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Journal ArticleDOI

Wireless Sensor Network for Radiometric Detection and Assessment of Partial Discharge in High‐Voltage Equipment

TL;DR: In this paper, a wireless sensor network is proposed that utilizes only received signal strength to locate areas of PD activity within a highvoltage electricity substation, which consists of low power and low-cost radiometric sensor nodes which receive the radiation propagated from a source of PD.
Abstract: Monitoring of partial discharge (PD) activity within high-voltage electrical environments is increasingly used for the assessment of insulation condition. Traditional measurement techniques employ technologies that either require off-line installation or have high power consumption and are hence costly. A wireless sensor network is proposed that utilizes only received signal strength to locate areas of PD activity within a high-voltage electricity substation. The network comprises low-power and low-cost radiometric sensor nodes which receive the radiation propagated from a source of PD. Results are reported from several empirical tests performed within a large indoor environment and a substation environment using a network of nine sensor nodes. A portable PD source emulator was placed at multiple locations within the network. Signal strength measured by the nodes is reported via WirelessHART to a data collection hub where it is processed using a location algorithm. The results obtained place the measured location within 2 m of the actual source location.
Citations
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Journal ArticleDOI
28 Feb 2019-Sensors
TL;DR: The aim of this review was to present state-of-the-art UHF sensors in PD detection and facilitate future improvements in the UHF method.
Abstract: Condition monitoring of an operating apparatus is essential for lifespan assessment and maintenance planning in a power system. Electrical insulation is a critical aspect to be monitored, since it is susceptible to failure under high electrical stress. To avoid unexpected breakdowns, the level of partial discharge (PD) activity should be continuously monitored because PD occurrence can accelerate the aging process of insulation in high voltage equipment and result in catastrophic failure if the associated defects are not treated at an early stage. For on-site PD detection, the ultra-high frequency (UHF) method was employed in the field and showed its effectiveness as a detection technique. The main advantage of the UHF method is its immunity to external electromagnetic interference with a high signal-to-noise ratio, which is necessary for on-site monitoring. Considering the detection process, sensors play a critical role in capturing signals from PD sources and transmitting them onto the measurement system. In this paper, UHF sensors applied in PD detection were comprehensively reviewed. In particular, for power transformers, the effects of the physical structure on UHF signals and practical applications of UHF sensors including PD localization techniques were discussed. The aim of this review was to present state-of-the-art UHF sensors in PD detection and facilitate future improvements in the UHF method.

73 citations


Cites background from "Wireless Sensor Network for Radiome..."

  • ...With the development of wireless communication technology, wireless sensors provide high flexibility for sensor installation and data transmission [45,46]....

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Journal ArticleDOI
09 Jul 2019-Sensors
TL;DR: The method of transmitting data with the best hop count is proposed, which fully reduces the power consumption of the data transmission and can effectively reduce the energy consumption and prolong the lifetime of wireless sensor networks.
Abstract: Wireless sensor networks are widely used in many fields. Nodes in the network are typically powered by batteries. Because the energy consumption of wireless communication is related to the transmission distance, the energy consumption of nodes in different locations is different, resulting in uneven energy distribution of nodes. In some special applications, all nodes are required to work at the same time, and the uneven energy distribution makes the effective working time of the system subject to the node with the largest energy consumption. The commonly used clustering protocol can play a role in balancing energy consumption, but it does not achieve optimal energy consumption. This paper proposes to use the power supply line to connect the nodes to fully balance the energy. The connection scheme with the shortest power line length is also proposed. On the basis of energy balance, the method of transmitting data with the best hop count is proposed, which fully reduces the power consumption of the data transmission. The simulation results show that the proposed method can effectively reduce the energy consumption and prolong the lifetime of wireless sensor networks.

