Tambayar Da Dukkin Karamin Kirkiro a Zaune na HVDC

Tushen kawu mai sauki na HVDC:
An amfani da tushen kawu mai sauki na HVDC (DS) don inganta hanyoyi daban-daban a jikohin haɗaƙar HVDC. Misali, an amfani da DS na HVDC don ƙwarewa yadda kare mafi girma ko kable, kare ƙwarewa ciki, ko kable, ko kare kan fitaccen ƙwarewa, ko kable, ko kare kan fitaccen ƙwarewa, ko kable, da kuma inganta abubuwa masu shiga sama kuɗi (thyristor valve), sama filtri, da kula na ƙasa. An amfani da DS na HVDC a ƙwarewa DC don ƙare kare ta ƙaramin ƙwarewa bayan ƙare kare ta ƙaramin ƙwarewa.

Tsawon 1: Misali na rubutu mai tsayi na HVDC disconnecting switch a cikin sistemai na bipolar HVDC

Tsawon 1 ya nuna misali na rubutu mai tsayi na HVDC disconnecting switch da abubuwan ƙwarewa (babu Metallic return transfer breaker) a cikin sistemai na bipolar HVDC na Japan. A gaba daya, zaɓuɓɓuka na HVDC DS da ES a cikin sistemai na HVDC suna ƙunshi waɗannan zaɓuɓɓuka na HVAC DS da ES a cikin sistemai na AC, amma wasu abubuwa suna ƙunshi zabubbukan da suka ƙunshi ga muhimmanci saboda muhimman aiki. Tafirin 1 ta bayyana ƙwarewar ƙwarewa masu muhimmanci da aka ƙwareta waɗannan DS na HVDC (CIGRE JWG A3/B4.34 2017).

Tafirin 1: Ƙwarewar ƙwarewa masu muhimmanci da aka ƙwareta disconnecting switch (DS) a cikin sistemai na bipolar HVDC

Kungiyoyi na tushen kawu mai sauki na HVDC:
Kungiya A: Yana bukata DS don ƙare kare mai tsayi na ƙwarewa saboda karamin ƙwarewa na kable mai ƙasa wanda yake da kapasiti mai yawa (daga 20 μF). Karamin tsayi na ƙwarewa ta fara ne a ƙwarewa ba ƙaramin ƙwarewa bayan samun ƙaramin sama kuɗi ta ƙare kare a matsayin snubber circuit a cikin sama kuɗi a C/Ss (Anan C/S da Kihoku C/S) zuwa ƙasa. Tsayin ƙare kare shine kadan 40 s, wanda yana ƙare kare kadan 3 min. An ƙare kare ƙaramin ƙwarewa 0.1 A saboda ƙaramin ƙwarewa da aka faɗa daga ƙaramin ƙwarewa na 125 kV da rausa snubber circuit a cikin thyristor valve.

Kungiya B: An amfani da DS don ƙare kare ƙwarewa da ke kusa don ƙare kare ƙwarewa da ke lafiya a ƙasa na ƙwarewa don ƙare kare ƙwarewa da ke lafiya zuwa ƙwarewa da ke lafiya na ƙasa ba da ƙaramin lokacin da an ƙara sassa. Wadannan yana ƙunshi waɗannan zaɓuɓɓuka na kungiya A DS.

Kungiya C: Yana bukata DS don ƙare kare ƙaramin ƙwarewa daga DS zuwa bypass switch (BPS) da aka ƙare kare a matsayin sama kuɗi don ƙare kare sama kuɗi. Zaɓuɓɓukan ƙaramin ƙwarewa shine 2800 A a wannan ƙungiyar. Tsawon 2 ta nuna prosesi ƙare kare ƙaramin ƙwarewa daga DS zuwa BPS.

A ƙaramin farko, sama kuɗi na ƙasa ya ƙara ƙwarewa da sama kuɗi na ƙasa ya ƙare kare. Don ƙare kare sama kuɗi na ƙasa daga ƙaramin ƙwarewa, an ƙare kare DS C1 don ƙare kare ƙaramin ƙwarewa zuwa BPS. Daga bincike da ƙaramin ƙwarewa na ƙare kare ta haka a cikin Tsawon 2 c, zaɓuɓɓukan DS na kungiya C shine tsayin DC 1 V a ƙaramin ƙwarewa na 2800 A, inda an faɗa tsayin ƙaramin rausa da induktansi a ƙaramin ƙwarewa na ƙare kare da DC-GIS.

Tsawon 2: Ƙare kare ƙaramin ƙwarewa DS na kungiya C. (a) ƙare kare DS, (b) ƙare kare DS, (c) ƙaramin ƙwarewa na DS

Kungiya D: Yana bukata DS don ƙare kare ƙaramin ƙwarewa na sama kuɗi idan an ƙara ƙwarewa sama kuɗi. Idan an ƙara ƙwarewa thyristor valve, ƙaramin ƙwarewa ta ƙare kare a ƙaramin kapasiti na sama kuɗi. Binciken ta nuna cewa ƙaramin ƙwarewa yana iya ƙare kare kadan 1 A, da kuma tsayin ƙaramin ƙwarewa da kaɗan daga ƙaramin ƙwarewa na sama kuɗi da ƙaramin ƙwarewa na ƙwarewa da ke ƙare kare ƙaramin ƙwarewa shine kadan 70 kV kamar yadda ake nuna a Tsawon 3.

Tsawon 3: Tsayin ƙaramin ƙwarewa a matsayin DS contacts

Nau'in ƙare kare kungiyoyin tushen kawu mai sauki na HVDC:
An yi ƙare kare ƙaramin ƙwarewa daban-daban na HVDC DS na kungiyoyi A zuwa D a matsayin ƙare kare ƙaramin ƙwarewa na AC, da kuma an tabbatar ƙaramin ƙwarewa a matsayin ƙaramin ƙwarewa da aka bayyarta a Tafirin 1. Babu ƙaramin ƙwarewa mai yawa a matsayin HVAC DS da HVDC DS, amma tsayin ƙaramin ƙwarewa na HVDC shine kadan 20% mai yawa.

Tsawon 4: DC-DS&ES, DC-CT&VT, DC-MOSA (LA) da aka amfani a matsayin 500 kV-DC GIS

Gas-insulated switchgear (DC-GIS) da aka ƙare kare daga ƙaramin ƙwarewa na HVDC da earthing switches (ES) an amfani a cikin sistemai na HVDC na ƙasa. Tsawon 4 ta nuna misali na DC-GIS da aka ƙare kare daga ƙaramin ƙwarewa na HVDC da DC ES da aka ƙare kare a converter station a cikin sitemai na bipolar HVDC, wanda aka ƙare kare a shekarar 2000.