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Proceedings ArticleDOI

2012 IEEE I2MTC - International Instrumentation and Measurement Technology Conference, Proceedings

About: This article is published in The Journal of Thoracic and Cardiovascular Surgery.The article was published on 2012-08-06 and is currently open access. It has received 7 citations till now. The article focuses on the topics: Instrumentation (computer programming).

Summary (2 min read)

INTRODUCTION

  • Partial Discharge (PD) is a clear ageing agent in electrical insulation of power systems.
  • The measurement procedure is always done in industrial environments, where low Signal-to-Noise Ratio (SNR) signals are obtained or several microscopic sites are usually discharging simultaneously.
  • This is the reason to add new measurement techniques where PD pulse waveform analysis is a fruitful methodology for noise rejection and PD source separation [3] .
  • In order to solve this, acoustic and UHF PD detection techniques are recently being applied to these systems, since these are non-contact measurements that can help in on-line PD monitoring and location [4] - [7] .
  • It is not fully understood the relationship between conventional HF or VHF signals and UHF signals [8] .

A. Partial Discharge generation

  • A constant and predictable partial discharges activity is necessary to ensure the repeatability of results.
  • It has been found, that using new and dry transformer paper sheets, the partial discharges activity (internal PDs in microscopic air voids between papers) starts around 2 kV and is stable during at least three hours which is enough to acquire proper signals in VHF with the HFCT and in UHF with the antennas.
  • Hence, the high voltage source is slowly set slightly above the inception voltage and the measuring campaign starts.

B. Antennas deployment

  • The distances between the test object and the antennas are not critical parameters at this stage because the experiment is focused on studying the frequency response of the signals and not the pulses in the time domain; nevertheless, distances were of a similar range, as can be seen in Fig. 2 .
  • Since PD source location is not the focus of this paper, the lengths of the coaxial cables are random too.
  • PDs activity is a stochastic phenomenon that depends on several factors such as applied voltage level, insulation ageing status, environmental conditions, etc.
  • During the experiments in laboratory, most factors were controlled to assure uniformity in Figure 3 .

III. SIGNAL ACQUISITION AND PROCESSING

  • Prior to starting the acquisition of partial discharge pulses, the background noise is characterized to be compared with the FFT in the presence of pulses.
  • The importance of these results lays on the FFT content that appears in the range from 1300 to 1900 MHz and that is directly related to the UHF emission of the partial discharge pulse, compare Fig. 6 and Fig. 4 .
  • The column on the right represents the ratio between the power content in squared volts in those ranges with PD and without PD.
  • This study opens a research trend to characterize the behavior of monopole antennas with different lengths and shapes.
  • Their significant components above 1.3 GHz are an interesting characteristic for PDs location, where the geometric sensitivity is determined by the bandwidth of the antennas.

IV. CONCLUSION

  • The 10 cm monopole and zig-zag antennas show an overall better performance in the two frequency bands of study after comparing the behaviour of the four antennas.
  • The 5 cm monopole antenna is the best detecting PDs emitting in UHF from 1300 to 1900 MHz band.
  • Monopoles and zig-zag antennas are strong candidates for further studies because these antennas are inexpensive, simpler, smaller, easier to manufacture and can be tuned to a frequency band of interest by changing their lengths.
  • The paper also gives practical indications about PDs detection with different antennas.

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Citations
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Journal ArticleDOI
TL;DR: In this paper, four antennas are thoroughly studied by means of their theoretical and experimental behavior when measuring electromagnetic pulses radiated by PD activity and the results are analyzed in detail.
Abstract: Partial discharge (PD) detection is a widely extended technique for electrical insulation diagnosis. Ultrahigh-frequency detection techniques appear as a feasible alternative to traditional methods owing to their inherent advantages such as the capability to detect PDs online and to locate the piece of equipment with insulation problems in substations and cables. In this paper, four antennas are thoroughly studied by means of their theoretical and experimental behavior when measuring electromagnetic pulses radiated by PD activity. The theoretic study of the band of frequencies in which the pulse emits and the measurement of the parameters $S_{11}$ are complemented with the frequency response and wavelet transform of a set of 500 time signals acquired by the antennas, and the results are analyzed in detail.

