燃气电厂天然气短期订购优化决策

由于天然气日前市场早于电力日前市场关闭,大部分发电商需要为所属燃气电厂在未知实际发电量的情况下制定次日的燃料订购决策。这是一个市场机制下的新问题。文中提出一种用于日前市场天然气订购的分步模拟优化方法。首先通过蒙特卡罗模拟方法得到机组最优发电量和所有可行的天然气订购决策下的利润分布情况;由此构建机组利润的有效前沿,然后利用效用最大化理论得到最优的天然气订购决策。在决策过程中综合考虑了燃料市场和电力市场的双重不确定因素。最后用算例说明了该模拟优化方法的有效性。     

Development of transmission system reliability performancebenchmarks

The reliability of an electric utility transmission system is a measure of its ability to continuously meet the demands of all its customers (i.e., points of delivery). Enhancing the supply reliability is one of planning and design targets of any utility within the constraints of capital investments, intense free-market competition, variable and higher level of customer preferences, and safety and environmental considerations. The utilization of transmission system facilities is changing from its traditional role in this new deregulated era and raising significant concerns about the possible erosion of the reliability of utility transmission facilities. It has been recognized that, with the movement toward a deregulated and competitive electricity market, decisions to improve reliability will be heavily influenced by industrial and commercial customer preferences requiring service level benchmarks to be defined. This paper presents an approach to establish realistic transmission system reliability performance benchmarks that provide a measure against which the different planning and design procedures can be evaluated to assist in achieving the primary objective of providing reliable electricity with competitive rates to utility customers     

Managing emergency response operations for electric utility maintenance

One of the most important criteria used to measure the quality of service in the electric utility industry is the uninterrupted service supplied to the customers. So, preventive maintenance is very relevant to avoid failures in the electric utility network. However, when failure is inevitable, it is very important that emergency repair operations are accomplished as soon as possible so the operators can avoid high-risk situations. Service unavailability can be decreased, reducing the frequency of power interruptions, number of customers affected per interruption, and duration of the interruption. A MAS for managing maintenance and emergency response operations in the electric utility industry was presented. The proposed system has the capability to support maintenance operations and make planning decisions.     

Cost-benefit analysis of power system reliability: two utility casestudies

There is an emerging recognition that utility investments and other decisions that affect electric service reliability should be explicitly evaluated on the basis of their cost and benefit implications. A cost-benefit approach that quantifies the reliability benefits of alternatives in terms of the reduction in costs resulting from unserved energy enables the evaluation of generation and transmission capacity additions on a consistent, economic basis. This approach has been applied to two utility case studies. In a case study for Pacific Gas and Electric Company, it was used to evaluate three options for maintaining reliability in a major load center-two involving local generation, and the third, a new 230 kV transmission connection. In a case study for Duke Power Company, the approach was used to evaluate alternative designs for proposed additions to a transmission station. This paper describes the methodology and presents the two utility studies     

Electric power system planning under time-of-use rates

Investment decisions under time-of-use rates and their relationship to utility system planning are examined. Optimal investment and price under social welfare maximization are derived and compared with the results of static analyses. For a multiplant case, the optimal pricing and investment policy are characterized by a plant of lower cost in a wide range of cost parameters. It is found that the second-best price, the so-called Ramsey price, is higher than the best price by an amount proportional to the ratio of deficit to revenue of an electric utility     

Consulting end-users on infrastructure worth

Considers how a methodological approach is evolving in the electric utility industry to determine users' evaluation of the worth of electric service and as a means to conduct realistic cost/benefit analysis at the planning stage. The essence of the argument is that, only if the worth of our infrastructure is known can defensible decisions be taken with respect to the expenditures to maintain or retrofit the infrastructure. Obtaining meaningful users' worth assessments of the infrastructure is a critical component in evolving definable cost/benefit analysis of major technological infrastructures     

