Dakunan da Kulaɗin LTAC Don Turbin Mai Sauran

1 Bincike

A cikin takardun da na standardi na kasar GB/T 1094.3-2017, yadda ake iya yi abin da aka sa shi a wurin LTAC (Line Terminal AC) don muhimmanci masu karamin gida shine don bayyana tsarin jirgin ruwa mai girma daga tushen mafi girma zuwa talaka. Ba ake amfani da shi don bayyana jirgin ruwa daga tasha zuwa tasha ko bayan wasu tushuka.

A matsayin hanyoyin binciken jirgin ruwa (kamar LI da SI), LTAC na da kayan bayyana game da tsarin jirgin ruwa mai girma daga tushen mafi girma, tushen mafi girma da kuma abubuwan da suka fito da turawa a cikin karfin da kuma tafin da ke da sabon zane, saboda ingantaccen lokacin da ya kara (fiye 30 detari don transformashi 50 Hz da 36 detari don transformashi 60 Hz).

Akwai misalai da suka nuna cewa irin karamin gida suna iya tabbatar da binciken LI da SI, amma suka dogara ne a lokutan LTAC, yawanci a farkon lokacin da ake yi binciken. Wannan yana nuna yadda akwai muhimmanci a kan lokacin da ake yi binciken don bayyana tsarin jirgin ruwa mai girma, kuma yadda LTAC yana da kayan bayyana wajen bayyana tsarin jirgin ruwa mai girma.

Saboda haka, ita ce da ake bukata da masu kudin karamin gida su yi hasashen tsarin jirgin ruwa a lokacin LTAC a lokacin da ake kudin karamin gida, don haka za a yi kudin jirgin ruwa mai girma da ma'adanar daidai.

2 Bayanin Standardi

Binciken LTAC (Line Terminal AC) wanda ake yi a cikin karamin gida shine babban abin da aka sa shi a cikin standardin da na kasar GB/T 1094.3-2017. An yi shi daga ACSD (short-time induced withstand voltage test) da ke cikin standardin da ya bace GB/T 1094.3-2003. Tushen bayanan LTAC suna cikin kofin da ke cikin kula:

Standardin ya ba bayanin binciken LTAC (Line Terminal AC) a cikin karamin gida kamar haka:

• Don karamin gida da Um ≤ 72.5 kV, da suka tabbatar da su duka da jirgin ruwa mai girma, za a iya bayyana tsarin jirgin ruwa mai girma daga tushen mafi girma zuwa talaka ta hanyar binciken applied voltage (AV). Saboda haka, binciken LTAC ba da kyau.

• Don karamin gida da 72.5 < Um ≤ 170 kV:

• Idan su duka da jirgin ruwa mai girma, hakan ya ba tabbatar da za a iya bayyana tsarin jirgin ruwa mai girma ta hanyar binciken applied voltage (AV), amma binciken LTAC an yi shi da matsala. Yana nufin haka cewa ba da kyau a lokacin da ake yi binciken lokaci, amma za a iya yi shi idan an yi la'akari a kan masu amfani da shi.

• Idan suka sami tap-changer (graded insulation), binciken LTAC an yi shi da lokaci, kuma za a iya yi shi a cikin karamin gida daban-daban a lokacin da ake yi binciken lokaci a birnin kudin. Amma idan an yi la'akari a kan masu amfani da shi, za a iya kawo shi da binciken switching impulse (SI).

• Don karamin gida da Um > 170 kV, idan su duka da jirgin ruwa mai girma ko graded insulation, binciken LTAC an yi shi da matsala—ba da kyau a lokacin da ake yi binciken lokaci, amma za a iya yi shi idan an yi la'akari a kan masu amfani da shi. Amma a wannan lokacin, ba za a iya kawo shi da binciken switching impulse (SI).

A cikin harkokin, don karamin gida da su duka da jirgin ruwa mai girma, ba za a iya yi binciken LTAC, saboda tsarin jirgin ruwa mai girma daga tushen mafi girma zuwa talaka za a iya tabbatar da shi da kadan da kadan a lokacin da ake yi binciken applied voltage (AV) lokaci.

Ya kamata a lura cewa don karamin gida da Um > 170 kV, binciken LTAC ba za a iya kawo shi da binciken SI. Hasashen na musamman da tarihin magana sun nuna cewa don bayyana tsarin jirgin ruwa mai girma daga tushen mafi girma zuwa talaka a karamin gida da yawan kirkiyar aiki > 170 kV, binciken LTAC yana da kayan bayyana kiman 10% da ya fi binciken SI.

3 Hukumar Hasashen

Yadda ake yi binciken LTAC (Line Terminal AC) a cikin karamin gida shine don induku min faden mutum a tushen mafi girma, kuma a tushen mafi karfi za a iya samun adadin faden mutum da ya kama da shi. Babu hukumar na musamman wajen bayyana hukumar hasashen. Hukumar LTAC na da shahara shine "opposite-phase shorted and grounded support method." A cikin kula, za a bayyana hukumar hasashen a cikin misali na karamin gida SZ18-100000/220.

