Withstand Voltage Characteristics Research Articles

Comprehensive Analysis of Insulator Performance in High Voltage Transmission Systems: Implications for Efficient Power Transfer

This research article examines the performance of insulators in high-voltage transmission systems, specifically focusing on their role in facilitating efficient power transfer along transmission lines. The study evaluates different types of insulators used in various geographical regions and assesses their withstand voltage characteristics. The research demonstrates that glass insulators outperform plastic and ceramic insulators in terms of electric field behavior. The study also investigates the behavior of AC-energized insulators in polluted and non-polluted conditions, providing insights for improving HVAC insulation design in polluted environments. The research recommends further experiments to examine insulator behavior under different applied voltage scenarios. Overall, the study emphasizes the importance of insulators in high-voltage transmission systems and provides valuable insights for developing advanced insulator technologies to enhance power transfer efficiency.

Preparation of highly condensed porous carbon used in EDLCs with high voltage and high volumetric energy density

Conventional porous carbons as the electrode material for electric double layer capacitors (EDLCs) normally have low volumetric energy density due to the low density and poor withstanding voltage characteristic. Therefore, it is very meaningful to construct porous carbon with high density and high voltage resistance. In this paper, using sulfonated pitch and graphene oxide as precursors, highly condensed porous carbon (SGx) with improved withstanding voltage characteristic is prepared by the π-π conjugated interaction and simple chemical activation with secondary high temperature treatment. The prepared porous carbon material with 3 wt% graphene oxide (SG3%) well-balances the specific surface area (SSA) and packing density, exhibiting high SSA of 2700 m2 g−1 and high packing density of 0.53 g cm−3. Besides, low oxygen content (9.82 at.% of surface O atoms) and stable surface chemical composition (ether bonds dominating) avoid the side reactions between the oxygen-containing functional groups and electrolyte, thus improving the withstanding voltage characteristics. At 3.2 V voltage in TEABF4/PC electrolyte, Cv and the maximum energy density reach 80.6 F cm−3 (1 A g−1) and 31.1 Wh L−1, respectively. Almost no capacity fading is found after 20,000 cycles testing. This work provides a new strategy for the development of high withstanding voltage EDLCs.

High-Power Microwave Limiters Using Recess-Free AlGaN/GaN Schottky Barrier Diodes

In this letter, a thin-barrier AlGaN/GaN Schottky barrier diode (SBD) is proposed and implemented in a three-stage high-power RF limiter module. Benefited from the thin-barrier epitaxy, a recess-free process in the Schottky region is allowed to avoid the plasma damage, resulting in low ON-resistance of 5 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> and high withstand voltage characteristics. In addition, the proposed SBDs have achieved a low junction capacitance of 0.35 pF at 0 V bias and a turn-on voltage of 0.5 V. With the optimized SBD and well-designed matching circuits, the limiter has reached a high power capacity of over 10 W in continuous wave (CW), 20 W in pulse mode, and a fast recovery time of 30 ns at a frequency of 3.5 GHz, exhibiting better characteristics than traditional limiters. Both simulation and measured results agree with each other. It indicates that the AlGaN/GaN-based SBD is promising for high-power and high-frequency limiters.

Microwave Plasma Assisted Aerosol Deposition (μ-PAD) for Ceramic Coating Applications

To improve plasma and chemical resistance on various vacuum components used for semiconductor manufacturing equipment, various ceramic coating techniques have been applied. Among these methods for ceramic coating, the well-known atmospheric plasma spray (APS) is advantageous for providing thick film (100 µm or more) deposition. However, there are problems associated with the phase transition of the coating film and poor film quality due to formation of voids. To solve these problems, the aerosol deposition (AD) method has been developed. This method provides nice ceramic film quality. However, the coating rate is quite slow and has difficulty producing thick films (&gt;30 µm). To overcome these limitations, microwave plasma-assisted aerosol deposition (μ-PAD) is applied at low vacuum conditions without the AD nozzle. This method uses a microwave plasma source during the AD process. After enduring a long-term durability test, as a trial run, μ-PAD has been applied on the actual process site. With the Al2O3 powder, μ-PAD shows a coating rate that is 12 times higher than the AD method. In addition, the formation of a thicker film (96 µm) deposition has been demonstrated. On the other hand, the coating film hardness, porosity, adhesion, and withstand voltage characteristics were confirmed to be less than the AD method.

