FIBRE-OPTIC SENSORS FOR EARLY DAMAGE DETECTION IN PLASTIC INSULATIONS OF HIGH-VOLTAGE FACILITIES (original) (raw)
Related papers
A Fiber-Optic Sensor for Acoustic Emission Detection in a High Voltage Cable System
Sensors, 2016
We have proposed and demonstrated a Michelson interferometer-based fiber sensor for detecting acoustic emission generated from the partial discharge (PD) of the accessories of a high-voltage cable system. The developed sensor head is integrated with a compact and relatively high sensitivity cylindrical elastomer. Such a sensor has a broadband frequency response and a relatively high sensitivity in a harsh environment under a high-voltage electric field. The design and fabrication of the sensor head integrated with the cylindrical elastomer is described, and a series of experiments was conducted to evaluate the sensing performance. The experimental results demonstrate that the sensitivity of our developed sensor for acoustic detection of partial discharges is 1.7 rad/(m • Pa). A high frequency response up to 150 kHz is achieved. Moreover, the relatively high sensitivity for the detection of PD is verified in both the laboratory environment and gas insulated switchgear. The obtained results show the great potential application of a Michelson interferometer-based fiber sensor integrated with a cylindrical elastomer for in-situ monitoring high-voltage cable accessories for safety work.
Sensors, 2012
A fiber optic interferometric sensor with an intrinsic transducer along a length of the fiber is presented for ultrasound measurements of the acoustic emission from partial discharges inside oil-filled power apparatus. The sensor is designed for high sensitivity measurements in a harsh electromagnetic field environment, with wide temperature changes and immersion in oil. It allows enough sensitivity for the application, for which the acoustic pressure is in the range of units of Pa at a frequency of 150 kHz. In addition, the accessibility to the sensing region is guaranteed by immune fiber-optic cables and the optical phase sensor output. The sensor design is a compact and rugged coil of fiber. In addition to a complete calibration, the in-situ results show that two types of partial discharges are measured through their acoustic emissions with the sensor immersed in oil.
Optical-only Detection of Partial Discharge with Fluorescent Polymer Optical Fiber Sensors
Procedia Engineering, 2015
This paper reflects recent progress in the field of fluorescent polymer optical fiber sensors (F-POF) for partial discharge (PD) detection in high voltage (HV) cable accessories using optical-only PD detection by coincidence single photon counting. In experiments with artificial PD sources these sensors show the ability to detect optical emissions from picocoulomb-level PDs in a real-scale model of a translucent high voltage cable accessory. False positives (caused by detector noise) are efficiently suppressed while maintaining sufficient sensitivity, even when the sensor is located in an unfavorable position.
2014
A novel optical detection method for partial discharge in HV/EHV cable terminations has been proposed. Optical sensor fibres integrated into the HV equipment provide high sensitivity as well as immunity to electromagnetic interference and enable therefore on-line monitoring in electromagnetically noisy environment. The availability of optically transparent silicone rubbers that meet strict dielectric and mechanical criteria is a crucial prerequisite for the implementation of this method. The optically transparent silicone rubbers can be applied for the fabrication of a modern rubber stress cone as well as for the development of a new optical sensing element sensitive to PD activities. In this thesis, AC dielectric strength behaviour and mechanical properties of three types of commercially available silicone rubbers were investigated. One of the characterized silicone rubbers was a translucent type whereas the two others were optically transparent types, however with different chemic...
Fiber fabry-perot sensors for acoustic detection of partial discharges in transformers
SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference Proceedings, 2009
Acoustic emission monitoring is often used in the diagnosis of electrical and mechanical incipient faults in high voltage apparatus. A great number of methods are available for condition monitoring and diagnosis of power transformer insulation, but only a few can take direct measurements inside a transformer. Partial discharges are a major source of insulation failure in power transformers and their detection can be achieved through the associated acoustic emissions. This paper reports the development of two sensing head configurations based on extrinsic and intrinsic fiber Fabry-Pérot interferometers for the detection of incipient faults in oil-filled power transformers. These sensors can be placed inside the transformer tank without affecting the insulation integrity, improving fault detection and location. The performances of the sensing heads are characterized and compared with the situations where it operates in air, water and oil and promising results are obtained, which will allow the industrial development of practical solutions.
