Agar transformator to'satdan qisqa-tushib qolsa, nima qilishim kerak?

Kundalik faoliyatda transformatorning qisqa tutashuvi{0}} bilan bog'liq avariyalarni bartaraf etish uchun tekshirish va sinovdan o'tkazish orqali muammoning mohiyatini aniqlash kerak. Transformator to'satdan qisqa tutashuvga uchrasa, yuqori va past kuchlanish tomonlari katta qisqa tutashuv oqimiga duchor bo'ladi. Qisqa vaqt ichida elektron to'xtatuvchining ochilishi juda kech bo'lganda, qisqa tutashuv oqimi transformatorning sariqlariga ta'sir qiladigan oqim kvadratiga mutanosib elektromotor kuchni hosil qiladi. Elektrodinamik kuchni radial kuch va eksenel kuchga bo'lish mumkin.

Qisqa tutashuv vaqtida o'rashga ta'sir qiluvchi radial kuch yuqori kuchlanishli o'rashning kuchlanish ostida bo'lishiga va past kuchlanishli o'rashning bosim ostida bo'lishiga olib keladi. O'rashlar dumaloq bo'lganligi sababli, dumaloq jismlar kuchlanishdan ko'ra bosim bilan oson deformatsiyalanadi, shuning uchun past kuchlanishli o'rashlar osonroq deformatsiyalanadi. To'satdan qisqa tutashuv paytida hosil bo'lgan eksenel kuch o'rashni siqib chiqaradi va yuqori va past kuchlanishli sariqlarning eksenel siljishiga olib keladi va eksenel kuch ham temir yadro va qisqichga ta'sir qiladi. Shuning uchun transformator to'satdan qisqa tutashuvdan aziyat chekganda, past kuchlanishli o'rash va muvozanat o'rashlari, keyin esa yuqori- va o'rta{3}} kuchlanishli o'rashlar deformatsiyalanishi ehtimoli katta. temir yadrolar va kliplar. Transformatorning qisqa tutashuvidagi avariyadan so'ng asosiy sariqlarni, temir yadrolarni, qisqichlarni va boshqa qismlarni tekshirishdan tashqari, jarayonda bir qator tegishli masalalarga ham e'tibor qaratish lozim:

■ Inspection and testing of windings

Transformator qisqa tutashuvda{0}}, elektr quvvati ta'sirida, o'rashlar bir vaqtning o'zida siqish, taranglik, egilish va hokazo kabi turli xil kuchlarga duchor bo'ladi. Ulardan kelib chiqadigan nosozliklar juda yashiriladi va ularni bartaraf etish oson emas. tekshirish va ta'mirlash. o'rash holati.

■ Measurement of transformer DC resistance

Transformatorning doimiy qarshiligining o'lchangan qiymatiga ko'ra, o'rashning doimiy qarshilik muvozanat tezligini tekshirish va uni oldingi o'lchangan qiymat bilan solishtirish uchun transformator o'rashining shikastlanishini samarali tekshirish mumkin. Masalan, transformatorning qisqa tutashuvi-dan so'ng, past kuchlanishli C-tomonda doimiy tok qarshiligi taxminan 10 foizga oshdi. Shundan kelib chiqqan holda, o'rashning yangi iplari bo'lishi mumkinligi aniqlandi. Nihoyat, o'rash tekshirish uchun ko'tarildi va C-fazali o'rashning bir ipi uzilganligi aniqlandi.

■ Measurement of Transformer Winding Capacity

O'rashning sig'imi o'rashning{0}}burilishlari, qatlamlararo-va-keklarning o'zaro sig'imlaridan va o'rash hosil qiluvchi sig'imlaridan iborat. Bu kondansatör o'rash va temir yadro va zamin orasidagi bo'shliq, o'rash va temir yadro orasidagi bo'shliq, o'rashning burilishlari orasidagi bo'shliq, qatlamlar orasidagi bo'shliq va kekler orasidagi bo'shliq bilan bog'liq. O'rash deformatsiyalanganda, u odatda bir shaklda egiladi, bu o'rash va temir yadro orasidagi masofani kichikroq bo'lishiga olib keladi va o'rashning erga sig'imi katta bo'ladi va bo'shliq qanchalik kichik bo'lsa, shuncha katta bo'ladi. sig'im o'zgaradi, shuning uchun o'rash Kapasitans o'rashning deformatsiya darajasini bilvosita aks ettirishi mumkin.