53 citations

Journal ArticleDOI
16 Nov 2018-Sensors
TL;DR: A novel received signal strength (RSS) based localization algorithm is proposed that only requires the energy of the received signal rather than the PD pulse itself to locate a PD source for nine different positions.
Abstract: The term partial discharge (PD) refers to a partial bridging of insulating material between electrodes that sustain an electric field in high-voltage (HV) systems. Long-term PD activity can lead to catastrophic failures of HV systems resulting in economic, energy and even human life losses. Such failures and losses can be avoided by continuously monitoring PD activity. Existing techniques used for PD localization including time of arrival (TOA) and time difference of arrival (TDOA), are complicated and expensive because they require time synchronization. In this paper, a novel received signal strength (RSS) based localization algorithm is proposed. The reason that RSS is favoured in this research is that it does not require clock synchronization and it only requires the energy of the received signal rather than the PD pulse itself. A comparison was made between RSS based algorithms including a proposed algorithm, the ratio and search and the least squares algorithm to locate a PD source for nine different positions. The performance of the algorithms was evaluated by using two field scenarios based on seven and eight receiving nodes, respectively. The mean localization error calculated for two-field-trial scenarios show, respectively, 1.80 m and 1.76 m for the proposed algorithm for all nine positions, which is the lowest of the three algorithms.

24 citations


Cites background or methods from "Wireless Sensor Network for Radiome..."

  • ...The experimental study suggests that PD signal bandwidth remains between 50–800 MHz, the used passbands have a frequency range from 30 to 75 MHz and 255 to 320 MHz [34,35]....

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  • ...The use of RF filters and LNA enables RF front end part of the system to generate the frequency response in the range of 30 to 75 MHz and 255 to 320 MHz with the noise figure value from 5–7 dB and passband gain value of 12–14 dB....

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  • ...Spectral analysis insi a l. Sensors 2018, 18, 4000 9 of 19 As illustrated in Figure 6, the frequency span was chosen from 50 MHz to 1 GHz covering the whole desired band....

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  • ...RF Filters 30 – 75 MHz 255-320 MHz LNA Envelope Detector 0.1 – 1000 MHz RF Front End Microcontroller ADC WirelessHart Transceiver ( LTC5800 ) 2.4GHz Transmitter part Comparator Integrator Monostable Signal Conditioning Unit Amplifier Microcontroller Unit Rx antenna Tx antenna Figure 7....

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  • ...Sensors 2018, 18, 4000 9 of 19 As illustrated in Figure 6, the frequency span was chosen from 50 MHz to 1 GHz covering the whole desired band....

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Journal ArticleDOI
TL;DR: In this article, a multiple signal classification (MUSIC) algorithm-based partial discharge (PD) localization method with an angle of arrival (AOA) and ultra-high frequency (UHF)-received signal strength indicator (RSSI) is proposed.
Abstract: To monitor the insulation deterioration of power equipment and realize prompt fault warning systems in air-insulated substations, in this study, we propose a multiple signal classification (MUSIC) algorithm-based partial discharge (PD) localization method with an angle of arrival (AOA) and ultrahigh frequency (UHF)-received signal strength indicator (RSSI). Compared with traditional UHF time-difference-based techniques, this RSSI-based AOA localization method is a more economical solution. In addition, by comparing the measured RSSI vector to a prebuilt reliable reference data set, the MUSIC method can effectively locate the direction of the PD source with high accuracy. Compared with the method that directly determines the smallest RSSI values by several sensors, this method can accomplish localization by fewer sensors without impeding accuracy. Furthermore, the interpolation method was adopted to improve the precision of the relationship curve of AOA/RSSI, which it did with a limited number of sensors. Laboratory tests were conducted to verify the accuracy of the proposed method, and most of the localization errors were less than 1°, which indicates its potential application in the prompt identification of faults regarding the insulation deterioration of power equipment in substations.

14 citations

Journal ArticleDOI
TL;DR: A radiometric sensor is proposed which utilizes a gated, pipelined, sample-and-hold based folding analogue-to-digital converter structure that only samples when a signal is received, reducing the power consumption and increasing the efficiency of the sensor.
Abstract: Partial discharge is a well-established metric for condition assessment of high-voltage plant equipment. Traditional techniques for partial discharge detection involve physical connection of sensors to the device under observation, limiting sensors to monitoring of individual apparatus, and therefore, limiting coverage. Wireless measurement provides an attractive low-cost alternative. The measurement of the radiometric signal propagated from a partial discharge source allows for multiple plant items to be observed by a single sensor, without any physical connection to the plant. Moreover, the implementation of a large-scale wireless sensor network for radiometric monitoring facilitates a simple approach to high voltage fault diagnostics. However, accurate measurement typically requires fast data conversion rates to ensure accurate measurement of faults. The use of high-speed conversion requires continuous high-power dissipation, degrading sensor efficiency and increasing cost and complexity. Thus, we propose a radiometric sensor which utilizes a gated, pipelined, sample-and-hold based folding analogue-to-digital converter structure that only samples when a signal is received, reducing the power consumption and increasing the efficiency of the sensor. A proof of concept circuit has been developed using discrete components to evaluate the performance and power consumption of the system.

