Forward and inverse parameter estimation algorithms of interdigital dielectrometry sensors

Lesieutre, Bernard C.; Mamishev, A.V.; Du, Yiqun; Keskiner, E.; Zahn, M.; Verghese, George C.

doi:10.1109/94.946710

Cited by 14 publications

(15 citation statements)

References 12 publications

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“…For example, the earlier continuum model by Zaretsky and Melcher [25] required the electrodes to be nearly infinitely thin. Later, this model was modified to account for electrode thickness [91]. In general, the entire manufacturing arsenal of the electronics industry is available to the designer at a fairly low cost.…”

Section: Electrodesmentioning

confidence: 99%

“…5, 11, and 12, and the fluid (typically air or liquid dielectric) trapped between the sensor's surface and the surface of the tested specimen. The finite thickness of the copper electrodes (35 or 17.5 m for different sensor designs) may also contribute to these differences; however, recent computational models take the thickness of electrodes into account [91].…”

Section: ) Three-wavelength Sensor On a Kapton Substratementioning

confidence: 99%

“…This assumption introduces a nonnegligible error into parameter estimation algorithms. If desired, it can be removed by assuming an additional dielectric layer between the side walls of interdigital electrodes that have finite thickness [91]. Also, the surface layer analysis in the continuum model can be achieved by specifying a very thin layer with bulk properties that lead to equivalent total conduction.…”

Section: ) Continuum Modelmentioning

confidence: 99%

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Interdigital sensors and transducers

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Section: Electrodesmentioning

confidence: 99%

Section: ) Three-wavelength Sensor On a Kapton Substratementioning

confidence: 99%

Section: ) Continuum Modelmentioning

confidence: 99%

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“…The first paper on the subject by Zaretsky et al addressed the forward problem in a planar geometry [37]. Efforts since then by Lesieutre et al have eliminated the assumption of zero thickness electrodes [49]. Sheiretov & Zahn added the effect of a zero order term [50] erroneously dismissed in [37].…”

Section: Solving the Forward Problem Solutionsmentioning

confidence: 99%

“…• Include the effect of electrode thickness into φ, z, and generalized planar periodic sensor solutions using [49] as a foundation.…”

Section: Theoretical Workmentioning

confidence: 99%

Dielectrometry Measurements of Moisture Diffusion and Temperature Dynamics in Oil Impregnated Paper Insulated Electric Power Cables

Thomas

Zahn

2008

Conference Record of the 2008 IEEE International Symposium on Electrical Insulation

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Paper insulated lead covered (PILC) cables have played an important role in underground power distribution for a hundred years. Replacing aged PILC before failure is critical to managing power distribution. Three prominent failure mechanisms accelerate cable aging: temperature stresses, moisture ingress, and partial discharge. The research focuses on the effect of temperature and moisture on the effective (complex) permittivity of the cable insulation. Measurements are performed using cylindrical dielectrometry sensors designed to be wrapped around the cable. The lead sheath of the cable is removed so that the sensors can be placed directly in contact with the insulation. From the measurements, the electrical properties of the material as a function of temperature and transient moisture diffusion are found.A theoretical treatment of the interdigital dielectrometry sensors with a cylindrical geometry is presented. Two classes of the geometry are studied. The φ periodic sensor geometry has electrodes aligned with the cylindrical axis and periodic around the circumference. The z periodic sensor geometry has the electrodes forming rings around the cylinder that are periodic along the cylindrical axis. The material is modeled by concentric rings of homogeneous materials. The electric field solution consists of an infinite summation of Fourier series terms. In finding the field solution and as a consequence of it, the potential, electric field lines, and the impedance between the driving and sensing electrodes are found. A generalized solution to the planar dielectrometry sensor topology is also presented. This solution allows for an arbitrary placement and excitation of electrodes, providing the analytical tools for a new generation of sensors.Dielectrometry sensors for use in φ and z periodic geometries are designed and manufactured on a 4 mil PTFE substrate. An experimental setup is designed and built to provide a temperature and humidity controlled environment for measurements. Special clamping mechanisms are used to secure the sensor to the sample. Custom built hardware is used to excite the sensor at frequencies ranging from 0.005 Hz to 10,000 Hz (over six decades), measure and record the response, and deliver it to a computer for storage and analysis.Steady state measurements are performed at temperatures ranging from room temperature to 100• C. Plastics, woods, and the PILC cable samples are measured. Using the theoretical model, the effective permittivity is estimated from the measurements. An Arrhenius temperature dependence is observed for several materials including the PILC cables. We characterize the temperature dependence of these materials by a master curve and activation energy. Together they give a complete description of the effective permittivity's frequency and temperature dependence.Transient measurements of moisture diffusion are made at constant temperatures for several 4 materials. For some experiments the boundary conditions limit the diffusion of moisture to one direction. When the z...

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A Sylvester–Arnoldi type method for the generalized eigenvalue problem with two‐by‐two operator determinants

Meerbergen

Plestenjak

2015

Numerical Linear Algebra App

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In various applications, for instance in the detection of a Hopf bifurcation or in solving separable boundary value problems using the two-parameter eigenvalue problem, one has to solve a generalized eigenvalue problem of the form (B 1 ⊗ A 2 − A 1 ⊗ B 2)z = µ(B 1 ⊗ C 2 − C 1 ⊗ B 2)z, where matrices are 2 × 2 operator determinants. We present efficient methods that can be used to compute a small subset of the eigenvalues. For full matrices of moderate size we propose either the standard implicitly restarted Arnoldi or Krylov-Schur iteration with shift-and-invert transformation, performed efficiently by solving a Sylvester equation. For large problems, it is more efficient to use subspace iteration based on low-rank approximations of the solution of the Sylvester equation combined with a Krylov-Schur method for the projected problems.

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Forward and inverse parameter estimation algorithms of interdigital dielectrometry sensors

Cited by 14 publications

References 12 publications

Interdigital sensors and transducers

Interdigital sensors and transducers

Dielectrometry Measurements of Moisture Diffusion and Temperature Dynamics in Oil Impregnated Paper Insulated Electric Power Cables

A Sylvester–Arnoldi type method for the generalized eigenvalue problem with two‐by‐two operator determinants

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