IEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 19, NO. 1, FEBRUARY 2004
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What Future Distribution Engineers Need to Learn S. S. Venkata, Fellow, IEEE, Anil Pahwa, Fellow, IEEE, Richard E. Brown, Senior Member, IEEE, and Richard D. Christie, Member, IEEE
Abstract—It is getting increasingly clear that electric distribution systems are undergoing rapid changes due to deregulation, the penetration of distributed generation and power electronics technologies, and the adoption of efficient computation, communications, and control mechanisms. The primary goal of this paper is to recommend the development of a new two-course sequence to reflect the radical changes occurring or expected to happen in the future. Index Terms—Deregulation, distribution systems, engineering curriculum.
II. PRESENT STATE AND FUTURE TRENDS Distribution systems are changing from nearly every stake holder’s perspective, including customer’s, the regulator’s, the planner’s, the engineer’s, the operator’s, and the financier’s. Although it is beyond the scope of this paper to address each of these issues in detail, the following sections describe the major factors related to the present state and the future of distribution systems. A. Uncertainties About Industry Restructuring
I. INTRODUCTION
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HE authors propose a two-course sequence at the senior elective/graduate level that they consider critical for the success of future distribution engineers. The need for such a sequence is clear due to several exciting changes that have been occurring and continue to do so in the electric power industry. The need also arises because the subject of distribution systems is getting more complex and did not receive adequate attention in the past. Presently, very few universities teach even a single course on this topic around the world. As a matter of fact, power engineering education curriculum is at a crossroads and needs complete rejuvenation. The readers are encouraged to read the article by Heydt and Vittal entitled “Feeding Our Profession” in the premier 2003 issue Electric Power and Energy Magazine [1]. The present state and future trends are addressed in Section II which, in essence, establishes the motivation for developing this paper. The new technologies for the future are covered in Section III. These technologies represent the beginning of new and exciting changes that will make future distribution systems more complex. The challenges and the curriculum issues in designing the sequence are summarized in Section IV. Some of the pedagogical challenges for designing and delivering the two courses are outlined in Section V. Section VI lists the authors’ view of the outline and syllabus for the two courses. The topics recommended are by no means complete and comprehensive. Finally, the summary concludes the paper.
Manuscript received July 7, 2003. S. S. (Mani) Venkata is with Iowa State University, Ames, IA 50011–3060 USA (e-mail:
[email protected]). A. Pahwa is with Kansas State University, Manhattan, KS 66503 USA (e-mail:
[email protected]). R. E. Brown is with the KEMA Consulting, Raleigh, NC 27607 (e-mail:
[email protected]). R. D. Christie is with the University of Washington, Seattle, WA 98195-2500 USA (e-mail:
[email protected]). Digital Object Identifier 10.1109/TPWRS.2003.821017
The electric utility structure is moving away from vertical integration to an unbundled model of generation companies (GENCOs), transmission companies (TRANSCOs), distribution companies (DISCOs), and energy service providers (ESPs) or energy service companies (ESCOs). In the past, all distribution-related functions could be transparently coordinated along the complete supply chain. In the future, many distribution companies will manage third-party contracts by delivering bulk power from GENCOs and TRANSCOs to meters owned by ESCOs. As the same time, many state regulatory commissions are considering the viability of retail wheeling (small generators connected to the distribution system selling electricity directly to customers). In addition to planning, operating, and remuneration difficulties, retail wheeling asks distribution systems to perform functions for which they were not designed. B. Increased Regulatory Oversight In the U.S., distribution systems are subject to state jurisdiction. Statutes and approaches vary widely, but there is a general trend toward increased oversight. In addition, recent merger activity has resulted in a majority of investor-owned electric utility holding companies having to deal with multiple state commissions. Fig. 1 shows that a majority of utility holding companies still only sell retail electricity in one state. However, many utilities are active in two or more states and these tend to be much larger than single-state utilities. Ironically, increased oversight is partially due to rate freezes. Although rate freezes result in less regulatory activity, they can lead to under-investment and performance degradation. As such, many commissions are freezing rates but are placing heavy reporting requirements on distribution system performance and may even assess penalties for not meeting targets. Presently, more than half of all states have reliability reporting requirements and more than a dozen have penalties for excessively poor reliability [2].