Experimental study on discharging current to reduce voltage stress during underwater shock wave generation

In food processing using underwater shock waves, the intensity of shock waves is determined by a discharging current from an output capacitor. In past studies, to realize efficient food processing, the underwater shock wave has been generated by charging a high voltage to the output capacitor with high withstand voltage characteristics. For this reason, the conventional method suffers from high manufacturing costs. Furthermore, the conventional method is dangerous due to high voltage requirements such as 3.5 kV. In this work, a low-cost and safe non-heat treatment technology using underwater shock waves is presented for food processing. Unlike the conventional methods, the proposed method generates underwater shock waves by using multiple large output capacitors with low withstand voltage characteristics. Therefore, the proposed method can achieve safe and low-cost non-thermal food processing, because the output capacitors do not need to be charged at high voltage. In the proposed method, the output voltage is about one-fourth that of the conventional methods. The effectiveness and reliability of the proposed technique are confirmed by several experiments using a laboratory experimental system. The experiment revealed that the proposed technique can process a target food at 865 V output, where the rise time of the high voltage generator is 126 s and the output capacitor is 3300 μF.

Electrical Characteristics of Multilayered Ceramic Capacitors Depending on BaTiO3 Particle Size

Multilayer ceramic capacitors were prepared with BaTiO3-based ceramics of different grain sizes (150–500 nm), having appropriate dielectric properties and high-temperature stability. The grain size effect on the dielectric properties and insulation resistivity of fine-grained BaTiO3 ceramics at room temperature and high temperatures under electric fields were investigated. The reduction in particle size has a strong effect on DC-bias characteristics and withstanding voltage characteristics per unit thickness. BaTiO3 ceramic capacitor with smaller grains had higher reliability under the DC bias and higher withstanding voltage per unit thickness due to the shell with para-electricity. The highly accelerated lifetime test showed that the insulation resistance with smaller particle size exhibited one order higher as the voltage increases at higher temperatures and the samples with a size of 500 nm had a sharp drop in insulation resistance at 200 V. Small particles (150, 250 nm) have a smaller product of insulation resistance and capacity than larger particles (500 nm). But, the withstanding voltage per unit thickness of the small particles (150, 250 nm) was 82, 71 V/μm, respectively, which was greater than 58 V/μm of the larger particles (500 nm). This is thought to be an effect of suppressing the movement of defects in the smaller particles because small grains have many grain boundaries.

Design, construction, and testing of solution resistive divider applied in hundreds of kilovolts nanosecond pulse measurement.

The solution resistive divider is often used considering its excellent high-frequency and withstanding voltage characteristics. This paper develops a nanosecond pulse measurement system based on the CuSO4 solution resistive divider, which can be used to measure high voltage impulses with rise time of 50 ns and amplitude of 300 kV. The low-voltage arm of the newly designed solution resistive divider is composed of noninductive metal film resistors. The newly designed resistive divider combines the advantages of the conventional solution resistive divider and metal film resistive divider. The stray parameters of the resistive divider are theoretically calculated and the circuit simulation is studied. Besides, the square wave response characteristics of the resistive divider are studied in the experiments. Considering the effect of frequency on the surge impedance of the cable, a matching cable of the same type with the transmission cable instead of a common matching resistor is used to improve the matching effects. In order to reduce the effects of electromagnetic interference on the measurement results, some shielding measures are taken. The experimental results show that the measurement system has good response characteristics in the practical application.

3상 3선식 Plug-In MCCB의 인장력 및 접촉저항 평가에 관한 연구

The purpose of this paper is to evaluate the performance of a Plug-In MCCB developed for rapid power supply restoration when the MCCB is installed in a power system and to verify its reliability. Since the developed 3 <TEX>${\Phi}$</TEX> 3 W Plug-In MCCB can be installed on and removed from a bus bar by one touch using a plug housed at the rear, it can be replaced in a short period of time. Therefore, it can quickly respond to the normalization of a power system. When the Plug-In MCCBB is installed on a bus bar, the resistance between each phase and plug was measured to be 0.46 <TEX>$m{\Omega}$</TEX> in average. When the Plug-In MCCB is installed, the tension in the vertical direction was measured to be 112.78 N in average, which is greater than the tension of 50 N specified in the related regulation. The withstanding voltage tests performed 5 times repeatedly by applying 6 kV to the developed Plug-In MCCB for 60 seconds shows good withstanding voltage characteristics. In addition, both the general waterproof test using a water injection method and the insulation resistance analysis using a Mega meter showed good waterproof and insulation characteristics.

