Safety Design Oil Cooled Power Transformer Installation

1. Core Precautions for Installation & Design

(1) Power Supply System Configuration

• Adopt the TN-S power supply system (three-phase five-wire system), which strictly separates the working neutral line (N) and the special protection line (PE) at the main power source. The PE line is dedicated to carrying fault current, ensuring equipment and personnel safety.

(2) Leakage Protection Implementation

• Follow the principles of three-level protection and “one machine, one switch, one leakage protector, one distribution box”.
• The leakage protector in the switch box adjacent to the transformer must have a rated leakage current ≤30mA and a leakage action time ≤0.1s (note: user’s “not less than 0.1s” is corrected to comply with safety norms—action time should be shorter for rapid protection).

(3) Safety Voltage Application

• In special occasions (e.g., humid, confined spaces), use power supplies that meet the corresponding safety voltage level. Safety voltage refers to the voltage that does not cause human body damage when touched without protective equipment.

(4) Compliance with Electrical Specifications

• All links (equipment manufacturing, installation, protection, location selection, power distribution classification, wire selection, wiring) must adhere to national and industry electrical specifications (e.g., GB 50150, IEC 60076).

(5) Sound Pre-Construction Management Systems

1. Construction organization design and safe electricity use technical measures.
2. Technical disclosure system (clarify design requirements and safety points to construction personnel).
3. Safety inspection system (regular inspection of equipment and wiring).
4. Electrical maintenance system (formulate maintenance procedures and records).
5. Project demolition system (standardize dismantling operations to avoid hazards).
6. Safety inspection and evaluation system (assess safety risks and rectify deficiencies).
7. Electricity safety responsibility system (clarify roles and responsibilities of all parties).

2. Standardized Installation & Design Procedures

(1) Pre-Construction Preparation

• Complete the 7 management systems mentioned above, and organize technical training and disclosure for construction personnel.
• Verify the quality of transformer equipment and accessories (e.g., windings, insulation oil, grounding parts) to ensure compliance with design requirements.
• Prepare construction tools (e.g., cranes, insulation testers) and safety protection equipment (e.g., insulating gloves, voltage detectors).

(2) Design Scheme Confirmation

• Determine the installation location (comply with distance requirements from buildings, flammables, and water sources) and power distribution classification based on load characteristics and on-site conditions.
• Optimize wire selection and wiring design (ensure wire cross-section matches current, and wiring is firm and insulated).

(3) On-Site Installation Implementation

• Install the transformer foundation (meet height, load-bearing, and drainage requirements) and fix the transformer securely.
• Complete wiring of the TN-S system, ensuring correct connection of N and PE lines, and reliable grounding of all iron components.
• Install leakage protectors, switches, and distribution boxes in accordance with “three-level protection” requirements.

(4) Post-Installation Inspection & Acceptance

• Conduct electrical tests (e.g., insulation resistance test, leakage protector action test) to verify compliance with specifications.
• Inspect the completeness of safety signs (e.g., high-voltage warning signs) and the effectiveness of protective measures.
• Organize acceptance by technical and safety personnel, and put into operation only after passing the inspection.