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C. Increased Equipment Loading Short-term financial pressures have led most utilities toward increased levels of “asset utilization.” Although high equipment loading is well understood from the perspective of thermal aging and conductor sag, it is less understood in other ways. With everything else equal, high loading increases failure probability. Detailed failure rate models do not exist, but the probability of second-order failures increases with the square of failure rate, the probability of third-order failures increases with the cube of failure rate, and so forth. Coupled with reduced reconfiguration flexibility due to capacity constraints, extreme loading often results in systems that are much more vulnerable to major events than the same system during moderate loading. Reliability aside, thermal aging of organic insulation increases exponentially with temperature. This does not only substantially impact the useful life of moderately loaded equipment, but becomes a financial concern when systematic increases in equipment loading begin to materially reduce useful life. D. Aging Infrastructure Before the 1970s, electricity usage grew at an annual rate of approximately 7%. Without considering failures, this implied that 14% of equipment would have been older than 30 years and 0.5% would have been exceeding 50 years. For the last 30 years, growth has been lower at approximately 2.5%, resulting in minimal procurement need for new equipment. This implies currently 49% of existing equipment is older than 30 years and 8% older than 50 years. Aging infrastructure is a major problem due to growth rate alone, is exacerbated by higher equipment loadings and less aggressive replacement programs, and has been recognized by the Department of Energy and one of the major issues facing electric utilities [3]. E. Increasing Demand for Power Quality and Reliability While utilities are under increasing pressure to reduce cost and deal with aging infrastructures, many customers are demanding higher levels of power quality and reliability. Long interruptions halt production, short interruptions cause computer systems to crash, and waveform distortions, such as sags, can
cause motor contacts to drop out and electronic controls to malfunction. To complicate matters, many customers are not willing to pay for increased quality; many see perfect reliability as an entitlement, and as an opportunity to ride free on others willing to pay for premium service. Different customers have different needs, and existing distribution systems are not able to differentiate reliability accordingly. Reliability is too high for most, too low for some, and just right for few [4]. F. Performance-Based Regulation In general, performance-based regulation allows utility performance to dictate profitability. This generally takes the form of a rate freeze, which encourages efficiency by allowing utilities to retain cost savings for the duration of the rate freeze. Since rate freezes often lead to under investment, many regulatory commissions combine rate freezes with penalties for poor performance. In concept, penalties for poor performance provide an explicit financial incentive to maintain or improve performance levels. In practice, penalties are small and indirect factors drive investment behavior. The regulatory trend, however, is clear. Future distribution companies might not have guaranteed returns on their asset base. Asset management and operational efficiency by these companies might become increasingly critical for survival, and profits will be increasingly linked to performance measures such as customer satisfaction and reliability. III. NEW TECHNOLOGIES FOR THE FUTURE Restructuring of the power industry, changing expectation of the customers of the digital age, and advancements in technology will gradually impact distribution systems. The technologies that would have the biggest impact are distribution automation, power electronics, distributed energy resources, and distribution management systems (DMS), and distribution control centers (DCCs). A. Distribution Automation The concept of distribution automation dates back to the 1970s. The main motivation at that time was to use evolving computer and communications technology to improve operating performance of distribution systems. Since then, the growth of distribution automation has been dictated by the level of sophistication of existing monitoring, control, and communication technologies, and performance and economic factors associated with the available equipment. Evolution of supervisory control and data acquisition (SCADA) systems, which have been in use for monitoring the generation and transmission systems, has also helped progress in the field of distribution automation. Although distribution systems are a significant part of power systems, advances in distribution control technology have lagged considerably behind advances in generation and transmission control. Small pilot projects were implemented by a few utilities to test the concept in the 1970s. In the 1980s, there were several major pilot projects. By the 1990s, the technology had matured
VENKATA et al.: WHAT FUTURE DISTRIBUTION ENGINEERS NEED TO LEARN
