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| 04-25 | Evaluation of Distributed Electric Energy Storage and Generation
This report summarizes the present state of distributed energy resources (DER), including distributed generation (DG) and distributed energy storage (DES). It identifies issues that should be considered by a distribution utility in connecting DER to the grid today and in planning for the future. The report consists of a literature search, a list of available test and operating data, and a summary of manufacturers’ data for available DER equipment.This is the final report for PSERC Project T-21, Evaluation of Distributed Electric Energy Storage and Generation. Uploaded 7/15/2004. | Ward Jewell | 11/19/2004 | 975.0k | PDF |
| 04-26 | Intelligent Transformer Monitoring System Utilizing Neuro-Fuzzy Technique Approach
Maintaining the health and reliability of the power substation has been a concern for
many years. For this reason, maintenance crews would periodically take transformers
and circuit breakers off-line, in order to assess whether the equipment is operating
normally. With this method, there are still catastrophic failures, not to mention much
unneeded maintenance. With a growing need for lower cost and more efficient
diagnostic tools, the advent of on-line monitoring and artificial intelligence analysis
techniques have been applied to the electrical power substation. This report details
development of an advanced predictive maintenance and diagnostic system that can be
used to monitor the health of the transformer and other substation equipment. Thus,
maintenance can be performed on a needed rather than scheduled basis.
This is the final report for PSERC Project T-5, Intelligent Substation. Uploaded 7/27/2004. | Rahmat Shoureshi, Tim Norick, and Ryan Swartzendruber | 11/19/2004 | 1.3M | PDF |
| 04-27 | Optical Sensor for Transformer Monitoring
Transformers are a vital part of the transmission and distribution system. Monitoring
transformers for problems before they occur can prevent faults that are costly to repair
and result in a loss of service. Current systems can provide information about the state of
a transformer, but are either offline or very expensive to implement. This report outlines
a new approach that is based on using light absorbance to monitor the state of a
transformer. Given that the most critical components of a transformer are immersed in its
oil, by monitoring and identifying the condition of the oil, the state of the transformer can
be diagnosed. Based on the developed monitoring system, oil is continually sampled from
the transformer through a closed circuit, and light is passed through the oil and tested for
absorbance. Preliminary experiments have demonstrated that a system based on certain
wavelengths could determine the difference between an acceptable or unacceptable
sample of oil. Samples of failed transformers showed a general increase in absorbance of
the light by oil during the experiment. Additional wavelengths can be identified, which
provide more information about the state of the transformer and make the system more
versatile in determining fault types. Basic principles of operation, experimental data, and
a prototype of this monitoring system are developed under this project, and are presented
in this report.
This is the final report for project T-20, Smart Sensor. Uploaded 7/27/2004. | Rahmat Shoureshi, Virdiansyah Permana, Robert Wood, Ryan Swartzendruber, and Marcelo Simoes | 11/19/2004 | 676.6k | PDF |
| 04-32 | Evaluation of Critical Components of Nonceramic Insulators (NCI) In-Service: Role of Defective Interfaces
This report contains the results and analysis of electric field computation performed to investigate the possibility of detecting internal defects in non-ceramic insulators (NCI) via the measurement of electric field outside the insulator. A three-dimensional commercial software package, COULOMB, has been utilized. Various type of defects have been simulated. Since most problems with NCI are related to interfaces, the defects simulated are assumed to be interfacial, i.e, residing at an interface.
The following are the conclusions:
The defect detection is position dependent and has the best possibility of being detected if it is closer to the high voltage electrode.
Larger and longer defects produce higher field changes; hence, they are more easily detected than the smaller ones.
The change in field value observed depends on the type of the defect. The more conductive the defect is, greater is the possibility of detecting it.
The range of the field probe can be greatly enhanced if measurements are taken radially instead of conventional axial measurements.
This is the final report for project T-14, "Evaluation of Critical Components of Nonceramic Insulators In-Service: Role of Seals and Interfaces". Uploaded: 8/27/2004. | Ravi Gorur | 11/19/2004 | 851.3k | PDF |
| 04-33 | Structuring Electricity Markets for Demand Responsiveness: Experiments on Efficiency and Operational Consequences
Efficient markets require the active participation of many buyers and sellers who have complete information. Unfortunately, the characteristics of electricity markets in those regions of the U.S. that have them fall far short of this theoretical ideal. In electricity markets instead of active participation by end-use customers, utilities or load serving entities (LSEs) merely estimate the quantity demanded by all of their customers and enter that quantity bid into the wholesale market for energy. The analysis explored the extent to which active customer participation in these markets might improve efficiency with less oversight. Three alternative demand-side market structures were evaluated: 1) customers pay the same fixed price (FP) in all periods - the base case; 2) a demand response feature (DRP) is added to the fixed price case in periods of supply shortages wherein buyers receive a pre-specified credit for reduced purchases; and 3) a real time pricing (RTP) case where prices are forecast for the upcoming day/night pair, then buyers select their quantity purchases sequentially, but are charged the actual market-clearing price, period-by-period. Overall, the RTP structure resulted in the greatest market efficiency, despite the difficult cognitive problem it poses for buyers. In addition, the level of price spikes that appeared under FP were reduced in most cases under RTP and DRP. Finally, the predictability of electricity flows on several transmission lines was explored as a function of overall system load for the three two-sided market regimes and under a simulation of the former cost-based regulatory regime. The results suggest that a conceivable benefit of deregulation requiring further study is the extent to which active customer participation can reduce the design capacity of many lines for a given average load.
This is the draft final report for project M-7 by the same title. Uploaded 10/12/2004. | Richard E. Schuler | 2/22/2005 | 321.2k | PDF |
| 04-34 | Consequences of Fault Currents Contributed by Distributed Generation
This report concerns fault currents in systems with distributed generation. The main concept described is that fault current throughout power systems is likely to increase when distributed generation is installed. The nature of the increase is described in some detail, mainly using the Zbus method of calculation. IEEE standards are used to apply correction factors. The requirements of IEEE Standard 1547 are applied as well – this is a standard for distributed generation use. In the report, an index called the average change of fault current or “ACF” is proposed. The ACF can be used to indicate the severity of the change of fault current due to installing new DGs. We propose the least squares method to approximate the ACF for a given system. By this proposed technique, the pre-fault voltages and the fault current calculation may not be needed in the preliminary design stage.
This is an intermediate report for project S-20, "New Implications of Power System Fault Current Limits". Uploaded: 10/26/2004. | N. Nimpitiwan and G.T. Heydt | 2/22/2005 | 1.3M | PDF |
| 04-35 | The Evaluation of Stochastic Available Transfer Capability for Transmission Expansion
This report relates to available transfer capability (ATC) between two points in a power network. The ATC is a limit to the amount of power that can be exchanged between two points. The calculation of ATC has traditionally been a deterministic calculation. However, loads and line status are stochastic phenomena that possess random elements. In this report, the ATC calculation is treated as a stochastic process and the calculation is made using stochastic power flow technology. In doing this, the probability density of the ATC is obtained. It is then possible to calculate the expected level of ATC (and therefore the expected level of revenue that can be obtained from transmission resource). In addition to expected values, the standard deviation and other statistical data can be calculated. Some simple examples are produced to illustrate the concept.
This is an intermediate report for project M-10, "Uncertain Power Flows and Transmission Expansion Planning". Uploaded: 11/19/2004. | Gerald T. Heydt and Jonathan W. Stahlhut | 2/22/2005 | 1.1M | PDF |
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