Subdivision of Grading Units Can Increase the Reliability of Performance Testing

Author(s):  
Douglas H. Harris

This study examined the effect of subdividing grading units on performance test reliability. That is, instead of increasing test length by adding grading units comparable to existing grading units, this experimental approach attempted to increase test length, and hence reliability, by subdividing existing grading units into comparable subunits. The effect of subdividing grading units was assessed empirically using a performance test of the ultrasonic detection of cracks in pipe welds. Five-hour performance tests involving the examination of 10 pipe-weld specimens were completed by each of 52 experienced ultrasonic operators as part of their qualification for performing tasks of this type in nuclear power plants. Subdivision of grading units was found to increase the reliability of the test from 0.28 to 0.92, to decrease the standard error of measurement of the test from 13.81 to 1.35, and to decrease the 90% confidence band around test scores from ± 22.60 to ±2.20. Moreover, the increased reliability was predicted by the Spearman-Brown Prophecy Formula, the method commonly employed for predicting the effect of increased length on test reliability.

Author(s):  
Shane E. Powers ◽  
William C. Wood

With the renewed interest in the construction of coal-fired power plants in the United States, there has also been an increased interest in the methodology used to calculate/determine the overall performance of a coal fired power plant. This methodology is detailed in the ASME PTC 46 (1996) Code, which provides an excellent framework for determining the power output and heat rate of coal fired power plants. Unfortunately, the power industry has been slow to adopt this methodology, in part because of the lack of some details in the Code regarding the planning needed to design a performance test program for the determination of coal fired power plant performance. This paper will expand on the ASME PTC 46 (1996) Code by discussing key concepts that need to be addressed when planning an overall plant performance test of a coal fired power plant. The most difficult aspect of calculating coal fired power plant performance is integrating the calculation of boiler performance with the calculation of turbine cycle performance and other balance of plant aspects. If proper planning of the performance test is not performed, the integration of boiler and turbine data will result in a test result that does not accurately reflect the true performance of the overall plant. This planning must start very early in the development of the test program, and be implemented in all stages of the test program design. This paper will address the necessary planning of the test program, including: • Determination of Actual Plant Performance. • Selection of a Test Goal. • Development of the Basic Correction Algorithm. • Designing a Plant Model. • Development of Correction Curves. • Operation of the Power Plant during the Test. All nomenclature in this paper utilizes the ASME PTC 46 definitions for the calculation and correction of plant performance.


1966 ◽  
Vol 19 (2) ◽  
pp. 611-617 ◽  
Author(s):  
Donald W. Zimmerman ◽  
Richard H. Williams

It is shown that for the case of non-independence of true scores and error scores interpretation of the standard error of measurement is modified in two ways. First, the standard deviation of the distribution of error scores is given by a modified equation. Second, the confidence interval for true score varies with the individual's observed score. It is shown that the equation, so=√[(N−O/a]+[so2(roō−roo)/roō]̄, where N is the number of items, O is the individual's observed score, a is the number of choices per item, so2 is observed variance, roo is test reliability as empirically determined, and roō is reliability for the case where only non-independent error is present, provides a more accurate interpretation of the test score of an individual.


2019 ◽  
Vol 2 (3) ◽  
pp. 28
Author(s):  
Elena Markoska ◽  
Aslak Johansen ◽  
Mikkel Baun Kjærgaard ◽  
Sanja Lazarova-Molnar ◽  
Muhyiddine Jradi ◽  
...  

Performance testing of components and subsystems of buildings is a promising practice for increasing energy efficiency and closing gaps between intended and actual performance of buildings. A typical shortcoming of performance testing is the difficulty of linking a failing test to a faulty or underperforming component. Furthermore, a failing test can also be linked to a wrongly configured performance test. In this paper, we present Building Metadata Performance Testing (BuMPeT), a method that addresses this shortcoming by using building metadata models to extend performance testing with fault detection and diagnostics (FDD) capabilities. We present four different procedures that apply BuMPeT to different data sources and components. We have applied the proposed method to a case study building, located in Denmark, to test its capacity and benefits. Additionally, we use two real case scenarios to showcase examples of failing performance tests in the building, as well as discovery of causes of underperformance. Finally, to examine the limits to the benefits of the applied procedure, a detailed elaboration of a hypothetical scenario is presented. Our findings demonstrate that the method has potential and it can serve to increase the energy efficiency of a wide range of buildings.