and that resulted in several large and many small projects at various utilities. Some people speculated that most of the utilities would embark on large-scale distribution automation. However, many utilities found it difficult to justify distribution automation based on hard cost-benefit numbers. Business uncertainties due to deregulation and restructuring of the power industry slowed wide scale implementation of distribution automation. Thus, it is prudent to re-examine the overall philosophy of distribution automation. Instead of undertaking mega projects, it is time to “think small.” In other words, instead of a top-down approach, it is perhaps better for the utilities to opt for the bottom-up approach. Moreover, selection of distribution automation functions for implementation should always be need based. Improvements of system reliability and voltage profile on the feeders are two examples of the needs for utilities. Need-based automation would be easier to justify and win approval of the management. Distribution automation also provides many intangible benefits, which should be given consideration while deciding to implement distribution automation. After the deregulation and restructuring issues are settled, distribution automation activities should increase. Automation allows utilities to implement flexible control of distribution systems, which can be used to enhance efficiency, reliability, and quality of electric service. Flexible control also results in more effective utilization and life-extension of the existing distribution system infrastructure. Many utilities are contemplating providing performance-based rates to their customers. They would be willing to pay compensation to the customers if the performance falls below a minimum level. Such actions will allow utilities to brace for the upcoming competition from other parties interested in supplying power to the customers. Although higher reliability and quality are the goals of the utilities, they would like to accomplish this while optimizing the resources. Another goal for a utility should be improvement in system efficiency by reducing system losses. The functions that can be automated in distribution systems can be classified into two categories, namely, monitoring functions and control functions [5]–[7]. Monitoring functions are those needed to record (1) meter readings at different locations in the system, (2) the system status at different locations in the system, and (3) events of abnormal conditions. The data monitored at the system level are not only useful for day-to-day operations but also for system planning. Distribution supervisory control and data acquisition (DSCADA) systems perform some of these monitoring functions. The control functions are related to switching operations, such as switching a capacitor, or reconfiguring feeders. The function that is the most popular among the utilities is fault location and service restoration or outage management. This function directly impacts the customers as well as the system reliability. Some customer-related functions, such as remote load control, automated meter reading (AMR), and remote connect/disconnect may also be considered as distribution automation functions. However, AMR has evolved significantly itself as a separate area. In addition, system protection can also be a part of overall distribution automation schemes.
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B. Power Electronics Devices Electric power quality has become an increasingly problematic area in power system distribution systems. Power quality may be defined as “the measurement, analysis, and improvement of bus voltage, usually a load bus voltage, to maintain that voltage to be a sinusoid at rated voltage and frequency [8].” Any deviation due to harmonics, transients, voltage sag, and interruption results in power-quality problems. A direct correlation exists between the lack of electric power quality delivered to the customer and the number of complaints received from the customer. Although power quality is not a very huge concern for residential customers, it can have significant impact on the industrial and the commercial customers. Momentary loss of power or sag in voltage could reset the manufacturing process or the computers, resulting in loss of millions of dollars. Similarly, such events can be disastrous for hospitals. Society will be increasingly more digital in the future. The demands of customers to receive better quality of service will increase. Even for residential customers, it will not be just the nuisance of resetting blinking clocks, but several appliances and devices would need to be reset and require reprogramming. The Electric Power Research Institute (EPRI) has directed substantial research efforts into the development of advanced technologies to improve the performance of utility distribution systems. The technology, called custom power, seeks to integrate modern power electronics-based controllers such as the solid-state breaker (SSB), the static compensator (STATCOM), and the dynamic voltage restorer (DVR) with distribution automation and integrated utility communications to deliver a high grade of electric power quality to the end user [9]. Although extremely useful, custom power devices have been used in distribution systems only on a limited basis. Recently, several new devices have been developed which allow rapid control. Application of distribution-level power electronic devices such as the STATCOM for distribution system control has already been demonstrated [10]. These devices are continuously controlled and respond in real time to system changes. Coordination of a STATCOM with load-tap-changer (LTC) and mechanicallyswitched capacitors reduces fluctuations in system voltage, improving the quality of service. The power electronics devices that control quality of power in the distribution systems have been used very sparingly mainly due to cost considerations. Only the very critical loads such as hospitals and some manufacturing facilities can justify investment in such devices. The most prevalent power electronics device is the uninterrupted power supply (UPS), which is very commonly used for the computer systems. Even for individual computers, inexpensive UPS are available. As computer technology penetrates the homes and businesses, the need for inexpensive devices to provide ride-through capabilities against momentary interruptions, voltage sags, and other power-quality problems will increase. It is quite conceivable that the appliances of the future would have a built-in module to provide such features.
