA Wind Task 25 reveals improved integration study methodologies based on real wind integration experiences. This Expert Group Report describes the methodologies, study assumptions, and inputs needed to conduct a wind integration study. Findings and results from previous wind integration studies are discussed in the two summary reports (Holttinen et al. 2009; and 2013). The Task 25 Expert Group developed a flow chart that outlines the phases of a complete wind integration study. The flow chart could also direct integration studies for other variable renewables, such as photovoltaics.
    No preview · Book · Oct 2013
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    ABSTRACT: This paper provides an overview of major transmission planning activities related to wind integration studies in the US and Europe. Transmission planning for energy resources is different from planning for capacity resources. Those differences are explained, and illustrated with examples from several regions of the US and Europe. Transmission planning for wind is becoming an iterative process consisting of generation expansion planning, economic-based transmission planning, system reliability analysis, and wind integration studies. A brief look at the policy environment in which this activity is taking place is provided.
    No preview · Article · Jan 2010
  • J. C. Smith · R. Piwko · W. Grant · M. Patel · S. Beuning · M. Ahlstrom
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    ABSTRACT: This paper reviews six IVGTF tasks related to interconnection and operating requirements, and provides a report on their objectives, milestones and status. The three interconnection tasks are: Interconnection Requirements Enhancement (Task 1.3); Low Voltage Ride-Through (LVRT) Requirements (Task 1.7); and Balancing Authority (BA) Communications (Task 2.2). The three operating tasks are: Incorporating Forecasting in Operations (Task 2.1); Ancillary Services and Balancing Area Solutions (Task 2.3); and Operating Practices, Procedures and Tools (Task 2.4). These tasks are part of a larger series of thirteen tasks identified in Phase 1 of the IVGTF work, and further described in the companion panel session papers.
    No preview · Article · Jan 2010
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    ABSTRACT: State and potential federal policies such as Renewable Portfolio Standards (RPS) are expected to significantly increase renewable generation in North America in the immediate future. Much of this growth will be from wind generation and solar photovoltaic (PV), both of which vary in their electrical output as the availability of the underlying fuel (wind and sunlight) varies. As the amount of variable generation (VG) increases, the reliability of the bulk power system can be negatively impacted if provisions are not made to accommodate the additional variability and uncertainty. As such, in December 2007, NERC created the Integration of Variable Generation Task Force (IVGTF) to prepare a report to identify technical considerations associated with integrating high penetrations of VG and specific mitigating actions, practices and requirements needed to ensure bulk system reliability. This paper broadly summarizes the work of this task force and focuses more specifically on the system planning recommendations developed.
    Full-text · Conference Paper · Jul 2009
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    ABSTRACT: There are already several power systems coping with large amounts of wind power. Hi h penetration of wind power has impacts that have to be manage through proper plant interconnection, integration, transmission planning, and system and market operations. This report is a summary of case studies addressing concerns about the impact of wind power.s variability and uncertainty on power system reliability and costs. The case studies summarized in this report are not easy to compare due to different methodology and data used, as well as different assumptions on the interconnection capacity available. Integration costs of wind power need to be compared to something, like the production costs or market value of wind power, or integration cost of other production forms. There is also benefit when adding wind power to power systems: it reduces the total operating costs and emissions as wind fossil fuels. Severalissues that impact on the amount of wind power that can be integrated have been identified. Large balancing areas and aggregation benefits of large areas help in reducing the variability and forecast errors of wind power as well as help in pooling more cost effective balancing resources. System operation and working electricity markets at less than day-ahead time scales help reduce forecast errors of wind power. Transmission is the key to aggregation benefits, electricity markets and larger balancing areas. From the investigated studies it follows that at wind penetrations of up to 20 % of gross demand (energy), system operating cost increases arising from wind variability and uncertainty amounted to about 1.4 ./MWh. This is 10 % or less of the wholesale value of the wind energy.
    No preview · Book · Jan 2009
  • J.C. Smith · B. Parsons

    No preview · Article · May 2008 · IEEE Power and Energy Magazine
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    ABSTRACT: As the size and number of wind power plants (also called wind farms) increases, power system planners will need to study their impact on the power system in more detail. As the level of wind power penetration into the grid increases, the transmission system integration requirements becomes more critical. A very large wind power plant may contain hundreds of megawatt-size wind turbines. These turbines are interconnected by an intricate collector system. While the impact of individual turbines on the larger power system network is minimal, collectively, wind turbines can have a significant impact on the power systems during a severe disturbance such as a nearby fault. Since it is not practical to represent all individual wind turbines to conduct simulations, a simplified equivalent representation is required. This paper focuses on our effort to develop an equivalent representation of a wind power plant collector system for power system planning studies. The layout of the wind power plant, the size and type of conductors used, and the method of delivery (overhead or buried cables) all influence the performance of the collector system inside the wind power plant. Our effort to develop an equivalent representation of the collector system for wind power plants is an attempt to simplify power system modeling for future developments or planned expansions of wind power plants. Although we use a specific large wind power plant as a case study, the concept is applicable for any type of wind power plant
    Full-text · Conference Paper · Jan 2006
  • R.M. Zavadil · J.C. Smith
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    ABSTRACT: As the number and size of wind power plants continue to grow, utility system operators and transmission network operators around the globe have begun to take note of the possible impact of the plants on power system performance during both normal and abnormal system conditions. Until recently, the number and size of wind power plants was such that it was not uncommon for interconnection practices to require that the plant be disconnected from the grid during a system disturbance, and reconnected when the system had returned to a normal state. This is no longer commonly accepted practice, as the size of recent wind power plants is as large as a typical fossil unit, and their behavior is an important component of overall system behavior both during normal and abnormal conditions.
