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Industrial and Commercial Power Systems Technical Conference, 2008. ICPS 2008. IEEE/IAS

Date 4-8 May 2008

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  • 2008 IEEE industrial & commercial power systems technical conference

    Page(s): i
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    Freely Available from IEEE
  • Table of contents

    Page(s): i - iv
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    Freely Available from IEEE
  • [Copyright notice]

    Page(s): ii
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    Freely Available from IEEE
  • I&CPS 2008 Conference Committee

    Page(s): iii - iv
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    Freely Available from IEEE
  • Understanding NFPA 70E electrical safety requirements

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (126 KB) |  | HTML iconHTML  

    There are numerous OSHA regulations, as well as consensus standards, that address the hazards of electricity and the work practices and personal protective equipment (PPE) required for the protection of employees. Over the last 10 to 15 years there have been significant revisions and additions to electrical safety standards and regulations, which were needed in order to increase the knowledge and understanding of the electrical hazards by employers and employees. The NFPA 70E-2004, Standard for Electrical Safety in the Workplace [1] is the base consensus standard, used by OSHA to establish electrical safety regulations, and requires an electrical hazard analysis be performed prior to employees working on or near exposed energized electrical conductors and circuit parts operating at 50-volts or more. These requirements are especially critical if the circuits have not been placed in an electrically safe work condition (lockout/tagout). View full abstract»

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  • Designing out Flash Hazard

    Page(s): 1 - 9
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (119 KB) |  | HTML iconHTML  

    The control of incident energy and subsequent Flash - protection boundary for systems using large blocks of power has been established, which uses either the direct protection of fuses or the controlled switching of a circuit-breaker. This paper will correct a inadvertent error in the examples given in the paper ldquoMitigation of Flash Hazard Using Transformers on Industrial Machinesrdquo presented a the I&CPS Conference 2005 Saratoga Springs NY. The paper will develop the application of the concepts presented in the original paper. View full abstract»

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  • Risk Category 3 or 4?

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (86 KB) |  | HTML iconHTML  

    Often misunderstood risk categories are briefly discussed and the significance of risk categories 3 and 4 are discussed with the objective of clarifying their application. View full abstract»

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  • Basic elements of electro-forensic engineering

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (882 KB) |  | HTML iconHTML  

    The basic elements of forensic engineering are presented with emphasis on the electrical engineerpsilas function as a forensic engineer. The elements of forensic engineering including the application of the scientific method to forensic investigations are discussed. The importance and function of electrical codes and standards in the legal system are emphasized. View full abstract»

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  • Switching transient analysis and specifications for practical hybrid high resistance grounded generator applications An IEEE/IAS working group report #2

    Page(s): 1 - 9
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (373 KB) |  | HTML iconHTML  

    This paper reports on the continuing efforts of an IAS Working Group to investigate industry concerns with excessive stator fault-point burning damage in conjunction with various industrial generator grounding and ground fault protection practices. Previous working group efforts were reported in a series of papers discussing typical voltage bus connected industrial generator applications. These papers proposed a new method of grounding, called hybrid grounding, that offered the ability to limit damage while still providing the required level of ground fault current under all operating conditions. This new Working Group paper reports on the detail design requirements for hybrid grounding. The paper reports the results of switching transient studies that formed the bases for recommended over-voltage protection. It also provides guidance in selection of equipment and fault protection required for hybrid grounding. The experience gained with several hybrid grounding applications is also reported. View full abstract»

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  • Coordination of generator protection with generator excitation control and generator capability

    Page(s): 1 - 17
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (294 KB)  

    This paper was written by a Working Group of the IEEE Power System Relay Committee to provide guidance to the industry to better coordinate generator protection with generator control. The paper discusses specific calculation methods that can be used to insure generator protection and excitation system control are fully coordinated. It also specifically addresses the coordination of relays with generator full load capability and machine steady state stability limits. Because of recent blackouts, NERC (North American Electric Reliability Council) is developing standards [1–3] for the coordination of generator protection and control. This paper provides practical guidance on providing this coordination. View full abstract»

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  • Considerations and improvements of configuration and protection of a 72 kV mining resistance neutral grounded system