■ Inspection behind the hood

Transformator to'xtatilgandan so'ng, transformator ichida eritilgan mis shlaki, alyuminiy shlaki yoki yuqori zichlikdagi kabel qog'ozining bo'laklari- bo'lsa, o'rash katta darajada deformatsiyalangan va iplar singan va hokazo. Bunga qo'shimcha ravishda, o'rash moslamasi blokidan siljish, tushish, bosim plitasining tenglashtirilishi, bosim tirnoqining siljishi va boshqalar ham o'rashning shikastlanish darajasini baholashi mumkin.

■ Inspection of iron cores and clamps

Transformatorning temir yadrosi etarli mexanik kuchga ega bo'lishi kerak. Temir yadroning mexanik mustahkamligi temir yadrodagi barcha qisish qismlari va ularning birlashtiruvchi qismlarining mustahkamligi bilan kafolatlanadi. O'rash elektr energiyasini ishlab chiqarganda, o'rashning eksenel kuchi klipning reaktsiya kuchi bilan qoplanadi. Agar klip va tortish plitasining kuchi eksenel quvvatdan kamroq bo'lsa, klip, tortish plitasi va o'rash buziladi. Shuning uchun temir yadro, qisqichlar, tortish plitalari va ularning birlashtiruvchi qismlarining holatini diqqat bilan tekshirish va shartlarni tekshirish kerak:

① Check whether the iron yoke chip on the iron core moves up and down.

② The insulation resistance of the grommet screw and the iron core should be measured, check whether the jacket of the grommet screw is damaged, and check whether the pull plate and the connecting parts of the pull plate are damaged.

③ When the transformer is short-circuited, displacement may occur between the pressure plate and the clamp, causing the ground connection piece of the iron yoke on the pressure plate and the pressure nail to be broken or burnt due to overcurrent. Therefore, for the winding pressure plate, in addition to checking the damage of the pressure nail and the pressure plate, it is also necessary to check whether the ground connection between the winding, the pressure nail and the upper iron yoke is reliable.

■ Analysis of transformer oil and gas

Transformator qisqa tutashuv bilan urilgandan so'ng, gaz rölesida katta miqdorda gaz to'planishi mumkin. Shuning uchun transformator avariyasidan so'ng, gaz rölesidagi gaz va transformatordagi yog'ni sinovdan o'tkazish va avariya xarakterini aniqlash uchun tahlil qilish mumkin.

■ Matters needing attention in transformer short-circuit fault handling

(1) Izolyatsiya qiluvchi qismlarni almashtirishda izolyatsion qismlarning ishlashi kafolatlanishi kerak

Qayta ishlash jarayonida almashtirilgan izolyatsion qismlarning ishlashini sinab ko'ring va ulardan faqat talablarga javob bersa foydalaning. Xususan, qo'rg'oshin braketi yog'och blokining izolyatsiyasiga e'tibor qaratish lozim va yog'och blokning izolyatsiyasini ta'minlash uchun yog'och blokni o'rnatishdan oldin taxminan 80 graduslik issiqlik transformator moyiga bir muddat qo'yish kerak.

(2) Transformator izolyatsiyasi sinovi transformator hali 24 soat davomida moylangan bo'lsa, o'tkazilishi kerak

Since some damp insulating parts are soaked in hot oil for a long time, the water will diffuse to the surface of the insulation, so the test after oil injection often cannot detect insulation defects. For example, the low-voltage side of a 31.5MVA 110kV transformer was replaced with a wooden support block of 10 kV copper bar during treatment. After the transformer was filled with oil, everything was normal, and the insulation resistance of the 10kV low-voltage side to the iron core, clamps and ground was reduced to about 1 MΩ. After inspection of the hood, it was found that the insulation of the wooden block of the support of the 10 kV copper bar was very low. Therefore, the insulation test should be performed more reliably after the transformer has been oiled for 24 hours.

