Installation of 110KV High-voltage Transformer

   Regarding the installation of the 110KV high-voltage transformer, strict technical specifications and safety standards need to be followed. The following are the core key points of the installation process and matters needing attention, which are sorted out in combination with the characteristics of the China-Thailand cooperation project as follows:

 I. Preparation before Installation

1. **Site and Foundation Acceptance**

    - Check the geological stability of the substation site (in the mountainous areas of western Thailand, the risk of landslides needs to be prevented).

    - The concrete foundation should comply with the IEC 60076 standard, and reserve grounding devices and fixing points for channel steel.

    - Considering the high-temperature and high-humidity climate in Thailand, the foundation should have a waterproof and moisture-proof design.

2. **Equipment Inspection and Transportation**

    - The transformer body and its accessories (bushings, radiators, etc.) need to pass the factory tests (such as withstand voltage test, partial discharge test).

    - Use a special bracket during transportation to ensure that the inclination angle does not exceed 15° (Some mountain roads in Thailand need to be surveyed in advance).

II. Core Installation Steps

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1. **Main Body Installation**

    - Use a crane to hoist the transformer onto the foundation, and adjust the levelness error to ≤1mm/m.

    - When installing the bushing, clean the surface and tighten the bolts according to the torque value specified by the manufacturer to avoid partial discharge.

    - In the Thai environment, special attention should be paid to preventing small animals (such as snakes) from entering the cabinet.

2. **Connection of Accessories and Systems**

    - Install radiators, oil conservators, and breathers (the silica gel desiccant needs to be replaced regularly).

    - The high-voltage side is connected by GIS (Gas Insulated Switchgear) or overhead lines, and it should comply with the wiring standards of EGAT in Thailand.

    - The neutral point grounding resistance value should meet the requirements of the system short-circuit capacity (usually ≤4Ω).

3. **Oil Filling and Vacuum Treatment**

    - Fill oil under vacuum to a slightly positive pressure state (the vacuum degree ≤133Pa, lasting for 24 hours).

    - The oil quality should comply with the IEC 60296 standard, and focus on detecting the dielectric loss and water content (in tropical regions, it needs to be controlled at ≤10ppm).

III. Debugging and Acceptance

1. **Electrical Tests**

    - Test the DC resistance of the winding (the deviation ≤2%), check the transformation ratio and polarity.

    - Conduct no-load loss and short-circuit loss tests to ensure an efficiency ≥99%.

    - Conduct the impulse closing test (at least 5 times, with an interval of 5 minutes each time).

2. **Joint Debugging of the Automation System**

    - Connect to the monitoring system (such as SCADA) of the National Power Dispatch Center (NSC) of Thailand.

    - The protection devices (differential protection, overcurrent protection) need to be set according to the fixed value list of EGAT.

3. **Environmental Protection and Compliance**

    - The waste oil treatment should comply with the Hazardous Waste Management Act of Thailand, and a professional recycling company should be used.

    - Noise control: ≤65dB at a distance of 3 meters from the equipment (additional sound insulation barriers are required in residential areas).

IV. Special Considerations for the China-Thailand Cooperation Project

1. **Localized Collaboration**

    - The Thai construction team needs to pass the safety training of Chinese power enterprises (such as the "Ten Prohibitions" regulations).

    - Key processes (such as bushing installation) require joint acceptance by Chinese and Thai technicians.

2. **Standard Connection**

    - Thailand implements the IEEE C57 series standards, and China needs to provide a comparison table of the differences between IEC and IEEE.

    - The metering device needs to comply with the certification of the Industrial Standards Institute (TISI) of the Ministry of Commerce of Thailand.

3. **Emergency Response**

    - During construction in the rainy season, waterproof canvas and drainage equipment should be equipped to prevent insulation parts from getting damp.

    - Establish a Chinese-Thai bilingual emergency contact mechanism to ensure a rapid response to failures.

V. Reference Materials

- Substation Design Specification of the Electricity Generating Authority of Thailand (EGAT)

- Construction and Acceptance Specification for Power Transformers (GB 50148) in China

- IEC 61378 Power Transformers - Part 2: Liquid-Immersed Power Transformers