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (82 KB) |  | HTML iconHTML  

    This paper provides a discussion on grounding of the neutral of a 72 kV mining system supply with high and low resistance grounding (HRG/LRG), and proposes improvements to the configuration and protection associated with neutral resistance grounded (NRG) systems. For safety reasons, the ground potential rise (GPR) of the switchyards in the mine is limited to 100 Volt. In addition to the reduction of the mine switchyardpsilas ground resistance, the line-to-ground-fault current is reduced by inserting NGR between the ground and the neural of the source transformer. The paper examines the technical viability of extending techniques used for systems of lower voltages such as those used on some generatorpsilas HRG, to a 72 kV mine system. With the advancement of numerical relays and the economical availability of such relays improved protection systems could be adapted for the subject installations. View full abstract»

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  • An introduction to IEEE Std 1458™-2005 “recommended practice for the selection, field testing, and life expectancy of molded case circuit breakers for industrial applications”

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4160 KB) |  | HTML iconHTML  

    IEEE Std 1458trade-2005 is a new Recommended Practice that, for the first time, provides in one document the information that is necessary to select, apply, and maintain (determine the remaining life of) molded case circuit breakers. The document also provides information on the basics of circuit breaker design, and presents a detailed procedure to determine when molded case circuit breakers must be replaced. View full abstract»

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  • Monitoring classifier for power quality discrimination using wavelet-grey relational analysis

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (154 KB) |  | HTML iconHTML  

    This paper proposes a method of power quality (PQ) discrimination for power system using wavelet-grey relational analysis (WGRA). The monitoring classifier based on WGRA can be divided into two stages, Gaussian wavelets are used to extract the features from distorted waves and reconstruct various patterns, and grey relational analysis (GRA) discriminates the disturbance events. The proposed monitoring classifier was used to test for the power quality disturbances, including those caused by harmonics, voltage sag, voltage swell, and voltage interruption. Compared with the wavelet networks, the test results will show accurate discrimination, good robustness, and faster processing time for detecting disturbing events. View full abstract»

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  • Investigation of non-linear devices modeled as a harmonic current source

    Page(s): 1 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (133 KB) |  | HTML iconHTML  

    IEEE std. 519-1992 recommends that nonlinear devices can be modeled generally as a harmonic current source. However, some literatures propose that the voltage-source nonlinear devices actually behave as a harmonic voltage source. The need to verify if nonlinear devices can be treated as harmonic current sources in power system analysis and harmonic mitigation remains strong and challenging. In this paper, laboratory testing results at the drive input for both current-source and voltage-source drives are investigated. Simulations were performed using modified 6-pulse harmonic current spectrums for both voltage-source and current-source drives. Comparison between the simulation and lab testing indicates that both types of drives are harmonic current sources. Even though the voltage-source drives show relatively large harmonic current distortions at the drive input compared to the traditional harmonic current source model, but from the power systems point of view such type of drives should be treated as a harmonic current source. Field measurements for 33 voltage-source drives located in different locations of a large industrial distribution system are investigated for the further verification. Induction motors are primary loads in industrial distribution systems, and also loads of harmonic currents generated by nonlinear devices. Harmonic characteristics of induction motors are investigated using harmonic equivalent circuits, which provide theoretical explanations of nonlinear devices as suppliers of harmonic currents are harmonic current sources in nature. View full abstract»

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  • Harmonic filter design for mixed single-phase three-phase load

    Page(s): 1 - 9
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (279 KB) |  | HTML iconHTML  

    A metals plant contains large 12-pulse rectifier loads and a single-phase induction melting furnace. Recently, the available fault current from the utility increased by 50% due to line improvements. Previously, the capacitor fuses on the induction furnace blew occasionally and replacing them solved the problem. After the utility line improvements, replacing the fuses does not solve the problem, and there are high harmonics throughout the system. Power and harmonic measurements were taken at all significant loads over a period of time to capture the operational cycle of the plant. The system was simulated in EMTP as a three-phase, three-wire system with the single-phase load included. A harmonic filter was designed to mitigate the resonance problem. The design was simulated and validated using the EMTP model. View full abstract»

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  • Four color theorem explained by electrical operational procedures?

