DL/T 1176-2025 in English

DL/T 1176-2025 Standard Revision Background and Technological Evolution

DL/T 1176-2025 "Operation and Maintenance Procedures for 1000kV Oil-Immersed Transformers and Shunt Reactors" is an important technical standard in the field of ultra-high voltage AC transmission and replaces the 2012 version. This revision fully takes into account the actual needs of the rapid development of my country's ultra-high voltage power grid, and combines the accumulated operating experience of 1000kV oil-immersed transformers and shunt reactors to systematically optimize and improve the technical content.

Comparative Analysis of Major Technical Changes

In-depth analysis of operation technical requirements

Temperature control standards

The standard clearly stipulates The operating temperature limits for 1000kV oil-immersed transformers and shunt reactors are: 85°C for the top oil of the main transformer, 95°C for the voltage-regulating compensating transformer and shunt reactor, and 100°C for the neutral reactor. These temperature limits are based on the thermal aging characteristics of the equipment's insulation materials to ensure long-term reliability. The standard requires that the main unit's heavy gas protection device trip, the main unit's light gas protection device trip, and the on-load tap changer's oil flow relay trip. For protective devices such as sudden pressure relays and pressure relief valves, the standard stipulates that signals should be activated. This configuration ensures rapid fault clearance in the event of an equipment fault while avoiding unnecessary tripping.

Inspection System Architecture and Implementation Key Points

Four-Level Inspection System

The standard establishes a four-level inspection system consisting of daily inspections, periodic inspections, special inspections, and pre-commissioning inspections. Daily inspections focus on operating parameters and status parameters, regular inspections are conducted at least monthly, special inspections target severe weather conditions and abnormal operating conditions, and pre-commissioning inspections ensure that the equipment is in good initial condition.

Technical Requirements for Intelligent Inspection

The newly added maintenance requirements for the intelligent inspection system reflect the standard's technological foresight. They require inspections of system image clarity and analysis result accuracy, ensuring camera lens cleanliness, flexible controls, and proper sensor operation. These requirements provide technical support for the intelligent operation and maintenance of 1000kV transformers.

Key technical requirements of maintenance standards

Special maintenance cycle and content

Maintenance items	Maintenance cycle	Technical requirements	Standard basis
Thermometer calibration	Combined with power outage	Comply with DL/T 1400.3 requirements	Article 6.2
Gas relay inspection	2-3 years	Internal structure and action reliability inspection	Article 6.7
Pressure relief valve calibration	At overhaul	Comply with JB/T 7065 Requirements: Article 6.6 Water Spray System Inspection Monthly/Quarterly/Annual Grading Inspection Requirements Article 6.15 Emergency Oil Drain System Test Three-Year Electric Ball Valve Operation Test Article 6.16 Oil Chromatography Monitoring Technology Upgrade A new Appendix A specifies detailed thresholds and abnormal handling strategies for oil chromatography data. The cautionary and shutdown values for online monitoring data are 1 μL/L and 5 μL/L for acetylene, 150 μL/L for hydrogen, and 450 μL/L for total hydrocarbons. For acetylene gas, the standard specifically focuses on incremental changes, requiring appropriate measures to be taken when the weekly increment is ≥2μL/L. Standard Implementation Recommendations and Precautions Technical Management Recommendations When implementing the new standard, it is recommended that power companies establish a standard difference analysis mechanism, focusing on comparing the changes with the 2012 version of the standard and developing a detailed transition implementation plan. Particular attention should be paid to the newly added maintenance requirements for intelligent inspection systems and water spray fire extinguishing systems, which were not included in the previous version of the standard. Personnel Training Requirements In response to the new technical requirements in the standard, it is recommended to strengthen specialized training for operations and maintenance personnel, particularly for new technical content such as oil chromatography data anomaly handling strategies and intelligent inspection system maintenance. Training should focus on combining theory with practice to ensure that operations and maintenance personnel can accurately understand and implement the standard requirements. Equipment Upgrade and Retrofit For existing 1000kV oil-immersed transformers and shunt reactors that fail to meet the new standard, a plan for equipment upgrade and retrofit should be developed. Key considerations include adding external oil pipelines, improving water spray fire extinguishing systems, and upgrading intelligent inspection systems. Technical Value of the Standard and Its Industry Impact The release and implementation of DL/T 1176-2025 marks a further improvement in my country's UHV equipment operation and maintenance standards system. While retaining the essence of the original technology, the standard adds intelligent and refined operation and maintenance requirements, reflecting new trends in UHV power grid technology development. The implementation of the standard will effectively improve the operational reliability and safety of 1000kV oil-immersed transformers and shunt reactors, providing a solid technical foundation for the safe and stable operation of my country's UHV power grid. More samples: DL/T 368-2010 JGJ 94-2008 GB 50021-2001(2009) Sample only — not a preview of DL/T 1176-2025 Previous Page: 1 / 0 Next Zoom Out 100% Zoom In Search Loading PDF document... Error loading PDF. Please make sure the file is valid and try again. Terms of Service Privacy Cancellation & Refund Policy My Account About Us Contact Us All Rights Reserved © 2026 WWW.CHINASTANDARDS.NET