Tipi ta l-Interruptur tal-Kors Elettriku ta'alta Tensjoni u Guida dwar l-Avverimentijiet

Kutturghaxxi ta' Tensjoni Alta: Klassifikazzjoni u Diagnostika tal-Falliment

Il-kutturghaxxi ta' tensjoni alta huma dispożitivi protettivi kritici fis-sistemi tal-enerġija. Jinterruppu l-korrent rapidament meta jwassal inċident, biex jiġboru d-danni tal-apparatu minn sovraccarichi jew short circuits. Però, għal effett tal-operazzjoni ta' lunga durata u fatturi oħra, il-kutturghaxxi jistgħu jiġu b'fallimenti li rikiedu diagnosi u soluzzjonijiet tempestivi.

I. Klassifikazzjoni tal-Kutturghaxxi ta' Tensjoni Alta

1. Skont il-Lokazzjoni tal-Installazzjoni:

• Tip Intern: Installati f'kamre enċlosi tal-switchgear.

• Tip Ester: Disegnat għall-installazzjoni esterna, bl-enċlożuri resistenti tal-meteo.

2. Skont il-Medju tal-Arc-Quenching:

• Kutturghaxx tal-Żejt
  Uża l-żejt insulatur kif-medju tal-arc-quenching.

• Bulk Oil Circuit Breaker (Multi-oil): Il-żejt serve bil-mod ta' medju tal-extinguishing tal-arc u insulazzjoni bejn parti live u enċlożuri mgroundati.

• Minimum Oil Circuit Breaker (Less-oil): L-żejt jintużaw biss għal extinguishing tal-arc u insulazzjoni tal-kontatti; l-insulazzjoni esterna (pereżempju, porċellana) tinsula parti live mid-ground.

• Vacuum Circuit Breaker：Jextingwi l-ark fi ambient ta' vacuum ħafi, jilqgħu mill-forza dielettrika ta' l-vacuum. Widament użat fil-applikazzjonijiet ta' tensjoni medja għal-ħajja tajba u manutenzjoni żgħira.

• Sulfur Hexafluoride (SF₆) Circuit Breaker：Uża l-gas SF₆—miftuh għal propjetajiet eccellenti ta' arc-quenching u insulazzjoni—bħala medium ta' interrupting. Dominant fis-sistemi ta' trasferiment ta' tensjoni alta għal-affidabilità u dissenj kompatt.

• Compressed Air Circuit Breaker：Employs compressed air to extinguish the arc and provide post-interruption insulation. Less common today due to complexity and maintenance needs.

• Magnetic Blow-Out Circuit Breaker：Uses electromagnetic force to drive the arc into narrow slits where it cools and deionizes. Typically used in DC or specialized AC applications.

II. Fallimenti Komuni u Soluzzjonijiet tal-Kutturghaxxi ta' Tensjoni Alta

1. Falliment tal-Ċessjon (Refusal to Close)

Dan jista' jipprovi minn problemi mekaniki, fallimenti fit-tielet kontroll, jew erori operattivi. Verifika s-sistema tieletta kontroll u l-komponenti mekanika.

Fallimenti elettriku jinkludu:

(1) Il-lamp tad-dinjura ma tgħix jew mhux normali

• Verifika jekk il-voltàġġ tal-control power tkun identika mal-valur ratifikat.

• Jekk il-lamp rossa ma tisfelx meta is-silġ huwa fl-“close” position, l-każi possibbli huma: opening closing circuit o blown fuse.

• Jekk il-lamp verda (trip position) tagħmel off ma dannekk sax-xita l-lamp rossa (close position) tfalleg, verifika l-integrity tal-lamp rossa.

• Jekk il-lamp verda tfalleg u tirrisetja: possibbli low voltage o mechanical failure in operating mechanism.

• Jekk il-lamp rossa tifleg b'mod brev u tagħmel off u l-lamp verda tifleg: il-breaker ikkompli momentanament ma dannekk sax-xita—probabbilment mechanical fault o excessively high control voltage causing impact failure.

(2) Il-closing contactor ma jagħmilx

• Jekk il-lamp verda hija off: verifika l-fuses tal-control bus (positive/negative).

