Tsamakanin Yadda a Kula PT Resonance a 500kV GIS Switching Station

1. Resonance na Tashin Da

An gina tashar GIS na 500kV ta ɗaya da yawa da amfani da ƙarin hukuma kan abubuwa masu ƙasa da hanyoyi kan abubuwa masu biyu. Wannan PT na ƙarin ƙasa ba ta ƙunshi karamin gagarwa, kuma ya shiga zabe-zaben GIS. A nan, a cikin nuna bayanan abin da aka taba, lokacin da karamin gagarwa 5021 ya sauya, kapasitas na karamin gagarwa da PT sun duka suka ƙara wata sabbin karamin gagarwa. Duk da haka, tasiri mai ƙasa, a tsakanin PT, ta yi nasara da mutane na ƙasa. Kapasitas an samu karfi, wanda ya haɓaka resonance.

Sauke na current ya ci gaba da ɗaya ɗaya da shekaru 40, wanda ya haɓaka hoton PT da damar ƙwayo. An sanya ƙware-ƙwarai na iya ƙara wannan zuwa ƙware-ƙwarai mai kyakkyawan voltage (Es), karamin gagarwa (CB), kapasitas na karamin gagarwa (Cs), kapasitas na ƙasa-ta-ƙasa (Ce), da ƙware-ƙwarai da inductance na PT (Re, Lcu).

Don in bincika tushen da ya faru, an yanke abubuwan biyu. Bayan in tafiya ƙware-ƙwarai na insulation na PT, ƙware-ƙwarai na DC, da pressure na gas SF₆, ban samu abu mai ƙwai. Saboda PT na electromagnetic yana da inductance mai ƙasa da iron core, da kuma abubuwan GIS suna da kapasitas, a wasu ƙarin, LC series circuit yana iya haɗa da resonance conditions, wanda ya haɓaka resonance daɗi.

2. Hanyoyi na Ilimi Don Kula Resonance
2.1 Babban Hanyoyi

PT resonance yana ɗauke a tashar GIS na 500kV. Permeability na materials na ferromagnetic yana canza da magnetic field: idan magnetic field yake soja → magnetic induction intensity yake soja. Ba da ranar da ake sauyi, permeability yake raba. Idan magnetic field yake soja, permeability yake rage. Daga formula na coil induction:

(N shine number of turns, μ shine permeability, S shine equivalent cross - sectional area na magnetic circuit, da l_m shine equivalent magnetic circuit length), turns na coil da parameters na magnetic circuit na PT electromagnetic suna da alamar ɗaya, inda inductance yana da alamar linear da permeability; lokacin da iron core ya sauya, permeability yake rage, inductance yake rage, wanda yake nuna alamar nonlinear. Idan voltage na low-frequency yake faru a cikin circuit, iron core na PT yake sauya, inductance yake rage, da kuma current na excitation yake soja da hundreds of times, wanda ya haɓaka resonance heating.

Don resonance, an bayyana hanyoyi masu ƙarin:

• Canza sequence na power-on/off: Lokacin da ake yanke ƙasa, ya sauya PT kafin ƙasa, kuma lokacin da ake magana, za a magana ƙasa kafin PT. Wannan zai iya kula resonance conditions amma yana buƙatar canza sequence na operation da PT yana buƙatar karamin gagarwa.

• Yanka capacitance na karamin gagarwa: Yana iya kula resonance conditions amma zai rage interrupting capacity na karamin gagarwa.

• Ƙara damping resistance: Amma a cikin yadda ake da shi, ƙara damping resistance zuwa set na cable na PT na ƙasa don kula overvoltage da overcurrent na resonance.

2.2 Neman Abubuwa

PT na incoming-line na tashar GIS na 500kV ta ɗaya da resonance daɗi lokacin da ake yanke ƙasa, wanda ya haɓaka PT da kuma ake rage aiki. Lokacin da ake yanke incoming-line (daɗi hot standby → cold standby, etc.), PT ta ɗauke resonance. Saboda haka, an tafiya parametere na PT, an canza number of primary/secondary winding turns don rage density na flux da kuma canza inductance; an fito anti-resonance coil, kuma an ƙara PT na ƙarin da PT na incoming-line. Ba a samu resonance a tashar, da kuma aikinsu ta ɗauke ɗaya.

3. Hanyoyi na Ikkoba: Fitowa Equipment na Automatic Resonance Elimination

Idan PT na ƙasa ta shiga ƙasa-zabe GIS, ba a ƙara PT da ƙasa-to-ground resistances. Za a iya ƙara inductance na PT zuwa L da ƙara capacitance na ƙasa-to-ground zuwa C; biyu sun ƙara sabbin impedance Z, da formula na ƙara

Ta haka, tare da fitowa equipment na automatic resonance elimination, resonance zai iya kula daidai da alamar impedance.

Don rage impact na resonance na PT na ƙasa na 500kV GIS, an ƙara air switches da nonlinear resistors zuwa PT residual voltage windings (ta hanyar coordination da manufacturers a lokacin da ake yanke ɗaya) don automatic resonance elimination. Yana buƙatar emergency plan don resonance failure na no-load ƙasa.

Busbars na 500kV GIS suna da fitowa open-type; wasu abubuwa suna da insulation na SF₆ (footprint mai ƙaci, reliability mai ƙasa, maintenance intervals 20 years+, kamar yadda ake amfani a Three Gorges Project). Reliable automatic resonance eliminators (misali, LXQ-type na SiC, compact da take da inganci a fitowa; WXZ196 na microcomputer-based, high-integration don real-time harmonic elimination) zai iya kula resonance.

3.2 Canza Regulations na Operation

Don operation na 500kV GIS:

• Pre-analysis: In neman risks na PT resonance; bayyana roles na operators na power/NCS.

• Control na Device: Kafin ake yanke karamin gagarwa na ƙarin, za a ƙara ƙasa. Ya sauya K1/K2 a box na PT; a entrance na station, ya faru resonance eliminator na ƙasa (suya K3, prepare resistors).

• Real-time monitoring: NCS yana tafiya karamin gagarwa da voltages na ƙasa. Zero voltage = babu resonance; fluctuating voltage = resonance an samu.

• Response: Don resonance, suya K3 don ƙara resistors. Idan ba yana ƙarfin, ya sauya disconnectors na karamin gagarwa don manual elimination.

4. Muhimmiya

A lokacin da ake ƙirƙira tashar 500kV GIS, ya kamata a simular resonance na PT na ƙasa don zama da PT masu ƙasa (don rage core saturation a lokacin da ake ƙara). Don resonance da ke cika, ya kamata a yi actions masu ƙarin (misali, replacement na ƙasa/PT) don ƙara aiki mai ƙasa. Wannan "prevention-operation-design" system yana ƙara anti-resonance capabilities.