The Electrical Aspects of Cogeneration System Design

Cogeneration and the reasons that it is a viable industry today are discussed. Both bottoming and topping cycles may be employed for cogeneration; however, the topping cycle is the major focus of current cogeneration projects due to its applicability in large cogeneration power plants. The effect and reasons for the Public Utility Regulatory Policies Act removal of many of the disincentives of cogeneration are discussed. The relative efficiencies of conventional and combined-cycle cogeneration power plants are compared in a typical example of a large cogeneration power plant currently under construction. Many considerations face the electrical engineer in the design of a cogeneration power plant. Many applications will be found in industrial plants and will utilize industrial thinking within the plant; however, many decisions will be influenced by conventional electric utility thinking, due to the interface with the electric utility in the switchyard. Basic discussion of the considerations required of the electrical engineer, including electrical system arrangement, integration of the new generation into the plant electrical system, short-circuit matters, one-line diagrams, generator characteristics, excitation systems, step-up transformer ratings and characteristics, auxiliary transformers (station service), distribution systems, and system grounding, is given for preliminary guidance in design.     

关于电力企业信息化建设与管理的几点思考

在电力体制发生不断变革的时期,电力企业的发展正面临巨大的挑战和机遇。通过对电力企业在信息化建设过程中面临的部分问题和薄弱环节的分析,从提高企业竞争力的角度和观点出发,探索在新环境下电力企业信息化下一步的工作思路和相应的对策。     

Optimization-based sale transactions and hydrothermal scheduling

Selling and purchasing power are important activities for electric utilities because of potential savings. When a selling utility presents an offer including prices, power levels and durations, a purchasing utility selects power levels and durations within the offered range subject to relevant constraints. The decision making process is complicated because transactions are coupled with system demand and reserve, therefore decisions have to be made in conjunction with the commitment and dispatching of units. Furthermore, transaction decisions have to be made in almost real time in view of the competitiveness of the power market caused by deregulation. In this paper, transactions are analyzed from a selling utility's viewpoint for a system consisting of thermal, hydro and pumped-storage units. To effectively solve the problem, linear sale revenues are approximated by nonlinear functions, and nonprofitable options are identified and eliminated from consideration. The multipliers are then updated at the high level by using a modified subgradient method to obtain near optimal solutions quickly. Testing results show that the algorithm produces good sale offers efficiently     

电能量监控系统在用电管理中的应用

电能量监控系统采用通用分组无线业务（GPRS)公用网络．是集防窃电、实时在线监测用电参数、用电分析、提高原计量装置精度于一体的新产品．减少用电管理工作量和管理费用,提高用电监察的针对性和效率,结合具体实例．将电能量监控系统应用于用电管理工作中．减少了抄表出车频率．降低了事故隐患．具有极大的社会效益。     

ECONOMICAL GENERATION RESERVE IN ISOLATED POWER SYSTEMS

ABSTRACT

This paper presents a new technique to determine the economical generation reserve for isolated power systems. The reserve is classified as short-term and long-term. For planning short-term power reserve to determine the required load shedding for avoiding blackout for severe emergency conditions, the dynamic behavior of the system after generating unit outages is performed, and the resulting frequency decay is analyzed. Therefore, the economical short-term reserve is determined to minimize the summation costs for reserve provision, plus the equivalent cost of the required load shedding.

For planning of long-term reserve, the utility investments and other decisions factors that affect electric service reliability should be explicitly evaluated, on the basis of their cost and benefit implications. A cost benefit approach, that quantifies the power reserve benefit in terms of the reduction in unserved energy cost, enables the evaluation of generation capacity additions.

To determine the economic short-term and long-term generation reserve, these approaches have been applied to areal regional utility     

Coordinated tuning of power system stabilizers in multimachine power systems

In this paper a new approach to simultaneously tuning the power system stabilizer (PSS) settings in a multimachine electric utility system is presented. The approach is based on eigenvalue assignment, which is treated as a problem of solving a set of non-linear equations. The possibility of meeting additional specified performance criteria is discussed. The flexibility of the proposed method is demonstrated using an operating utility system.     

