Cur ergo quinque tentamina impulsi voltaginis requiruntur pro transformatoribus distributionis vel transformatoribus reparatione subactis ante commissionem officialem

Experimentum impulsionis transformatoribus novis vel reparatorum ante commissionem

Scisne cur transformatores novi vel reparatorum oportet subire experimentum impulsionis ante commissionem officialem? Hoc experimentum verificat an fortitudo insulationis transformatoris possit sustinere impactum totius voltage vel overvoltage commutationis.

Principium experimenti impulsionis relatum est ad id quod fit cum transformator non onustus disjungitur. Interruptor circuitus interrumpit parvam currentem magnetizationis, potenter cogens interruptionem currentis antequam ad nullum perveniat propter current chopping. Hoc creat overvoltages in transformatore inductivo. Magnitudo harum overvoltages dependet ab performance interruptoris, structura transformatoris, et crucialiter, methodo neutralis grounding. In transformatoribus non groundatis vel per arc suppression coils groundatis, overvoltage potest attingere 4-4.5 vices phase voltage, dum transformatores directe groundati neutrales solent experiri overvoltages non excedentes 3 vices phase voltage. Hoc est cur transformatores sub experimento impulsionis oportet ut habeant suas neutrales directe groundatas.

Experimentum impulsionis servit duobus aliis finibus: verificando fortitudinem mechanicam transformatoris sub magnis currentibus inrush, et probando num systemata protectionis relae maloperabuntur sub conditionibus significantis currentis inrush.

Quantum ad frequentiam experimenti: transformatores novi oportet quinque experimenta impulsionis, dum transformatores reparatorum oportet tres experimenta.

Cum energizatur transformator non onustus, occurrunt currentes inrush magnetizationis, attingentes 6-8 vices currentem nominalem. Hic currentus inrush decrescit celeriter initio, reducendo se ad 0.25-0.5 vices currentem nominalem intra 0.5-1 secundum, quamvis completa decrementatio longior sit—several seconds for small/medium transformers and 10-20 seconds for large transformers. Durante periodo initialis decrementi, differential protection may maloperate, preventing transformer energization. Ergo, sine onere impulsionis claudendi permittit verificationem practicalis wiring, characteristics, and settings of differential protection under inrush current conditions, enabling evaluation of whether protection systems can be properly commissioned.

Per IEC 60076 standards, full-voltage no-load impulse testing requires five consecutive impulses for new products and three consecutive impulses after major overhauls. Each impulse should be separated by at least 5 minutes, with personnel monitoring the transformer on-site for abnormalities, stopping operations immediately if problems are detected. After the first impulse, the transformer should operate continuously for over 10 minutes, with subsequent impulses separated by at least 5 minutes. The requirement for five impulses is specified in regulations, likely representing a comprehensive consideration of mechanical strength, overvoltage effects, and inrush current characteristics.

Procedura experimenti impulsionis energizationis transformatorum in systematibus electricis

• Certe interruptores circuitus et disconnect switches on the generator side sunt aperti. Si opus est, disjunge conexiones terminales in parte low-voltage transformatoris.

• Activa systemata protectionis relae transformatoris et controllos systematis refrigerationis, protectionis, et signaling.

• Engage the transformer neutral grounding switch.

• Claude interruptorem circuitus high-voltage transformatoris ad perficiendum quinque impulsiones energizationis ab systemate electrico, cum intervallis circa 10 minutas inter singulas. Proba transformatorem ad abnormalitates et monitor operationem protectionis differentialis et Buchholz (gas) protection.

• Quando possibile, registra oscillogrammas currentis inrush magnetizationis durante energizationem transformatoris.

Durante experimento, technici examinant insulationem terminalium transformatoris et audiant attentissime sonos internos poniendo baculum ligneam vel rodum insulandum contra enclosure transformatoris. Si detectentur soni explosivi intermittentes vel repentinae voces magnae, operatio statim oportet cessare. Solus post feliciter transgressas quinque impulsiones, transformator potest commissionari ad operationem normalem.