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB) |  | HTML iconHTML  

    In human reasoning and multi-modal information processing, the diagrams offer a visual clarity in examining spatial constraints. Special diagrams like transitions maps are introduced for assisting the elaboration of operational procedures and for helping the training of operators. Adding visual-logic weights like values, colors or level curves, the diagrams assist better in recognizing conditioned inferences and in elaborating correctly procedures. The transitions maps extend the Euler-Venn diagrams and concur to an explanation of the four-color theorem. View full abstract»

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  • The application of droop-control in distributed energy resources to extend the voltage collapse margin

    Page(s): 1 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (567 KB) |  | HTML iconHTML  

    The growth in distributed energy resources has the potential to reduce system stresses caused by transmission grid congestion by supplying power and voltage regulation closer to load centers. However, the additional voltage regulation provided by these resources can mask the onset of voltage collapse. Local voltage support flattens the slope in the upper region of the power-voltage nose curve. Coordinating voltage-regulation behavior with the droop-control scheme in distributed resources improves the observation of voltage collapse margins. Incorporating distributed resource models in the continuation power flow analysis, allows the exploration of the power transfer gains by the application of distributed resources. The analysis provides insight to the impact of droop control on the behavior of the power-voltage curve and voltage collapse. The analysis is applied to a fixed speed induction generator wind farm with separate reactive compensation and the interconnection to the local power system. Results reveal that coordinating the droop control strategy allows the distributed resource to significantly increase the voltage collapse margin without hiding the threat of voltage stability problems. View full abstract»

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  • Voltage profile estimation and control of a distribution feeder

    Page(s): 1 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (463 KB) |  | HTML iconHTML  

    Monitoring the voltage profile of a distribution feeder can improve the reliability and quality of the distribution power system. However, economic constraints limit widespread deployment of monitoring equipment. This paper presents a method to estimate the voltage profile of a radial distribution feeder with limited number of monitoring points. Using the voltage profile estimation, load forecasting information, and the bus impedance matrix, this paper also describes a technique to find an optimal capacitor bank switching sequence that minimizes the number of switching changes along the feeder for a 24 hour period. View full abstract»

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  • Multi-area load forecasting for system with large geographical area

    Page(s): 1 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (785 KB) |  | HTML iconHTML  

    In a power system covering large geographical area, a single model for overall load forecasting of the entire area sometimes can not guarantee satisfactory forecasting accuracy. One of the major reasons is due to the load diversity, usually caused by weather diversity, throughout the area. Multi-area load forecasting will be a feasible and effective solution to generate more accurate forecasting results, as well as provide regional forecasts for the utilities. However, the major challenge is how to optimally partition/merge the areas according to the load and weather conditions. This paper investigates the electricity demand and weather data from an electric utility in Midwest US. Based on the data analysis, we demonstrate the existence of weather and load diversity within its control area, and then develop a short-term adaptive multi-area load forecasting system based on support vector regression (SVR) for day-ahead operation and market. The proposed multi-area forecasting system can find the optimal area partition under diverse weather and load conditions, and finally achieve more accurate aggregate load forecasts. The proposed forecasting system has been tested by using the real data from the system. The numerical results obtained for different area partition schemes validate the effectiveness of the proposed multi-area forecasting system. The detailed discussions on the forecasting results have also been given in this paper. View full abstract»

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  • Short-term load forecasting using comprehensive combination based on multi- meteorological information

    Page(s): 1 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (249 KB) |  | HTML iconHTML  

    Short-term load forecasting is always a popular topic in electric power industry because of its essentiality in energy system planning and operation. In the deregulated power system, the increase for a few percentages in the prediction accuracy would bring benefits worth of millions of dollars, which makes load forecasting become more important than ever before. This paper focuses on the short-term load forecasting for a power system in the United States, where several alternative meteorological forecasts are available from different commercial weather services. To effectively make use of the alternative meteorological predictions to the load forecasting system, a new comprehensive forecasting methodology has been proposed in this paper. Specifically, combining forecasting using adaptive coefficients is applied to share the strength of the different temperature forecasts in the first stage, and then ensemble neural networks has been used to improve the model's generalization performance based on Bagging. The proposed load forecasting system has been verified by using the real data from a utility. A range of comparisons with different forecasting models have been conducted. The forecasting results demonstrate the superiority of the proposed methodology. View full abstract»

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  • Reliability and cost comparison of power distribution configurations

    Page(s): 1 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB) |  | HTML iconHTML  

