Installation, debugging and acceptance standard of control cabinet in Thailand distribution project

The installation, debugging and acceptance criteria of control cabinets in Thailand power distribution project should be combined with local electrical codes, international standards and industry requirements. The following are the key points of comprehensive combing, covering legal basis, installation and debugging process and acceptance criteria:

I. Basis of Regulations and Standards

Thai local standard

TIS standards: electrical specifications formulated by the Thai Industrial Standards Association (TISI), such as:

TIS 113-2548 (Low-voltage switchgear and controlgear)

TIS 116-2548 (Electrical Safety Requirements for Rotating Electrical Machines)

NEC Thailand: refer to the localized version of National Electrical Code (NEC), which is suitable for low-voltage distribution systems.

The Electricity Authority of Thailand (EGAT) requires that the access standard for grid-connected equipment should conform to the distribution system specification of EGAT.

international standard

IEC 60439 (Assembly of Low Voltage Switchgear and Control Equipment)

IEC 61439 (Low-voltage switchgear and controlgear)

ISO 4150 (safety standard for electrical equipment)

Second, the preparation before installation and environmental requirements

environmental conditions

Temperature: -5℃~40℃ (indoor), -25℃~55℃ (outdoor need protection), humidity ≤95% (no condensation).

Altitude: ≤ 1000m. If it exceeds the altitude, it needs to be used with reduced capacity (for example, the heat dissipation design of the cabinet needs to be adjusted).

Protection grade: indoor IP31 or above, outdoor IP54/IP65, salt fog prevention in coastal areas (cabinet material can be 316 stainless steel).

Installation foundation

The cabinet should be fixed on a horizontal and solid foundation (such as channel steel base) with an inclination of ≤ 5.

Outdoor installation needs waterproof slope, and the foundation height is ≥150mm to prevent rain soaking.

III. Installation Specifications and Technical Requirements

Cabinet installation

Spacing: the spacing between cabinets is ≥800mm, the front operation channel is ≥1.5m, and the back maintenance channel is ≥600mm (in line with the requirements of TIS 113).

Grounding: Yellow-green double-color wires shall be used for cabinet grounding, with cross-sectional area ≥ 4 mm, grounding resistance ≤ 4 Ω (stipulated by EGAT), and the distance between independent grounding electrode and building grounding ≥ 5 m..

Electrical wiring

Cable selection: it shall conform to TIS 60228 (conductor classification), XLPE insulated cable shall be used for power line, and the control signal line shall be shielded (such as RVVP).

Wiring process:

Special tools are required for terminal crimping, and copper-aluminum nose is required for copper-aluminum transition. Direct connection is prohibited.

Color distinction of three-phase cables: A-phase yellow, B-phase green, C-phase red, neutral line blue, and grounding line yellow and green (same as IEC standard).

Bridge/trunking: Hot-dip galvanized material shall be used, copper braided tape (cross-sectional area ≥ 4 mm) shall be bridged at the joint, and the grounding continuity test resistance shall be ≤0.01Ω.

Component installation

Inverter, circuit breaker and other components should be fixed on the guide rail or bottom plate, installed vertically (inclination ≤ 5), and heat dissipation space ≥200mm should be left above.

Vulnerable components such as fuses and relays should be easy to replace, and the signs should be in Thai or Chinese and Thai (for example, "closing" and "opening" should be translated into """).

IV. Debugging Process and Test Items

Insulation test

Using a 500V megohmmeter to measure the insulation resistance between phases and ground, it is required to be ≥10MΩ(TIS 113 standard), and it can be relaxed to ≥1MΩ in humid environment, but it needs to be recorded and rechecked.

Grounding system test

Grounding resistance ≤ 4Ω (required by EGAT), and ≤10Ω in case of lightning protection grounding, use grounding shaking table (such as Fluke 1623) to test.

functional test

No-load debugging:

Turn on the control power supply, and check that the Thai display on the display screen (such as touch screen) is normal and the parameter setting function is effective (such as voltage and frequency display should meet the Thai power grid standard: 380V/50Hz).

Test the start-stop button and emergency stop button, and the response time is ≤0.5 seconds. When emergency stop, cut off the power supply of the main circuit (meeting the safety requirements of TIS 116).

Load test:

Connect the motor load, test the functions of variable frequency starting and soft starting, and the peak starting current is less than or equal to 3 times of the rated current (EGAT limits the motor starting).

Measure the voltage fluctuation during operation: the three-phase voltage imbalance is ≤3%, and the frequency deviation is ≤±0.5Hz.

Protection function verification

Simulate overload (1.1 times rated current), short circuit (10 times rated current), phase loss, overvoltage (110% rated voltage) and undervoltage (85% rated voltage). The equipment should be stopped within 10 seconds and give an alarm. The fault code should be displayed in Thai (such as ""for phase loss).

V. Acceptance criteria and document requirements

Appearance and structural acceptance

There is no scratch on the surface of the cabinet, the paint surface conforms to TIS 10007 standard, and the protection grade is clearly marked (for example, "IP54" should be marked in Thai).

There is no sundries inside, the noise of the cooling fan during operation is ≤65dB (measured at a distance of 1m), and the ventilation holes are not blocked.

Safety protection acceptance

The live parts should have insulation sheaths, and the high-voltage areas (such as copper bars) should have Thai warning signs (such as "High Voltage Danger") when the cabinet door is opened.

The control cabinet used in explosion-proof places shall conform to the Thai explosion-proof standard TIS 60079, and the explosion-proof certification documents (such as Ex d IIC T6) shall be certified by TISI.

Document acceptance

Technical documents in Thai are required, including:

Factory certificate (including TISI certification mark) and instruction manual (Thai translation).

Electrical schematic diagram (marked with Thai component name) and wiring diagram (cable color and terminal number should be consistent with the real thing).

Debugging records (including data of insulation test, grounding resistance test and function test) shall be signed by local supervision engineer in Thailand.

Grid-connected projects need to provide access permission documents of EGAT and harmonic test report (THD≤5%, in line with EGAT's restrictions on power grid pollution).

Trial operation and final acceptance

Test run for 72 hours without failure, and record the operation data (voltage, current and temperature), and the fluctuation range should be within 5% of the rated value.

After acceptance, Thai version of operation training (such as startup process and fault handling) shall be provided to Thai owners, and the warranty period is usually one year (it can be extended to two years through negotiation).

VI. Supplementary Requirements for Special Scenes

Tropical climate adaptation:

The cabinet should be equipped with a temperature-controlled fan (starting temperature ≥40℃), and a heating dehumidifier (starting when humidity ≥70%) can be installed inside to prevent condensation.

Lightning protection requirements:

The outdoor control cabinet shall be equipped with a surge protector (SPD) with a nominal discharge current of ≥10kA(8/20μs waveform). The grounding terminal is shared with the cabinet grounding, but a separate lead shall be provided to the lightning protection grounding electrode.

Summary of acceptance process

Self-inspection by the constructor (according to TIS standard) → 2. Initial inspection by Thai supervisor (document review+visual inspection) → 3. Insulation/grounding test (report issued by a third-party inspection agency) → 4. Function and load test (on behalf of the owner) → 5. Trial operation (EGAT grid-connected projects need to submit operation data synchronously) → 6. Final acceptance (signing the Thai version of the acceptance report).

As the electrical specifications in Thailand refer to IEC standards, the localization requirements (such as language, certification and power grid parameters) need special attention. It is recommended to communicate with local power departments (such as EGAT) or TISI certification bodies in advance to ensure compliance.