(3) Temir yadroni qayta yig'ishda uning o'tkir burchaklariga e'tibor berish kerak

Temir yadro temir bo'yinturug'iga qaytarib qo'yilganda, temir yadro chiplarining o'tkir burchaklariga e'tibor berish kerak va yog 'yo'llari orasidagi izolyatsiyani o'z vaqtida o'lchash kerak, ayniqsa yog' o'tish joylarida chiplarning o'tkir burchaklari. , chiplarning bir-birining ustiga chiqishi sababli temir yadroning bir necha nuqtada tuproqli bo'lishiga yo'l qo'ymaslik uchun. Misol uchun, 120MVA 220kV transformator uchun o'rash past{2}}kuchlanish tomoniga almashtirilganda va temir bo'yinturuq o'rnatilganda, chunki chipning o'tkir burchaklariga e'tibor berilmagan. qayta yig'ish va yog 'yo'laklari orasidagi izolyatsiya o'z vaqtida o'lchanmagan, yog 'yo'laklari orasidagi izolyatsiya o'rnatilgandan keyin 0 deb o'lchangan, uni topish uchun uzoq vaqt kerak bo'ldi, chunki temir yadro chipining o'tkir burchagi yog' o'tish joyini qisqartirgan. .

(4) O'rash materialini kuchli qisqa tutashuvga-qarshilik bilan almashtiring

Yaxshilangan konstruktiv transformator o'rashining mexanik kuchi asosan quyidagi ikki jihat bilan belgilanadi:

① One is the mechanical strength of the winding, which is determined by the structure of the winding itself;

② The second is the mechanical strength determined by the support on the inner diameter side of the winding, the axial compression structure of the winding, and the manufacturing process of the pull plate and the clip. At present, most transformer manufacturers use semi-hard copper wire or self-adhesive transposed wire to improve the short-circuit resistance of the winding, and use a better quality cardboard tube or increase the number of struts to improve the radial force of the winding. And the use of pull plates or spring pressure nails to improve the ability of the winding to receive axial force.

Transformator ishlab chiqaruvchi korxonaning texnik bo'limi sifatida transformatorni sotish shartnomasini imzolashdan oldin texnik ko'rgazma o'tkazilganda va transformator sargisi almashtirilganda, o'rashning qisqa tutashuv qarshiligi to'liq o'rganilishi va unga etarlicha e'tibor berilishi kerak.

(5) Transformatorlarni quritish

Transformator qisqa tutashuvdan ta'sirlanganligi sababli, texnik xizmat ko'rsatish uchun odatda uzoq vaqt talab etiladi. Transformator nam bo'lishining oldini olish uchun ikkita chora ko'rish mumkin:

① One is to buckle the transformer cover and use a vacuum pump to evacuate the transformer to remove the free water on the surface of the transformer body. When starting work the next day, use dry nitrogen or dry air to release the vacuum. After the maintenance, the hot oil can be directly put into operation after 24 hours of circulation.

② The second is to take rain-proof measures for the transformer after finishing work every day. After the work is completed, use the hot oil spray method to dry the transformer. This method generally takes 7 to 10 days.

(6) Diqqat qilinishi kerak bo'lgan boshqa masalalar

Transformatorda qisqa tutashuv avariyasi- sodir bo'lgandan so'ng, transformatorni an'anaviy elementlarga muvofiq sinovdan o'tkazishdan tashqari, transformator moyi, gaz rölesidagi gaz, o'rashning doimiy qarshiligi, o'rash sig'imi va o'rash deformatsiyasining sinov natijalari ko'rsatilishi kerak. nosozlikning tabiatini baholash va tahlil qilish va o'rashning deformatsiyasini, temir yadro va qisqichning siljishi va bo'shashmasligini tekshirish uchun ishlatiladi, so'ngra transformatorni davolash rejasini va amalga oshiriladigan profilaktika choralarini aniqlang. Transformatorning qisqa tutashuvi tufayli o'rash jiddiy deformatsiyalangan-va o'rashni almashtirish kerak bo'lganda, temir yadro chipini qayta yig'ishga, barcha izolyatsion qismlarni quritishga, ishlov berishga e'tibor berish kerak. transformator moyining va transformatorning umumiy quritilishi.