Röðunarsjálfstæður straumspennutakmarkara byggður á venjulegum hlutum Einingar: Ódýr og stöðug lausn fyrir sturtustraum

13yrs + staff 30000+m² US$100,000,000+ China

Inngangur: Rannsóknarbakgrunnur og aðalmarkmið

Seriousness of the Short-Circuit Current Problem
Með óafbrotna stærkun á stöðu rafmagnsnetsins og óhlutleyska stigfræði hans, hefur stig short-circuit straumsins örugglega hækkt, nálægt eða jafnt eða hærra en þróunarmörk núverandi tæna.
• Gögnum studd: Vakstur sýnir að forspáðu short-circuit straumur í sumum 500kV, 220kV, og jafnvel 10kV umflutningastöðum er orðinn yfir 100 kA; hæsta periodískt efni short-circuit straumsins í mikilvægum orkugjöfum nálgast 300 kA.
• Alvarleg hættu: Mikill short-circuit straumur valdi vandamálum eins og brún viðeigandi háspennutengingu, skemmun á rafbúnaði vegna yfirferðar hita og elektró-dýnamískrar krafta, og getur líka valdi öryggisvandamálum eins og elektromagnétisk störf í samskiptakerfum, hækka markmiði jarðar og step voltage. Þetta hefur orðið aðal teknileg flóknar sem takmarka öruggu og kostefna þróun rafmagnsnetsins.
Takmarkanir núverandi FCL teknologíu
Núverandi aðal fyrirbærum fault current limiter (FCL) teknologíu hafa inbyggðar galla, sem gera stórleika notkun erfitt:
• Superconducting FCL: Byggir á superconducting efnum, teknologi sem er ekki enn fullkomin, veitir lága öruggu, fer með hágildi starfsemi og viðhaldskostnað, og er ekonomísk óþægileg, sem heldur til baka raunverulega notkun í stutt til miðlungs tíma.
• Power Electronic FCL: Takmarkað af spennuvirkni og straumsvirkni raforkuefnis, mörgum vandamálum í series/parallel spenna og straum deilingu, flóknari kerfi skipulag (sem krefst aukalegra straumlíms hluta og hratt varnaraðgerða), og er dýr.
Aðalmarkmið þessarrar rannsóknar
Til að leysa þessi vandamál, ætti þessi rannsókn að búa til series resonant fault current limiter lausn byggða á venjulegum rafmagnshlutum, sem er ekki superconducting og ekki power electronic. Sérstaklega eru tvö topologies studaðar:
Series Resonant FCL based on a Saturable Reactor
Series Resonant FCL based on a ZnO Arrester
Þessi rannsókn mun nota Electromagnetic Transients Program (EMTP) simulation til að djúpt greina þeirra transient straumlíms eiginleikar, framkvæma samanburð, og lokalega staðfesta þeirra mikilvægar kostgildi í teknísku hugsanleika, ekonomíu, og starfssemi.

II. Series Resonant FCL Based on Saturable Reactor

Kringaskipulag og virkni
• Topologie skipulag: Kjarninn er myndar af saturable reactor L_B, capacitor C, og series reactor L. L_B er tengdur parallel við C, og þessi sameining er síðan tengdur series við L í kerfið.
• Virkni:
o Normal virkni: Straumur í línu er litill. L_B virkar í unsaturated svæði (its equivalent inductance L_B1 er mjög stórt). Its parallel combination with C behaves inductively. Together with the series reactor L, they satisfy the power frequency series resonance condition (ωL - 1/ωC ≈ 0). The device presents very low impedance, resulting in minimal system losses.
o Fault State: A surge in short-circuit current rapidly saturates L_B (its equivalent inductance drops sharply to L_B2). Its parallel branch effectively short-circuits capacitor C, thus breaking the resonant condition. At this point, the series reactor L and the saturated reactor L_B2 are both inserted into the system, effectively limiting the short-circuit current.
o Fault Clearance: After the fault is cleared, the current decreases. L_B automatically exits saturation, the capacitor is re-engaged, and the circuit returns to the resonant state, achieving self-triggered switching without an external power source.
• Parameter Selection Principles:
o ω²L_B1C >> 1 (Ensures the parallel branch behaves inductively during normal operation)
o ωL - 1/ωC ≈ 0 (Satisfies the resonance condition for normal operation)
o ω²L_B2C << 1 (Ensures the parallel branch behaves capacitively during a fault, effectively shorting the capacitor)
Current-Limiting Characteristic Simulation Analysis (EMTP)
Simulation was conducted under a single-phase-to-ground short-circuit fault condition in a 220kV system (prospective short-circuit current peak: 110kA). Key conclusions are as follows:

