Pagsulay ug Pagkumision sa 10kV Dry-Type Transformers

Gikan sa James, 10 Ka Tuig nga Kasinatian sa Pag-maintain sa Electrical Equipment

Kamusta tanan, ako si James, ug nagsilbi nako sa pag-repair sa mga problema sa electrical equipment samtang 10 ka tuig.

Sa nakalabay nga dekada, nagtrabaho ko sa mga pabrika, substations, ug distribution rooms sa tanang sukal, na involbar sa installation, commissioning, maintenance, ug troubleshooting sa dry-type transformers. Ang dry-type transformers usa sa labi kumunon nga electrical devices nga atong gisulay sa adlaw-adlaw.

Karon, ang usa ka bag-ong kasinabantohan naka-usab nako:

“Nakadawat mi karon og bag-ong dry-type transformer — unsa ang dapat nako buhaton aron makahimo nako og installation ug commissioning? Unsa ang dapat nako pangutanaan?”

Usa kini ka praktikal nga pangutana, lalo na sa mga mosugyot sa karon nga industriya — sama sa “must-know” nga beginner topic. Busa, ipapahibalo nako ang tanan sa simple nga termino, batasan sa akong real-world experience sa nakalabay nga tuig, aron mas maayo ninyo mapahimulos ug trabahon ngadto sa confident.

1. Ano ang Dry-Type Transformer?

Pagsugyot ta sa usa ka quick introduction:
Ang dry-type transformer mao ang air-cooled, epoxy-resin insulated transformer, gigamit sa office buildings, hospitals, shopping malls, data centers — sa mga lugar diin importante ang fire safety.

Dili sama sa oil-immersed transformers, wala kini mogamit og insulating oil, kini lisod ug mas environmentally friendly. Apan, mas sensitive usab kini — lalo na sa humidity, ventilation conditions, ug quality sa installation.

2. Unsa ang Dapat Ihanda Bago ang Installation

Bago mo-start ang installation, importanti ang preparation. Ayaw magmadali — siguradoha nga klaro ang sumala sa mosunod nga puntos:

1. Unboxing Inspection

• Susiha kung ang packaging walay dani;

• Konfirmaha nga ang product certificate, manual, ug factory test report kompleto;

• Verifikaha ang nameplate parameters (capacity, voltage ratio, wiring group) match sa design requirements;

• Inspeksyonha alang sa bisan unsang physical damage, deformation, o rust;

• Siguradoha nga ang windings, busbars, fans, ug temperature controllers kompleto.

2. Environmental Inspection

• Ang installation site dapat dry ug well-ventilated, away sa direct sunlight;

• Walay corrosive gases o flammable/explosive materials nearby;

• Ang floor level ug load-bearing capacity meets equipment requirements;

• Humidity sa switch room dapat below 60% aron i-prevent ang insulation dampness;

• Kung posible, install dehumidifiers o space heaters.

3. Tools and Documentation

• Installation drawings, wiring diagrams, manufacturer technical manuals;

• Torque wrench, multimeter, megohmmeter, infrared thermometer;

• Ground resistance tester, insulating mat, personal protective equipment;

• Lifting tools (e.g., crane, hoist, lifting straps).

3. Key Steps During Installation

Ania ang standard installation process nga napuli ko sa nakalabay nga tuig:

Step 1: Positioning the Transformer

• Place the dry-type transformer on its pre-prepared foundation;

• Use a level to ensure it's properly aligned;

• Tighten mounting bolts and mark them for future inspection of looseness.

Step 2: Primary and Secondary Side Wiring

• Connect high and low-voltage cables according to the wiring diagram;

• Use a torque wrench to tighten terminals per specifications;

• Ensure correct phase sequence to avoid reverse rotation or short circuits during power-up;

• Wrap exposed parts with heat-shrink tubing or insulating tape;

• Use a multimeter to check continuity after wiring.

Step 3: Grounding System Installation

• The transformer enclosure and core must be reliably grounded;

• Use copper grounding wire ≥50mm²;

• At least two grounding points connected to the main grounding grid;

• Test ground resistance ≤4Ω using a ground resistance tester.

Step 4: Temperature Controller and Fan Wiring

• Insert temperature probe into designated hole and secure it;

• Pay attention to fan motor phase sequence to ensure correct airflow;

• Set alarm and trip temperatures (typically 130°C alarm, 150°C trip);

• Test fan start/stop function.

Step 5: Cleaning and Covering

• Clean internal dust and debris;

• Double-check all fasteners are tightened;

• Close cabinet door, label with device number, capacity, and purpose.

4. Key Points During Commissioning

Installation isn't the end — proper commissioning and testing are essential to ensure safe and reliable operation.

1. Insulation Resistance Test

• Use a 2500V megohmmeter to measure insulation between windings and ground, and phase-to-phase;

• Low-voltage side insulation ≥100MΩ, high-voltage side ≥500MΩ;

• If value is low, could be due to moisture — dry and retest;

• Record R15 and R60 values, calculate absorption ratio (R60/R15 ≥1.3).

2. DC Resistance Test

• Measure DC resistance of each winding;

• Detect open circuits, shorts, or poor connections;

• Three-phase imbalance should not exceed ±2%.

3. Voltage Ratio Test

• Verify voltage ratio matches nameplate;

• Identify turn-to-turn short circuits or incorrect wiring;

• Tolerance within ±0.5%.

4. No-Load Test

• Keep low-voltage side open, apply rated voltage on high-voltage side;

• Measure no-load current and losses;

• Determine if there's core damage or local short circuit.

5. System Integration & Trial Run

• Power up temperature controller and fan control system;

• Observe normal fan startup/shutdown;

• Run under light load for at least 2 hours;

• Use infrared thermography to monitor connection temperatures;

• Ensure no abnormal heating, noise, or vibration.

5. Common Issues and Solutions

From my field experience, here are some common issues and how to handle them:

6. My Suggestions and Experience Summary

As someone with 10 years of electrical equipment repair experience, I always say:

“Installation is the first step, commissioning is critical, and maintenance ensures reliability.”

Dry-type transformers may look simple, but their performance directly affects the stability and safety of your power system.

So here are my suggestions:

Installation Tips:

Follow manufacturer instructions and technical standards strictly;

• Pay attention to details like torque, phase sequence, and grounding;

• Better to spend an extra 30 minutes checking than to face emergency repairs later.

Commissioning Tips:

• Don’t skip any test steps, especially insulation and ratio tests;

• Keep complete records for future analysis;

• Closely monitor during trial operation and address issues immediately.

Maintenance Tips:

• Regular cleaning, especially around windings and air vents;

• Check fans, temperature controllers, and terminal blocks;

• Monitor hotspots with infrared thermometers;

• Maintain equipment logs and track performance trends.

7. Final Thoughts

Installing and commissioning dry-type transformers may sound technical, but once you understand the basic steps and precautions, it becomes manageable.

Remember this key message:

“Details determine success or failure; safety comes first.”

If you're dealing with similar issues on-site and aren’t sure how to proceed, feel free to reach out — we can work through it together and find the best solution.

May every time you close the breaker bring a smooth “click” — not a sudden “bang!”

— James