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C. Distributed Energy Resources (DERs) Deregulation of the power industry, advancements in technology, and a desire of the customers for cheap and reliable electric power has led to an increased interest in distributed energy resources. Distributed resources are attractive due to lower capitol cost, potential for reduced emissions, and possibility of deferment of transmission upgrades. Unlike bulk power resources, the distributed resources are directly connected to the distribution system, most often at the customer end. In some cases, utility-installed distributed resources are located in the distribution substation. Wind, solar, microturbine, minihydro, miniturbines, combined heat and power (CHP) sources, super magnetic energy storage (SMES), and fuel cells are some of the common technologies available for distributed resources [11]. Cost associated with these technologies is still reasonably high, and must be considered along with technical issues such as increased capacity, improved efficiency, and better power quality and reliability of the systems. Issues related to reliability and maintenance also have impeded the penetration of distributed resources. The most common application of distributed resources has been for situations where extremely high reliability of power supply is needed, especially for businesses with very critical loads. Businesses such as automated electronics fabrication facilities, manufacturing facilities with computer-based controls, hospitals, and a data processing center are examples of such businesses. Penetration of distributed resources in the residential sector is far from realization. Poor reliability and steep rise in price of electricity from the grid coupled with reduction in cost of distributed resources will be attractive for residential customers. None of these are forthcoming in the near future in the U.S. and other developed countries. Distributed resources are a viable alternative for developing countries where grid supply has reliability below desirable levels. Microturbines have the potential of being the most popular distributed generation resource for the industrial sector. However, high penetration of microturbines could put adverse pressure on the natural gas supply network. Due to increased demand, the natural gas market could become very volatile. Since the utilities are not embarking on building large generating plants, they could use microturbines as an opportunity to develop generating resource. As a possible scenario, they could subsidize the purchase of microturbines by the customers and provide them maintenance services at a reasonable cost. Also, they can buy the excess energy generated by the customers. High penetration (say more than 20%) of distributed generation will also raise new challenges in the operation of distribution systems. Currently, most of the distribution systems operate in the radial configuration, that is, the power flows only in one direction. Installation of distributed resources will not alter the topology of the system, but the power will be able to flow in multiple directions. The biggest impact of this is on the protection of distribution systems. Present protection schemes are simple in which fuses are used for protection of laterals and these fuses are backed by recloser on the main feeder or breaker at the substation. Such simple schemes will not work with distributed re-
IEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 19, NO. 1, FEBRUARY 2004
sources. Advanced protection schemes, which can adapt to the changing distribution system configuration, would be essential. They will depend on measurement of data at strategic locations and communication of these data to intelligent relays for protection of the system. Therefore, protection will become an integral part of distribution automation. Large numbers of distributed generation could also lead to stability and frequency control problems. The problems that were only relevant to transmission systems will become relevant to distribution systems too. Therefore, new technologies to operate and manage the micro-grid at the distribution system will be needed. Regulatory issues are also significant for the growth of distributed resources. Presently, regulations on citing and metering are not very well defined. The issue of metering, which is called “net metering” is the most important issue. Regulation on net metering will set rules for buying and selling the power between the utility and the customers. Setting such rules will be very crucial for the growth of distributed resources. D. Distribution Management Systems (DMS) and Distribution Control Centers (DCCs) Increased applications of advanced technologies will promote the evolution of distribution management systems (DMSs) and distribution control centers (DCCs) similar to energy management systems (EMS) and energy control centers (ECCs) [12]. DMS/DCC will be used for complete management and operation of distribution systems during normal as well as