Core Mantra: Look Position → Listen Sound → Measure Temperature → Prevent Misoperation → Seal Openings
I. Structure at a Glance (Four Compartments + One Truck)
Component | One-Sentence Summary |
|---|---|
Busbar Compartment | Upper rear of cabinet, main busbar channel |
Breaker Compartment | Middle of cabinet, houses the breaker truck (core) |
Cable Compartment | Lower rear, incoming/outgoing cables + CTs/PTs |
Instrument Compartment | Upper front, protection relays + buttons + indicators |
Truck | Can be cranked in/out; has Service and Test positions |
II. Three Positions of the Truck (Must Memorize)
Position | Main Circuit | Secondary Circuit | Breaker Operable? |
|---|---|---|---|
Service Position | Connected | Connected | Can open; cannot close |
Test Position | Disconnected | Connected | Can open and close (for testing) |
Removed Position | Disconnected | Disconnected | Not operable |
⚠️ Before moving the truck, ALWAYS confirm the breaker is OPEN!
III. Daily Inspection – "Four Must-Dos"
No. | Action | What to Check |
|---|---|---|
① | Check Position | Truck indicator aligned; red/green lights normal; protection relay no alarms |
② | Listen to Sound | Normal: silent; Buzzing → discharge; Crackling → breakdown (EMERGENCY STOP) |
③ | Measure Temperature | IR scan busbars/cable lugs/contact boxes; temp rise ≤60K; phase difference ≤10K |
④ | Check Environment | No condensation inside; heaters working; cable holes properly sealed |
IV. Five-Protection Safety Interlocks (Never Break Any)
1. Prevent incorrect opening/closing of breaker
2. Prevent moving truck under load
3. Prevent closing earthing switch while energized
4. Prevent energizing with earthing switch closed
5. Prevent entry into energized compartments
🚫 Strictly prohibited to bypass or short-circuit any interlock!
V. Operation Taboos (Three Red Lines)
Red Line | Consequence |
|---|---|
❌ Crank truck while breaker is closed | Arc flash destroys contacts |
❌ Force-close breaker when truck is not fully seated | Poor contact → overheating → explosion |
❌ Open compartment doors while energized | Arc flash injury |
VI. Common Fault Quick Check (Three Questions)
Fault | What to Check |
|---|---|
Truck won't crank in/out | Is breaker open? Is earthing switch open? Any obstruction on rails? |
Won't close | Is spring charged? Control power on? Lockout light on? |
Discharge sound / burning smell | STOP POWER IMMEDIATELY! Check insulation, contacts, moisture. |
VII. Annual Must-Dos (During Power-Off Maintenance)
· Insulation resistance test (≥1000 MΩ)
· Tighten all busbar bolts
· Inspect tulip contacts (replace if blackened or loss of spring tension)
· Verify protection relay settings and perform trip tests
· Clean dust and replace desiccant
One-Sentence Summary:
Check truck position before any move; charge spring before closing; never tamper with interlocks; IR temperature scanning is your top priority.
