scholarly journals Research on Consistency of Transient Response Characteristics of Current Transformers for DC application in DC Engineering

2021 ◽  
Vol 2087 (1) ◽  
pp. 012024
Author(s):  
Xiaopin Deng ◽  
Hua Huang ◽  
Yong Liu ◽  
Xiaozhou Wang ◽  
Bin Liu
Keyword(s):  
Delay Time ◽  
Stable Operation ◽  
Differential Protection ◽  
Current Transformers ◽  
Transient Characteristics ◽  
Factors Affecting ◽  
Maximum Peak ◽  
Dc System ◽  
Response Characteristics ◽  
Limit Value

Abstract In ultra high voltage(UHV) DC system, the transient characteristics for fault current monitoring of current transformers for DC application (DCCTs) and the consistency of response characteristics when different types of DCCTs are used for differential protection have become important factors affecting the safe and stable operation of DC system. In this paper, transient characteristics of all-fiber DCCTs and shunt DCCTs mainly used in DC system were studied, the main parameters of the transient characteristics including delay time and maximum peak instantaneous error were tested, and the key parameters influencing the response consistency of DCCTs were analyzed. The results show that the maximum peak instantaneous errors of all-fiber DCCTs and shunt DCCTs can meet ±5% limit requirement, meeting the demand for protection application in DC system. The delay time is the main factors affecting the maximum peak instantaneous error of DCCT. The longer the delay time is, the greater the maximum peak instantaneous error is, which may even exceed the limit value of ±5%. If necessary, the delay time of DCCTs participating in differential protection can be compensated. The research results provide a theoretical basis for preventing the malfunction of protection device caused by the inconsistent response characteristics of DCCTs in DC system.

Factors affecting time to seeking medical advice and start of treatment in breast cancer (BC) patients in Turkey.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. e17529-e17529
Author(s):  
Vahit Ozmen ◽  
Sukru Boylu ◽  
Engin Ok ◽  
Zafer Canturk ◽  
Varol Celik ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Delay Time ◽  
Patient Delay ◽  
Multilevel Regression ◽  
System Delay ◽  
Medical Visit ◽  
Total Delay ◽  
Factors Affecting ◽  
Screening Programs ◽  
Low Middle Income Countries

e17529 Background: One of the most important reasons of BC mortality is delay in treatment. Due to lack of BC awareness and organized screening programs, total delay time (from first symptoms of BC to initiation of treatment; TDT) is longer in low-middle income countries. The primary goal of this survey was to identify factors affecting TDT in patients with BC. Methods: As a part of previously presented multinational survey, a total of 1.031 BC patients from 12 cities of 5 districts in Turkey were surveyed using a uniform questionnaire. TDT was determined using 8 individual scales, including one pertaining to patient delay and 7 related to subsequent steps in a typical diagnostic process. Regression models were constructed using 17 variables concerning diverse contextual and personal patient characteristics. Time between first symptom and first medical visit (Patient Delay Time; PDT) and time between first medical visit and start of therapy (System Delay Time; SDT) were modeled separately with multilevel regression. Results: Mean PDT, SDT and TDT were 4.8, 10.5 and 13.8 weeks respectively, with 42% of the patients with a delay of >12 weeks. Multilevel regression equation indicated that disregard of discovered symptoms (p<0.001) and having at least secondary level of education (p=0.021) were significantly correlated with longer PDT. Patients with stronger self-examination habits (p=0.009), reporting more support from friends and family (p<0.001) and living in metropolitan areas (>500k) (p=0.006) had shorter PDT. Predictors of longer SDT included disregard (p<0.001) and having a PDT>4 weeks (p<0.001). Shorter SDT was correlated to being older than 60 years of age (p=0.027). Results revealed that diagnosis during periodic check-up or opportunistic mammography vs. symptomatic BC (p<0.001) and having first medical examination by a surgeon resulted in shorter SDT. Conclusions: TDT in Turkey is unacceptably long and system delay accounted for a substantial part of the total delay experienced by breast cancer patients. This points to a need for shortening clinical pathways if possible. A long patient delay calls for research into patient awareness of BC.

