The Role of Right Interpretation of Space Charge Distribution for Optimized Design of HVDC Cables

Imburgia, A.; Romano, Pietro; Ala, Guido; Sanseverino, Eleonora Riva; Giglia, G.

doi:10.1109/tia.2019.2927669

Cited by 11 publications

(12 citation statements)

References 26 publications

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“…In order to correctly evaluate the signal depicted in Figure 4, a model able to simulate the acoustic waves behavior within the PEA cell and the cable has been used. The model has been developed and widely described in a previous work published by the authors in [27,28]. The model is essentially based on the analogy between acoustic and mechanical quantities, such as the analogy between force and velocity of an acoustic wave with voltage and current of an electrical wave, respectively [34].…”

Section: The Pea Cell Modelmentioning

confidence: 99%

“…A detailed explanation of the developed PEA cell model used in this work is provided in [27,28]. Due to the one-dimensional approach referred to a single charge propagation phenomenon, the wave propagation model, developed for the flat specimens, has been identically applied to a cylindrical cable geometry.…”

Section: The Pea Cell Modelmentioning

confidence: 99%

“…For this reason, it is important to evaluate before or after a space charge measurement the acoustic wave behavior with the aim to establish the temporal location of both main peaks as well as their reflections. For this aim, in a previous work, a PEA cell model for flat specimens has been developed by the authors [27,28]. In this work, after minor changes, the same model has been used for a cable specimen.…”

Section: Introductionmentioning

confidence: 99%

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The Industrial Applicability of PEA Space Charge Measurements, for Performance Optimization of HVDC Power Cables

et al. 2019

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Cable manufacturing industries are constantly trying to improve the electrical performance of power cables. During the years, it was found that one of the most relevant degradation factors influencing the cable lifetime is the presence of space charge in the insulation layer. To detect the accumulated charge, the pulsed electro-acoustic (PEA) method is the most used technique. Despite the wide use of the PEA cell, several issues are still present. In particular, the PEA output signal is strongly disturbed by the acoustic waves reflections within the PEA cell. This causes the distortion of the output signal and therefore the misinterpretation of the charge profiles. This, in turn, may result in an incorrect cable characterization from the space charge phenomenon point of view. In 2017, due to the proved degradation effect of the space charge accumulation phenomenon, the IEEE Std 1732 was developed. This standard describes the steps to be followed for the space charge measurement in cables specimens during pre-qualification or type tests. Therefore, cable manufacturing industries started to take a particular interest in these measures. In the light of this, the aim of the present work is to highlight that the enacted standard is not easily applicable since various problems are still present in the PEA method for cables. In particular, in this work, the effect of multiple reflected signals due to the different interfaces involved, but also the effect of the signal attenuation due to cable dielectric thickness, as well as the effect of the PEA cell ground electrode thickness in the output charge profile, are reported. These issues have been demonstrated by means of an experimental test carried out on a full-size cable in the Prysmian Group High Voltage laboratory. To better understand the PEA cell output signal formation, a PEA cell model was developed in a previous work and it has been experimentally validated here. In particular, simulations have been useful to highlight the effect of the reflection phenomena due to the PEA cell ground electrode thickness on the basis of the specimen under test features. Moreover, by analyzing the simulation results, it was possible to separate the main signal from the reflected waves and, in turn, to calculate the suitable ground electrode thickness for the cable specimen under test.

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Section: The Pea Cell Modelmentioning

confidence: 99%

Section: The Pea Cell Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Industrial Applicability of PEA Space Charge Measurements, for Performance Optimization of HVDC Power Cables

et al. 2019

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“…Based on the reflection phenomenon mentioned above, the authors proposed several works, as well as a MATLAB model simulating the acoustic wave behavior within the PEA cell [13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

“…Concerning the PEA cell simulation model, it has already been widely explained and validated for a single layer specimen [14]. In the present work, it is used to confirm the predictable and obtainable experimental behaviors, thus only the simulation results are reported.…”

