In the early 1990s, China introduced a groundbreaking innovation in high-voltage electrical equipment: an oil-free, gas-free, and porcelain-free fluoroplastic material was used as internal insulation. This marked a significant shift from traditional designs, both domestically and internationally. The new equipment featured silicone rubber as the outer insulation, offering a completely different structure compared to conventional oil-filled porcelain bushings. Its unique design and advanced technology not only met but exceeded international standards like IEC and national Chinese standards (GB), quickly gaining widespread acceptance.
This dry-type series of products, including wall bushings, current transformers, and cable terminations, has seen remarkable progress and rapid development. Their key advantages include being oil-free, gas-free, and porcelain-free, along with compact size, lightweight, fire resistance, explosion protection, and strong anti-pollution flashover performance. Since 1990, over 10,000 units have been operating safely within the power system without any reported incidents.
Traditionally, high-voltage wall bushings, cable terminations, and current transformers rated at 66kV and above have relied on oil-filled porcelain structures. However, these systems come with several drawbacks—such as leakage risks, flammability, susceptibility to pollution flashovers, and heavy maintenance requirements. As environmental conditions worsened, the risk of flashovers on porcelain surfaces increased significantly. Although increasing the creepage distance was once a common solution, this approach had limitations. The larger the creepage distance, the lower the firing rate of the porcelain casing, which led to inefficiencies.
To address these challenges, a new generation of products was developed, featuring innovative structural designs and entirely new materials. This marked a major breakthrough in the field of high-voltage insulation technology.
The development of dry high-voltage wall bushings gained momentum in the early 1990s, driven by urban network upgrades and the rapid growth of indoor substations. With the rising demand for wall bushings, it became necessary to adopt a new approach, replacing oil-ceramic insulation with organic insulating materials.
In 1990, the first STA-type wall-through bushing was developed and successfully tested at the Dalian Laohutan Substation. Following this, over 200 units were deployed across the Northeast and Yunnan regions. However, the STA model still had some limitations, as it required post insulators at both ends due to its construction using XLPE cables. In response, we launched the STB high-voltage wall bushing in 1994. To date, more than 10,000 STB units have been in operation across the grid, covering over 20 provinces and municipalities—from Hainan in the south to Daqing in the north, and from the eastern coast to Xinjiang in the west.
Pulse Controller is the main part of dust collector to control pulse valves. Its output signals control pulse valves to blow air to remove dust from the filter bags.
Output Digits: 8, 10, 12, 20, 24, 30, 36, 52, 64
Input Voltage: 24VDC, 110VAC, 220VAC
Output Voltage: 24VDC, 24VAC, 110VAC, 220VAC
Pulse Width: 0.1 to 999.9s
Pulse Interval: 1 to 9999s
Cycle Interval: 1 to 9999s
Pulse Controller, Pulse Valve Controller, Dust Collector Controller, Dust Collector Pulse Controller
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