Fiber optic interferometric sensor for acoustic detection of partial discharges
Journal of Optical Technology, 2007
The detection of acoustic partial discharge signals produced in power transformers is reported. Detection is based on optic phase changes in an intrinsic Mach-Zehnder fiber optic interferometric sensor of high sensitivity. The sensor can be placed within transformers and is suitable for the detection of weak acoustic signals associated with the PD. The calibration of the interferometric fiber optic acoustic sensor at typical frequencies displayed by partial discharges is presented. Interferometric multi-fringe outputs are used for high-precision measurements during calibration. The demodulation of such signals is presented for obtaining the optical phase readout. Partial discharges are generated in laboratory conditions and are detected using the fiber optic sensor immersed in mineral oil.
Detection of Partial Discharges and its Effect on Solid Insulation used in High Voltage Cable
— Most of the high voltage (HV) power equipment is made up with solid insulation like paper insulation, glass insulation, epoxy insulation etc. The oldest kind of insulating material among all insulation, the paper insulation is used in cable and nowadays the Cross linked Polyethylene (XLPE) is commonly used for cable insulation. The presence of impurities in the insulation system is one of the root causes of insulation failure as they are form a weak zone inside the healthy insulation system. Therefore, early identification of degradation process like formation of electrical tree structures inside such solid electrical insulation due to high voltage tress during its operating life is utmost requirement to prevent the electrical power equipment from a sudden and complete insulation failure. To study the growth mechanism of electrical tree structure inside the insulation with different applied high voltage a commonly used insulating material like XLPE insulation in HV power cable are consider for this present work. This work also describes the ageing process by conducting the partial discharge (PD) test on the same insulating materials. Finally, the effect of PD on insulation i.e., formation of electrical tree structure on solid insulation was observed by using Scanning Electron Microscope (SEM) and analyzed.
High-voltage transformer is the most critical and expensive component in a power system network in order to ensure the stability of the system. Partial discharge (PD) detection is a technique widely used for high voltage equipment insulation condition monitoring and assessment. In this paper, the characteristics of two acoustic sensors multimode fiber optical (FO) and piezoelectric (PZT) sensor haves been successfully explored and monitor the condition of high voltage equipment insulation. Both the sensors were placed in an oil tank in which optical breakdown was produced by neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (1064 nm) device. The optical signal of light source was linked by a photodetector which was also connected with multimode fiber (MMF) by means of a fiber optical adapter. The data obtained by both sensors were then analyzed in time and frequency domain. These experimental results are interesting and suggest that both sensors have peculiar characteristics for the detection of AE and can be used for any PD detection requirements.
Optical Detection of Partial Discharges on Insulator Strings of High-Voltage Transmission Lines
IEEE Transactions on Instrumentation and Measurement, 2009
Leakage current detection is a promising method for measuring pollution levels on insulators of overhead transmission lines. This paper describes the development of a leakage current sensor based on a fiber-coupled light-emitting diode, as well as the development of a processing module that detects, stores, and classifies leakage current peaks that are directly related to partial discharges on the surface of the high-voltage insulators. The relative humidity is also detected and stored for further analysis. The processing module uses a PIC 16F877A microcontroller and can register the rate of partial discharges for two months on three different levels.
Development of new partial discharge sensors for condition monitoring of power system equipment
Partial discharge measurement is a very effective method to assess the condition of power system equipment. This paper reviews recent developments on optically-interrogated sensing systems to detect the acoustic pressure induced by partial discharges. Also presented is work in progress by the authors on new sensing systems using fibre Bragg grating (FBG) and distributed feedback fibre laser (DFBFL).