Influencing Factor	Core Conclusion	Typical Simulation Data (Example)
1. Unsaturated Inductance L_B1	Increasing L_B1 significantly reduces capacitor overvoltage but has little effect on short-circuit current; effect saturates.	L_B1=1317mH: Capacitor voltage 270kV; L_B1=1321mH: Capacitor voltage 157kV (42% decrease)
2. Saturated Inductance L_B2	An optimal range exists (1-7mH). Too small gives poor limiting; too large causes severe capacitor overvoltage.	L_B2=7mH (C=507μF, L=20mH): Short-circuit current 25kA, Capacitor voltage 157kV
3. C/L Parameter Coordination	An optimal combination exists to cooperatively control short-circuit current and capacitor overvoltage.	Optimal combination (C=406μF, L=25mH): Short-circuit current 22kA, Capacitor voltage 142kV
4. Short-Circuit Inception Angle	Transient characteristics are highly influenced by phase angle; most severe overvoltage at 0°/180°; design must consider worst case.	0° phase: Short-circuit current 18kA, Capacitor voltage 201kV; 90° phase: Short-circuit current 22kA, Capacitor voltage 142kV

III. Series Resonant FCL Based on ZnO Arrester

Kringaskipulag og virkni
• Topologie skipulag: Saturable reactor L_B er skipt út fyrir ZnO arrester. Eftirverandi skipulag (parallel C + series L) er óbreytt.
• Virkni: Virkni er sama og saturable reactor tegund. Á normal virkni, sýnir ZnO hæga mótvíð, og kringan gangur í resonance. Á villu, hækkandi capacitor spenna valdi ZnO að leiða (sýnir lágan mótvíð), short-circuit capacitor, og brestur resonance. Series reactor L takmarkar straum. Kerfið endurræsist sjálfvirkt eftir villu. Allt ferli notar ólíklegt volt-ampere eiginleika ZnO fyrir sjálfvirk skipting.
Current-Limiting Characteristic Simulation Analysis
Simulation under the same system conditions yielded key conclusions:

Influencing Factor	Core Conclusion	Typical Simulation Data (Example)
1. Arrester Residual Voltage & C/L Coordination	Easy to limit capacitor overvoltage, but increasing L to pursue lower short-circuit current leads to excessive voltage on the series reactor.	C=254μF, L=40mH: Short-circuit current 20kA, Reactor voltage 246kV; C=507μF, L=20mH: Short-circuit current 35kA, Reactor voltage 173kV
2. Short-Circuit Inception Angle	Transient characteristics are insensitive to short-circuit phase angle, only affecting current magnitude; maximum current at 90°.	90° phase (C=507μF, L=20mH): Short-circuit current 35kA; 0° phase: Short-circuit current 28kA

IV. Comprehensive Comparison of the Two FCL Schemes

Comparison Dimension	FCL Based on Saturable Reactor	FCL Based on ZnO Arrester
Core Advantage	Superior current-limiting effect; good balance between short-circuit current and component overvoltage achievable through parameter optimization.	Easy limitation of capacitor overvoltage; transient characteristics unaffected by short-circuit phase angle; simpler design.
Core Limitation	Requires precise optimization of core hysteresis characteristics and C/L parameters; difficult control of capacitor overvoltage; significantly affected by short-circuit phase.	Prominent overvoltage issue on the series reactor when pursuing low short-circuit current; requires strict control of L value.
Key Parameter Requirement	Optimal equivalent saturated inductance L_B2 ≈ 1/3 of the capacitive reactance.	Inductance value of the series reactor should not be too large.
Applicable Scenario Preference	Suitable for medium-low voltage levels (e.g., 110kV) in high-voltage grids, where high current-limiting performance is required.	Suitable for scenarios sensitive to capacitor overvoltage with moderate short-circuit current limiting requirements.
Common Characteristics	1. Simple structure: Composed entirely of conventional electrical components, no complex control; 2. Good economy: Cost far lower than superconducting and power electronic types; 3. High reliability: Automatic operation based on physical characteristics, no external control needed; 4. Automatic switching: Instantaneous recovery after fault clearance.

V. Conclusion

This study proposes two innovative series resonant fault current limiter solutions based on conventional components, successfully overcoming the technical and economic bottlenecks of traditional superconducting and power electronic FCLs.

Saturable Reactor FCL: Through meticulous optimization of the core hysteresis loop characteristics, setting the saturated inductance value (L_B2) to approximately 1/3 of the capacitive reactance, and ensuring good coordination with the capacitor and series reactor parameters, it can effectively suppress capacitor overvoltage and achieve excellent transient current-limiting performance. It is particularly suitable for medium-low voltage level grids such as 110kV.
ZnO Arrester FCL: Utilizing the nonlinear characteristics of ZnO easily limits capacitor overvoltage, and its performance is unaffected by the short-circuit phase angle. However, attention must be paid to avoiding overvoltage on the series reactor itself caused by excessive L values. It is more suitable for occasions with high requirements for capacitor safety and moderate current-limiting needs.

08/26/2025

Mælt með

Meira