scholarly journals Detection of Self-Healing Discharge in Metallized Film Capacitors Using an Ultrasonic Method

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1893 ◽  
Author(s):  
Yusheng Ma ◽  
Haitao Shen ◽  
Chunming Pei ◽  
Huanyu Zhang ◽  
Muhammad Junaid ◽  
...  
Keyword(s):  
High Speed ◽  
Performance Test ◽  
Reactive Power ◽  
Ultrasonic Method ◽  
Test Procedure ◽  
Detection Algorithm ◽  
The Self ◽  
International Electrotechnical Commission ◽  
Self Healing ◽  
Ultrasonic Emission

Benefiting from self-healing features, metallized film capacitors (MFCs) are widely employed to compensate reactive power (VAR) and thus improve the performance of AC systems. To ensure the aforementioned functions, self-healing testing is a compulsory quality inspection for every type of MFC. In 2014, the International Electrotechnical Commission (IEC) issued a standard that recommended a general and instructive test procedure based on audible noise or ultrasound signals. However, more details relevant to this high voltage (HV) test were not provided. In this paper, we focused on the ultrasonic detection technique to reveal the self-healing characteristics of two typical MFCs. By launching a series of HV tests with star and delta MFCs, the waveform features, discharge energy, and spectrum distributions were analyzed. It was observed that the partial discharge always occurs before self-healing discharge with the same spectrum features ranging above 40 kHz. To solve the entanglement of these two discharge processes, a relative amplitude difference method is proposed. Based on the experimental observations, a detection algorithm incorporated with the ultrasonic emission sensors, preamplifier, and high-speed A/D converter was developed to assist the self-healing performance test.

Influence of Cement Coarse Particle on the Self-Healing Ability of Concrete Based on Ultrasonic Method

2010 ◽  
Vol 177 ◽  
pp. 526-529 ◽  
Author(s):  
Zhi Qiang Li ◽  
Zong Hui Zhou ◽  
Dong Yu Xu ◽  
Jing Hua Yu
Keyword(s):  
Particle Size ◽  
Wave Amplitude ◽  
Ultrasonic Method ◽  
The Self ◽  
Experimental Results ◽  
Coarse Particle ◽  
Head Wave ◽  
Self Healing ◽  
Before And After ◽  
The Relationship

The influences of particle size and mixing content of coarse cement on the self-healing ability of concrete were researched by ultrasonic method. Damaged degree was measured through the decrease of ultrasonic head wave amplitude (UHA) before and after loading. The relationship between damaged degree and self-healing ratio of concrete was built based on the experimental results as well as the relationship between cement diameter and self-healing ratio of concrete. Analyzing results show that UHA can evaluate the damaged degree of concrete clearly. There exists a damaged threshold of the concrete during loading. Under the same mixing content of coarse cement, when the damaged degree is higher than the threshold, the self-healing ratio of concrete decreases with the increase of damaged degree and increases with the increase of coarse cement diameter, however, while the damaged degree is less than the threshold, the self-healing ratio of concrete increases with both the increase of damaged degree and coarse cement diameter.

scholarly journals Technology and application of high speed fault location,isolation and self-healing in DC distribution network

2021 ◽  
Vol 256 ◽  
pp. 01042
Author(s):  
Kuo Tan ◽  
Guo Hu ◽  
Hai Wu ◽  
Feng Huang
Keyword(s):  
Power Supply ◽  
High Speed ◽  
Fault Location ◽  
Reactive Power ◽  
Operation Mode ◽  
Distribution Network ◽  
Self Healing ◽  
Continuous Increase ◽  
Dc Distribution ◽  
Flexible Operation

With the continuous increase of DC load, the research of DC distribution network has been developed rapidly. Compared with the traditional AC distribution network, DC distribution network has the advantages of less conversion times, high efficiency, low cost, simple control structure, no need to consider the frequency and phase and reactive power compensation equipment. Compared with AC distribution network, DC distribution network has more flexible operation mode and less power supply points However, the more flexible operation mode of DC distribution network also brings the problem of fault location and self-healing. The fault location, isolation and self-healing control strategy of AC distribution network can not be applied to DC distribution network. In this paper, a high-speed fault location, isolation and self-healing method for DC distribution network is proposed. Based on high-speed goose communication, a comprehensive evaluation is carried out according to the fault status of the power grid, and the millisecond level fault location, isolation and self-healing of DC distribution network are completed. The coordinated control equipment based on this method is successfully applied in Tongli integrated energy service center. When the fault occurs in this area, uninterrupted power supply is realized in the non fault area, which verifies the correctness and practicability of this method.