9 citations

References
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Journal ArticleDOI
Li Li1, Jian Yao1, Renping Xie1, Menghan Xia1, Wei Zhang2 
22 Dec 2016-Sensors
TL;DR: Experimental results on a large set of challenging street-view panoramic images captured form the real world illustrate that the proposed system is capable of creating high-quality panoramas.
Abstract: In this paper, we propose a unified framework to generate a pleasant and high-quality street-view panorama by stitching multiple panoramic images captured from the cameras mounted on the mobile platform. Our proposed framework is comprised of four major steps: image warping, color correction, optimal seam line detection and image blending. Since the input images are captured without a precisely common projection center from the scenes with the depth differences with respect to the cameras to different extents, such images cannot be precisely aligned in geometry. Therefore, an efficient image warping method based on the dense optical flow field is proposed to greatly suppress the influence of large geometric misalignment at first. Then, to lessen the influence of photometric inconsistencies caused by the illumination variations and different exposure settings, we propose an efficient color correction algorithm via matching extreme points of histograms to greatly decrease color differences between warped images. After that, the optimal seam lines between adjacent input images are detected via the graph cut energy minimization framework. At last, the Laplacian pyramid blending algorithm is applied to further eliminate the stitching artifacts along the optimal seam lines. Experimental results on a large set of challenging street-view panoramic images captured form the real world illustrate that the proposed system is capable of creating high-quality panoramas.

863 citations

Journal ArticleDOI
10 Aug 2016-Sensors
TL;DR: This work presents an innovative multimodal context mining framework to inspect and infer human behaviour in a more holistic fashion and extends beyond the state-of-the-art, since it not only explores a sole type of context, but also combines diverse levels of context in an integral manner.
Abstract: There is sufficient evidence proving the impact that negative lifestyle choices have on people’s health and wellness. Changing unhealthy behaviours requires raising people’s self-awareness and also providing healthcare experts with a thorough and continuous description of the user’s conduct. Several monitoring techniques have been proposed in the past to track users’ behaviour; however, these approaches are either subjective and prone to misreporting, such as questionnaires, or only focus on a specific component of context, such as activity counters. This work presents an innovative multimodal context mining framework to inspect and infer human behaviour in a more holistic fashion. The proposed approach extends beyond the state-of-the-art, since it not only explores a sole type of context, but also combines diverse levels of context in an integral manner. Namely, low-level contexts, including activities, emotions and locations, are identified from heterogeneous sensory data through machine learning techniques. Low-level contexts are combined using ontological mechanisms to derive a more abstract representation of the user’s context, here referred to as high-level context. An initial implementation of the proposed framework supporting real-time context identification is also presented. The developed system is evaluated for various realistic scenarios making use of a novel multimodal context open dataset and data on-the-go, demonstrating prominent context-aware capabilities at both low and high levels.

447 citations

Proceedings ArticleDOI
01 Nov 2015
TL;DR: This work presents a WuRx design using an RF energy harvesting circuit (RFHC) that can provide a wake-up range sensitivity around 4 cm/mW at low transmit RF powers, which scales to a long wake- up range at high powers.
Abstract: Wake-up receivers (WuRxs) can improve the lifetime of a wireless sensor network by reducing energy consumption from undesirable idle listening. The amplitude level of the incoming RF signal is used by a WuRx to generate an interrupt and wake up the radio of a sleeping sensor node. Existing passive WuRx designs are generally based on RFID tags that incur high cost and complexity. Thus, there is a need for cost-effective and low-complexity WuRxs suited for both long-range and directed wake-ups. In this work, we present a WuRx design using an RF energy harvesting circuit (RFHC). Experimental results show that our RFHC-based WuRx can provide a wake-up range sensitivity around 4 cm/mW at low transmit RF powers (< 20 mff), which scales to a long wake-up range at high powers. Our design also obtains accurate selective wake-ups. We finally present simulation-based studies for optimizing the design of RFHCs that enhance decoding efficiency with improved rise and fall times.

