Unsa ang mga paagi sa pag-awhag sa kaso sa current transformers?
Isipag-utana sa mga kahibalo sa pagpangita sa kasala, ang among gibuhat kada adlaw mao ang pagtumong sa mga current transformers (CTs). Ang secondary winding sa CT nga nagoperasyon dili pwede mag-open circuit! Kon mag-open circuit na, ang secondary current ug demagnetizing potential mosunod. Ang tanang primary-side magnetic potential mosunod isip exciting potential sa iron core, naka-increase ang iyang magnetic flux density. Ang taas nga voltage sa secondary side magdudulot og panganak sa kalambigitan anytime.
Bisan kon may strict nga mga regulasyon sa power operation, ang mga electrician sa user adunay dili maayo nga management ug teknikal nga kalidad. Bisag molihok na ang power operation market, ang mga design units adunay dili maayo nga pagdesign, ug ang installation teams dili mogamit sa mga drawing o safety measures. Busa, ang CT accidents sa panahon sa operasyon walay limitado nga mobusog. Ang usa ka typical capacity-increase project accident nga gi-handle ko niadto ililisay kini, ug ipabahin nako.
1. Pagdiskubre sa Kasala: Ang Lugar sa Naka-burn nga Transformer
Sa Setyembre 27, 2012, ang among engineering installation company nagsugyot og substation capacity-increase project. Sa panahon namo og pagcut-off sa power aron mopalit sa CT sa incoming line cabinet, giguol ko kini ug nakita nako nga ang CT giburn beyond recognition! Nagmaintain na ko sa daghan nga tuig, nakita nako daghan na nga burned-out, apan ang CT nga nagburn out suddanan dili normal, kini kinahanglan dugayan sa mas sayon nga pagdiskubre sa rason.
2. Pagsusi sa Rason: Man-made Open Circuit + Management Chaos
(1) On-site Investigation, Locking on "Secondary Wires Cut"
Ang akong team ug ko mi nagconduct og thorough investigation: Ang secondary outgoing wires sa CT sa incoming line cabinet gisunod gyud! Tracing back, ang matang sa butang mao ang commissioning sa substation:
(2) Misjudging the Fault, Man-made Open Circuit
Sa higayon, sa pagtaas sa electricity consumption, ang over-current protection mobati gyud. Ang user electrician wala makita ang problema ug mis-isip nga CT fault ang nag-cause sa relay nga mobati, ug giputli ang secondary wires! Pagkatapos sa power transmission, ang protection wala mobati, apan ang secondary circuit sa CT direkta open-circuited - disaster!
(3) Hazards of Open Circuit: Iron Core Saturation → Burning
Ang secondary side sa CT orihinal nga gamay ra ang impedance ug operasyon close to short-circuit. Kon mag-open circuit, ang magnetic force gikan sa primary current dili mahatagan og offset sa secondary side, ang iron core severe saturation, ang iron loss mobati, ug ang CT mismo overheats ug burn out.
Sa final analysis, ang insidente mao ang major management loophole: Ang construction team wala gipalit sa CT sa incoming line cabinet, ang protection setting value wala giusab, ug ang electrician blind operation, leading to the CT being damaged layer by layer.
3. Preventive Measures: A "Life-saving Checklist" for Maintenance Workers
Sa aming trabaho, kita kinahanglan plug ang loopholes gikan sa source. Combining this accident, I have sorted out 6 strict measures, and operation and maintenance, design, and installation must all follow the rules:
(1) Design + Drawing Review: Strictly Comply with Specifications
Design units must conduct on-site surveys and produce drawings in accordance with specifications; the owner must supervise the drawing review to prevent "wrong designs" from entering the site.
(2) Equipment Control: Full-process Supervision
The owner must follow national and industry standards for procurement, testing, and acceptance to prevent defective products from entering the power grid.
(3) Operation Qualifications: Electricians Must Be Certified
If operation and maintenance personnel have no qualifications? Don't let them touch the equipment! Moreover, random modification of wiring and disassembly of equipment are strictly prohibited — this is a red line.
(4) Installation and Acceptance: Keep an Eye on the Construction Team
The installation team must follow the procedures, and any wrong installation, corner-cutting, or under-installation must be reworked immediately! The acceptance must be strict to avoid hidden dangers.
(5) Regular Inspections: Strengthen in Special Periods
Daily inspections and panel monitoring are essential, and special periods such as high load, high temperature, and typhoon days must be closely monitored! Check the appearance, smell for peculiar odors, and listen for abnormal noises to detect abnormalities early.
(6) Overhaul and Testing: Don't Let "Sick CTs" Be Put into Use
Overhauls must be carried out in strict accordance with standards, and the process must be in place; electrical tests must be thorough, and CTs with defects must never be put into use.
4. Conclusion: CT Open Circuit is Extremely Dangerous, Maintenance Workers Must Know "Prevention and Rescue"
A secondary open-circuit of a CT is no small matter; it can cause equipment outages, protection maloperations/refusals to operate, and lead to major accidents at any time. As front-line maintenance workers, we must thoroughly understand the hazards and causes of open circuits, conduct more inspections and investigations in daily work, and be able to solve problems immediately when abnormalities occur. Only by implementing these measures can CTs operate stably and the power grid have fewer troubles!