A Study on the Safety Estimation of Wiring Connection Connector Manufactured by Housing Type

The purpose of this study is to evaluate the safety of a wire connector fabricated for the effective installation of a lighting fixture including its contact resistance, insulation resistance, withstanding voltage characteristics, etc., and to provide the basis for the analysis and judgment of PL(Product Liability) dispute by presenting a damage pattern due to a general flame and overcurrent. This study applied the Korean Standard (KS) for the incombustibility test of the connector using a general flame and performed an overcurrent characteristics test of the connector using PCITS (Primary Current Injection Test System). The contact resistance of the housing connector was measured using a high resistance meter and the insulation resistance was measured using a multimeter. In addition, a supply voltage of AC 1,500V for testing the withstanding voltage characteristics was applied to both ends of the connector. Measurement was performed on 5 specimens and the measured values were used as a basis for judgment. Since the connector is fabricated in the form of a housing, it can be connected and separated easily and has a structure that allows no foreign material to enter. In addition, since it has a structure that allows wires to be connected only when their polarity is identical, any misconnection that may occur during installation can be prevented. When the incombustibility test was performed by applying a general flame to the connector, it showed outstanding incombustibility characteristics and the blade and blade holder connected to the housing remained firmly secured even after the insulation sheath (PVC) was completely destroyed by fire. In addition, the mechanism of the damaged connecting wire showed a comparatively uniform carbonization pattern and it was found that some residual melted insulation material was attached to both ends. In the accelerated life test (ALT) to which approximately 500% of the rated current was applied, the connector damage proceeded in the order of white smoke generation, wire separation, spark occurrence and carbonization. That is, it could be seen that the connector damaged by overcurrent lost its own metallic color with traces of discoloration and carbonization. The contact resistance of the connector at a normal state was 2.164mV/A on average. The contact resistance measured after the high temperature test was 3.258mV/A. In addition, the insulation resistance after the temperature test was completed was greater than and the withstanding voltage test result showed that no insulation breakdown occurred to all specimens showing stable withstanding voltage and insulation resistance characteristics.

Effects of A-site Ca and B-site Zr substitution on dielectric properties and microstructure in tin-doped BaTiO 3–CaTiO 3 composites

In an effort to enhance dielectric properties and sinterability in a BaTiO 3–CaTiO 3 composite, substitution of Ca ion to Ba-site and Zr ion to Ti-site as well as tin doping were considered. Nominal forms of (Ba 1− x Ca x )(Ti 0.96− y Zr y Sn 0.04)O 3 (0.15 ≤ x ≤ 0.20, 0.09 ≤ y ≤ 0.14) were synthesized by conventional solid-state processing technique, and their subsequent sinterability and dielectric properties were investigated. As Ca content was increased more than 15 mol%, the precipitation of second phase, whose main composition was CaTiO 3, started to form and the fraction of second phase was increased. Increase in Ca content appears to decrease the Curie temperature by the factor of 1.7°/mol% and to decrease the maximum dielectric constant by the factor of 200 (mol%) −1 possibly due to the effect of second phase having relatively lower dielectric constant. Increase in Zr content was also shown to decrease the Curie temperature by the factor of 10°/mol%, and to decrease the maximum dielectric constant by the factor of 217 (mol%) −1 presumably due to the increase of a diffuse phase transition (DPT). Sinterability and withstanding voltage characteristics were shown to improve by suppressing the abnormal grain growth due to the incorporation of second phases. An appropriate composition compatible with the Y5U (EIA standard) condenser which needs high breakdown voltage and dielectric constant is possible to be developed by controlling a DPT, in other words controlling the temperature stability, with incorporating Zr ion into the composite.

Withstand Voltage Characteristics of Two Series Vacuum Interrupters

To realize the high-voltage vacuum circuit breaker, we investigated the voltage-distribution ratio after current interruption at the double-break vacuum circuit breaker. We used the spiral CuCr (20%) electrodes and the axial magnetic-field CuCr (50%) electrodes as the experimental electrodes. At the double-break vacuum circuit breaker, where two vacuum interruptions that had the same and different characteristics of the electrode structure and contact materials were connected in series, there was a bias in the voltage-distribution ratio of each vacuum interrupter after current interruption. This seems to be because there was difference in the postarc current that passed through each vacuum interrupter after current interruption.

Improved calculations for no-load transformer switching surges

This paper deals with a modeling of components and calculation of transient overvoltages that build up on the transformer primary terminals after the transformer has been switched off by a vacuum circuit breaker (VCB). The transformer is connected to the circuit breaker by a cable. The transient overvoltages are calculated for different cable lengths, and the cumulative probability of different arc angles is investigated. In this study two cases are considered: transient overvoltages due to steady-state magnetizing current switching, and transient overvoltages due to inrush current switching. It is shown that the case of inrush current switching is worse, as virtual current chopping is possible. The cable is modeled by pi sections, whereas the transformer model is based on a terminal impedance. The VCB re-ignitions are modeled by means of withstand voltage characteristics and high-frequency quenching capability. Due to shortage of field tests, this work uses only literature references to compare the results with actual measurements.