3.1 Parametuta na Karamin Gida

Tsunukan faden mutum: 230 ± 8 × 1.25% / 37 kV
Tsunukan sana: 100 / 100 MVA
Faduwar daidaita: 50 Hz
Vector group: YNd11
Nau'in tsarin jirgin ruwa: LI950 AC395 – LI400 AC200 / LI200 AC85

3.2 Cikin Hasashen

Cikin hasashen binciken LTAC (Line Terminal AC) na karamin gida yana nuna kamar haka:

Diagram na Cikin Hasashen binciken LTAC (Phase A as Example)

Tushen mafi girma a tap 9, tushen mafi karfi a yi faden mutum da ya kama da shi 2.0 kowane adadin faden mutum da ya faruwa

Muhimman abubuwan cikin hasashen LTAC sun haɗa:

• Binciken LTAC za a iya yi shi phase by phase, yana nufin cewa ake yi shi a cikin phase kada kada, da induction factor da ya kama da 2 kowane adadin faden mutum da ya faruwa. A wasu lokutan, ba za a iya samun 2 kowane kadan, amma ana iya samun kisan karamin da ya kama da shi.

• Idan ake yi misali na binciken LTAC a phase A tushen mafi girma: ake yi faden mutum *Uax* a tushen mafi karfi ax, da x a ci talaka; tushen mafi karfi b da c an yi shi da damu. A tushen mafi girma, B da C an yi shi da kusa da talaka, amma A da neutral (0) an yi shi da damu (ba a ci gaba).

• Tushen mafi girma ya kamata a yi shi a tap da aka tabbatar, don haka za a iya samun faden mutum da aka tabbatar da 395 kV (da kisan karamin da ya kama da shi ±3%) a tushen mafi girma A.

3.3 Hasashen Hasashen

Ta hanyar hukumar Faraday da tsarin daidaita, a cikin hasashen na biyu, flux a cikin core limbs na B da C yana da adadin da ya kama da half da flux a cikin core limb na A, amma a cikin haguwa na biyu. Saboda haka, faden mutum da aka induku a cikin windings na B da C yana da adadin da ya kama da half da faden mutum da aka induku a cikin winding na A.

Schematic Diagram of Core Flux Distribution during LTAC Test
(High-voltage Phase A as Example)

Idan ake yi induction factor da ya kama da faden mutum a low-voltage phase a da *K*, da tushen mafi girma a tap position *N*. Ana iya kawo kalmomin:

Uₐ₀ + U₀₈ = 395
(Idan B a ci talaka, Uᵦ = 0)

Idan adadin flux a cikin core limb na B yana da adadin da ya kama da half da flux a cikin core limb na A, yana nufin cewa:
U₀₈ = ½ Uₐ₀

Saboda haka:
1.5 × Uₐ₀ = 395

Idan ake kawo tsunukan faden mutum da tap settings:
(230 / 1.732) × [1 + (9 − N) × 1.25%] × K × 1.5 = 395

Wannan kalmomi yana da abubuwa biyu, *N* da *K*, kuma ta da kalamai da ya kama da infinity. Amma daga rarrabe, abubuwan da suka sami da kammal: *N* yana da adadin da ya kama da integer bayan 1 da 17, da *K* da ya kama da 2.

Idan ake yi kalmomin da *N = 9* an samu *K = 1.98*.
Ko kuma idan ake yi *K = 2* da *N = 9* an samu faden mutum *Uₐ = 398.4 kV*.

Ta hanyar kalmomin na biyu, za a iya samun faden mutum da aka induku a cikin karamin gida a lokacin da ake yi binciken LTAC.

3.4 Tsarin Faden Mutum

Ta hanyar hukumar hasashen na biyu, za a iya samun tsarin faden mutum a cikin windings a lokacin da ake yi binciken LTAC a phase A tushen mafi girma kamar haka:

Tsarin Faden Mutum a cikin Windings a lokacin da ake yi Single-Phase LTAC Test on Phase A

Daga diagram na faden mutum, ana iya gano cewa a lokacin da ake yi single-phase LTAC test, adadin faden mutum da aka induku a cikin windings yana da adadin da ya kama da kisan karamin. Saboda haka, binciken LTAC ba za a iya bayyana tsarin jirgin ruwa mai girma daga tasha zuwa tasha, amma za a iya bayyana tsarin jirgin ruwa mai girma daga tushen mafi girma zuwa talaka (wannan bayanin yana nuna cewa wato graded-insulation transformers). A lokacin da ake kudin karamin gida, ya kamata a tabbatar da tsarin jirgin ruwa mai girma daga tushen mafi girma, tushen mafi girma da kuma abubuwan da suka fito da turawa a cikin karfin da kuma tafin da ke da sabon zane a lokacin da ake yi binciken LTAC.