A Study on Performance Test of the Self-Cooled System of High-Voltage SVC Valve Group

2015 ◽  
Vol 713-715 ◽  
pp. 1322-1324
Author(s):  
Zhong Lin Zhang ◽  
Qian Hui Gang ◽  
Peng Qiu ◽  
Shu Han Wang ◽  
Cong Yu Bai
Keyword(s):  
Heat Pipe ◽  
High Voltage ◽  
Performance Test ◽  
Reactive Power ◽  
Cooling System ◽  
The Self ◽  
Real Time Control ◽  
Time Control ◽  
Performance Indexes ◽  
High Level

The high-voltage SVC realizes the dynamic reactive power compensation through the real-time control over the breakover and cut-off of thyristor. Because the current passing through thyristor is large, the frequent break-make will lead to a lot of thermal loss, so it should be cooled in time. The self-cooled heat pipe cooling system is a traditional high-voltage SVC cooling system, which is expensive and heavy because it adopts relatively expensive copper product and aluminium product.This paper introduces a new heat pipe radiator. Compared to the traditional heat pipe radiators, it is light in weight, small in volume and low in cost. The performance test shows that the thermal resistance of the radiator is 0.064°C/W, that the main performance indexes are superior to those of the similar heat pipe radiators at home and abroad and that its self-cooling ability has achieved a high level. Therefore, it will greatly promote the promotion and application of this technology in China.

Review of The Self-Healing Personality: Why Some People Achieve Health and Others Succumb to Illness.

1992 ◽  
Vol 37 (1) ◽  
pp. 88-88
Author(s):  
Beth Leedham
Keyword(s):  
The Self ◽  
Self Healing

scholarly journals Research on Performance Test System of Space Harmonic Reducer in High Vacuum and Low Temperature Environment

Machines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Jing Wang ◽  
Zhihua Wan ◽  
Zhurong Dong ◽  
Zhengguo Li
Keyword(s):  
Low Temperature ◽  
High Speed ◽  
Performance Test ◽  
High Reliability ◽  
High Vacuum ◽  
Test System ◽  
Low Noise ◽  
Speed Ratio ◽  
Space Harmonic ◽  
Temperature Environment

The harmonic reducer, with its advantages of high precision, low noise, light weight, and high speed ratio, has been widely used in aerospace solar wing deployment mechanisms, antenna pointing mechanisms, robot joints, and other precision transmission fields. Accurately predicting the performance of the harmonic reducer under various application conditions is of great significance to the high reliability and long life of the harmonic reducer. In this paper, a set of automatic harmonic reducer performance test systems is designed. By using the CANOpen bus interface to control the servo motor as the drive motor, through accurately controlling the motor speed and rotation angle, collecting the angle, torque, and current in real time, the life cycle test of space harmonic reducer was carried out in high vacuum and low temperature environment on the ground. Then, the collected data were automatically analyzed and calculated. The test data of the transmission accuracy, backlash, and transmission efficiency of the space harmonic reducer were obtained. It is proven by experiments that the performance data of the harmonic reducer in space work can be more accurately obtained by using the test system mentioned in this paper, which is convenient for further research on related lubricating materials.

Effect of epoxy resin healing agent viscosity on the self-healing performance of capsules reinforced polymer composite

2021 ◽  
Vol 28 (4) ◽  
Author(s):  
Raj Kumar Pittala ◽  
Satish Ben B ◽  
Avinash Ben B
Keyword(s):  
Epoxy Resin ◽  
Polymer Composite ◽  
The Self ◽  
Self Healing ◽  
Reinforced Polymer ◽  
Healing Agent

Robust efficient cruise control for high-speed train movement based on the self-triggered mechanism

2021 ◽  
Vol 128 ◽  
pp. 103141
Author(s):  
Shukai Li ◽  
Xi Wang ◽  
Lixing Yang ◽  
Tao Tang
Keyword(s):  
High Speed ◽  
The Self ◽  
High Speed Train ◽  
Cruise Control
Sign in / Sign up

Export Citation Format

Share Document