emergency conditions. The activities during normal operation would include switching and control of various components in the distribution system for efficient and reliable operation of the system, control and coordination of distributed energy resources, demand side management (DSM), protection of the system, and work-order management for routine maintenance. Outage management, fault location, repair coordination, and restoration are some of the activities during emergencies. The distribution system would have several intelligent remote terminal units (RTUs) installed at strategic locations, which will make local control decisions as well as send information to DMS/DCC. In addition to fixed terminals, the system can have mobile terminals for entry and retrieval of data. Either one or a combination of different communication media including radio, satellite, power line carrier, telephone, fiber optics, and Internet would provide communication between the RTU and EMS/DCC. Internet and Global Positioning System (GPS) are already being used by utilities to manage work orders in distribution systems. Such applications will become commonplace in the future. The DMS/DCC is expected to communicate with an ECC or even a control center at the ISO level. In this case, the role of communications and computing requirements may have to be designed to achieve proper hierarchy of data and information flow. The demand on communication may have to be addressed also. IV. CHALLENGES AND ISSUES FOR CURRICULUM Unfortunately, there is not a single textbook available that covers all of the topics that will be required for distribution engineers of the future. There are several textbooks covering basic
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component and system modeling [13], [14], but a large amount of practical knowledge must still be accessed from industry references not intended for pedagogical purposes [15]–[19]. Specific curriculum challenges are now described.
Although these other topics are important, they can be best learned with a solid foundation of system analysis.
A. Distribution Automation The challenge in designing this aspect of the curriculum lies in introducing all of the relevant issues of automation in the context of future distribution systems. These include newer functions related to the integration of DERs with the connected system to effectively monitor, control, protect with high reliability, power quality and efficiency. The role of proper communication, control, computing, and information technologies has to be included in the course syllabus. B. Reliability Evaluation Aging Infrastructure Aging infrastructure will be one of the most critical issues for distribution engineers, and proper treatment is critical for a distribution curriculum. The challenge lies in balancing equipment-specific failure modes related to aging, translating these failure modes into quantifiable failure rates, and computing the impact of increasing failure rates on system performance. C. Efficient Management of Existing Assets Another critical topic for future distribution engineers is asset management including life-cycle costing and reliability-centered maintenance. The challenge is to balance a wide array of capital, operations, and maintenance strategies that can be used to maximize asset performance over their useful lifetime.
A. Web-Based Courseware The proposed course takes advantage of the latest computer pedagogical tools available. The course can be effectively taught by exploiting the Web as the medium for both off-and on-campus audience. B. Computer-Based Approach The proposed material is designed to incorporate the latest modeling and simulation packages to make it a self-paced learning course. Familiarizing students with computer analyses is important for several reasons. First, it links theory with applications. Second, it allows realistic examples to be analyzed, which will give students a better feel for actual distribution systems and their characteristics. Examples of computer applications that should be utilized include power flow, reliability analysis, fault analysis, dynamic analysis, and protection coordination. C. Models for Classical and New Distribution Components Every attempt is made to cover the modeling of both standard and new devices such as DERs, power electronic devices for all modes of operation: steady-state, dynamic, and transient. D. Methodologies for Design, Planning, and Operations Proper emphasis is placed on covering the methodologies for design, planning, and operation of distribution systems keeping future trends and technologies in mind.
D. Distributed Energy Resources
E. Application to Practical Systems
This topic is receiving wide publicity and attention due the lack of understanding of the needs of integrating DERs with the local utility network by both parties. The IEEE Standard 1547 is a good starting point that addresses the interconnection issues. Additional challenges relate to the breadths of technologies for both energy conversion and energy storage.
