Mga Uri ng High-Voltage Circuit Breaker at Gabay sa Mga Sakuna

High-Voltage Circuit Breakers: Classification and Fault Diagnosis

Ang mga high-voltage circuit breakers ay mahahalagang mga protective devices sa mga power systems. Sila ay mabilis na nag-i-interrupt ng current kapag may fault, at nagpapahinto ng pagkasira ng equipment dahil sa overloads o short circuits. Gayunpaman, dahil sa matagal na operasyon at iba pang mga factor, maaaring magkaroon ng mga fault ang mga circuit breakers na nangangailangan ng oportunong diagnosis at troubleshooting.

I. Klasipikasyon ng High-Voltage Circuit Breakers

1. Batay sa Lokasyon ng Pagsasakatuparan:

• Indoor-type: Nakasakatuparan sa mga enclosed switchgear rooms.

• Outdoor-type: Nilikha para sa external installation, may weather-resistant enclosures.

2. Batay sa Arc-Quenching Medium:

• Oil Circuit Breaker
  Gumagamit ng insulating oil bilang arc-quenching medium.

• Bulk Oil Circuit Breaker (Multi-oil): Ang oil ay ginagamit bilang arc-extinguishing medium at insulation sa pagitan ng live parts at grounded enclosure.

• Minimum Oil Circuit Breaker (Less-oil): Ang oil ay ginagamit lamang para sa arc extinction at contact insulation; ang external insulation (halimbawa, porcelain) ang nag-insulate ng live parts mula sa ground.

• Vacuum Circuit Breaker：Nag-eextinguish ng arcs sa high-vacuum environment, gumagamit ng mataas na dielectric strength ng vacuum. Malawakang ginagamit sa medium-voltage applications dahil sa matagal na buhay at mababang maintenance.

• Sulfur Hexafluoride (SF₆) Circuit Breaker：Gumagamit ng SF₆ gas—kilala sa excellent arc-quenching at insulating properties—bilang interrupting medium. Dominant sa high-voltage transmission systems para sa reliability at compact design.

• Compressed Air Circuit Breaker：Gumagamit ng compressed air para i-extinguish ang arc at magbigay ng post-interruption insulation. Mas kaunti ang ginagamit ngayon dahil sa complexity at maintenance needs.

• Magnetic Blow-Out Circuit Breaker：Gumagamit ng electromagnetic force para idrive ang arc sa narrow slits kung saan ito lumalamig at deionizes. Karaniwang ginagamit sa DC o specialized AC applications.

II. Common Faults and Troubleshooting of High-Voltage Circuit Breakers

1. Failure to Close (Refusal to Close)

Ito maaaring galing sa mga mechanical issues, control circuit faults, o operational errors. Suriin ang mga electrical control circuits at mechanical components.

Electrical faults include:

(1) Indicator light not working or abnormal

• Suriin kung ang control power voltage ay tumutugon sa rated value.

• Kung ang red light ay hindi lumiliwanag nang ang switch ay nasa "close" position, posibleng dahilan: open closing circuit o blown fuse.

• Kung ang green light (trip position) ay nawawala pero ang red light (close position) ay hindi lumiliwanag, suriin ang red lamp integrity.

• Kung ang green light ay nawawala at bumabalik, posibleng dahilan: low voltage o mechanical failure sa operating mechanism.

• Kung ang red light ay lumiliwanag nang maikling panahon at nawawala, at ang green light ay lumiliwanag, posibleng dahilan: mechanical fault o excessively high control voltage na nagdudulot ng impact failure.

(2) Closing contactor does not operate

• Kung ang green light ay off: suriin ang control bus fuses (positive/negative).

• Kung ang green light ay on: gamitin ang test pen o multimeter para suriin ang control switch, anti-pumping relay, auxiliary contacts, at suriin ang coil open circuit o secondary wiring break.

(3) Closing contactor operates but breaker does not move

• Posibleng dahilan: poor contactor contact, arc chute jamming, open closing coil, o blown AC fuse sa closing rectifier.

(4) Closing contactor operates, breaker moves but fails to close fully
Posibleng dahilan:

• Mechanical failure sa operating mechanism

• Low DC bus voltage

• Secondary wiring mix-up accidentally energizing trip circuit

• Improper operation (halimbawa, operator releasing control switch too early)

2. Failure to Trip (Refusal to Trip)

Mas mapanganib kaysa sa failure to close, dahil ito ay maaaring magresulta sa upstream breaker tripping (cascade tripping), at lalong lumalaking outage scope.

(1) Causes of failed electric trip

• Red light not lit: nagpapahiwatig ng open trip circuit.

• Suriin: lamp integrity, fuse, control switch contacts, breaker auxiliary contacts.

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

• Trip coil operates weakly: maaaring dahil sa high coil pickup voltage, low operating voltage, stuck trip plunger, o coil fault.

• Trip plunger moves but breaker does not trip: posibleng dahilan ay mechanical jamming o detached drive linkage pin.

(2) Handling refusal to trip

• Manual trip fails: Agad na ipaalam sa dispatch.

• Kung may bypass switch: ilipat ang load sa bypass, buksan ang bus-side disconnectors ng faulty breaker, at tripin ang bypass breaker para i-de-energize ang circuit.

• Upstream breaker trips due to cascade fault:

• Kapag walang power, buksan ang disconnectors sa parehong gilid ng 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)
Nagaganap kapag ang breaker ay tripping nang walang protection activation o operator action. Posibleng dahilan:

• Two-point DC grounding sa control circuit—suriin at alisin ang ground fault bago ireclose.

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

• Kung may ebidensya ng internal fault bagama't walang relay activation, suriin nang angkop.

(2) Unintended Closing (False Close)
Ang de-energized breaker ay nag-closing nang walang command. Dahilan:

• 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

Pangunahing sintomas: overheated tank (lalo na sa minimum-oil breakers), heated frame.

• Dahilan: Poor contact o oxidation sa conductive parts.

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

• Action: Strengthen patrols, detect early, at 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.

• Kung ang apoy ay nagsisimula lang: Agad na remotely tripin ang breaker.

• Kung ang apoy ay malubhang: Gamitin ang upstream breaker para i-isolate ang circuit, at buksan ang disconnectors sa parehong gilid para i-fully isolate ang unit. Extinguish with dry-type fire extinguisher (halimbawa, CO₂ o powder).

(2) Trip/Close Coil Smoking
Ang trip/close coils ay disenyo para sa short-time duty. Ang prolonged energizing ay nagdudulot ng overheating at burnout.

• Action: Agad na ipaalam sa dispatch at humiling ng replacement.

• Kung ang closing fuse ay nabubura sa panahon ng operasyon, palitan lamang ng specified rating—huwag gumamit ng oversized fuse upang i-prevent ang coil damage.

(3) Emergency Manual Trip Required
Agad na alisin ang oil circuit breaker mula sa serbisyo kung anumang sumusunod ang nangyari:

• Severe porcelain insulator cracking, flashover, o explosion

• Melting o disconnection ng 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.