76 citations

Journal ArticleDOI
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.

17 citations

Proceedings ArticleDOI
09 Jun 2013
TL;DR: In this article, a wide bandwidth Archimedean spiral antenna was designed and its main parameters were analyzed by computer simulation software, and three typical partial discharge models were used to detect the three models.
Abstract: Partial discharge (PD) is an important indicator for electrical equipment's insulation property in power industry. Through the measurement of partial discharge we can have a good understanding of the equipment's performance. Ultra High Frequency (UHF) detection techniques are being recently a more and more important method to detect partial discharges. In this paper, a wide bandwidth Archimedean spiral antenna was designed. Its main parameters were analyzed by computer simulation software. A partial discharge test platform was built and three typical partial discharge models were designed. We used the designed Archimedean spiral antenna to detect the three models. The experiment results show that the designed Archimedean spiral antenna has good performance to measure electrical equipment partial discharge signals.

12 citations

Proceedings ArticleDOI
03 Jul 2016
TL;DR: In this paper, the exact phase angle displacement of each Partial Discharge, PD, pulse with respect to the voltage reference waveform is estimated using a customized electronic device, the "phase check", consisting of a server to collect remote measurements and a Look up table to provide corrections to the measured phase shift values.
Abstract: The main objective of this paper is the assessment of the exact phase angle displacement of each Partial Discharge, PD, pulse with respect to the voltage reference waveform. Such problem also referred to as ‘synchronization’ is relevant when the cable is not accessible and the PD measure is carried out in wireless mode. It is well known, that the angle phase shift, due to the propagation phenomenon on the transmission line, can be calculated knowing the line type and length and typical operating conditions of the transmission line. The setup comprises a customized electronic device, the “Phase check”, a server to collect remote measurements and a Look up table to provide corrections to the measured phase shift values. To evaluate the voltage phase shift introduced by a transmission line, different simulations have been carried out in PSCAD. Then, to prove the correctness of simulated results and verify the “Phase check” precision, experimental measurements have been carries out on three transmission lines in Sicily, Italy. The experimental measurements prove that the proposed setup is effective and quite useful to provide precise assessment of voltage phase shift for PD wireless diagnosis.

4 citations

Journal ArticleDOI
30 Jan 2021-Sensors
TL;DR: In this paper, a diagnostic method to localize Partial Discharges (PDs) inside medium voltage (MV) and high voltage (HV) equipment is presented, which is based on Electromagnetic (EM) measurements which are used to reconstruct the EM field produced by the PD and localize the PD itself.
Abstract: This work presents a novel diagnostic method to localize Partial Discharges (PDs) inside Medium Voltage (MV) and High Voltage (HV) equipment. The method is well suited for that equipment presenting a bounded domain with fixed Boundary Conditions (BCs) such as Oil-Filled Power Transformers (OFPTs), Air Insulated Switchgears (AISs), Gas Insulated Switchgears (GISs) or Gas Insulated Transmission Lines (GILs). It is based on Electromagnetic (EM) measurements which are used to reconstruct the EM field produced by the PD and localize the PD itself. The reconstruction and localization tasks are based on the eigenfunctions series expansion method which intrinsically accounts for the physical information of the propagation phenomenon. This fact makes the proposed diagnostic method very robust and accurate even in real and complex scenarios. The promising experimental results, obtained in two different test cases, confirmed the ability and powerfulness of the proposed PD localization method.

3 citations

Frequently Asked Questions (1)
Q1. What contributions have the authors mentioned in the paper "Antenna selection and frequency response study for uhf detection of partial discharges" ?

In this paper, four antennas will be tested in order to compare their response to this physical phenomenon.