Chinese power grids incur losses due to poor lightning protection quality
China's power companies faced the problem of poor efficiency of lightning protection devices installed in local distribution lines. As shown by practice, the non-linear surge arresters applied in China are often not capable to withstand overvoltages induced by direct lightning strikes.
As per scope of application, surge arresters may be divided into two types. Ones are intended to protect the expensive equipment, while the others protect power lines directly from lightning impacts. As Mikhail Zhitenev, Streamer expert on lightning protection equipment installation, said, the expensive equipment is usually equipped with high capacity top-quality surge arresters efficient at their task. As for power lines, electric engineers mount cheaper devices trying to save money. For example, the multi-chamber LLPDs' discharge capability is 2-3 times as high as that of such arresters.
The thing is that non-linear surge arresters and varistor manufacturers have driven themselves into a hopeless price race, Mikhail said. Apart from bona fide manufacturers, there appeared companies in the market who fail to follow high requirements for lightning protection products.
"This in no way blackens bona fide producers, but due to enormous extent of the market and high competition, the Chinese power engineers often face poor quality products," Mikhail Zhitenev said.
China's energy companies pay heavy prices due to quality problems of the purchased products. In one province, it is a common practice to replace all lightning protection devices along the entire line once the number of outages exceeds those of the previous years. This is due to the fact that region's electricians have a plan for the maximum allowable number of outages for 100 kilometers of lines per year, which is a key indicator of their work efficiency. Therefore, the local specialists are in constant search for the most rational ways to use funds intended to increase the lightning performance of lines, and they have already appreciated the Streamer products.
The outcomes of experimental-industrial operation of multi-chamber devices in the vicinity of Guangzhou city have proved the efficacy of these products, and experience of subsequent operation of the equipped lines confirms both the technology reliability and high quality of the delivered products.
Note that first LLPDs were installed in Guangzhou in the summer of 2013. Since then, the number of LLPDs installed in the region have increased at least twice each year, and the number of interruptions in the modified lines has not exceeded the set standards.