① External insulation problem:
With the deterioration of the operating environment, the anti-pollution flashover ability of porcelain post insulators is insufficient. For UHVDC, pure porcelain post insulators require a large creepage distance and structure, while too high post insulators are difficult to achieve strong bending and seismic strength.
② Earthquake resistance:
The high-voltage porcelain insulator is always referred to as the high-voltage porcelain insulation equipment, which is difficult to solve the problem. In the 2008 Wenchuan earthquake, most of the damage to high-voltage equipment was due to the fracture of porcelain bushing. For the UHV DC system, the post insulator used for smoothing the reactor requires an overall height of 12m and a supporting mass of 40t, while the converter station is located in Chuxiong, Yunnan, an earthquake-prone area. Obviously, it is very difficult for porcelain post insulators to meet the seismic requirements.
③ Manufacturing quality problems:
As a porcelain post insulator manufacturer, we suggest you should pay more attention to selecting a good manufacturer of porcelain insulators, especially post porcelain insulators. Post-insulator is very difficult to manufacture because of their complex process, equipment conditions, raw material quality problems, and other limitations. Changsha rich power company started to produce post porcelain insulators in 1990, and our city is the main production base of ceramic production in china since 1820. On the basis of a large number of investigations, the accident investigation working group of high-voltage post porcelain insulators of the former generation and transmission operation Department of State Power Corporation counted the accidents of Post Porcelain Insulators according to technical reasons and came to the conclusion that the majority of the reasons for the fracture of post porcelain insulators were product quality.
The function of a post porcelain insulator?
Post porcelain insulator is a special insulation product in the electric system, which can play an essential function in the overhead transmission lines. We are a porcelain post insulator manufacturer in China. In the early years, post porcelain insulators have been mainly used for power poles. They were slowly developed at one quit of the excessive-voltage energy line connection tower. Many suspension insulators have been hung to grow the creepage distance. All of them are normally made from silicon rubber or ceramics. So we call them insulators, including porcelain insulators and polymer insulators. Insulators play primary roles in overhead transmission lines, that is, supporting conductors and preventing contemporary from returning to the ground. There are many post insulators in the double disconnector breakers too. These two roles should be assured. Insulators should no longer fail due to flashover and breakdown caused by modifications in environmental and electric load conditions. In any other case, insulators will lose their feature and harm the provider lifestyles and operation life of the whole line.
From time to time, more and more disc-shaped insulators are hung at one end of the high-voltage wire connection tower to increase the creepage distance. They are usually made of glass or ceramic or rubber, which are called glass insulators and porcelain insulators, and composite insulators. In order to prevent floating dust and other pollutants from adhering to the insulator surface and forming a path, it is flashover and breakdown at both ends of the insulator, i.e. creepage. Therefore, increasing the surface distance, that is, the creepage distance, and the discharge distance along the insulating surface, that is, the leakage distance, is called the creepage distance. Creepage distance = surface distance / maximum system voltage. According to different pollution levels, the creepage distance is generally 31 mm / kV in heavily polluted areas. Zero value insulator refers to the insulator whose potential distribution at both ends of the insulator is close to or equal to zero during operation. Influence of zero value or low-value insulator: the insulation of the line conductor depends on the insulator. Due to manufacturing defects or external effects, such as dirty insulator surface, lightning stroke, etc. The insulation performance of insulators will deteriorate continuously. When the insulation resistance decreases or is zero, it is called a low value or zero value insulator. The insulator is smooth, which can reduce the capacitive reactance between wires and reduce the loss of current.