Takaitaccen Bayanin da Kammalawa na Current Transformer

An karamin mutanen kuli da a cikin mazauna, suna da muhimmanci a kan abincin rayuwar addinin system. Idan an karamin mutanen kuli yake, zai iya haifar da circuit breaker da zai iya haifar da wani abu mai zurfi don kula, wanda zai iya haifar da abin da shi ne da aiki a kan abincin rayuwar addinin power grid. Daga baka, a cikin misalai na aikin kula da ya faruwa saboda hankali na current transformer a karamin mutanen kuli a karamin mutanen kuli a 66 kV substation, a nan amfani da tashar gaba, review ta bayanai, da kuma research ta karfin, ana samun tashar tushen kula da kuma tashar tushen kula, kuma ana ba da tashar magana game da yanke da za su iya haifar da kula na wani abu mai zurfi.

1 Tushen Kula da Diagnosis
1.1 Yadda Ake Samun Cikin Gaba
A watan Satumba 2020, a nan aikin computer ta gaba ta 66 kV substation, ana nufin cewa set na biyu na longitudinal differential protection na No. 2 main transformer ya faru. Circuit breakers a karamin high-voltage da karamin low-voltage na No. 2 main transformer suka haifar, section automatic reclosing ya faru, kuma section circuit breaker ya ciyar da damar da ba a yi laifi ba. A nan aikin masu aiki a gaba suka dole zuwa gaban da suka dole zuwa gaba da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole zuwa gaban da suka dole......

1.2 Tushen Kula
Sabon kula na protection device suna cikin Tabular 1, da kuma parametoro na current transformer a karamin low-voltage suna cikin Tabular 2. Ba a nan tushen bayanai, sabon kula su ne sahihi, da kuma abubuwan samun accuracy, ratio braking, differential, da kuma second harmonic braking sun fi shi da ma'ana. A nan tushen wiring na secondary side na current transformer a karamin low-voltage na main transformer, ana nufin cewa wiring na gaban su ne sahihi.

A nan tushen data da waveforms na differential protection, ana nufin cewa an yi shunt a Phase A na set na biyu na low-voltage current transformer. Don haka, an yi amfani da 30 A a Phases A/B na primary side. Set na daya ya nuna halayen daidai (A: 0.100 A, B: 0.099 A); set na biyu ya nuna B 0.098 A amma A 0.049 A, wanda yake cewa akwai kula a Phase A.

Amfani da ~5 A a 1S1-1S2 na secondary, an yi amfani da small current a set na biyu; amfani da direct a set na daya, bane an yi amfani da current a set na biyu, wanda yake cewa wiring na secondary su ne sahihi. Withstand voltage da partial discharge tests na transformer suna ci shi da standards. Bayan a ciya wiring na gaban na Phase A, an yi inter-phase insulation test, wanda ya nuna 0 resistance a 1S2 da 2S1, wanda yake cewa an yi complete breakdown.

Waɗannan breakdown ya haifar da shunt a Phase A na set na biyu, wanda ya haifar da errors a measurements. Idan an yi protection, set na daya ya nuna 8.021 A, set na biyu 4.171 A - an yi actual error 3.850 A. An yi conversion, wanda ya haifar da 3.217 A differential current (wanda ya haifar da setting), wanda ya faruwa protection.

1.3 Diagnosis na Kula

A nan karfin faulty current transformer, da kuma tushen structure da manufacturing process, ana nufin cewa root cause: A nan production, enameled wire leads (da excess enamel removal) suna ciyan da secondary terminals. Amma ba a nan amfani da insulating tubes, manual operations da space constraints suna haifar da insufficient insulation clearance a bayan wiring na secondary. Idan an yi exposure da current da tsawo, suna haifar da insulation na secondary winding, wanda ya haifar da inter-winding breakdown da kuma triggering na kula.

2 Handling na Kula

Phases B da C current transformers a wata interval suka dole zuwa gaba. Ba a nan verify correct installation/wiring da kuma passing re-conducted handover tests, suna ciyar da su. Urgently sourced current transformers (same specs, different batch) suka ciyar da su ba a nan passing tests, wanda ya haifar da normal substation operation (stable as of now).

3 Suggestions and Pre-control Measures

Daga wannan kula:

• Manufacturers must strengthen production process control (e.g., re-inspect lead/mold-fitting steps) and enforce strict quality checks.

• Increase voltage levels for inter-coil withstand tests during factory inspections.

• Operation/maintenance units should schedule proactive maintenance, stock spare parts, and inspect same-batch current transformers thoroughly—replacing faulty units promptly.