Partial discharge measurement and analysis under lightning impulse superimposed DC voltage in SF6 gas

Abstract

The presence of lightning impulses (LIs) on the DC waveform can seriously influence the insulation performance of a GIL system. The waveshape can be a superposition of the DC and impulse waveform. In this study, the behaviour of partial discharge (PD) on an epoxy surface is investigated under DC and LI superimposed voltage in SF 6 . The lightning impulses with different polarities are superimposed on the epoxy surface under both positive and negative DC voltages, respectively. Positive lightning impulses are superimposed on a negative DC voltage with a 90% of the partial discharge inception voltage (PDIV) magnitude. The number and amplitude of the PDs are used to evaluate the insulation performance. The experimental results show that the LI with a different polarity applied to DC can excite the PDs on the epoxy surface. The excitation effect of positive LI superimposed on negative DC is more significant. According to the impulse amplitude and PD characteristics, the influence of superimposed LI on PD excitation can be divided into three stages. As the superimposed LI increases, the amplitude of the excited PD increases gradually, while the PD number first increases and then decreases. This study is expected to provide reference for manufacture and protection of power equipment.

Digital calibration technology and device design for SF6 hexafluoride

“…When inhaled at high concentrations, it can cause pulmonary edema, respiratory bleeding, and pleural effusion. If there are symptoms, high vigilance should be exercised [3]. SF6 gas is not flammable, but containers (cylinders and gas storage tanks) and pipelines filled with SF6 gas may experience high heat and rapidly increase the pressure inside the container or pipeline, which may lead to cracking and explosion of the container and pipeline.…”

“…There is a risk of explosive metal fragments, hose shaking, high-pressure gas impact injury, and harmful combustion products such as sulfur oxide and hydrogen fluoride poisoning [4]. At the same time, SF6 gas is often stored as a high-pressure liquid in containers, and the SF6 gas released under high pressure can quickly diffuse and form low temperatures, which can cause frostbite to the human skin [3]. Due to the fact that SF6 gas comes into contact with various qualities of SF6 gas during the process of recovery, purification, and recycling, in the event of SF6 gas leakage, any gas that has not been purified or tested unqualified should be considered as SF6 faulty gas.…”

“…The sulfur hexafluoride sensor is a sensor designed specifically for monitoring sulfur hexafluoride, which can effectively monitor the concentration of sulfur hexafluoride and timely alarm when the limit is exceeded, reminding people to avoid harm. Based on different monitoring principles, sulfur hexafluoride sensors are divided into eight categories: highfrequency ionization method, laser photoacoustic method, laser photoacoustic method, laser spectrum method, infrared spectrum method, high-voltage breakdown method, electron capture method and negative ion capture method [3]. Various monitoring technologies mainly detect the content of sulfur hexafluoride gas in the ambient air.…”

SF6 decomposition behaviour under partial discharge of typical insulation defects in gas‐solid insulated valve‐side bushing of converter transformer

“…Investigations have shown that freely moving conductive particles, protrusions on the conductors and metal particles attached to the surface of ERIP can significantly deteriorate the dielectric performance of gas-solid-insulated systems, which may lead to PD [5][6][7][8]. Partial discharge measurements, as an important tool for testing the dielectric integrity, can be used for online condition monitoring and fault diagnosis.…”

High‐altitude tunnel‐catenary gap impulse discharge characteristics and breakdown voltage correction

“…Bian [27] explored the role of air pressure in the variation of negative corona-generated space charge. Wang [28] studied partial discharge measurement under lightning impulse superimposed DC voltage in SF 6 gas. Gurlek [29] found the breakdown process on rod-rod air gap under lightning impulse voltage.…”