Fuska na Tsakiyar Goma Da Dukkiya | Ingantaccen ɗakunan da Dukkiya a 10ms Don Haɓaka Masu Turbin

Fusai na gajarta tsari a kan zafi suna da amfani a taimaka da kyakkyawan abubuwa kamar transfomar da motoro. Wani fusai shi ne wani wurin da idan yadda adadin amfani a kan zafi ya yi karfin duka, yana rarrabe alama a kan zafi da ke fito ta hanyar yanayin waɗannan wurare da suka bincike. Fusai na gajarta tsari ba su iya inganta masu adadin zafi mai ban sha'awa (overloads bayan 6 zuwa 10 marubucin adadin zafi), don haka ana amfani da su a cikin wurin da ke da switching devices.

Fusai na gajarta tsari suna faɗinsu a kan zafi ta hanyar fitowa wani wurin metal (fusai element) a kan zafi. Idan adadin zafi mai yawa ko kuma short-circuit ya fito a kan element, za mu samun hoton kaɗanda ta hanyar yanayin wani, don haka za mu rubuta a kan zafi idan adadin zafi ya yi karfin duka. Saboda haka, fusai suna da resistance mai uku, wanda ya haɗa da hoton kaɗanda a kan zafi. Misali, fusai na 125A yana samu hoton kaɗanda kimanin 93W, fusai na 160A yana samu 217W, kuma fusai na 200A yana samu 333W. A kan sashe, fusai na 12kV suke samun adadin zafi har zuwa 355A, wanda ya haɗa da samun hoton kaɗanda mai uku.

A kan amfani da switchgear, adadin zafi mai da fusai ya kasance zai iya kasance kimanin 1.25 marubucin adadin zafi mai da load a kan lokacin da ya yi aiki a tunani. Idan fusai suke fito a kan cabinet na uku bayan ƙasa ko kuma a kan resin-encapsulated tubes, akwai matsalolin hoton kaɗanda a kan compartment na fusai. Hoton kaɗanda da ya fi samu mafi yawa da 100W zai iya haɗa da samun dogon hoton kaɗanda, wanda zai buƙata a kan ƙirƙira adadin zafi mai da fusai.

Daga ma, saboda matsaloli na ƙarfi a ring main units (RMUs), diameter na compartment na fusai a RMUs na gas-insulated yana kasance kimanin 90 mm, wanda ya haɗa da fitowa fusai har zuwa 160A (amfani da su har zuwa 125A). Wannan ya haɗa da taimakawa da transfomar har zuwa kimanin 1250 kVA. Transfomar da suke da 1250 kVA zai buƙata taimakawa da circuit breakers. Duk da haka, a kan F-C (fuse-contactor) circuits da ake amfani da su don taimakawa da motoro, wannan ya haɗa da amfani da motoro har zuwa 1250 kW. Motoro masu uku zai buƙata taimakawa da circuit breaker-based control and protection.

A kan amfani da motor control, F-C combination yana amfani da high-voltage current-limiting fuse a hanyar backup protective device. A kan F-C circuit, idan fault current ya kasance kimanin ko kuma ita breaking capacity na vacuum contactor, integrated protection relay ya kasance, wanda zai haɗa da contactor ya rarrabe zafi. Fusai zai faɗi idan fault current ya yi karfin setting na relay ko kuma idan vacuum contactor bai faɗe ba.

Taimakawa da short-circuit an yi a hanyar fusai. Ana zaba fusai da adadin zafi mai uku da motor full-load current don in taimaka da inrush currents a lokacin da ya fara, amma bai iya taimaka da overload protection ba. Saboda haka, inverse-time ko kuma definite-time relays su ne da buƙatar don taimakawa da overloads. Components kamar contactors, current transformers, cables, motor itself, da sauransu suna iya ƙara da damar hoton kaɗanda ko kuma let-through energy mai uku.

Taimakawa da overcurrents da suka faru saboda overloads, single-phasing, rotor lock, ko kuma repeated starts an yi a hanyar inverse-time ko kuma definite-time relays, wanda suke haɗa da contactor. A kan phase-to-phase ko kuma phase-to-ground faults da suka faru saboda breaking capacity na contactor, taimakawa an yi a hanyar relay. A kan fault currents da suka yi karfin breaking capacity na contactor har zuwa maximum withstand level, taimakawa an yi a hanyar fusai.

Fuse-combination switchgear suna da amfani da su don taimakawa da transfomar. Amfani da su suna da transformer feeder circuits a ring main units (RMUs), inda SF6 load switch yana haɗa da fuses don samun design mai ƙarfi da ba da laifi. Wannan configuration na biyu shi ne draw-out trolley solution, inda fuse-load switch combination unit yana haɗa da medium-voltage switchgear (misali, metal-clad switchgear), wanda yana haɗa da withdrawal for maintenance and fuse replacement.

Idan combination appliances suna amfani don taimakawa da transfomar, an yi two-stage protection scheme ta hanyar relay protection. A kan overloads ko kuma moderate overcurrent conditions, relay yana haɗa da trip command to the load switch don clear the fault. A kan severe short-circuit faults, fusai zai faɗi don trigger the switch to trip, wanda zai haɗa da interruption of the circuit.

Idan internal fault kamar short circuit ya faru a cikin transfomar, za mu samun arc da ya haɗa da insulating oil into gas. A cikin lokacin da fault ya ci, pressure na ƙarshen ya yi karfin, wanda zai haɗa da tank rupture or explosion. Don in ƙara tank failure, fault ya buƙace a kan 20 milliseconds (ms). Amma, total breaking time na circuit breaker—composed of relay operating time, inherent tripping time, and arcing time—yana kasance kimanin 60 ms, wanda ba su da buƙatar don effective transformer protection. Duk da haka, current-limiting fuses suna da fault interruption mai tsawon lokaci, wanda suke iya clear faults within 10 ms, wanda yana haɗa da highly effective protection for the transformer.