The proposed models and methods are designed for application to practical systems. This is the primary philosophy of the proposed courses.
E. Business Model for Distribution Utilities of the Future As distribution companies continue to be restructured, students need to understand different business models under which they can operate in compliance with various regulatory rules, standards and other requirements. In addition, various marketing models and strategies should be covered for future distribution engineers to posses as wide a background as possible. The challenge is to appropriately integrate these “soft” topics into a technical course. V. PEDAGOGICAL ISSUES FOR A NEW COURSE Due to the breadth of topics required for future distribution engineers, the authors recommend a two-course sequence. Further, the authors recommend the extensive use of computer-based analysis tools since the size of distribution systems precludes hand analyses for many real-world problems. Last, the authors recommend that this course focus on systems analysis rather than component-level analysis or system design.
VI. COURSE CONTENT AND SYLLABUS As stated previously, the required knowledge for future distribution engineers cannot be practically covered in a single course. Therefore, this paper proposes a two-course sequence at the senior elective/graduate level entitled Electric Distribution Systems Engineering: a Computer-based Approach. An outline of the proposed topics is: 1) Introduction. • structure of distribution systems: U.S. and international practice; • basic components of distribution systems; • historical perspective; • impact of computers on distribution practice; • looking to the 21st century distribution systems. 2) Distribution System Devices and Models (Include Hardware Pictures). • computer modeling concepts with introduction to popular packages; • power devices: lines and cables, transformers; • control devices: Capacitors, reactors, SVC, AVC, harmonic filters, reclosers, regulators;
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• protective devices: Fuses, circuit breakers, relays, surge arrestors; • load devices: Motors, lighting, furnaces, computers; • accessories: Poles, insulators, switches; • modeling and model evaluation. Distributed Energy Resources. • different technologies description; • interconnection issues; • IEEE 1547 standards; • performance evaluation. Computer-Based Tools for Analysis. • system modeling using network analysis; • single-phase, three-phase, and multiphase models; • power flow and short circuit analysis; • transients analysis; • harmonic analysis. Economic Analysis. • background; • basic methods; • selection of devices: lines and transformers; • tariffs and pricing; • cost-benefit analysis. System Reliability. • overview of distribution reliability; • component modeling; • analytical methods; • Monte Carlo methods; • reliability indexes and customer cost; • modeling and analyzing a system; • reliability optimization. Computer-Based Planning. • review of methods; • load evaluation and demand forecasting; • design criteria and standards (voltage, equipment); • design of substations, primary and secondary systems, and grounding; • design evaluation; • reliability and maintenance. System Operation and Automation. • automation functions; • voltage/var control; • system restoration; • reconfiguration for reliability; • loss minimization; • trouble call analysis; • outage management; • demand side management; • SCADA and DMS architecture; • database and graphs; • case studies of economic and technical feasibility; • practical applications. System Protection. • philosophy and architecture; • protective device selection; • feeder and transformer protection; • protection against overcurrents, overvoltages, and transients;
