It can make the operation of the power system safer and more reliable. The new lightning arrester developed by Shanghai Jinshan Power Supply Company won international awards.
How to detect arrester faults in time without affecting residents’ electricity consumption during maintenance? The innovative achievement "Lightning Arrester for Distribution Transformer Protection Switch Box with Built-in Disconnector" developed by Shanghai Jinshan Power Supply Company has solved this problem and recently won the silver medal at the 49th International Exhibition of Inventions in Geneva.
According to reports, this invention developed a built-in automatic disconnector on the lower end face of the low-voltage arrester of a traditional distribution transformer, with a built-in automatic fuse device. When the melting point reaches 150°C, the disconnector will automatically break away and be driven by the disconnection device. Fall to the outside of the switch box. Even in a dark environment, maintenance personnel can easily find the source of the fault through the fluorescent indicators installed on the disconnector.
This product solves the technical problem of traditional arresters that after failure or failure due to lightning strikes, the fault circuit cannot automatically disconnect, the fault part cannot automatically detach, and requires power outage for maintenance. It fills the gap that low-voltage arresters cannot match the disconnector.
The origin of this invention can be traced back to the sudden power outage that occurred to many users in Jinshan District a few years ago. Maintenance personnel checked house to house and found no fault points. They even updated the wires, connectors and other devices, but found that the fuse was still blown after the electricity was sent in. After the distribution transformer switch box was removed and sent to a specialized testing agency for testing, it was discovered that the arrester was damaged.
It has always been a common problem in the power supply industry that lightning arresters are difficult to detect due to hidden faults, and users have long power outages for maintenance. "The traditional low-voltage arrester is installed in a distribution transformer switch box weighing nearly 500 kilograms. If the box is not opened for inspection, the fault point is not easy to find." Zhai Wanli, a senior engineer at Jinshan Power Supply Company, said that when the arrester suffers multiple lightning strikes or runs for a long time , aging will occur internally and leakage current will occur. Over time, arresters can become damaged, melt, or even explode. However, due to the high installation position of the box, the entire removal process is time-consuming and labor-intensive.
As a result, the R&D team came up with the idea of developing a device that can directly detect arrester faults and avoid long-term power outages for users. After three years of technical research and repeated experiments, the new arrester was put into trial operation in 2019 and will be promoted for use in residential areas, small businesses, schools and other fields in Shanghai in 2021. Currently, more than 41,000 arresters have been installed.
"We have made technological innovations in the temperature control and hot-melt detachment systems in this product. We have developed a low-thermal melting point, highly sensitive nano-temperature-controlled hot-melt material. The melting point has been reduced from 220°C to 150°C, and it has been innovatively used in low-voltage arresters. field." Zhai Wanli said that when the heat generated by the leakage current of the faulty arrester reaches the melting point of the hot melt material, the arrester will automatically fuse from the line to avoid fire and combustion, which solves the technical problem that traditional disconnectors cannot achieve automatic fuse in the low-voltage field. .
In response to maintenance issues, the R&D team also designed three sets of independent, single-phase replaceable arrester structures, and developed a matching non-power-off maintenance tool - an insulated operating rod, so that traditional arrester maintenance can be replaced by a complete switch box to a faulty arrester alone. Replacement enables non-stop maintenance.
According to reports, it originally required 7 to 8 staff members and took 5 to 6 hours from inspection and emergency repair to sending a crane and changing boxes. Now, replacing a lightning arrester only requires 1 to 2 workers and can be completed in 3 minutes. The maintenance efficiency is increased by an average of 90% and the cost is reduced by 92%. In the five years since this achievement has been applied, there has never been an explosion or fire accident caused by arrester failure.
