• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.52 no.10
• /
• pp.431-435
• /
• 2003

It is very difficult and dangerous to measure PD(Partial Discharges) from high voltage equipments in outdoor situation. But that is very important thing for preventing them from more serious accident by defects made by insulating degradation. This paper provides useful method to detect PD signals easily without any dangerous situation. Electric field sensor by the principle of capacitor can detect PD signals without direct connection between sensor and high voltage equipment and has very wide frequency range suitable for noise rejection. Electric field sensor and related circuit for processing PD signal show good performance as a PD sensor when it is applied to simulated high power equipment generating PD pulses.

• Transactions of the Korean hydrogen and new energy society
• /
• v.8 no.4
• /
• pp.145-154
• /
• 1997

The $H_2$ and $H_2S$ sensing characteristics of Pd and Pd-Rh gate MOS sensor and the effect of Pd deposition condition on the hydrogen sensing performance of Pd gate MOS sensor was investigated. The increase of rf power and deposition temperature led to the decrease in the sensitivity and the initial response rate. The deposition temperature gave more effects on the decrease of the sensitivity and the initial response rate than the rf power. The sensitivity of Pd-Rh sensor gave better performance than pure Pd sensor. As the concentration of Rh in the gate increased, the sensitivity decreased. For Pd-Rh sensor, the sensitivity to $H_2$ was higher than that to $H_2S$. It was demonstrated that rf power, deposition temperature had an important role in the sensor performance.

• Proceedings of the KIEE Conference
• /
• 1998.11c
• /
• pp.922-924
• /
• 1998

In this paper, an optical fiber sensor(OF sensor) utilizing the principal of Mach-Zehnder interferometer were proposed to detect the partial discharge signals in insulating oil. At first the AC breakdown signals were detected to check the response of the OF sensor. The detected signals from OF sensor was consistent with that from current probe. After the response checking, simultaneous measurements and continuous recording were made of electrical and the OF sensor signals from partial discharge(PD) produced by IEC(b) electrode system immersed in insulating oil. The continuous recording made it possible to extract basic quantities of PD from the OF sensor signals, such as pulse phase and pulse amplitude distribution. Through the signal analysis, the absolute peaks of the OF sensor PD signal was found to be increased with the amplitude of electrical signals, and these results mean that there is a strong correlation between OF sensor and electrical PD signals. It was demonstrated that the OF sensor in this research had a possibility to detect the PD signals in power apparatus.

• Journal of Sensor Science and Technology
• /
• v.6 no.3
• /
• pp.221-227
• /
• 1997

The Pd/NiCr gate MISFET-type sensors were fabricated for detecting hydrogen dissolved in high-capacivity transformer oil. To improve stability and high concentration sensitivity of the sensor, Pd/NiCr double catalysis metal gate was used. To reduce the serious gate voltage drift of the sensor induced by hydrogen, the gate insulators of 2 FETs were constructed with double layer of silicon dioxide and silicon nitride. The hydrogen sensitivity of the Pd/NiCr gate MISFET is about a half of Pd/Pt gate MISFET's sensitivity but the Pd/NiCr gate MISFET has good stability and high concentration detectivity up to 1000 ppm.

• Journal of Sensor Science and Technology
• /
• v.29 no.6
• /
• pp.394-398
• /
• 2020

In this paper, we report the sensing performance of H₂ gas sensors composed of Pd/carbon nanotube (CNT) buckypaper at room temperature. The CNT buckypaper was made using a simple filtration process and subsequently deposited with Pd as the sensing material. The sensitivity of the sensor increased with respect to the gas concentration. To investigate the effect of Pd thickness, Pd layers of different thickness were deposited on the buckypaper, and the response of the sensor was evaluated. The proposed sensor exhibits excellent sensing properties with optimized Pd thickness at room temperature (25℃). Pd nanoparticles significantly impact the sensitivity and selectivity of the sensor because of the spillover effect. In addition, the sensor is highly suitable for bendable and wearable devices owing to its structural flexibility.

• Proceedings of the KIEE Conference
• /
• 2006.07c
• /
• pp.1480-1481
• /
• 2006

It is very difficult and dangerous to measure partial discharge from high voltage equipment in outdoor situation. But that is very important thing for preventing serious accidents from defects which originated in insulating degradation. This paper provides useful method to detect PD signals easily without any dangerous situation. Electric field sensor by the principle of capacitor detect PD signals without direct electrical connection between sensor and high power equipment and has very wide frequency range suitable for noise rejection. Electric field sensor and related circuit for processing PD signal showed good performance as a PD sensor when it is applied to simulated high power equipment generating PD pulse.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.53 no.2
• /
• pp.83-90
• /
• 2004

This paper describes investigations of the UHF(Ultra High Frequency) PD(Partial Discharge) measuring technology designed for monitoring of PD in high power apparatus. Based on the spiral antenna theory, the hole type sensor for GIS with metal flange spacer and injection type sensor for oil filled transformer are developed. The experimental results show measurement characteristics of the PD sensor for several artificial defects in gas-insulated system(GIS) and oil transformer. Moreover, we proposed the new $\phi$-f-q method for the purpose of condition assessment of high power apparatus.

• Journal of IKEEE
• /
• v.22 no.2
• /
• pp.356-361
• /
• 2018

We investigated a hydrogen gas sensor which is available in a high temperature atmosphere. The hydrogen sensors were fabricated into a metal-oxide-semiconductor (MOS) structure made of $Pd/Ta_2O_5/SiC$, and the thin tantalum oxide ($Ta_2O_5$) layer was fabricated by rapid thermal oxidation (RTO). In the experiment, we made three types of sensors with different palladium (Pd) patterns to evaluate the effect of Pd electrode on response characteristics. As the result, the response characteristics in capacitance were improved further when the filled area of the Pd electrode became larger.

• Proceedings of the KIEE Conference
• /
• 1999.11b
• /
• pp.442-445
• /
• 1999

In this work, to detect of hydrogen in DI water in the generator area of nuclear power plants was fabricated Pd/Pt gate MISFET sensor using Pd membrane. $H_2$ permeation through Pd accounts for external mass transfer, surface adsorption and desorption, transitions to and from the bulk metal, and diffusion within the metal. The identification of pinholes in the generator area of plant is an important safety consideration, as hydrogen build-up gives rise to explosion. For this type of application the sensor needs to be isolated in DI water, accordingly, a Pd membrane was used to separate the DI water. The hydrogen in the DI water was then absorbed on the Pd thin film and diffused into the oil through the thin film. The Pd/Pt gate MISFET sensor, encapsulated by oil, will thereby detect permeated hydrogen.

• Journal of Sensor Science and Technology
• /
• v.32 no.4
• /
• pp.219-222
• /
• 2023

Partial discharges (PD) have long been recognized as a major contributing factor to catastrophic failures in high-power equipment. As the demand for high voltage direct current (HVDC) facilities continues to rise, the significance of on-line and real-time monitoring of PD becomes increasingly prominent. In this study, we have designed, fabricated, and characterized a highly sensitive and cost-effective PD sensor comprising a pair of copper electrodes with different arc lengths. The key advantage of our sensor is its non-invasive nature, as it can be installed at any location along the entire power cable without requiring structural modifications. In contrast, conventional PD sensors are typically limited to installation at cable terminals or insulation joint boxes, often necessitating invasive alterations. Our PD sensor demonstrates exceptional accuracy in estimating PD location, with a success rate exceeding 95% in the straight sections of the power cable and surpassing 89% in curved sections. These remarkable characteristics indicate its high potential for realtime and on-line detection of PD.