• protection system coordination; • grounding; • computer-aided protection. 10) Power Quality. • harmonics, surges, and sags; • motor starting and flickering; • behavior of sensitive transients loads; • power-quality monitoring and auditing; • custom power devices. 11) Distribution System of 21st Century & Deregulation. • intelligent systems approach to distribution; • interaction of geographic information systems (gis) and the information highway; • survey of regulatory status and trends. VII. SUMMARY Electric distribution systems are undergoing rapid changes due to deregulation, the penetration of distributed energy resources and power electronics technologies, and the adoption of efficient computation, communications, and control mechanisms. The primary goal of this paper is to justify the need for the development of a new two-course sequence to reflect the radical changes occurring or expected to happen in the future. The paper identifies the challenges in designing the sequence. The paper also recommends a course outline and syllabus for those contemplating such a sequence. REFERENCES [1] G. T. Heydt and V. Vittal, “Feeding our profession,” IEEE Power & Energy Mag., vol. 1, pp. 38–45, Jan./Feb. 2003. [2] C. A. Warren and M. J. Adams, “Reliability on the regulatory horizon,” in Proc. IEEE Transm. Dist. Conf. Expo., Atlanta, GA, Oct. 2001. [3] “Interim Rep. U.S. Dept. Energy’s Power Outage Study Team,” U.S. Dept. Energy, Jan. 2000. [4] R. E. Brown, Electric Power Distribution Reliability. New York: Marcel Dekker, 2002. [5] A. Pahwa and J. K. Shultis, “Assessment of the Present Status of Distribution Automation,” Eng. Experiment Station, Kansas State Univ., Manhattan, KS, Rep. 238, Mar. 1992. [6] D. Bassett, K. Clinard, J. Grainger, S. Purucker, and D. Ward, Tutorial Course: Distribution Automation. [7] J. B. Bunch, “Guidelines for Evaluating Distribution Automation,”, EPRI Rep. EL-3728, Nov. 1984. [8] G. T. Heydt, Electric Power Quality. West Lafayette, IN: Stars in a Circle Publication, 1991. [9] J. Douglas, “Power quality solutions,” IEEE Power Eng. Rev., vol. 14, no. 3, Mar. 1994. [10] J. S. Paserba, N. W. Miller, S. T. Naumann, M. G. Lauby, and F. P. Sener, “Coordination of a distribution level continuously controlled compensation device with existing substation equipment for long term var management,” in IEEE Power Eng. Soc. Summer Meeting, Vancouver, BC, Canada, July 1993, Paper no. 93 SM 437-4 PWRD. [11] X. H. Chao, “System studies for DG projects under development in the US,” in Proc. Summary of the Panel Discussion, IEEE Summer Power Meeting, Vancouver, BC, Canada, 2001. [12] G. L. Clark and S. W. Bowen, “Power system operation and control,” in The Electric Power Engineering Handbook. Boca Raton, FL: CRC, 2001, pp. 6-67–6-76. [13] W. H. Kersting, Distribution System Modeling and Analysis: CRC Press, 2001. [14] T. Gönen, Electric Power Distribution System Engineering. New York: McGraw-Hill, 1986. [15] Electric Utility Engineering Distribution Reference Book: Distribution Systems. Pittsburgh, PA: Westinghouse Electric Corporation, 1959. [16] J. J. Burke, Power Distribution Engineering: Fundamentals and Applications. New York: Marcel Dekker, 1994.
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[17] E. Lakervi and E. J. Holmes, Electricity Distribution Network Design. Stevenage, U.K.: Peter Peregrinus, 1995. [18] H. L. Willis, Power Distribution Planning Reference Book. New York: Marcel Dekker, 1997. [19] Electrical Distribution System Protection, Cooper Power Systems, Milwaukee, WI, 1990.
Anil Pahwa (F’03) received the Ph.D. degree in electrical engineering from Texas A&M University, College Station, in 1983. Currently, he is a Professor at Kansas State University, Manhattan, specializing in distribution automation, distribution system planning and analysis, and intelligent computational methods for power systems analysis.
Richard E. Brown (SM’00) received the Ph.D. degree in electrical engineering from the University of Washington, Seattle, in 1996. Currently, he is the Director of Technology for ABB Consulting, Raleigh, NC, specializing in distribution systems, reliability assessment, and computer applications.
S. S. (Mani) Venkata (F’89) received the Ph.D. degree in electrical engineering from the University of South Carolina, Columbia, in 1971. Currently, he is the Palmer Chair Professor at Iowa State University, Ames, specializing in distribution systems, intelligent systems, and engineering education.
Richard D. Christie (M’76) received the Ph.D. degree in electrical engineering from Carnegie-Mellon University, Pittsburgh, PA, in 1989. Currently, he is an Associate Professor at the University of Washington, Seattle, specializing in power system operations, distribution system reliability, and software engineering.
