Bikarışa Analîz û Cihazên Kombinasyonê ya Switch û Fyûzêya Kirînêda Bîravkirina Dêran

Wêche wateya xwendîna bûyerên rêzan û operasyon û mîndarzina zeviya pêtgotin û stasyona peyvirkirî, êz dibejîn hîn dikarin taybetmendiyên cihedan de destpêkirin ku ji gasira berdesta herêmên çar derket. Berdas Regele Naverok û Karibikê, ji bo cihedan bi kapasiteya daşkirinê ya 250kW an 160kVA ve, naveroka berdesta 10(6)kV û formeyê yeketandina 220/380V vegerîne modelê keskin, ku zeviya pêtgotin û stasyona peyvirkirî yên navber jî ne di şebeka naveroyê de.

I. Strukturê Cihedan û Secimê Şemasê Parastinê
(I) Teya Cihedan

Zeviya pêtgotin û mêra hêsan din îro 2 intervala kablê pêtgotî û 1 intervala serdara transformator heye. Stasyona peyvirkirî yên navber transformator û cihedan berdesta û zevahî yên zeviya biçûk hatine integre kirin de pakete compact û peyvirkirî yên ji bo karbendana di navenda daxiliyan an derveyan de. Navbera xwe parastina transformatoran (wisa, qurtcile) li ser switchên berdesta hîn e.

(II) Pêşkeftina Şemanên Parastinê

Di pratîkê de, du metoda parastinê test kirin: circuit breaker û load switch + current-limiting fuse. Ra'î dawî ye - basit, ekonomîk û piştguhatar ji bo transformatoran. Testa qurtcile dikare bide ku transformatoran hewce ne ku qurtcila bikin bigerînin di 20ms de bi ten re çupakê biben; fuses ya current-limiting bigerînin di 10ms de, ji ber ku circuit breakers ~60ms (relay + operation + arcing time) digerin, ji ber vê yekê min ra'î yekam û fuses bikaram.

II. Piştguhî Load Switch + Current-Limiting Fuse
(I) Endamên Serok

Ji bo projeyên zeviya pêtgotin û stasyona peyvirkirî yên navber yên demê min partisipe kirin, guherbarî load switch + current-limiting fuses bikaranîn. Van cihedan struktura basit, bi cost-efektiv û parastina piştguh û transformatoran hene. Testa qurtcile (ji ber testa on-site) dikare bide ku fuses bigerînin di 10ms de (vs. ~60ms circuit breakers), ku ew neşan dike ku ew çavkaniya çupakê biben.

(II) Logika Yekgirtina

Fuses dikare karbendinên faseyên nederbas bikin ji bo qurtcile faseyek. Ji ber vê yekê, load switches hewce ne ku yekgirtin bikin: strikers fuses trigger load switch tripping ji bo breaking three-phase - ji ber vê yekê, yekgirtina kontrolkirî û neçalî ye.

III. Key Points of Cooperation between Load Switch and Fuse

Wek şoxistî, êz dibejîn ku yekgirtina wan neşan e. Standard IEC420 regele bike, ku ampera divîse be werên 4 (basisim ji bo debugging):

(I) Region I (I < Iak)

I_ak (combined appliance rated current) is less than fuse rated current I_a.nT (due to installation temperature/heat loss). Load switches break rated current and extinguish three-phase arcs - my daily inspection focus.

(II) Region II (Ia.nT< I < 3Ia.nT)

In overload, fuses bear over-current first. At ~2I_a.nT, melts act (but not arc-extinguishing), strikers trigger load switches for three-phase breaking. I test this time-difference logic to avoid protection failure.

(III) Region III (Transfer Current ITC, ~3Ia.nT Start)

Fuses can extinguish arcs after action. One three-phase fuse acts first, triggering strikers; load switches extinguish other two-phase currents. The key is transfer current (load switch's max breaking current at specific power factor, 5I_a.nT - 15I_a.nT), checked during selection/verification.

(IV) Region IV (Current-Limiting Range)

For extreme faults, fuses act in the first half-wave to limit fault current peaks; load switches act but don't break current. I verify this logic in drills for proper operation.

IV. Transfer & Hand-over Current Requirements

These parameters ensure equipment safety, key for my on-site debugging:

(I) Transfer Current

It's the critical value for function transfer between fuses and load switches. Below it, fuses break one phase, load switches handle the rest. Striker-equipped load switches need transfer current tests (usually > rated current) - a challenge for old equipment, verified per IEC420.

(II) Hand-over Current

It's the current fully broken by load switches (no fuse participation). For load switches with both strikers and releases, hand-over current tests are needed. If hand-over current > transfer current, transfer tests may be exempt. Release operation reduces fuse loss but increases vacuum load switch costs (adding relays/releases) - trade-offs made per project budgets/conditions.

V. Transformer Protection Suggestions

For load switch + fuse transformer protection, key verifications include:

• Striker Tripping: Check matching of actual and rated transfer currents for safe breaking.

• Over-current Release: Verify actual and rated hand-over currents for reliable operation.

These tasks are mandatory for new projects/old equipment transformations. As a front-line worker, I ensure stable power supply and safe fault handling for downstream users.