How to ensure that the installation and debugging process of control cabinet in Thailand distribution project meets international standards?

When installing and debugging the control cabinet of power distribution project in Thailand, it is necessary to strictly control it from many dimensions, such as specification compliance, technical implementation and quality control, to ensure that it meets international standards. The following is a systematic scheme combining international standards (such as IEC and ISO) with local requirements in Thailand, covering key points of the whole process:

First, preliminary preparation: standard system and compliance planning

Clarify the connection between international standards and local regulations

Core international standards:

Electrical safety: IEC 61439 (low-voltage switchgear) and IEC 60204 (mechanical electrical safety).

Electromagnetic compatibility: IEC 61800-3 (EMC requirements for frequency converters) and CISPR 32 (EMI limits for information technology equipment).

Protection level: IEC 60529(IP code, consistent with TIS 10007 protection standard).

Key points of localization compliance:

For the compulsory certification of imported equipment by TISI (such as TISI Mark certification), the TISI number shall be marked on the nameplate of the control cabinet.

Grid connection shall conform to the Specification for Low Voltage Distribution System of EGAT, such as voltage deviation of 10% and frequency of 50Hz±0.5Hz.

Standardization of technical documents

The design drawings shall conform to both IEC drawing standards (such as IEC 61346) and drawing specifications of Thailand Power Bureau (such as marking cable color code and terminal block number in Thai).

Component selection should be accompanied by international certification documents:

Circuit breakers and contactors shall be certified by CE, UL or VDE, and frequency converters shall conform to IEC 61800-5-1.

Components in explosion-proof occasions shall meet IEC 60079 explosion-proof standards and pass the Ex certification of TISI.

Second, the installation stage: the implementation of international standards.

1. Cabinet installation and environmental adaptation

Space and layout:

The width of the operation channel is ≥ 1.5m (as required by IEC 61439-1), the maintenance channel is ≥0.8m, and the distance from the wall is ≥0.6m, so as to ensure the ergonomics (ISO 6385).

The outdoor cabinet shall meet the IP54/IP65 protection of IEC 60529 and pass the tropical climate test in Thailand (for example, refer to Appendix B of TIS 113 for ultraviolet aging test).

Grounding system:

TN-S system (IEC 60364) is adopted, the protective grounding (PE) is separated from working grounding (N), and the grounding resistance is ≤ 4Ω (required by EGAT, equivalent to IEC 61010).

The connection between the cabinet body and the grounding trunk line needs copper braided tape (cross-sectional area ≥ 16 mm), and the joint is tinned to prevent oxidation (in accordance with IEC 60439-1).

2. Electrical wiring process

Cable selection and laying:

The insulation grade of power cable shall be ≥90℃(IEC 60228), and the control cable shall be shielded (such as RVVP cable specified in IEC 60227) to prevent EMI interference (IEC 61800-3).

The bridge/trunking shall conform to IEC 61537, made of hot-dip galvanized material, with copper braided tape (cross-sectional area ≥ 4 mm) and grounding continuity resistance ≤0.01Ω(IEC 61439-1).

Terminal connection:

Transition terminals (such as OT2.5-4 copper-aluminum nose) must be used for copper-aluminum connection, and direct crimping (IEC 60999-1) is prohibited.

The color code of three-phase cable strictly follows IEC 60446: A-phase yellow, B-phase green, C-phase red, zero line blue, PE line yellow and green, and Thai logo should be corresponding (such as ""marking zero line).

3. Components installation specification

Electronic components such as frequency converter and PLC are installed vertically, with an inclination of ≤ 5, and the heat dissipation space at the top is ≥200mm(IEC 61800-5-1).

Vulnerable parts such as fuses and relays shall be installed on detachable guide rails, with the height from the ground of 1.2~1.8m(ISO 6385 Man-Machine Height Standard), and the signs shall be in Chinese and Thai (such as ""for overvoltage).

Third, the debugging stage: testing and verification of international standards

1. Safety and insulation test

Insulation resistance test:

Use a 500V megohmmeter (IEC 60664-1) to measure phase-to-phase and ground insulation, with requirements of ≥10MΩ (dry environment) and ≥1MΩ (environmental temperature and humidity shall be recorded in accordance with IEC 61439-1).

Grounding system test:

The four-pole method is used to measure the grounding resistance (IEC 62305-3). The power frequency grounding resistance is ≤4Ω, and the lightning protection grounding is ≤10Ω. The testing instrument needs to be calibrated by the ISO 17025 certified laboratory.

