Ċavjar tal-Kirka ta' Vakju: Kaużi u Soluzzjonijiet

Analizz tal-Falj u t-Troubleshooting ta' Breakers tal-Kurkunt tal-Vakju à la Malti

L-avvantaggi tal-breakers tal-vakju mhux biss fil-disenju mingħajr l-oli. Huma joffru wkoll ħajja elettrika u mekanika twila, forza dielektrika għoli, kapacità ta' interruzzjoni mgħaġdija qawwi, dimensjonijiet kompakta, pejs etnofu, id-daħil fit-operazzjonijiet frekwenti, prevenzjoni mill-inċendji, u manutenzjoni bassa – benefiċċji li saret rikonoxxuti sewwa mill-operatori tas-sistema tal-enerġija, personel tal-manutenzjoni, u inġiniera. L-ewwel breakers tal-kurkunt tal-vakju ad altu prodotti f’Ċina kienu jaffrontaw problemi ta’ kwalità instabbli, overvoltage kbir tal-kurmat tal-kurrent fit-operazzjoni, u tfittxija okkażjonali tal-interrupter tal-vakju.

Ivver, għall-konferenza ta’ promozzjoni ta’ l-applikazzjoni tal-switch tal-vakju fl-1992, teknoloġija ta’ produzzjoni tal-breaker tal-vakju ta’ Ċina kienu arrivi lill-frent internazzjonali, markanti l-punt tal-inflessjoni fil-applikazzjoni u l-ħsara tagħhom. Bil-użu diffuz tas-switches tal-vakju, jistgħu jiġu verifikati falj. Din l-artiklu analizza l-falj komuni u tgħatid soluzzjonijiet moħħija.

Kondizzjonijiet Abnormali Komuni ta’ Operazzjoni

1. Il-Breaker ma jkunx jista’ jiftaħ jew jisilġ (Refusal to Operate)：Waqt li jirċevi l-ordni ta’ ftit (jew tripp), il-solenoid ta’ ftit (jew tripp) joperagħ, il-plunger jirrilaxxa l-latch, u s-spring ta’ ftit (jew isilġ) tirdi l-enerġija biex tiġi mohħla l-mekanizmu. Iwa, l-interrupter ma jkunx jiftaħ (jew jisilġ).

2. Tripping Involontarju (False Tripping)：Il-breaker jisilġ bla segnali ta’ kontrol esterni jew operazzjoni manwali waqt is-servizz normali.

3. Il-Motor tal-Storage Jilġu Minflok wara t-tas-silġ tas-Spring：Wara l-iftit, il-motor jibda jilqas tas-spring. Anki wara l-enerġija tkompli, il-motor jilġu.

4. Rizzistenza DC Ikbar：Warqa’ l-operazzjoni, ir-rizzistenza tal-kontatt tal-interrupter tal-vakju tismigħ għad-daqqs.

5. Ħin tal-Bounce tal-IFT ikbar：Fil-ħin, id-daqqa tal-bounce tal-kontatt fit-ftit tismigħ.

6. Discharge mill-Pżejża tal-CT għal Support Bracket fil-Kamra ta’ fil-Mejdx：Waqt l-operazzjoni, jipprodotu l-arc bejn is-surface tal-current transformer (CT) u l-support structure fil-kamra ta’ fil-mejdx.

7. Interrupter tal-Vakju Ma Jkunx Jisilġ：Warqa’ l-ordni ta’ tripp, l-interrupter ma jkunx jisilġ jew jisilġ biss parti (operazzjoni ta’ fase wahda jew żewġ).

Analizz tal-Kausa tal-Falj

1. Refusal to Close or Open

Meta l-mekanizmu ta’ operazzjoni ma jkunx jopragħ, wisla l-ewwel li tivverifika x’huwa s-silġ fiċ-ċirkwit tal-kontroll sekondari (pereżempju, protection relay) jew komponenti mekanika. Wara tikkonferma li l-ċirkwit sekondari hu normali, sar ivver li kell spazju eċċessiv fil-universal joint li jikkonektja l-braccio prinċipali tal-mekanizmu. Anki meta l-mekanizmu joperagħ normalment, ma jkunx jiddivella l-linkage, li jgħadi blu failure ta’ ftit jew tripp.

