Within one minute, the power grid automatically detects and locates the power supply fault, isolates the fault area, and restores the power supply to the non-fault area. Recently, the reporter learned from the State Grid Shandong Qingdao power supply company, by the end of this year, all 10 kV lines in Qingdao, Shandong will all have this power supply failure "self-healing" ability. This means that Qingdao distribution network fault "self-healing" ability has been comprehensively sunk to the "capillary" level, the coverage and application depth of the country's leading.

Fault "self-healing" is a basic capability for urban distribution network to become intelligent. The purpose is to realize uninterrupted power supply, so as to improve the power supply reliability of the entire city. In recent years, many Qingdao residents, especially those in urban areas, have had a clear feeling about the changes in electricity consumption: sudden power outages rarely occur, and obvious power supply instability, such as the flickering of lights, usually lasts only a second. These are largely related to the fault "self-healing" ability of Qingdao distribution network. In the past, when a power failure occurred in the distribution network and caused a power outage, the staff of the power supply company manually walked the lines to find the fault, then isolated the fault area and restored the power supply to the non-fault area. This process takes a long time, at least tens of minutes, more than several hours, not only users in the fault area can not use electricity, users in the non-fault area will also suffer a long time "affected blackout". Fault "self-healing" is done by automating the distribution network to reduce the process to less than one minute, meaning that users in non-fault areas of a line experience only a very brief flash of electricity, rather than being "blackouts".

If the urban distribution network is compared to the blood supply system of the human body, the 10 kV line is equivalent to the "capillaries" in this system, which connects the substations of the upper level and the residential communities. The significance that all 10 kV lines in Qingdao can realize fault "self-healing" is that the automatic fault location and isolation of the power grid and the power supply recovery capability of non-fault areas will be accurate to a smaller range such as the cell, further reducing the power failure impact, thus reducing the city's average power failure time, and improving the power supply reliability of Qingdao. It is estimated that the failure rate of all 10 kilovolt lines and the distribution areas radiated by the city will be reduced by more than 20 percent.

According to the staff of the transportation and inspection department of the State Grid Qingdao Power Supply Company, the "self-healing" capability of the distribution network involves both hardware and software transformation. In terms of hardware, according to the construction plan of Qingdao's world class city distribution network, all the 10 kV lines in Qingdao should be transformed from radial to ring network "handle", and the core area of the city should be transformed from simple ring network structure to double ring network, and real-time monitoring and control equipment such as fault indicator and automatic control terminal should be installed. In terms of software, a distribution automation system with data collection, analysis and judgment and automatic control functions has been built, and all 10 kV line control and monitoring devices are connected to the system. When a fault occurs, the power distribution automation system automatically locates the fault area based on the fault information, determines the fault and load transfer policy, and restores the power supply to the non-fault area by remote control.
Next year, Qingdao will further upgrade the "self-healing" capability of distribution network faults and promote the construction of the Internet of Things for distribution equipment, extending the "self-healing" capability of faults further to the "last kilometer" of power supply -- every single building in every residential community. When an anomaly occurs, every household will have access to the information in real time.
In addition, according to the introduction, the State Grid Qingdao power supply company also continuously enrich the distribution network equipment operating state detection means. The use of world-class partial discharge, infrared imaging, cable intelligent guard and other live detection technology, while ensuring the normal use of electricity for residents, real-time control of equipment operating conditions, find fault risk in advance through live operation maintenance or replacement, to ensure that residents' perception of power failure is further reduced.

(Source: Qingdao Full Search Electronic News)