Mtafutano wa Vifaa vya Kubadilisha Kilicho 10kV (Isolator, Load Switch, Circuit Breaker, na Fuse)

1. Nini ni Pole-Mounted Switch?​​
   Ni kifaa cha kupunguza kwa nguvu kinachoungazwa pole za umeme wa nje katika mstari wa utoaji wa umeme wa anga wa 10kV, linalotumiwa katika mitandao ya utoaji ya ukanda na desa. Limetengenezwa kufunga, kufungua, na kutumia mawimbi ya kiwango cha mstari na mawimbi ya hitilafu.
   Pole-mounted switches mara nyingi yanajumuisha mwili wa switch unaosimbwa + FTU (Feeder Terminal Unit). Pole-mounted switches zinazotambuliwa chini yanapatikana katika jamii ya pole-mounted disconnectors (isolators).

​2. Tofauti za Pole-Mounted Switches​
Pole-mounted switches zinaweza kutofautishwa kutoka kidimoni kadhaa. Njia muhimu za kutofautisha na sifa ni ivi:

​Kulingana na Uwezo wa Kupunguza:​​

• ​a. Pole-Mounted Disconnector (Isolator):​​ Hauna uwezo wa kupunguza maguta; haiwezi kufunga au kupunguza mawimbi ya kiwango cha mstari. Ina break visible (isolation gap). Maana yake msingi ni kuzuia mstari ili kukuhakikisha usalama wakati wa huduma.
• ​b. Pole-Mounted Load Switch:​​ Una uwezo wa kupunguza maguta asili; inaweza kufunga, kutumia, na kupunguza mawimbi ya kiwango cha mstari (≤630A). Inaweza kutumia lakini haiwezi kupunguza mawimbi ya hitilafu.
• ​c. Pole-Mounted Circuit Breaker:​​ Uwezo mkubwa wa kupunguza maguta; inaweza kufunga, kutumia, na kupunguza mawimbi ya kiwango cha mstari (≤630A) na mawimbi ya hitilafu (≥20kA).
• ​d. Pole-Mounted Fuse (Drop-Out Fuse):​​ Maana msingi ni kupunguza mawimbi ya hitilafu ya fupi; inatumika kwa uzalishaji wa usalama wa mstari.

​3. Pole-Mounted Disconnector (Isolator)​​
Pia inatafsiriwa kama "isolating knife switch," ni kifaa cha kudhibiti bila mekanizmo wa kupunguza maguta. Maana yake msingi ni kuzuia umeme ili kukuhakikisha usalama wa huduma ya vifaa vingine vya umeme. Huduma kwa mwingiliano haipatikani (inafanya/break low-power circuits kwa masharti maalum tu). Ni moja ya vifaa vinavyotumiwa sana na vinavyoopereshwa sana katika upunguzaji wa kiwango cha juu.

​3.1 Matumizi Makuu​

• Kutokupa umeme vifaa vya mstari kwa ajili ya huduma, kutafuta hitilafu, kutest kabeli, na kurudia aina za misingi ya matumizi.
• Marapo imefungwa, inazuia vifaa vilivyopewa kwa mstari ulio na umeme, kujenga faragha ya insulation yenye imani na kuwasaidia watu wanaojitahidi kwa kutathmini usalama.
• Inafanya kazi kama switch ya kuchukua hatua kati ya mstari wa anga na mali ya mtumiaji, au kati ya mstari wa kabeli na mstari wa anga.
• Imeinstale kwenye upande mmoja au wote wa tie load switch ili kusaidia kutafuta hitilafu, kutest kabeli, na huduma/replacement ya tie load switch.

​3.2 Sifa Muhimu​

• ​Faida:​​ Bei chache, muundo msafi, utaratibu.
• ​Mwishowe:​​ Haiwezi kutumika kwa mwingiliano wa kiwango au mzigo mkubwa; haiwezi kupunguza au kufunga mawimbi ya mwingiliano na mawimbi ya hitilafu.
• ​Mfumo wa Kutumia:​​ Kwa kutumia umeme: "Funga isolator kwanza, basi funge circuit breaker/load switch." Kwa kutokupa umeme: "Funga circuit breaker/load switch kwanza, basi funge isolator."
• ​Masharti Yaliyomoanishwa:​​ Inaweza kufunga/kupunguza mawimbi ya magnetizing ya transformers zenye mzingo mfupi (≤2A) na mawimbi ya capacitance ya mstari zenye mzingo mfupi (≤5A).
• ​Parameta Tekniki:​​ Mara nyingi, peak withstand current (dynamic stability) ≤40kA (yanapaswa kutathmini wakati wa chaguo). Umri wa kutumia kwa kiwango cha tekniki ni karibu 2000 cycles.

​4. Pole-Mounted Load Switch​
Una kifaa cha kupunguza maguta rahisi, inaweza kufunga na kupunguza mstari kwa mwingiliano. Inaweza kupunguza mawimbi ya mwingiliano na mawimbi za mzigo mkubwa lakini haiwezi kupunguza mawimbi ya hitilafu. Inahitaji kutumika kwa mfululizo na fuse ya kiwango cha juu (ambayo hupunguza mawimbi ya hitilafu). Funguo zake zinapatikana kati ya isolator na circuit breaker. Matumizi makuu yake ni kusegment mstari na kuzuia hitilafu.

