Bincike mafi yawan kisan cikin manyan insulatoci da ke tsakiyar hukuma da sadarwa da na'ura

Gajerar da Ma'anar Tsari

A lokacin daɗi na ƙoƙarin gudanar da AC ta filayin, yana faruwa cewa an samu shiga da hankali kan insulator da ke tsakiyar. Wannan yana nuna ma'anar da aka faru:
A lokacin da aka saka ƙungiyar 500 kV AC don kula tsakiya, an yi nasara da busbar differential protection na biyu, sannan an yi haɗa da ƙungiya. Tsari ya faru a tsari B, kuma adadin amfani ya zama 5,760 A. An yi tattaunawa daga bincike kan gas SF₆, kuma mafi girman SO₂ ya zama 5.3 μL/L (hukumar ta ita ce 2 μL/L).

Tatsuniyar Insulator da Ke Tsakiyar

Gas chamber ta ƙunshi insulator da ke tsakiyar uku, particle traps, pull plates, da sauransu. Kamar yadda aka bayyana a Figura 1, a lokacin daɗi, ana fi tsaro insulator da ke tsakiyar uku da particle traps zuwa metal pull plate ta hanyar bolt. Ana fitowa shielding cover zuwa metal insert a tsohon insulator ta hanyar bolt. Insert ta kasance da insulator ta hanyar casting. Ba daɗi, ana fi tsaro zuwa pipe busbar flange ta hanyar bolt na pull plate. Babban rawarwar insulator shine epoxy resin, particle trap shine alloy, kuma limit pad shine rawarwar da ba yake tsakiya.

Mafi girma da insulator da ke tsakiyar ya kamata shine taimakawa masu ilimin da ke tsakiya, kuma babu da ma'ana ga isolating gas chamber. Idan aikin ta shahara, insulator da ke tsakiyar yana samu stress sama da gas pressure sama, kamar yadda aka bayyana a Figura 2. Duk da haka, distribution da ke electric field na insulator da ke tsakiyar uku yana da abin da ba sama ba. Inta da electric field strength ya zama mai karfi shine a nahawu waɗanda an sanke metal insert da epoxy resin. Wannan abin da ba sama ba zai iya haifar da accumulation da ba sama ba na charge a insulator da ke tsakiyar uku. Idan akwai abubuwa ko wani abu a lokacin da aiki, yana iya faru flashover discharge.

Koyar da Dimensiyoyi da Nuna Nuna

An koyar da insulator da ke tsakiyar da aka faru zuwa factory don koyar da dimensiyoyi da nuna nuna. An koyar da insulator da ke tsakiyar da aka faru a busbar, kuma an koyar da marks. Ingantaccen insulator da ke tsakiyar yana da nuna daban-daban, kuma ba a samu crack, bubble, ko wani abu na da ƙarfin nuna.

Ta hanyar drawings, an koyar da key dimensiyoyi na biyu na insulator da ke tsakiyar, particle traps, shielding covers, pull plates, da sauransu. Wannan ta ƙunshi koyar da dimensiyoyi kamar center-to-center distance na insulator da ke tsakiyar uku, circumferential diameter, da angle. Duka dimensiyoyi suka zama qualified.

Nuna Penetrant Inspection

An yi penetrant inspection zuwa insulator da ke tsakiyar. Ba daɗi, an yi cleaning da grinding, kuma an yi inspection. An sanya cleaning agent zuwa paper, kuma an sanya penetrant na surface na insulator. Ba daɗi, ba a samu penetrant seepage, kuma ba a samu abu na da ƙarfin nuna penetrant inspection.

X-ray da Industrial CT Inspection

An yi X-ray inspection zuwa insulator da ke tsakiyar. An yi rotation 360° zuwa insulator, kuma ba a samu defects kamar poor bonding, bubbles, ko cracks.
An yi Industrial CT inspection tests zuwa insulator da ke tsakiyar. Internal insulation material ta ƙunshi uniform, kuma ba a samu air holes, cracks, impurities, ko wani abu na da ƙarfin nuna. Ba a samu poor bonding bayan low-voltage end insert da epoxy resin, ko bayan central cylinder da epoxy resin.

Mechanical Performance Test

An yi mechanical performance tests zuwa insulator da ke tsakiyar, ƙunshi pressure test (12 kN, holding pressure for 30 min) da torsion test (15 kN, holding pressure for 30 min). An nuna surface na insulator don samun abu na da ƙarfin nuna, cracks, ko damage. Ba a samu abu na da ƙarfin nuna through the mechanical performance test.

Insulation Performance Test

An yi assembly zuwa insulator da ke tsakiyar zuwa busbar test state ta hanyar new particle traps da old particle traps (ba da grinding) da aka ji daga site, kuma an yi filling zuwa 0.5 MPa SF₆ gas inside.
Kafin, an yi assessment ta hanyar in-factory withstand voltage test method: power-frequency withstand voltage (740 kV for 1 min - 381 kV for 5 min), and lightning impulse (±1675 kV, 3 times each); sannan, an yi assessment ta hanyar on-site withstand voltage test method: power-frequency withstand voltage (318 kV for 5 min - 550 kV for 3 min - 740 kV for 1 min - 381 kV for 45 min). Duka results ta zama normal, kuma ba a samu discharge ko wani abu na da ƙarfin nuna.

Fault Reproduction Test

Ta hanyar analysis da aka yi zuwa insulator da ke tsakiyar, an tabbatar da cewa ba a samu fault problems a design da manufacturing stages na insulator da ke tsakiyar. An yi initial judgment cewa foreign objects a surface na insulator da ke tsakiyar a lokacin daɗi na installation stage ne ke cause flashover discharge. Don inganta sababbin accident as analyzed, an yi reproduction tests under various working conditions, ƙunshi: applying 1/3 lubricating grease zuwa insulator da ke tsakiyar (no discharge), applying 1/2 lubricating grease zuwa insulator da ke tsakiyar (no discharge), applying 2/3 lubricating grease zuwa insulator da ke tsakiyar (no discharge), applying 1/3 lubricating grease zuwa insulator da ke tsakiyar da dust (dust onto the post insulator, no discharge), etc.

Ta hanyar reproduction test results under the above-mentioned working conditions, an iya conclude cewa single-source lubricating grease contamination ko metallic foreign objects ba za su iya cause surface flashover breakdown of the insulator; for insulators that break down under power-frequency voltage, both the central insert and the ground-potential insert have obvious ablation marks; for insulators that break down under lightning impulse voltage, the central insert has ablation marks, which is similar to the phenomenon of the on-site fault.