scholarly journals Dielectric loss and extended voltage response measurements for low-voltage power cables used in nuclear power plant: potential methods for aging detection due to thermal stress

2020 ◽  
Author(s):  
Ehtasham Mustafa ◽  
Ramy S. A. Afia ◽  
Zoltán Ádám Tamus
Keyword(s):  
Thermal Stress ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Low Voltage ◽  
Voltage Response ◽  
Insulation Material ◽  
Power Cables ◽  
Response Measurement ◽  
Low Frequencies

Abstract This paper discusses the effect of thermal stress on the electrical properties, conduction and polarization, of low-voltage CSPE/XLPE-based power cables used in a nuclear power plant. The cables were subjected to an accelerated thermal stress at 120°C for an equivalent service period of 20, 40, 60 and 80 years. The capacitance, tanδ, resistivity at different frequencies and extended voltage response were the methods used for the investigation. A significant variation in the values of tanδ at low frequency, i.e., at 100 Hz, was observed. For the extended voltage response measurement, the decay voltage slope increased, showing the increase in the conduction particles inside the insulation material. While the decrease in return voltage slope showed that the slow polarization processes occurring at very low frequencies were decreased with aging. A strong correlation between the tanδ and decay voltage slope was also observed, which increased as the insulation aging increased. The results showed that the methods could be used for the in situ measurement of conduction and polarization phenomenon in the low-voltage cables, and hence helping in the assessment of the condition of cable insulation.

scholarly journals Condition Monitoring Uncertainties and Thermal - Radiation Multistress Accelerated Aging Tests for Nuclear Power Plant Cables: A Review

2019 ◽  
Vol 64 (1) ◽  
pp. 20-32 ◽  
Author(s):  
Ehtasham Mustafa ◽  
Ramy S. A. Afia ◽  
Zoltán Ádám Tamus
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Thermal Radiation ◽  
Environmental Stress ◽  
Condition Monitoring ◽  
Nuclear Power ◽  
Low Voltage ◽  
Accelerated Aging ◽  
Radiation Environment ◽  
Insulation Material

The low voltage cables in the nuclear power plant have the same importance as veins have in the human body. Since, the cables inside the containment are under a number of environmental stress, out which the thermal and radiation stresses are important and become more effective with the presence of oxygen. These stresses cause the degradation of the insulation and hence may lead to insulation failure. To study the behavior of the cables under the nuclear power plant environmental stress, the cables are subjected to accelerated aging tests in laboratories which helps in determining their withstand capacity and degradation behavior in the harsh thermal-radiation environment. In this paper, the accelerated aging tests conditions are discussed with the focus on the role of certain uncertainty factors which effect the aging markers during the condition monitoring of the insulation material of cable after the accelerated aging tests. This review has been put into a framework to better understand the aging process in the low voltage nuclear power plant cables. In the conclusion part, some future directions in the field of the thermal-radiation multi-stress accelerated aging tests and condition monitoring techniques are also identified.

scholarly journals Radiation Testing of a Low Voltage Silicone Nuclear Power Plant Cable.

2014 ◽  
Author(s):  
Gregory Von White, II ◽  
John Lee. Schroeder ◽  
Patricia Sue. Sawyer ◽  
Derek Wichhart ◽  
Guillermo Adrian Mata ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Low Voltage ◽  
Radiation Testing

scholarly journals Condition Assessment of Low Voltage Photovoltaic DC Cables under Thermal Stress Using Non-Destructive Electrical Techniques

2020 ◽  
Vol 21 (5) ◽  
pp. 503-512
Author(s):  
Ehtasham Mustafa ◽  
Ramy S. A. Afia ◽  
Zoltán Ádám Tamus
Keyword(s):  
Thermal Stress ◽  
Condition Monitoring ◽  
Low Voltage ◽  
Research Work ◽  
Diagnostic Methods ◽  
Voltage Response ◽  
Insulation Material ◽  
On Line ◽  
Non Destructive ◽  
Line Condition

Abstract The output power of the photovoltaic system is heavily dependent on the low voltage (LV) DC cables which are exposed to multiple stresses such as climatic, mechanical, electrical, and thermal stress, hence makes them more exposed to aging as compared to other components in the system. Accordingly, it is essential to monitor the state and know the real cause of the insulation degradation of the cable. The physio-chemical changes inside the insulation during service is attributed to the thermal stress, which the cable has to endure constantly. Traditionally, destructive test techniques have been adopted to study the aging phenomenon in the cable insulation, making them unsuitable for on-line condition monitoring. This research work has been aimed to study the degradation in LV photovoltaic DC cables under thermal stress by measuring the dielectric properties; complex permittivity, tanδ with the change in frequency and decay and return voltage slopes using extended voltage response method. The non-destructive diagnostic methods used are based on the phenomenon of polarization and conduction in the insulation material. The noteworthy change in the values of the imaginary part of permittivity, tanδ at low frequencies, and the overall decrease in the values of return voltage slope showed the change in the structure of the polymer matrix under the stress which was related to the cross-linking based chemical reactions. The results show that the techniques can be adopted for the on-line condition monitoring of the cable for the PV system and the dielectric parameters can be used to study the chemical and physical changes happening inside the material effectively.

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