2. Function and performance testing

No-load debugging:

After controlling the power supply, verify the accuracy of HMI display in Thai, and the parameter setting function conforms to IEC 61131-3 programming standard (for example, the frequency setting range is 0~50Hz).

The response time of the emergency stop button is ≤0.5 seconds, and the power supply of the main loop is cut off and locked (IEC 60204-1 safety requirements).

Load and grid connection test:

When the motor is started, the peak starting current is ≤3 times the rated current (IEC 61800-2), and the three-phase voltage imbalance is ≤3%(IEC 61000-3-3).

Grid-connected projects need to test the harmonic distortion rate (THD)≤5%(IEEE 519 standard, EGAT synchronization requirements), and use a harmonic analyzer conforming to IEC 61000-4-7.

3. Electromagnetic compatibility (EMC) test

The enclosure of the control cabinet must pass the IEC 61000-6-3 (emission limit) and IEC 61000-6-2 (immunity limit) tests, focusing on suppressing conducted interference (150kHz~30MHz) and radiated interference (30MHz~1GHz) generated by the frequency converter.

The signal wire should be twisted and run through the metal bellows, and the distance from the power wire should be ≥30cm(IEC 61800-3) to prevent EMI coupling.

Fourth, quality control: process supervision of international standards

Third-party authentication and testing

Entrust a laboratory with ISO 17025 qualification to test key projects (such as insulation, grounding, EMC) and issue a test report meeting IEC standards.

The explosion-proof control cabinet shall be tested by an organization recognized by TISI, and conform to IEC 60079-0/-1/-14, and shall be provided with explosion-proof marks such as Ex d IIC T6.

Stage acceptance and record

Implement the acceptance process specified in IEC 61439-1 in stages:

Design document review (drawings and component list meet IEC standards).

Incoming inspection (complete certification documents for cables and components).

Inspection of installation process (grounding and wiring processes conform to IEC 60364).

Debugging report review (test data must meet IEC limits).

All records should be bilingual (English+Thai), and key data (such as insulation resistance and grounding resistance) should be attached with test curves (in line with ISO 9001 recording requirements).

Personnel qualification and training

The construction team shall have international certification qualification:

Electricians must hold IEC-recognized low-voltage electrician certificates (such as VDE 0105-100) or pass the electrician qualification examination of Thai Ministry of Energy (DE).

Debuggers should be trained in IEC 61800 series standards and be familiar with the parameter setting of frequency converters (such as IEC 61131-3 programming).

V. Special Scenarios: Adaptation of International Standards to Local Needs

Tropical climate adaptability

A temperature-controlled fan is installed inside the cabinet (starting temperature is 40℃, stopping temperature is 35℃, which conforms to IEC 60721-3-3 climate grade), and it has passed the high-temperature operation test of TIS 113 (continuous operation at 40℃ for 24 hours without failure).

Electrical components shall be damp-heat resistant (such as insulation materials conforming to IEC 60216-1, heat-resistant grade B or above), and PCB board shall be sprayed with three-proof paint (moisture-proof, mildew-proof and salt spray-proof).

Lightning protection and grounding strengthening

Outdoor cabinets shall be equipped with surge protector (SPD) conforming to IEC 61643-1, with nominal discharge current In≥10kA(8/20μs) and grounding lead length ≤0.5m(IEC 62305-3).

The lightning protection grounding network shall be set independently, with a distance of ≥ 5m from working grounding (IEC 60364-5-54) and passed the lightning protection certification of Thailand Meteorological Bureau (TMD).

VI. Final Acceptance: Confirmation of compliance with international standards

Acceptance of file system

Completion documents conforming to ISO 9001 shall be submitted, including:

IEC standard compliance statement (stating compliance with IEC 61439, IEC 60204, etc.).

Thai version of the operation manual (including IEC standard reference chapters, such as ""corresponding to IEC 60204-1 overvoltage protection).

Third-party test report (IEC standard number is required for EMC, insulation and grounding test results).

Trial operation and performance verification

After 72 consecutive hours of trial operation, the recorded data shall meet the following requirements:

Temperature: the temperature of the components inside the cabinet is ≤70℃(IEC 60068-2-1 temperature rise requirement).

Noise: 1 meter away from the cabinet ≤65dB(ISO 11201 industrial noise standard).

Grid-connected projects shall submit a harmonic test report conforming to IEC 61000-3-6 to EGAT to confirm that THD is ≤ 5%.