Ultra-Fast Current Limiter (FCL): Soluzzjoni Rivoluzzjonarja b’Interruzzjoni f’Livell ta’ Millisekonda u Benefiċċji Ekonomiċi

Ikktar: Il-ġabra ta’ Speed u Ekonomija fil-Protezzjoni tal-Kurtkit

Din is-soluzzjoni tikkonsentra fuq d-dispożitiv limitatur tal-kurtkit ġdid, disegnat biex jindirizza l-isfida li qed tisilġa ta’ kurtkit eċċessivi u tassegura s-sigurtà tal-grids tal-enerġija u tal-equipament.

1.1 Atributi Korni

Speġi Rappreżentativi tal-Interrużjon: Jiddeċkja l-erori u jlimita l-kurrent f'1 millisekonda, b'effett restringend il-kurtkit qabel ma jiġi rraggiunt il-pik prospettiv.
Kapaċità Rappreżentativi ta’ Interrużjon:

Adequati għal sistemi 12kV/17.5kV: kapaċità massima ta’ interrużjon 210kA (RMS).
Adequati għal sistemi 24kV/36kV/40.5kV: kapaċità massima ta’ interrużjon 140kA (RMS).

1.2 Vantaggi Korni

Efifienza Ekonominija: Jopera parallelament mal-limitaturi tal-kurrent biex jipprovduna s-soluzzjoni limitaturi ppijkolu ekonomika. Ivvita l-bidla ta’ pannelli kumpluti switchgear jew transformers minħabba l-kurtkit eċċessivi, bl-iżjed kbir ta’ investiment fit-substations ġdida jew aġġornata.
Kompatibilità Largha: Ideali għall-interconnessioni switchgear u substations; fi ħafna scenari (pereżempju, operazzjoni parallel ta’ multipli transformers), huwa s-soluzzjoni teknika unika possibbli.
Affidabilità Strukturale:

Piż 60 sena ta’ esperjenza globali (inventat fl-1955), verifikat fit-tmiem ta’ mijjar projetti madwar id-dinja.
Istatistika minn qrib 4,000 unitajt turi medi ta’ operazzjoni biss waħda kull erbgħa sena, dimostranti prestazzjoni stabili u affidabili.

Domandi Teknikali u Risposti Korni

Nru.	Domanġa Korni	Risposta Korni
1	X’hu l-kurrent massimu tal-kurtkit?
2	Perché limitu l-kurrent massimu tal-kurtkit?	Il-kurrenti massimi li jisghuvu l-parametri ta’ resistenza tas-silġa jistgħu jidamaġġjaw switchgear, circuit breakers, current transformers, u konnektör tal-kable permezz ta’ forzi elettromagnetiku potenti.
3	Kif adattar għal operazzjoni parallel ta’ multipli transformers?	Għal switchgear b’restituenza ta’ 2Ik, fis-sistema b’quddiem transformers (4Ik) parallel, tintiġieħ l-adattazzjoni perfetta mill-installazzjoni ta’ limitaturi tal-kurrent rapidi bejn bus sections (pereżempju, bejn sections 1-2 u 3-4).
4	Xi huma l-kriterji ta’ tripping? Kif evita l-falsi tripping?	kurrent instantaneu (I) u l-taqsima tal-kurrent (di/dt). It-tripping jiġi attivat biss meta tkun l-ewwel u l-ħanut jisghuvu l-limiti settati. Dan ikriterju doppju jassigura biss li l-kurrenti tal-kurtkit perikoluż jiġu interrotti, mentri l-erori ġenerali jiġu amministrati mill-circuit breakers downstream.
5	Kif manutenzjoni wara l-operazzjoni?

Funzjonali Korni u Valur

3.1 Funzjoni Korni

Jiddeċkja u jlimita l-erori wara l-faza inizjali tal-kurrent tal-kurtkit (fil-1ms), efettivament prevenend id-damage tal-equipament tal-enerġija minħabba l-istabilità dinamika u termika insufficenti. Jkompenża perfettament l-limiti inherenti tal-circuit breakers tradizzjonali - "slow to act and unable to suppress the first half-wave peak current."

3.2 Vantaggi Konfrontati

Oggett ta’ Konfront	Dettagli tal-Vantaggi
Circuit Breakers Tradizzjonali	Il-breakers jagħmlu decine ta’ millisecondi biex jinterrompu, mhux jistgħu jivitan l-impat tal-pik kurrent primu. Dan il-limitatur irrispondi fil-1ms, restringend il-kurrent massimu tal-kurtkit għal livell inferjuri.
Current-Limiting Reactors	Avoids voltage drop, active losses (copper losses), and reactive losses associated with reactors in continuous operation. Also eliminates the need to address generator regulation issues caused by reactor integration.

3.3 Skenari Applicabbli

Power plants
Large industrial grid substations
Specific key circuits/scenarios: Transformer/generator feeder circuits, bus tie sections, reactor bypass applications, and interconnection points between grids and captive power sources.