Author(s):  
Justin Zachary ◽  
Alex Khochafian

Based on the present revival of coal as the fossil fuel of choice for power generation, there is a high probability that several IGCC projects will materialize in the near future. One of the challenges facing the Owners, EPC Contractors and OEM’s will be to define the performance commercial guarantees and the practical means to determine them. In addition following the current huge upturn in conventional supercritical coal fired power plants, a large number of facilities will conduct thermal performance tests. The proper conductance of the test, data collection and correction to reference conditions, have many technical implications and could affect drastically the commercial outcome of a project both for the Contractor and the Owner. For IGCC plants, in anticipation of this probability, ASME Performance Test Committee had developed a Performance Test Code for such type of plant — PTC 47, which was published in January 2007. In the first part, the paper will provide details about the specific challenges facing the implementation of the Code, in particular the proposed use of the input/output method (mass and energy balance). The presentation will cover other highlights of the code recommendations. The methodology is fully applicable to conventional power plants, since they use same type of fuel. The determination of the heat input based on actual continuous measurement of the mass flow and composition of the coal will be discussed in details. The practicality and the measurement uncertainty associated with fuel composition will also be analyzed. A comparison with the indirect method for determination of the heat input will also be presented. The article will evaluate how the code requirements are reflected in the definition of the power plant design, configuration and instrumentation. The implications of test tolerance as a commercial issue and measurement uncertainty as a technical issue will also be presented and evaluated Other unique aspects of the entire IGCC plant performance testing will be discussed: (1) stability criteria related to the gasification and integration processes, (2) corrections from test to guarantees conditions due to complex chemical, mechanical processes. Finally, the article will indicate the progress on the development of performance evaluation methodologies for other main IGCC components: gasifier, air separation unit, gas cleaning systems and Power Island.


Author(s):  
Hyun-Jun Jo ◽  
Cheon-Woo Kim ◽  
Tae-Won Hwang

The Ulchin Vitrification Facility (UVF), to be used for the vitirification of low- and intermediate-level radioactive waste (LILW) generated by nuclear power plants (NPPs), is the world’s first commercial facility using Cold Crucible Induction Melter (CCIM) technology. The construction of the facility was begun in 2005 and was completed in 2007. From December 2007 to September 2009, all key performance tests, such as the system functional test, the cold test, the hot test, and the real waste test, were successfully carried out. The UVF commenced commercial operation in October 2009 for the vitrification of radioactive waste.


Author(s):  
Cecil Lawrence

Solar Photovoltaic (PV) power plants have high performance test measurement uncertainty due to instrument precision limitations and spatial variations associated with irradiance and soiling measurement. Accurate prediction of the measurement uncertainty is critical for both the Owner and the EPC contractor to appropriately manage their risk. While there are several methods for testing the performance of PV plants, regression analysis based methods, like the PVUSA Method and the PPI rating method, are widely used. However, there is limited guidance on uncertainty analysis when using these methods. Most utilities and power producers have familiarity with the ASME PTC 19.1 code for measurement uncertainty analysis and often require the guidelines of PTC 19.1 be followed for evaluating the measurement uncertainty for the performance testing of PV plants. However there is lack of published literature on using the ASME PTC 19.1 approach with regression based PV performance test methods. This paper expands on the limited guidance provided by ASME PTC 19.1 Section 8-6 for regression based analysis and presents a detailed approach of calculating measurement uncertainty for PV power plants when using regression based testing methods. The paper also presents the importance of obtaining a good regression fit to the measurement uncertainty and elaborates on methods to reduce the measurement uncertainty. The overall approach discussed in this paper was applied on performance testing of two large utility-scale PV plants.