• Jekk il-lamp verda hija on: uża test pen jew multimeter biex inspectja l-control switch, anti-pumping relay, auxiliary contacts, u verifika coil open circuit o secondary wiring break.

(3) Il-closing contactor agħmel imma l-breaker ma jmoviex

• Possibbli causes: poor contactor contact, arc chute jamming, open closing coil, o blown AC fuse in closing rectifier.

(4) Il-closing contactor agħmel, l-breaker jimove imma ma jkompliex close fully
Possibbli reasons:

• Mechanical failure in operating mechanism

• Low DC bus voltage

• Secondary wiring mix-up accidentally energizing trip circuit

• Improper operation (e.g., operator releasing control switch too early)

2. Falliment tal-Trip (Refusal to Trip)

Aktar perikolu mill-falliment tal-ċessjon, għaliex jista' jilġu l-trip tal-breaker ta' fuq (cascade tripping), bl-efett ta' zonni akbar ta' blackouts.

(1) Causes of failed electric trip

• Il-lamp rossa ma tgħix: indika open trip circuit.

• Verifika: integrity tal-lamp, fuse, control switch contacts, breaker auxiliary contacts.

• Verifika: anti-pumping relay coil, trip circuit continuity.

• Trip coil operates weakly: may be due to high coil pickup voltage, low operating voltage, stuck trip plunger, or coil fault.

• Trip plunger moves but breaker does not trip: likely mechanical jamming or detached drive linkage pin.

(2) Handling refusal to trip

• Manual trip fails: Immediately report to dispatch.

• If bypass switch available: transfer load to bypass, open bus-side disconnectors of faulty breaker, then trip bypass breaker to de-energize the circuit.

• Upstream breaker trips due to cascade fault:

• With power off, open disconnectors on both sides of the faulty breaker.

• Manually open all feeders on the affected bus.

• Report to dispatch for system restoration.

3. Unintended Opening or Closing (False Operation)

(1) Unintended Tripping (False Trip)
Occurs when breaker trips without protection activation or operator action. Possible causes:

• Two-point DC grounding in control circuit—check and eliminate ground fault before reclosing.

• Faulty interlock mechanism—isolate breaker (open source-side disconnector) and test close once.

• If evidence suggests internal fault despite no relay activation, investigate accordingly.

(2) Unintended Closing (False Close)
A de-energized breaker closes without command. Causes:

• Two-point DC grounding energizing closing circuit.

• Stuck auto-reclose relay contact.

• Low pickup voltage + high coil resistance, causing false closure during DC transient pulses.

4. Overheating of Circuit Breaker

Main symptoms: overheated tank (especially in minimum-oil breakers), heated frame.

• Cause: Poor contact or oxidation in conductive parts.

• Risks: Insulation damage, cracked porcelain, smoking, oil spraying, or even explosion.

• Action: Strengthen patrols, detect early, and address promptly.

5. Other Common Faults

(1) Oil Circuit Breaker Fire
Fire may result from dirty or damp bushings causing ground flashover, or internal arcing.

• If fire just started: Immediately remotely trip the breaker.

• If fire is severe: Use upstream breaker to isolate the circuit, then open disconnectors on both sides to fully isolate the unit. Extinguish with dry-type fire extinguisher (e.g., CO₂ or powder).

(2) Trip/Close Coil Smoking
Trip/close coils are designed for short-time duty. Prolonged energizing causes overheating and burnout.

• Action: Immediately report to dispatch and request replacement.

• If closing fuse blows during operation, replace only with specified rating—never use oversized fuse to prevent coil damage.

(3) Emergency Manual Trip Required
Immediately take oil circuit breaker out of service if any of the following occur:

• Severe porcelain insulator cracking, flashover, or explosion

• Melting or disconnection of conducting parts

• Loud internal arcing sounds

• Severe oil deficiency

Summary

This guide provides a comprehensive overview of high-voltage circuit breaker types, common operational faults, and corrective actions. Proper classification, regular inspection, and prompt troubleshooting are essential for ensuring system reliability, personnel safety, and equipment longevity.