    No preview · Conference Paper · Jul 2005
  • J. C. Smith · E. A. DeMeo · B. Parsons · M. Milligan
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    ABSTRACT: Electric utility system planners and operators are concerned that variations in wind plant output may increase the operating costs of the system. This concern arises because the system must maintain an instantaneous balance between the aggregate demand for electric power and the total power generated by all power plants feeding the system. This is a highly sophisticated task that utility operators and automatic controls perform routinely, based on well-known operating characteristics for conventional power plants and a great deal of experience accumulated over many years. System operators are concerned that variations in wind plant output will force the conventional power plants to provide compensating variations to maintain system balance, thus causing the conventional power plants to deviate from operating points chosen to minimize the total cost of operating the system. The operators' concerns are compounded by the fact that conventional power plants are generally under their control and thus are dispatchable, whereas wind plants are controlled instead by nature. Although these are valid concerns, the key issue is not whether a system with a significant amount of wind capacity can be operated reliably, but rather to what extent the system operating costs are increased by the variability of the wind.
    No preview · Conference Paper · Feb 2004
  • J.C. Smith · E.A. DeMeo · B. Parsons · M. Milligan

    No preview · Article ·
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    ABSTRACT: Wind energy continues to be one of the fastest growing technology sectors. This trend is expected to continue globally as we attempt to fulfill a growing electrical energy demand in an environmentally responsible manner. As the number of wind power plants continues to grow and the level of penetration reaches high levels in some areas, there is an increased interest on the part of power system planners in methodologies and techniques that can be used to adequately represent wind power plants in the interconnected power systems. Wind power plants can be very large in terms of installed capacity. The number of turbines within a single wind power plant can be as high 200 turbines or more, and the collector system within the wind power plant can have several hundred miles of overhead and underground lines. It is not practical to model in detail all individual turbines and the collector system for simulations typically conducted by power system planners. To simplify, it is a common practice to represent the entire wind power plant with a small group of equivalent turbine generators or a single turbine generator. The question is how much can a model be simplified and still preserve its faithfulness? In this presentation, we will describe methods to derive and validate equivalent models for a large wind farm. FPL Energy's 204-MW New Mexico Wind Energy Center, which is interconnected to the Public Service Company of New Mexico (PNM) transmission system, was used as a case study. The methods described are applicable to any large wind power plant. We will illustrate how to derive a simplified single-machine equivalent model of a large wind power plant (which includes an equivalent collector system model), preserving the net steady state and dynamic behavior of the actual installation. We use steady state as well as the dynamic analysis to derive the equivalent model. To verify the derivations, we compare the steady state and dynamic performance of the equivalent model against a detailed model of the wind power plant, which contains all the wind turbine generators and associated collector system.
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    ABSTRACT: This paper focuses on our effort to develop an equivalent representation of a wind power plant collector system for power system planning studies.
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    ABSTRACT: Because of wind power's unique characteristics, many concerns are based on the increased variability that wind contributes to the grid, and most U.S. studies have focused on this aspect of wind generation. Grid operators are also concerned about the ability to predict wind generation over several time scales. In this report, we quantify the physical impacts and costs of wind generation on grid operations and the associated costs.
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    ABSTRACT: In only 6 years, from 2000 to 2006, wind energy has become a significant resource on many electric utility systems, with nearly 74,000 MW of nameplate capacity installed worldwide at the end of 2006. Wind energy is now "utility scale" and can affect utility system planning and operations for both generation and transmission. The utility industry in general, and transmission system operators in particular, are beginning to take note. As a result, numerous utility wind integration studies are being conducted in the US under a variety of industry structures. This paper will summarize results from a number of case studies conducted recently in the US, and outline a number of mitigation measures based on insights from the recent studies.
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  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we describe methods to derive and validate equivalent models for a large wind farm. FPL Energy's 204-MW New Mexico Wind Energy Center, which is interconnected to the Public Service Company of New Mexico (PNM) transmission system, was used as a case study. The methods described are applicable to any large wind power plant.
    No preview · Article ·