scholarly journals Analysis of a Verifying Method of Consistency Between CT/ PT Polarity and Directional Protective Relaying

2018 ◽  
Vol 2 (1) ◽  
pp. 10 ◽  
Author(s):  
Meng Wang
Keyword(s):  
Nuclear Power ◽  
Dynamic Test ◽  
Current Transformer ◽  
Operating Conditions ◽  
Test Method ◽  
Voltage Transformer ◽  
Protective Relaying ◽  
Static Power ◽  
And Control ◽  
Plant Power

The coordination correctness of Nuclear power plant current transformer (CT) / voltage transformer (PT) polarity and relay protection is often verifed through the dynamic test on the unit no load / load operating conditions. This paper proposes a test method to prevent and circumvent the failure of the dynamic test abnormality caused by the static power test before the plant power is applied and the whole group is started. Reduce the dynamic test workload and test diffculty, to ensure that the dynamic test safety risk control and control in the state.

A Basis for Selecting the Most Appropriate Small Specimen Creep Test Type

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
T. H. Hyde ◽  
C. J. Hyde ◽  
W. Sun
Keyword(s):  
Creep Test ◽  
Nuclear Power ◽  
Bulk Material ◽  
Operating Conditions ◽  
Test Method ◽  
Small Ring ◽  
Test Type ◽  
Advantages And Disadvantages ◽  
Uniaxial Creep ◽  
Aero Engines

Many components in conventional and nuclear power plant, aero-engines, chemical plant etc., operate at temperatures which are high enough for creep to occur. These include plain pipes, pipe bends, branched pipes etc., the manufacture of such components may also require welds to be inserted in them. In most cases, only nominal operating conditions (i.e., pressure, temperatures, system load, etc.) are known and hence precise life predictions are not possible. Also, the proportion of life consumed will vary from position to position within a component and the plant. Hence, nondestructive techniques are adopted to assist in making decisions on whether to repair, continue operating or scrap certain components. One such approach is to use scoop samples removed from the components to make small creep test specimens, i.e., sub-size uniaxial creep test specimens, impression creep test specimens, small punch creep test specimens, and small ring (circular or elliptical) creep test specimens. Each specimen type has its own unique advantages and disadvantages and it may not be obvious which one is the most appropriate test method to use. This paper gives a brief description of each specimen and associated test type and describes their practical limitations. The suitability of each of the methods for determining “bulk” material properties is described and it is shown that an appropriate test type can be chosen.

A Basis for Selecting the Most Appropriate Small Specimen Creep Test Type

2012 ◽  
Author(s):  
T. H. Hyde ◽  
C. J. Hyde ◽  
W. Sun
Keyword(s):  
Creep Test ◽  
Nuclear Power ◽  
Bulk Material ◽  
Operating Conditions ◽  
Test Method ◽  
Small Ring ◽  
Test Type ◽  
Advantages And Disadvantages ◽  
Uniaxial Creep ◽  
Aero Engines

Many components in conventional and nuclear power plant, aero-engines, chemical plant etc, operate at temperatures which are high enough for creep to occur. These include plain pipes, pipe bends, branched pipes etc; the manufacture of such components may also require welds to be inserted in them. In most cases, only nominal operating conditions (i.e. pressure, temperatures, system load etc) are known and hence precise life predictions are not possible. Also, the proportion of life consumed will vary from position to position within a component and the plant. Hence, non-destructive techniques are adopted to assist in making decisions on whether to repair, continue operating or scrap certain components. One such approach is to use scoop samples removed from the components to make small creep test specimens, i.e., sub-size uniaxial creep test specimens, impression creep test specimens, small punch creep test specimens and small ring creep test specimens. Each specimen type has its own unique advantages and disadvantages and it may not be obvious which one is the most appropriate test method to use. This paper gives a brief description of each specimen and associated test type and describes their practical limitations. The suitability of each of the methods for determining “bulk” material properties is described and it is shown that an appropriate test type can be chosen.

Investigations of Road Wear Caused by Studded Tires

2014 ◽  
Vol 42 (1) ◽  
pp. 2-15
Author(s):  
Johannes Gültlinger ◽  
Frank Gauterin ◽  
Christian Brandau ◽  
Jan Schlittenhard ◽  
Burkhard Wies
Keyword(s):  
Traffic Safety ◽  
Test Bench ◽  
Operating Conditions ◽  
Test Method ◽  
Analytical Models ◽  
The Road ◽  
Driving Speed ◽  
Major Factors ◽  
Tire Friction ◽  
Variable Operating Conditions

ABSTRACT The use of studded tires has been a subject of controversy from the time they came into market. While studded tires contribute to traffic safety under severe winter conditions by increasing tire friction on icy roads, they also cause damage to the road surface when running on bare roads. Consequently, one of the main challenges in studded tire development is to reduce road wear while still ensuring a good grip on ice. Therefore, a research project was initiated to gain understanding about the mechanisms and influencing parameters involved in road wear by studded tires. A test method using the institute's internal drum test bench was developed. Furthermore, mechanisms causing road wear by studded tires were derived from basic analytical models. These mechanisms were used to identify the main parameters influencing road wear by studded tires. Using experimental results obtained with the test method developed, the expected influences were verified. Vehicle driving speed and stud mass were found to be major factors influencing road wear. This can be explained by the stud impact as a dominant mechanism. By means of the test method presented, quantified and comparable data for road wear caused by studded tires under controllable conditions can be obtained. The mechanisms allow predicting the influence of tire construction and variable operating conditions on road wear.

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