Author(s):  
Dave W. Price ◽  
Shawn M. Goedeke ◽  
Mark W. Lausten ◽  
Keith Kirkpatrick

The American Society of Mechanical Engineers (ASME) Performance Test Codes (PTCs) have provided the power industry with the premier source of guidance for conducting and reporting performance tests of their evolving base technologies of power producing plants and supporting components. With an overwhelming push for renewable energy in recent years, ASME PTCs are in the development of similar standards for the testing of concentrating solar thermal technologies based power plants by the formation of a committee to develop “PTC 52, Performance Test Code on Concentrated Solar Plants”, on July 2009. The U.S. Department of Energy’s (DOE) SunShot Initiative goal is to reduce costs and eliminate market barriers to make large-scale solar energy systems cost-competitive with other forms of energy by the end of the decade. The ASME PTC-52 similarly removes critical barriers hindering deployment and speeds the implementation of concentrating solar power technologies by reducing commercial risk by facilitating performance testing procedures with quantified uncertainty. As with any commercialization of power producing technologies, clearly defining risk and providing methods to mitigate those risks are essential in providing the confidence necessary to secure investment funding. The traditional power market accomplishes this by citation of codes and standards in contracts; specifically ASME PTCs which supply commercially accepted guidelines and technical standards for performance testing to validate the guarantees of the project (Power Output, Heat Rate, Efficiency, etc.). Thus providing the parties to a power project with the tools they need to ensure that the planned project performance was met and the proper transfer of funds are accomplished. To enable solar energy systems to be fully embraced by the power industry, they must have similar codes and standards to mitigate commercial risks associated with contractual acceptance testing. The ASME PTC 52 will provide these standard testing methods to validate Concentrating Solar Power (CSP) systems performance guarantees with confidence. This paper will present the affect that solar resource variability and measurement accuracies have on concentrating solar field performance uncertainty based on calculation methods like those used for conventional fossil power plants. Measurement practices and methods will be discussed to mitigate that uncertainty. These uncertainty values will be correlated to the levelized cost of electricity (LCOE), and LCOE sensitivities will be derived. The results quantify the impact of resource variability during testing, test duration and sampling rate to annual performance calculation. These uncertainties will be further associated with costs and risks based on typical technology performance guarantees. The paper will also discuss how the development of standard measurements and calculation methods help to produce lower uncertainty associated with the overall plant result, which is already being accomplished by ASME PTCs in conventional power genreation.


Author(s):  
Junichi Hirabayashi ◽  
Motohiro Sato ◽  
Kenta Murakami ◽  
Taira Okita

This study focuses on an experimental approach to quantifying irradiation-induced defects in structural materials used in nuclear power plants at an atomic scale. As a preliminary step, a procedure for observing metallic surfaces using a facility comprising an ion accelerator and a scanning tunneling microscope was developed. Using this experimental setup, atomic-resolution images of Au(111) surfaces were successfully obtained. A herringbone structure, which is characteristic of reconstructed Au(111) surfaces, was clearly observed, with individual atoms being distinguishable.


1967 ◽  
Vol 24 (5) ◽  
pp. 1117-1153 ◽  
Author(s):  
R. A. Bams

Two methods of performance testing were developed to measure differences in stamina in four groups of sockeye migrant fry, all of the Lakelse Lake (Skeena River, B.C.) stock. The four groups differed only in methods of incubation: one group was naturally propagated, the other three artificially. The results of the swimming performance tests and the vulnerability to predation tests agree closely, and analysis shows that the key factor responsible for differences in performance is size of the fish. Ranked in decreasing order of performance these four groups rate as follows: naturally propagated fish, fish incubated in gravel from time of hatching, fish incubated in gravel only for the last few weeks as premigrants, and fish that spent their entire incubation period without gravel in hatchery baskets. Independent of size is the influence of condition (K-factor) of the fish, optimum performance occurring at the time of almost complete yolk absorption. Of the two methods the swimming performance test was found to be more sensitive and is recommended as a tool for comparative "quality testing" of fish stocks.


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