Research and Application on Successive Action Zone and Dead Zone of Transverse Differential Protection in Parallel Lines

2014 ◽  
Vol 556-562 ◽  
pp. 1614-1617
Author(s):  
Nan Nan Gao ◽  
Ying Pei ◽  
Jie Zhan ◽  
Hong Bo Li ◽  
Lin Niu
Keyword(s):  
Dead Zone ◽  
Relay Protection ◽  
Stable Operation ◽  
Differential Protection ◽  
Analysis Software ◽  
Regional Networks ◽  
Parallel Lines

This paper deeply researches on successive action zone and dead zone of transverse differential protection in parallel lines, and improves the existing analysis software for relay protection action. First determine which zone the fault point belongs to, and then analyze the protection action according to the different zone concretely. This improvement will greatly increase the accuracy to analyze the relay protection action, and will be significant to the safe and stable operation of regional networks.

scholarly journals Impact of Bias Temperature Instabilities on the Performance of Logic Inverter Circuits Using Different SiC Transistor Technologies

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1150
Author(s):  
Yoanlys Hernandez ◽  
Bernhard Stampfer ◽  
Tibor Grasser ◽  
Michael Waltl
Keyword(s):  
Delay Time ◽  
Propagation Delay ◽  
Operating Conditions ◽  
Physical Models ◽  
Stable Operation ◽  
Reliability Models ◽  
Bias Temperature Instability ◽  
Propagation Delay Time ◽  
Aging Mechanisms ◽  
The Impact

All electronic devices, in this case, SiC MOS transistors, are exposed to aging mechanisms and variability issues, that can affect the performance and stable operation of circuits. To describe the behavior of the devices for circuit simulations, physical models which capture the degradation of the devices are required. Typically compact models based on closed-form mathematical expressions are often used for circuit analysis, however, such models are typically not very accurate. In this work, we make use of physical reliability models and apply them for aging simulations of pseudo-CMOS logic inverter circuits. The model employed is available via our reliability simulator Comphy and is calibrated to evaluate the impact of bias temperature instability (BTI) degradation phenomena on the inverter circuit’s performance made from commercial SiC power MOSFETs. Using Spice simulations, we extract the propagation delay time of inverter circuits, taking into account the threshold voltage drift of the transistors with stress time under DC and AC operating conditions. To achieve the highest level of accuracy for our evaluation we also consider the recovery of the devices during low bias phases of AC signals, which is often neglected in existing approaches. Based on the propagation delay time distribution, the importance of a suitable physical defect model to precisely analyze the circuit operation is discussed in this work too.

Rapid assessment of isoenzymes by high-performance liquid chromatography.

1978 ◽  
Vol 24 (8) ◽  
pp. 1351-1360 ◽  
Author(s):  
T D Schlabach ◽  
A J Alpert ◽  
F E Regnier
Keyword(s):  
High Performance ◽  
Rapid Assessment ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Detector Response ◽  
Liquid Chromatograph ◽  
Factors Affecting ◽  
Response Characteristics ◽  
Materials Used ◽  
Enzyme Detection

Abstract We describe the rapid profiling of isoenzymes by use of microparticulate anion-exchange chromatography supports and a continuous, post-separation enzyme detector in a high-performance liquid chromatograph. Chromatographic analysis and enzyme detection are fully automated and provide excellent reproducibility. Factors affecting the isoenzyme profile and detector response characteristics are assessed. Lactate dehydrogenase and creatine kinase isoenzymes in tissue extracts, control materials used as electrophoretic standards, and serum were profiled by this method to establish the resolution and reliability of the method. We show the clinical use of this method in detecting changes in these isoenzymes in serum associated with acute myocardial infarction.

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