Struttura u Disegnu

4.1 Komposizzjoni Korni

3 bases tal-bridge konduċtiv
3 bridges konduċtivi
3 matching current transformers
1 unità tal-kontroll

4.2 Dettagli tal-Komponenti Korni

Isem tal-Komponent	Komposizzjoni / Karatteristiki	Parametri Korni / Regoli
Base tal-bridge konduċtiv	Inkludi pjan ta’ montaġġ, isolatori, pulse transformer, u konekturi b’quick couplings	- Kurrent nominal ≥2500A u votaġġ 12/17.5kV: konnessjonijiet bolted. - Pulse transformer: ≤17.5kV (installat tikollha bil-fond); ≥24kV (installat ftit u fond biex isseħħ l-isolazzjoni affidabbli).
Bridge konduċtiv	Nuċel konduċtiv u ripleniment induttiv encapsulated in an insulating cover
Matching Current Transformer	Bushing or block type, series-connected in the main circuit	Features a gapped core (high overcurrent factor, low remanence) and shielded primary/secondary windings (low impedance) to ensure measurement accuracy and speed.
Control Unit	Includes power supply, control, indication, and anti-interference units	- Dimensions: 600mm (W) × 1450mm (H) × 300mm (D); weight: 100kg. - Indication unit: 5 flag relays (3-phase trip indication + readiness monitoring + power supply monitoring).

Prinċipju ta’ Operazzjoni: Realizzazzjoni ta’ 1ms Limitazzjoni tal-Kurrent

5.1 Komposizzjoni Korni

"Extremely fast switch (conductive bridge)": Carries rated current during normal operation and opens instantaneously during faults.
"High-breaking-capacity fuse": Ultimately interrupts the high current after the switch opens.

5.2 Sequenza ta’ Operazzjoni

Detection: Matching current transformers (CTs) continuously collect current signals; the control unit calculates instantaneous current (I) and rate of current rise (di/dt).
Judgment: When both I and di/dt exceed set values, the control unit immediately issues a trip command (independent three-phase judgment and triggering).
Interruption: The trip capacitor discharges into the pulse transformer, triggering the inductive filler in the conductive bridge. This generates high-pressure gas, causing the conductive core to rupture at its pre-cut within 1ms.
Current Limiting: Arc resistance increases rapidly, transferring current to the parallel fuse. The fuse begins limiting within 0.5ms and extinguishes the arc completely at the next current zero, clearing the fault.

5.3 Auxiliary Units

Power Unit: Provides 150V DC power to charge the trip capacitor and supply electronic components. Includes a watchdog circuit to monitor system health.
Anti-Interference Unit: All external wiring passes through this unit, providing effective protection against external electromagnetic interference and preventing false operations.

Commissioning and Testing

6.1 Testing Requirements

Regular functional testing is required, which can be executed by users or ABB service engineers.

6.2 Dedicated Equipment

Simulator: Temporarily replaces the conductive bridge during testing. Its built-in neon lamp lights up upon receiving a trip pulse, indicating proper operation.
Test Plug & Test Instrument: Used to check trip output voltage and overall functionality. Features a user-friendly interface and easy operation (dimensions: 400×215×320mm; weight: 11kg).

Scope of Supply and Parameters

7.1 Supply Models

Model Type	Applicable Scenarios	Core Configuration
Discrete Components	For installation in existing switchgear	3 bases + 3 conductive bridges + 3 CTs + 1 control unit
Drawout Cabinet	For metal-clad switchgear	Conductive bridges mounted on withdrawable carts (with isolating switch function); CTs fixed; control unit installed in the low-voltage compartment
Fixed Cabinet	- For 12/17.5/24kV systems - Mandatory for 36/40.5kV systems	All components fixed inside the cabinet. For 36/40.5kV systems, the control unit is often installed in a separate control box.

7.2 Key Technical Parameters (Example: Discrete Components)

Note: ¹ indicates forced air cooling is required; compatible with 50/60Hz frequency.

Technical Parameter	Unit	12kV	17.5kV	24kV	36/40.5kV
Rated Voltage	V	12000	17500	24000	36000/40500
Rated Current	A	1250-5000¹	1250-4000¹	2500-4000¹	1250-3000¹
Rated Short-Circuit Breaking Current (Max.)	kA RMS	210	210	210	140

Typical Application Scenarios

Application Scenario	Core Issue	Solution Value
Parallel System Operation	Short-circuit current from multiple transformers in parallel exceeds switchgear ratings	1. Allows reduced system impedance, minimizing voltage drop. 2. Optimizes transformer load distribution, reducing losses. 3. Enables uninterrupted load transfer during faults, improving supply reliability.
Grid-Captive Power Interconnection	Captive generator operation causes excessive short-circuit current at the common coupling point	The only rational solution. Can be equipped with directional tripping (requires CT at generator neutral) to ensure operation only for grid-side faults.
Bypassing Current-Limiting Reactors	Reactors in continuous operation cause losses and voltage drop	Bypasses reactors during normal operation (zero loss, zero voltage drop); rapidly interrupts during short circuits, diverting current to the reactor for limiting.
Selective Application of Multiple Units	Selective operation required when multiple limiters are installed on multi-section buses	Uses "current vector sum" criterion to ensure only the limiter closest to the fault operates. Supports up to 5 transformers in parallel (using 4 limiters).