231 citations

Journal ArticleDOI
TL;DR: In this paper, the displacement law of Fourier transformation (DSF) was used to increase the detection threshold, to improve the localization accuracy and to perform on-line measurements of Partial Discharge (PD) in noisy environments.
Abstract: The paper provides essentially a summary of PD measurements applying the UHF range in order to increase the detection threshold, to improve the localization accuracy and to perform on-line measurements of Partial Discharge (PD) in noisy environments. The electromagnetic UHF technique offers good signal to noise ratios, because external PD signals and disturbances can be shielded effectively. A new developed method allows the localization of PD in gas-insulated substations (GIS) by frequency domain measurements. The basic idea is the displacement law of Fourier transformation. The interference phenomena of superposed signals from two sensors give information about the time delay of the sensor signals. On-site PD measurements are made at cable connectors by means of monopole antennas housed in a barrel sleave, while the cable is in service. Thus a sensitive PD measurement even in noisy environment is possible. PD measurements on several 72 kV cable connectors were performed in an unshielded laboratory. On-site measurements during operation showed the great potential for condition assessment. For decoupling sensitive UHF PD signals from the inner of a power transformer tank UHF sensors applied through drain/oil valves are used. Experimental studies indicate that all relevant types of PD possibly occurring within a transformer emit high frequency spectra to be detected with UHF sensors. Furthermore in laboratory experiments and on-site measurements very moderate UHF signal attenuations have been observed.

181 citations


"Wireless Sensor Network for Radiome..." refers background in this paper

  • ...To avoid the measurements of PD intensity being inflated by communication signals, the measurement is limited to frequencies below 320 MHz, where the majority of PD activity occurs....

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  • ...800 MHz, with the majority below 300 MHz (Albarracín et al., 2016; Hoshino et al., 2001; Jaber et al., 2017; Robles et al., 2012, 2013; Tenbohlen et al., 2008; Xiao et al., 2009); therefore, a sensor bandwidth in this region was selected....

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  • ...358 800 MHz, with the majority below 300 MHz (Albarracín et al., 2016; Hoshino et al., 2001; Jaber et al., 2017; Robles et al., 2012, 2013; Tenbohlen et al., 2008; Xiao et al., 2009); therefore, a sensor bandwidth in this region was selected....

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  • ...The receiving antenna is connected to the RF front end, which contains a band-pass filter for the 30–320 MHz band, a band-stop filter for the 75–255 MHz band, an ADL5530 low-noise amplifier, and an LTC5507 RF envelope detector....

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  • ...There are two resulting pass-bands from 30 to 75 MHz and from 255 to 320 MHz, with a midband gain between 11.7 and 14.4 dB and a measured noise figure of 5–7 dB. Figure 3 shows the frequency response of the RF front end....

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Journal ArticleDOI
TL;DR: In this paper, the authors present a method based on the principle of wideband radio-frequency interference which can be used for noninvasive monitoring of discharges at substations.
Abstract: Partial discharges (PDs) generate wideband radio-frequency interference which can be used for noninvasive monitoring of discharges. This paper presents a novel method based on this principle for PD monitoring of substations. The significant advantage of this method lies in the ability to detect PD sources in energized equipment anywhere within a substation compound during normal operating conditions. The results obtained from the prototypes installed in the U.K. and U.S. substations are reported. Results include correlation with apparent charge and daily recordings obtained before, during, and after the failure of a 132-kV current transformer and 69-kV voltage transformer.

155 citations


"Wireless Sensor Network for Radiome..." refers methods in this paper

  • ...…the detection and location of PD sources, such as time of arrival and time difference of arrival (Judd, 2008; Li et al., 2017; Moore et al., 2003; Portugues et al., 2009; Robles et al., 2016; Zhu et al., 2016, 2017), employ technologies that require high-speed data acquisition and relatively…...

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  • ...Traditional radiometric techniques for the detection and location of PD sources, such as time of arrival and time difference of arrival (Judd, 2008; Li et al., 2017; Moore et al., 2003; Portugues et al., 2009; Robles et al., 2016; Zhu et al., 2016, 2017), employ technologies that require high-speed data acquisition and relatively large amounts of data processing, as well as synchronization between nodes, making the design of the sensor nodes complex and costly....

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