Distributed differential protection protection can realize the accurate positioning and fast isolation of the fault section of the distribution line，is the best choice to solve the current power protection problem of distribution network。Differential protection requires real -time exchange data between protection devices，Only fiber channels before met this high requirements，But there are more cloth points、Difficulty laying、Investment big、long cycle and many difficulties。5G communication has high bandwidth、Low latency、High reliability and other characteristics，It provides a new opportunity for solving the problem of the network difference protection channel。Professor Gao Houlei team of the School of Electrical Electrical Electrical Institute and the power grid company and manufacturer，The first application research in the protection of 5G communication in the distribution network in China; after more than two years of hard work，Developed and developed a new type of distribution differential protection device based on 5G slicing networks and faults，Get the national invention patent authorization，and pilot the network in June 2020。
In order to further evaluate the detection ability of the real failure of the power grid for further assessment，March 19，State Grid Qingdao Power Supply Company、State Grid Shandong Institute of Electric Sciences、Shandong University jointly organized the first domestic 10kV line artificial short circuit test and achieved success。This is after the team successfully implemented the first domestic cross -base station 5G communication differential protection test in October 2019，Major breakthroughs obtained in engineering applications，It marks that the results have engineering application conditions。
Test at the Gujia Transformation Power Station of Huangdao Military -civilian Integration Zone, Qingdao City, 10KV Kang Line。This line is a pilot project for the pilot project of Qingdao Power Supply Company 5G differential protection pilot project，Investment in two sets of 5G communication differential protection devices developed by the team in T1 and T1-01 Circle Network Cabinet，Loaning through a 5G special slicing network between the devices。Practice a short circuit of labor single-phase grounding ground through the T1-01 loop network cabinet bus，Make the fault point in the interior of a protective inner and another set of protected external，At the same time, evaluate the differential protection performance of the two sets of protective devices，Including communication delay and reliability、Data synchronization error、Failure recognition ability inside and outside the section、Protective action time、Technical indicators such as failure isolation time。
According to the test plan，Perform neutral points and unscrupulous ways to place orders for phase metallic grounded short circuit and small resistance under the local sectors of 0Ω、500Ω、500Ω、900Ω transition resistance single -phase grounding short circuit test。In all short -circuit faults implemented，The response of the two sets of protection devices is all correct; the time of fault protection in the area is 33-51ms，average 39.8ms; fault cutting time is 71-90ms,average 79ms; the average delay from the 5G communication terminal to the end is 10.35ms,Protective device end -to -end communication delay is 12.3ms; the data transmission packet loss rate is 0，Reliability is 100%; in low -resistance, the measurement error of the same amount at both ends is less than one sampling interval (3 & ordem;)，The synchronization error between the two ends of the two ends is not more than two sampling intervals (6 & ordem;)。
Test data indicates，Various performance indicators developed by 5G communication differential movements developed have reached the expected goal; three aspects of innovation design have been fully verified。First, adopt adaptive current mobilities，It can correctly determine the short circuit between phases and can be sensitive to respond to the single -phase grounding failure under the small resistance，Allows the transition resistance capacity of 1000Ω; the second is to use the fault time self -synchronization method，Synchronous detection accuracy of actual fault current is within 2 sample points，Meet engineering application requirements; third, the 5G URLLC section network is used as a data channel，Fast and fast -moving protection movements、Reliable，Realized the outlet within 60ms and faulty isolation in 100ms。The test results are further confirmed，5G Differential Protection of the application and promotion of the distribution network for the elimination of the protection of the more than the closing of the card、Short the failure of the failure to stop the power outage、Reduce the risk of personal electric shock、Relieving the reliability of power supply has an important supporting role，It will produce huge economic and social benefits。
State Grid Qingdao Power Supply Company、State Grid Shandong Institute of Electric Sciences、Shandong University、State Grid Huangdao District Power Supply Company、Shandong Kehui Company、The University of Petroleum (East China) and other units participated in and witnessed the trial process。
1. The test staff is in place 2. Set a short-circuited ring network cabinet T1-01
3. On -site ground control switch and ground phase cable 4. The ground point and transition resistance 
5. T1-01 Condor Network Cabinet Protection Device Monitoring Live 6. T1 ring network cabinet protection device monitoring site
7. Metal -phase ground failure diagram in the neutral point non -grounding system area
8. Single -resistant ground system area alone goes through 500ωDisproofing wave diagram of the transitional resistance area
