When the equipment needs to work in a higher overvoltage category, but the allowable overvoltage category of the equipment itself is not enough, it is necessary to take measures to reduce the overvoltage. The following methods can be used.

The electric field is divided into uniform electric field and non-uniform electric field. In the low-voltage switchgear, it is generally considered to be in the case of non-uniform electric field. As for the frequency, it is still under consideration. It is generally considered that the low frequency has little impact on the insulation coordination, but the high frequency still has an impact, especially on the insulating materials.

Under the sea crossing bridge connecting Beilun District of Ningbo, Zhejiang Province and Meishan island free trade zone, six "electric silver snakes" meander "along the bridge towards Meishan island port area. In June this year, with the commissioning of the 110kV Qixing power transmission and transformation project, this cross sea power channel will send a steady stream of power to the port area.

It is fully enclosed, fully protected, pollution-resistant and corrosion-resistant, meets the outdoor all-weather operation conditions, and can adapt to different working environments. The cable branch box is a floor mounted box with small volume and small floor area. If some cover an area of 0.65m2, the floor area with SF6 switch is only 1.45m2; The appearance is beautiful and will not damage the appearance of the town.

American cable branch box is a kind of cable engineering equipment widely used in the power distribution network system in North America. It is mainly characterized by one-way door opening and horizontal multi-pass busbar. It has the advantages of small width, flexible combination, full insulation and full sealing. According to the rated current, it can be generally divided into 600A main circuit and 200A branch circuit. The 600A main circuit is fixed and connected with screw in bolts; 200A branch circuit adopts plug-in connection and can be plugged with load. The cable joint used in American cable branch box shall comply with ieee386 standard.

Polaris power transmission and distribution network news: on April 24, China Southern Power Grid Corporation released the white paper on digital power grid promoting the construction of a new power system with new energy as the main body (hereinafter referred to as the white paper) in Guangzhou.

Polaris power transmission and distribution network news: Recently, the "14th five year plan" application plan for Beidou satellite navigation system of China Southern Power Grid Corporation (hereinafter referred to as the "plan") was released. According to the plan, China Southern Power Grid Corporation is building an operation service platform integrating Beidou location service, short message communication management, time-frequency monitoring and other basic modules. According to the plan, the platform will be put into operation at the end of June this year. At that time, it can provide Beidou high-precision positioning services for Guangdong, Guangxi, Yunnan, Guizhou and Hainan.

China Southern Power Grid Guangdong Corporation recently announced that the intelligent inspection robot developed by it has been put into use, which is expected to realize 24-hour monitoring of substations, which will improve the intelligent level of power systems. The first robot put into use began to "go to work" at the 500kV Wolong substation in Yunfu, Guangdong power grid on November 4.