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.

scholarly journals Implementation of Non-Destructive Electrical Condition Monitoring Techniques on Low-Voltage Nuclear Cables: I. Irradiation Aging of EPR/CSPE Cables

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5139
Author(s):  
Ehtasham Mustafa ◽  
Ramy S. A. Afia ◽  
Oumaima Nouini ◽  
Zoltán Ádám Tamus
Keyword(s):  
Condition Monitoring ◽  
Nuclear Power ◽  
Power Plants ◽  
Low Voltage ◽  
Research Work ◽  
Life Extension ◽  
Voltage Response ◽  
Elongation At Break ◽  
Monitoring Technique ◽  
Non Destructive

In a nuclear power plant environment, low-voltage cables experience different stresses during their service life which challenge their integrity. A non-destructive and reliable condition monitoring technique is desired to determine the state of these low-voltage cables during service and for the life extension of nuclear power plants. Hence, in this research work, an EPR/CSPE-based low-voltage cable was exposed to γ-rays for five different absorbed doses. The overall behavior of the cable under stress was characterized by frequency and time domain electrical measurements (capacitance, tan δ, and Extended Voltage Response) and a mechanical measurement (elongation at break). Significant variations in the electrical parameters were observed, as was a decline in the elongation at break values. A strong correlation between the measurement methods was observed, showing the ability of the electrical methods to be adopted as a non-destructive condition monitoring technique.

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.

Internet/Intranet Based Remote Condition Monitoring and Fault Diagnosis Scheme and System for Steam Turboset

2005 ◽  
Vol 293-294 ◽  
pp. 365-372 ◽  
Author(s):  
Yong Yong He ◽  
Wen Xiu Lu ◽  
Fu Lei Chu
Keyword(s):  
Fault Diagnosis ◽  
Power System ◽  
Electric Power ◽  
Condition Monitoring ◽  
Economic Benefits ◽  
Electric Power System ◽  
The Internet ◽  
Time Data ◽  
On Line ◽  
Line Condition

The steam turboset is the key equipment of the electric power system. Thus, it is very important and necessary to monitor and diagnose the running condition and the faults of the steam turboset for the safe and normal running of the electric power system. In this paper, the Internet/Intranet based remote condition monitoring and fault diagnosis scheme is proposed. The corresponding technique and methods are discussed in detail. And a real application system is developed for the 300MW steam turboset. In this scheme, the system is built on the Internet/Intranet and the Client/Server construction and Web/Server model are adopted. The proposed scheme can guarantee real-time data acquisition and on-line condition analysis simultaneously. And especially, the remote condition monitoring and fault diagnosis can be implemented effectively. The developed system has been installed in a power plant of China. And the plant has obtained great economic benefits from it.

Integrated Approach for On-Line Condition Monitoring of Piping

2006 ◽  
pp. 445-450
Author(s):  
Jung Taek Kim ◽  
Seung Hwan Seong ◽  
J.H. Park ◽  
S.W. Cheon ◽  
C.K. Lee ◽  
...  
Keyword(s):  
Condition Monitoring ◽  
Integrated Approach ◽  
On Line ◽  
Line Condition

scholarly journals Structural Health Monitoring (SHM) of Machine Using a Combination of Non-Destructive Testing for Heavy Manufacturing Industry

2020 ◽  
Vol 184 ◽  
pp. 01059
Author(s):  
Ashish Khaira ◽  
Ravi. K. Dwivedi ◽  
Sanjay Jain
Keyword(s):  
Structural Health Monitoring ◽  
Condition Monitoring ◽  
Health Monitoring ◽  
Manufacturing Industry ◽  
Research Work ◽  
Cost Benefit ◽  
Life Cycles ◽  
Destructive Testing ◽  
Structural Health ◽  
Non Destructive

Markets are affected by assorted consumer requirements, which insist on superior quality, shorter delivery time, better customer support, and lower prices. Simultaneously, product life cycles are becoming shorter. Success relies on having either a cost-benefit or a value benefit, or, both in any competitive context. Therefore, non-destructive techniques (NDT) become vital but in the conventional system, the maintenance personnel has to visit the machine that consumes time and energy. In the present COVID-19 situation and to save energy and time, there is a necessity of making condition monitoring contactless as much as possible. Therefore, in this research work, a structural health monitoring analysis presented that covers: firstly, enlisting of the NDT infrastructure commonly available in heavy manufacturing industries; secondly, common causes and reasons of machine failures and finally, discusses need of embedded structural health monitoring (e-SHM) system with the combination of NDT in place of existing monitoring practice. The presented work suggested that a combination of NDT with e-SHM is better for timely fault detection to ensure effective condition monitoring.

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