Improved Calculations for No Load Transformer Switching Surges

This paper deals with a modeling of components and calculation of transient overvoltages that build up on the transformer primary terminals after the transformer has been switched off by a vacuum circuit breaker (VCB). The transformer is connected to the circuit breaker by a cable. The transient overvoltages are calculated for different cable lengths, and the cumulative probability of different arc angles is investigated. In this study two cases are considered: transient overvoltages due to steady-state magnetizing current switching, and transient overvoltages due to inrush current switching. It is shown that the case of inrush current switching is worse, as virtual current chopping is possible. The cable is modeled by pi sections, whereas the transformer model is based on a terminal impedance. The VCB re-ignitions are modeled by means of withstand voltage characteristics and high-frequency quenching capability. Due to shortage of field tests, this work uses only literature references to compare the results with actual measurements.

Assessment of Basic Contaniination Withstand Voltage Characteristics of Polymer Insulators

An artificial contamination method for hydrophobic polymer insulators has been developed which can provide a uniform contaminant layer, similar to that found in nature, without either damaging the polymer surface or by adding any chemical agent to the conventional contamination slurry. Using this method, the basic contamination withstand voltage characteristics of polymer insulators were investigated compared with those of porcelain insulators. The results show that although hydrophobic polymer insulators generally have excellent contamination withstand voltage characteristics, critical reduction of withstand voltage sometimes occurs under rapid and heavy wetting and contamination conditions.

Assessment of basic contamination withstand voltage characteristics of polymer insulators

An artificial contamination method for hydrophobic polymer insulators has been developed which can provide a uniform contaminant layer, similar to that found in nature, without either damaging the polymer surface or by adding any chemical agent to the conventional contamination slurry. Using this method, the basic contamination withstand voltage characteristics of polymer insulators were investigated compared with those of porcelain insulators. The results show that although hydrophobic polymer insulators generally have excellent contamination withstand voltage characteristics, critical reduction of withstand voltage sometimes occurs under rapid and heavy wetting and contamination conditions.

Design of high density pin board matrix switches for automated main distributing frame systems

High-density pin board matrix switches composed of matrix boards and connecting pins are designed to provide the cross connection function of an automated main distributing frame (AMDF) system. The cross connection is performed by inserting a connecting pin into a through hole on the matrix board. A small economic AMDF system is made possible by using a laminated matrix board structure based on mass production technology for printed circuit boards and the simultaneous connection of a paired line by inserting a single connecting pin. The low normal contact force design and small insulation spacing between the neighboring conductor patterns give a through-hole pitch of 1.5 mm and a connecting pin diameter of about 1 mm. The layer design of the matrix boards based on the high insulation resistance and high withstanding voltage characteristics allows a matrix board thickness of about 4.2 mm and a connecting pin length of about 8.7 mm. Evaluations of the electrical and contact characteristics of the matrix boards and connecting pins satisfy the design requirements. >

汚損・雪に対するがいしの直流耐電圧特性

汚損・雪に対するがいしの直流耐電圧特性

Withstand voltage characteristics of insulator string covered with snow or ice

The authors describe the results of an investigation into the withstand voltage characteristics of an insulator string covered with snow or ice and the application of these results to the insulation design and maintenance of a transmission line in a heavy snow area. It was found that the characteristics of withstand voltage were affected by the specific gravity of snow, the conductivity of water melted from snow, the height of snow, and the ratio of snow-covered length. The lightning impulse flashover voltage of insulator string covered with snow is much lower than that of nonsnow-covered insulator, indicating that the efficiency of lightning protection greatly decreases under snowing conditions. When transmission lines pass through a heavy snow area, an extension of the transmission system fault is feared in 54 and 275 kV transmission lines because the existing insulator string length does not have sufficient dielectric strength for temporary AC overvoltage and switching surge. >

交流送電線における冠雪がいしの耐電圧特性

交流送電線における冠雪がいしの耐電圧特性

Improvement of the DC voltage insulation efficiency of suspension insulators under contaminated conditions

The authors describe the results of the research and development on a suspension-type insulator having a DC contamination withstand voltage 1.25 to 1.3 times higher than that of the standard DC fog insulator, as measured by the fog-withstand or the clean-fog method. Also described are the withstand voltage characteristics of the suspension insulator contaminated with soluble materials and nonuniformly contaminated, simulating natural-field conditions. Design criteria taking these results into account are also discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>