2. Unintended Tripping

Fil-operazzjoni normali, il-breaker ma jkunx jisilġ bla ordni estern. Wara li sarru l-erruri tal-ħadd, inspezzjoni rivelat short circuit fil-kontatt tal-switch auxiliari fil-kaxxa tal-mekanizmu. Il-tripp coil ġie energized permezz ta’ din is-short, li l-aħħar sabbagħa l-false tripping. Is-silġ fundamentali kien l-ingress tal-mixja tal-xita fil-kaxxa tal-mekanizmu, li saret tafal fil-output crank arm u direttament fuq is-switch auxiliari, li sabbagħa l-contact shorting.

3. Storage Motor Continues Running After Spring Charging

Warqa’ l-iftit, il-motor tal-energy storage ibda. Meta l-spring tkun qiegħed, signal jindika l-komplut. Il-ċirkwit tal-storage inkludiv kontatt auxiliari normalment open mis-swith u kontatt limit switch normalment closed. Warqa’ l-iftit, il-kontatt auxiliari jagħti start lil motor. Waqt li l-spring tkun qiegħed, il-lever tal-mekanizmu jifftah il-kontatt normalment closed tal-limit switch, tagħmel power off lil motor. Jiġifieri, jekk il-lever ma jkunx jifftah dan il-kontatt, il-ċirkwit jiġi energized, u l-motor jilġu.

4. Increased DC Resistance

Il-kontatt tal-interrupter tal-vakju huma butt-type. Rizzistenza eċċessiva tal-kontatt tipprovoka overheat under load, li jiġi affettata l-conductivity u l-performance tal-interrupting. Ir-rizzistenza għandha tkun ta’ sotto speċifikazzjonijiet tal-manufacturers. Il-pressure tal-spring tal-kontatt influwenza sigur ir-rizzistenza u għandha timmissur permezz ta’ proper overtravel conditions. Gradually increasing resistance reflects contact erosion. Contact wear and changes in contact gap are the primary causes of rising DC resistance.

5. Increased Closing Bounce Time

A small amount of contact bounce during closing is normal, but excessive bounce can cause contact burning or welding. The technical standard limits closing bounce to ≤2ms. Over time, the main causes of increased bounce are reduced contact spring force and wear-induced clearance in levers and pins.

6. Discharge from CT Surface to Support Bracket

The middle chamber houses a current transformer (CT). During operation, uneven electric fields can form on the CT surface. To prevent this, manufacturers coat the surface with semiconductor paint to equalize the field. During assembly, space constraints may cause the semiconductor coating around mounting bolts to be scraped off, leading to field distortion and surface-to-bracket discharge during operation.

7. Vacuum Interrupter Fails to Open

Under normal conditions, the breaker should reliably interrupt current whether tripped manually or by protection relay.

Vacuum circuit breakers differ from other types by using vacuum as both insulation and arc-quenching medium. If the vacuum level drops, ionization occurs inside the chamber, generating charged particles that reduce insulation strength, preventing proper current interruption.

Troubleshooting and Solutions

1. Refusal to Close or Open：Inspect all connecting parts in the operating mechanism for excessive clearance. Replace worn components with new, high-hardness, qualified parts.

2. Unintended Tripping：Seal all potential rain entry points; install protective silicone sleeves on the output crank linkage; activate the heating and moisture-removal device inside the mechanism box.

3. Storage Motor Continues Running After Spring Charging：Adjust the position of the limit switch so that the lever fully opens its normally closed contact when the spring is fully charged.

4. Increased DC Resistance：Adjust the contact gap and overtravel of the interrupter. Measure contact resistance using the DC voltage drop method (with test current ≥100A) as specified in standards. If adjustment fails to reduce resistance, replace the vacuum interrupter.

5. Increased Closing Bounce Time：Slightly increase the initial pressure of the contact spring or replace it. If lever or pin clearance exceeds 0.3mm, replace these parts. Adjust the drive mechanism by shifting it slightly toward the dead center point in the closed position—where transmission ratio is minimal—to reduce bounce.

6. Discharge from CT Surface to Support Bracket：Evenly reapply a layer of semiconductor paint on the CT surface to restore uniform electric field distribution.

7. Vacuum Interrupter Fails to Open

If vacuum integrity is confirmed below required levels, replace the vacuum interrupter. Follow these steps:

• Ensure the new vacuum interrupter passes vacuum integrity testing before installation.

• Remove the old interrupter and install the new one vertically. Ensure alignment between the moving contact rod and the interrupter. Avoid torsional stress during installation.

• After installation, measure contact gap and overtravel. Adjust as needed:① Adjust overtravel via the insulating pull rod’s threaded connection.② Adjust contact gap by modifying the length of the moving conductive rod.

• Use a circuit breaker analyzer to measure opening/closing speed, three-phase synchronization, and closing bounce. Make further adjustments if results are out of specification.