A standardized inspection process comprises five stages:
Pre-inspection Preparation: Review equipment technical records, formulate an inspection plan, and verify safety measures.
Visual Inspection: Examine the condition of visible components, such as the equipment enclosure, insulating parts, and connection points.
De-energized Testing: Systematically conduct tests requiring power disconnection-including insulation testing, circuit resistance measurement, and mechanical characteristic testing.
Energized Testing: Execute online monitoring procedures, such as infrared thermography and ultrasonic partial discharge detection.
Data Analysis: Compile inspection data and compare it against historical records and standard reference values. Specific operations must strictly adhere to the principle of "low voltage before high voltage, and static testing before dynamic testing." For circuit breaker inspections, a minimum of five opening and closing operations must be performed to assess operational stability.
The inspection of power distribution equipment must comply with a multi-tiered system of standards:
International Standards: The IEC 62271 series (High-voltage switchgear and controlgear) and IEC 60439 (Low-voltage switchgear and controlgear assemblies).
National Standards: GB/T 11022-2020 Common Specifications for High-voltage Switchgear and Controlgear Standards and GB 50150-2016 Standard for Commissioning Tests of Electrical Equipment in Electrical Installation Engineering.
Industry Standards: DL/T 596-2021 *Procedures for Preventive Tests on Electric Power Equipment* and DL/T 393-2020 *Procedures for Condition-based Maintenance Testing of Transmission and Transformation Equipment.
Operational Specifications: Q/GDW 1168-2013 .Procedures for Condition-based Maintenance Testing of Transmission and Transformation Equipment, as well as other corporate standards established by power grid companies. For power distribution equipment situated in special environments, reference must also be made to relevant industry standards addressing specific environmental requirements.