    Reliability and installed cost are key parameters in the selection of the appropriate power system distribution design. This paper presents a relative comparison of reliability and costs for radial, primary selective, looped, main-tie-main, synchronous bus, ring bus, and double bus medium voltage configurations. It also examines radial, main-tie-main and spot network for low voltage. To simplify the analysis, the alternate source is assumed always available. The derivation of the results for the medium voltage main-tie-main is shown in detail as an example to demonstrate the methodology. The advantages of the various topologies are discussed and compared. View full abstract»

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  • Reliability evaluation of a wind-diesel-battery hybrid power system

    Page(s): 1 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (316 KB) |  | HTML iconHTML  

    The paper presents a novel analytical approach of reliability evaluation for wind-diesel hybrid power system with battery bank for power supply in remote areas. The proposed approach is developed on the basis of the discrete wind speed frame analysis of the Weibull wind speed distribution. By employing wind speed frame analysis, an analytical model of wind-diesel hybrid system is developed that deals with system outage as a result of component failure and wind speed fluctuation. This model computes power output of wind turbine generators for each discrete wind speed frame, which is created by splitting the Weibull wind speed distribution curve. Then a model of battery bank is combined with that of the wind-diesel system. The reliability analysis of the overall system is conducted by combining power outputs of the wind and diesel generation units with battery throughout all wind speed frames to obtain the reliability indices, Loss of Load Probability (LOLP) and Expected Energy Not Supplied (EENS), which reflect a long term performance of the hybrid power system. By employing the wind speed frame the intermittent characteristics of wind speed and turbine failure can be easily taken into account. Simultaneously the modeling process can be greatly simplified and the calculation time can be saved as well. This model is suitable for system reliability assessment for both system planning and system optimization. View full abstract»

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  • Reliability analysis of utility single feeder circuit supplies

    Page(s): 1 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (126 KB)  

    The frequency and duration of interruptions at industrial and commercial facilities is dependent upon the reliability of utility power supplies to these facilities. IEEE Std. 493 -2007 presented the 1975 survey results of the reliability of electric utility power supplies to industrial plants which raises the question of how valid is this data today. This paper will present the results of a five year (2002 -2006) reliability study of 285 individual distribution feeder circuits to reveal the significant variance in the frequency and duration of feeder circuit unscheduled outages from different statistical perspectives. The paper will discuss and reveal the changing, temporal and spatial characteristics of the frequency and duration of feeder circuit outages and the difficulties in assigning particular reliability values for the utility supplying for a given facility. View full abstract»

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  • Electric motor standards, ecodesign and global market transformation

    Page(s): 1 - 9
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (655 KB) |  | HTML iconHTML  

    The use-phase cost of most industrial electric motors, namely the consumed electrical energy, dominates by far their overall life-cycle cost. Because electric motors use about 70% of the total industrial electricity use, they present attractive opportunities to save a huge amount of electricity in a cost- effective way, and contribute to mitigate climate change. The lack of global efficiency classes has prevented the large-scale adoption of high efficiency motors in most countries around the world. This paper addresses the most relevant electric motor efficiency-related international standards, including minimum efficiency requirements and a new efficiency classification standard, which have a profound impact on motor market transformation, being a powerful tool to reduce electric motor systems consumption. Moreover, the final results and conclusions of a European study to identify and recommend ways to improve the life-cycle environmental performance of electric motors at their design phase are presented, focusing life- cycle cost assessment of standard and best available electric motor technologies. It was found that if high efficiency or premium class motors replace standard efficiency class motors, significant reductions in the environmental impact will be achieved. View full abstract»

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  • A new approach to low-voltage circuit breaker short-circuit selective coordination

    Page(s): 1 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (512 KB) |  | HTML iconHTML  

    The expanded requirements in the 2005 NEC for selective coordination have prompted many engineers to question if selective coordination can be achieved with low-voltage circuit breakers. This is a valid question as the time-current curves of low-voltage circuit breakers often suggest that coordination can only be achieved in the overload and low level fault current zones. Therefore, how time-current curves are developed and their limitations are discussed. A new way for system designers to evaluate the level of selective coordination between low- voltage circuit breakers is introduced, indicating that higher levels of coordination can be achieved than those shown by the use of time-current curves alone. View full abstract»

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