​4.1 Aina Na Sifa Zinazofanana​

​4.2 Sifa Za Muundo Ya Bidhaa Mkuu​

• ​Vacuum Load Switch:​​ Aina ya three-phase common tank, imezinduliwa VSP5 electromagnetic/spring operating mechanism. Inaweza kuwa na built-in current transformers (CTs) na isolation gaps. Inasupport cable/terminal outgoing lines. Inaweza kuamshwa hanging au sitting.
• ​SF₆ Load Switch:​​ Aina ya three-phase common tank. Inaweza kuwa na built-in current transformers (CTs). External isolation device optional. Inasupport cable/terminal outgoing lines. Inaweza kuamshwa hanging au sitting.

​5. Pole-Mounted Circuit Breaker​
Ni kifaa cha kupunguza maguta kamili. Inaweza kufunga, kutumia, na kupunguza mawimbi ya mstari wa kiwango, na inaweza kutumia na kupunguza mawimbi ya mstari wa hitilafu (mzigo mkubwa, hitilafu) kwa muda unaoelekezwa. Funguo zake zinapatikana kama "fused switch + over/under thermal relay." Pole-mounted circuit breakers zinatafsiriwa kama "reclosers" au "auto-reclosers." Imeinstale pole, ni vifaa muhimu kwa uzalishaji na kudhibiti katika sehemu za mitandao ya utoaji.

​5.1 Matumizi Makuu​

• Kusegment, kuswitch, kudhibiti, na kuhakikisha usalama wa sehemu za mstari wa utoaji; inaweza kutoa kwa mawimbi ya hitilafu na kufunga mawimbi ya hitilafu.
• Marapo inatumika kufunga/funga mstari; wakati wa hitilafu, inafunga kwa mtaani au kwa mikakati (kwa kutumia vifaa vya kuhakikisha usalama).
• Imeinstale kwenye points za kuchukua hatua kwenye mstari wa utoaji wa 10kV; inaweza kutoa kwa hitilafu za earth fault single phase na kuzuia hitilafu za short-circuit. Ni vifaa muhimu kwa majanga ya kuboresha automation ya utoaji.

​5.2 Tofauti Na Bidhaa Mkuu​
Kutofautishwa kulingana na medium ya kupunguza maguta: Oil circuit breaker (katika umbali wa kupunguza), SF₆ circuit breaker, Vacuum circuit breaker (ya sasa).
Outdoor AC high-voltage intelligent vacuum circuit breakers zinapendelekwa kwa mstari wa utoaji, zinapatikana:

• ​Funguo:​​ Kutafuta hitilafu, kuhakikisha usalama, uhusiano.
• ​Mfumo Wa Kutumia:​​ Manual, electric, remote control, host computer remote operation.
• ​Muundo:​​ Body + operating mechanism + controller (inaweza kuwa na built-in isolator).
• ​Zinapatikana:​​ CT (Protection Current Transformer), ZCT (Zero-Sequence Current Transformer), PT (Voltage Transformer).

​5.3 Subtypes Ya Vacuum Circuit Breaker​

• ​SF₆ Insulated Vacuum Circuit Breaker:​​ Vacuum arc extinction + SF₆ insulation. Three-phase common tank. Spring operating mechanism. Inaweza kuwa na built-in CTs. External isolation device optional. Hanging or sitting mounting.
• ​Air Insulated Vacuum Circuit Breaker:​​ Vacuum arc extinction + air insulation. Three-phase solid-pole type. Spring or permanent magnet operating mechanism. External CTs. External isolation device optional. Sitting mounting.

​6. Drop-Out Fuse​
Inatafsiriwa kama "fuse cutout," ni switch ya kuhakikisha usalama wa mstari wa branch na transformer za utoaji wa 10kV. Ni rahisi, rahisi kutumia, na inapatikana kwa mazingira ya nje. Inatumika sana kwa uzalishaji na kuswitch kwa mstari wa 10kV na primary side ya transformer za utoaji.

​6.1 Matumizi Makuu​

• Imeinstale kwenye mstari wa utoaji wa branch 10kV: Inainsha eneo la power outages. Inapatikana kama isolator kwa sababu ya visible break, inajenga mazingira sahihi kwa huduma.
• Imeinstale kwa transformer za utoaji: Inapatikana kama usalama mkuu wa transformer, inahakikisha transformer zina protection dhidi ya mzigo mkubwa na hitilafu.

​6.2 Installation and Structure​

• ​Installation Location:​​ Can be installed on the source side of a load switch (preferred when fuses don't need frequent replacement, allows the load switch to isolate voltage) or on the load side.
• ​Core Components:​​ Insulator, lower support base, lower moving contact, lower fixed contact, mounting plate, upper fixed contact, "duckbill" contact, upper moving contact, fuse tube.

​7. Core Differences Between Pole-Mounted Switches​
The key differences between various pole-mounted switches lie in three main dimensions: arc-extinguishing capability, types of interruptible current, and protection function. A detailed comparison is below:

​Summary​

• ​Disconnector (Isolator):​​ Only breaks no-load current; provides a "visible break point" for safe maintenance.
• ​Load Switch:​​ Breaks normal load current, not fault current; requires a fuse for fault protection.
• ​Circuit Breaker:​​ Breaks both normal load and fault currents; requires relay protection coordination; core device for distribution network protection.
• ​Drop-Out Fuse:​​ Specifically breaks short-circuit/overload currents; provides low-cost protection for branch lines and transformers.