Section: Introductionmentioning

confidence: 99%

Reliability of PEA Measurement in Presence of an Air Void Defect

et al. 2020

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This paper deals with the reliability of the Pulsed Electro-Acoustic (PEA) technique in the case of a specimen containing an air layer. The first approach to this study has been proposed by the authors in previously published works. In these papers, the mathematical description, the PEA cell simulation model, and some experimental tests have been reported. In this work, a more accurate description of the acoustic wave behavior within the PEA cell and specimen with and without an air layer is given. Moreover, the comparison between simulation and experimental tests for both cases (specimen with and without air layer) allowed the validation of the previously developed PEA cell simulation model. The latter was previously validated only for a single layer specimen, here the good performances of the model have also been confirmed in the case of a multilayer specimen, also with an air layer. Experimental and simulation results show that the air layer acts as a barrier for the acoustic signal, due to the different acoustic impedance between the air and the solid dielectric material which constitute the specimen. Therefore, the aim of the present work is to demonstrate that in the case of a three-layers specimen, composed as dielectric-air-dielectric, the PEA cell is not able to provide the complete profile of the entire specimen under test.

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Scalable Polyimide‐Organosilicate Hybrid Films for High‐Temperature Capacitive Energy Storage

Dong

Qiu

et al. 2023

Advanced Materials

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well drilling. [1][2][3] Nowadays, dielectric materials with excellent high-temperature capacitive properties are in great demand because of the heat inevitably generated by compact high-power electronic systems. [4][5][6][7] For example, the operating temperature of capacitors is 140-150 °C in green-energy vehicle inverters and reaches 200 °C in electrified aircraft. Biaxially oriented polypropylene (BOPP), the mainstream commercial polymer dielectrics, has discharged energy densities (U e ) <4.0 J cm −3 and a maximum operating temperature below 105 °C. [5,8,9] Therefore, developing dielectric polymers with high working temperatures and large energy storage densities is of critical importance.The current high glass-transitiontemperature (T g ) dielectric polymers, including polyimide (PI), polyetherimide (PEI), polyetheretherketone (PEEK), and fluorene polyester (FPE), usually exhibit low breakdown strength (E b ) and poor capacitive performance at >150 °C because of an exponential increase in conduction loss with the applied field and temperature. [5,10,11] There are two types of conduction mechanisms in dielectrics, i.e., electrode-limited and bulk-limited conduction mechanisms. [6,[12][13][14][15][16][17] Unlike the electrode-limited conduction mechanism that depends on the electrode-dielectric interface, the bulk-limited conduction mechanism is determined by the electrical characteristics High-temperature polymer dielectrics have broad application prospects in next-generation microelectronics and electrical power systems. However, the capacitive energy densities of dielectric polymers at elevated temperatures are severely limited by carrier excitation and transport. Herein, a molecular engineering strategy is presented to regulate the bulk-limited conduction in the polymer by bonding amino polyhedral oligomeric silsesquioxane (NH 2 -POSS) with the chain ends of polyimide (PI). Experimental studies and density functional theory (DFT) calculations demonstrate that the terminal group NH 2 -POSS with a wide-bandgap of E g ≈ 6.6 eV increases the band energy levels of the PI and induces the formation of local deep traps in the hybrid films, which significantly restrains carrier transport. At 200 °C, the hybrid film exhibits concurrently an ultrahigh discharged energy density of 3.45 J cm −3 and a high gravimetric energy density of 2.74 J g −1 , with the charge-discharge efficiency >90%, far exceeding those achieved in the dielectric polymers and nearly all other polymer nanocomposites. Moreover, the NH 2 -POSS terminated PI film exhibits excellent charge-discharge cyclability (>50000) and power density (0.39 MW cm −3 ) at 200 °C, making it a promising candidate for high-temperature high-energy-density capacitors. This work represents a novel strategy to scalable polymer dielectrics with superior capacitive performance operating in harsh environments.

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The Role of Right Interpretation of Space Charge Distribution for Optimized Design of HVDC Cables

Cited by 11 publications

References 26 publications

The Industrial Applicability of PEA Space Charge Measurements, for Performance Optimization of HVDC Power Cables

The Industrial Applicability of PEA Space Charge Measurements, for Performance Optimization of HVDC Power Cables

Reliability of PEA Measurement in Presence of an Air Void Defect

Scalable Polyimide‐Organosilicate Hybrid Films for High‐Temperature Capacitive Energy Storage

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