This project belongs to the field of power system relay protection maintenance. With the widespread application of automation, integration, and intelligent technologies and devices in the field of relay protection, the requirements for the ability level of maintenance teams are becoming higher and higher. Especially in recent years, Internet +, Internet of Things, and 5G technologies have swept across the country. The maintenance industry will usher in unprecedented opportunities, and the relay protection maintenance model will also undergo fundamental changes. In this context, this project has been developed and practiced for more than ten years, and has gone through three stages with different focuses. The first stage focuses on various bottleneck problems faced in the maintenance of mainstream new microcomputer-based relay protection devices to solve technical bottlenecks. The second stage mainly focuses on solving bottlenecks in maintenance equipment and invented a number of efficient tooling; the third stage uses big data as the starting point to create a digital operation and maintenance platform, piloting the transformation from preventive maintenance to condition-based maintenance and even intelligent maintenance. The main innovations include: Technical achievements: invented efficient maintenance practical technologies such as integrated verification technology for grounding direction relays, differential protection harmonic braking voltage method test circuits, and high-impedance current loop maintenance processes, which solved key technical bottlenecks in the project implementation process. This project also proposed for the first time the five principles for generator electrical starting test, which can enable the generator to be connected to the grid to generate electricity six hours in advance, saving 1998 thousand cubic meters of blast furnace gas leakage and 151.2 tons of light oil loss, effectively reducing blast furnace gas emptying, light oil combustion cost loss and environmental pollution caused. Tooling achievements: A series of special equipment for relay protection maintenance represented by AC micro current generator have been invented, making maintenance simpler and more efficient, and greatly improving maintenance accuracy. In order to solve the verification problem of small current devices, ldquo; AC micro current generator rdquo; was developed. On this basis, a series of special equipment such as ldquo; AC micro voltage generator rdquo;, ldquo; new power tester rdquo;, ldquo; new grounding direction verification device rdquo; was developed. Among them, ldquo; AC Micro Current Generator rdquo; solves the problem of sudden distortion and discontinuity of output waveforms below AC 6ma of instruments at home and abroad. After novelty research, comprehensive technology is leading in China. Model breakthrough: Transformation from point-inspection and maintenance with ldquo; people-rdquo; as the core to a digital operation and maintenance platform with ldquo; datardquo; as the core. Spot inspection and scheduled maintenance with ldquo; people-rdquo; as the core is currently the mainstream maintenance model at home and abroad. With the arrival of Internet + and the real pressure of smart manufacturing and green manufacturing faced by Baosteel, it is moving towards digital operation and maintenance with ldquo; data-rdquo; as the core., is an inevitable trend in maintenance transformation. The ldquo; Relay protection maintenance big data platform rdquo;, ldquo; 10KV large wind turbine intelligent remote monitoring platform rdquo;, ldquo;BG-III transformer oil online intelligent monitoring system rdquo;, ldquo; on-site maintenance environmental risk management and control cloud platform rdquo; developed and applied in this project, etc., have made active practices in this regard. Actively docking and adapting to the new equipment condition management and control model, rather than passively participating in maintenance, will be a major opportunity for relay protection maintenance. This project has obtained 1 invention patent authorization and 4 utility model authorizations. 5 of the other 8 invention patents have been substantively reviewed and 3 inventions have been announced. The project has also obtained 13 corporate technical secrets. Many achievements of this project have won gold and silver awards at home and abroad invention exhibitions. The comprehensive technical level of this project is at the leading domestic level and internationally advanced level. The results of this project were first successfully applied in the maintenance of 5 generating units of Baosteel Power Plant, Baosteel Central Substation, and 35KV and 10KV power systems in various secondary plants, and were promoted to Units 1 and 2 of Baosteel Zhanjiang Power Plant, Ningbo Iron and Steel's CDQ Power Generation, and Power Plant Units 1 and 4, Xinjiang Bayi Power Plant, Fujian Chuangguan Environmental Protection Co., Ltd., Shanghai Jiangqiao Environmental Renewable Energy Company, Nanhui Laogang, Jinshan, Chongming Environmental Energy Co., Ltd. and other internal and external markets. From January 2016 to December 2018, the new output value was 78.181 million yuan.