Project valuation and power portfolio management in a competitivemarket

Deregulation in the US electric utility industry has lead to the entry of many new market participants, particularly power marketers, which in turn has lead to a much more active and fluid electricity market. With the advent of new market instruments that can be used to hedge one's exposure to market risks, power portfolio management takes on new meaning and new tools and techniques can be used to manage risk. This paper concentrates on long-term project valuation and power portfolio management issues in a competitive environment. It describes a method of valuing risky projects based on options pricing theory and decision analysis and its implementation to long-term power portfolio management or integrated resource planning for an electric utility in Texas. The author believes that the methodology described in this paper has wide application in the deregulated competitive electricity market from integrated resource planning for utilities facing competition and valuing a power plant investment by an independent power producer to pricing electricity options     

The Greta model: A decision making tool for operation and planning of generation systems at EDF

The purpose of the Greta Model is to synthesize for studies covering one or several years, the weekly optimal decisions taken by a utility to meet the demand for electric power at the least cost, using solely hydraulic and thermal generationNumerous predictive studies have been completed at EDF, using the Greta model, both in long term and in operation planning. It has recently become a tool contributing to decision making for yearly production schedulingThis paper deals with the uses as well as the methodological bases of the model. It is an expanded version of a paper presented at the 6th PSCC In Darmstadt     

Prospects for the Electric Vehicle: A Historical Perspective

The commercial failure of the electric vehicle in the first decades of this century was due to a number of factors, but one which has not yet been remarked upon by historians was the lack of interest of most electric utility companies in the vehicle charging business. Electric vehicle needed careful maintenance to presive their expensive and not very durable batteries, and in those businesses which were too small to use more than a few vehicles and which could not afford to operate charging and maintenance facilities, this was a serious drawback to their ability to use electric vehicles. In a few big cities in the period 1905-1920, a few utility companies aided the electric vehicle industry by setting up garages, giving specil chaging rates, making available technical serve, etc., but this was an uncommon phenomenon. Therefore, the use of commercial electric vehicles was usally restricted to those few large busineses which operated sizable fleets and their own prages. It is suggested that such lack of utility company support of the early electric vehicle may point up a lesson for the future acceptance of the electric vehicle in our own time.     

An efficient approach to identify and integrate demand-side management on electric utility generation planning

The electric utility planning environment has changed dramatically over the last few years. Utilities now need to include a wider variety of resources to meet the demand growth and increasing technical, economic, and environmental constraints. As a result, demand-side management (DSM) is widely implemented as part of the generation planning process. Since DSM programs have immediate benefits with respect to system reliability and financial performance, it is necessary that probabilistic production costing and reliability analysis be performed for the available DSM options. An efficient approach is presented which utilizes the eigenvector method (EVM) and a new load duration curve (LDC) model for the analysis. The EVM technique, based on expert opinions and mathematical analyses, estimates DSM impacts on future electricity demand. These impacts are than properly reflected in the load duration pattern and integrated into the supply-side planning process by using the new LDC model. A case study involving selected peak reduction programs in a medium-sized US electric utility is presented to show how DSM load impacts can be evaluated with the proposed approach.     

Revisiting Bonbright’s principles of public utility rates in a DER world

Professor James Bonbright’s Principles of Public Utility Rates, first published in 1961, was built around a model of vertically integrated electricity monopolies and approached ratemaking largely as an exercise in balancing the interests of capital attraction with those of ratepayers, all within a ‘public interest’ framework. This article seeds a new conversation about changes to the venerable Bonbright principles and introduces new principles of public utility rates for an era of electric utility transformation.     

电力市场中效用风险指标及其决策模型的研究

电力市场条件下的可靠性问题已经引起人们的广泛关注,尤其是如何提供有效的手段保障市场条件下系统运行可靠性和经济性的协调发展。文中针对上述问题,提出了电力系统元件的效用风险指标的基本概念和计算方法。该指标考察了电力系统元件故障前后全社会福利的变化值,并将其与电力系统元件的物理可靠性结合起来．形成了一个可以同时评估系统元件可靠性和经济性的新方法,从而为电力市场条件下的电力系统可靠性研究提供了一条崭新的思路。为了验证所提出的理念,文中基于经过简化的电力市场模式．构造了新型的考虑效用风险指标的购电决策模型,并给出了求解过程。算例分析验证了文中提出的理念的可行性和合理性。     

Electric Utility Flicker Limitations

In providing electric service to a utilization device which creates a variation in electrical demand, one of the considerations facing the utility is the prevention of unacceptable voltage fluctuation on the supplying system. The criteria as applied by various utilities in the United States are discussed presenting general background and development of the existing guidelines. Attention is given to how a utility can more realistically evaluate potential flicker if provided with certain information by the party requesting electric service.