Sagot ng Combined Instrument Transformer (CIT) Solution: Perspektibo sa Engineering Design & Integration

1. Pangunahing Konsepto ng Solusyon: Modular na Platform na may Pamamahagi ng Insulasyon

Disenyo: Lumikha ng iisang uniporme, modular na platform na naglalaman ng mga function ng pag-sense ng kasalukuyan at voltahan sa isang optimisadong istraktura.
Insulasyon: Gamitin ang pamamahagi ng insulating envelope. May dalawang opsyon ang inihanda:

SF6 Gas: Nakatapos na mataas na dielectric strength at kamangha-manghang arc-quenching properties para sa mas mataas na voltage classes (hal. 72.5 kV pataas). Ang disenyo ay may gas density monitoring at napapatunayan na sealing technology.
Composite Housing (Solid Insulation): Kapaligiran-sustenable na solusyon na gumagamit ng high-grade polymer materials na may silicone sheds. Ideal para sa mas mababang hanggang medium na voltages o kung kinakailangan ang pag-iwas sa SF6. Optimized para sa creepage distance at pollution performance.

Modularity: Disenyo ang mga internal components at interfaces upang payagan ang:

Scalability sa iba't ibang voltage classes (hal. sa pamamagitan ng pag-aadjust ng haba ng insulator).
Pag-adapt sa espesipikong bushing interface requirements.
Potential para sa future sensor technology upgrades.

2. Implementasyon ng Integrated Sensing Technology

Sensor: Mataas-accuracy, temperature-compensated Rogowski coils. Pinili dahil sa:

Wide Dynamic Range: Kamangha-manghang linearity mula sa maliliit na bahagi ng nominal current hanggang sa mataas na fault currents (hal. >40 kA).
No Saturation: Pundamental na advantage sa iron-core CTs, na nagwawala ng risk ng saturation sa panahon ng faults.
Lightweight: Nagsasanggalang nang lubos sa mechanical stress sa buong istraktura.

Integration: Strategically placed ang coils sa loob ng insulator envelope, concentric sa primary conductor. Secure mechanical mounting na resistant sa vibration.

Sensor: High-stability capacitive voltage dividers (CVDs) bilang standard. Resistive dividers (RVDs) inisip para sa espesipikong DC o wide-bandwidth applications na nangangailangan ng mabilis na transient response.
Integration: CVD sensing electrodes (low-impedance) na integrated diretso sa insulator structure. Precision grading electrodes na nagse-secure ng uniform field distribution at thermal/pollution stability. Critical shielding na nagbabawas ng external field interference.

3. Advanced Electromagnetic Field Modeling & Isolation (Critical Engineering Challenge)

Modeling: Kinakailangan, high-fidelity 3D Finite Element Method (FEM) modeling ng buong platform:

Precisely characterizes ang internal electromagnetic fields sa ilalim ng lahat ng operational conditions (sinusoidal, transient, distorted waveforms).
Evaluates ang proximity effects mula sa mga conductor, enclosure, at adjacent phases.

Physical Separation: Optimal geometric arrangement ng sensing elements (coils, CVD electrodes) batay sa resulta ng modeling. Maximize ang distansya sa loob ng constraints.
Active Shielding: Implementation ng grounded electrostatic shields na strategically placed sa pagitan ng mga sensor elements batay sa field simulation data.
Guard Rings: Gumamit ng conductive guard rings sa paligid ng Rogowski coil outputs upang drainin ang displacement currents.

Dedicated Signal Paths: Routing ng signals mula sa individual sensors gamit ang shielded, twisted-pair cabling sa loob ng enclosure kaagad pagkatapos ng capture.
Compensated Circuit Design: Electronic conditioning circuits na disenyo na may crosstalk cancellation techniques na informed ng FEM models.
Validation: Rigorous factory testing (kabilang ang harmonic injection tests) upang characterize at verify ang isolation margins at crosstalk levels (< 0.1% specified).

4. Integrated Digital Processing & Standardized Interfaces

Dedicated, low-power ASICs o high-reliability microcontrollers na directly integrated sa sensor platform o adjacent sealed module.
Mga function kabilang: Rogowski coil integrator, scaling, ADC conversion, harmonic computation (kung applicable), linearization, temperature compensation, at timestamping.

Embedded Interfaces: Incorporate IEC 61869 compliant digital output circuitry direktamente sa CIT unit.
Protocols: Standardized support para sa:

IEC 61850-9-2: Sampled Values (SV) stream over Ethernet (karaniwang multicast).
IEC 61850-9-3LE: Lightning Edition SV profile para sa guaranteed low-latency determinism.

Additional Options: Provision para sa legacy outputs (analog, IEC 60044-8 FT3) kung kinakailangan via optional modules.

Data Quality: Integrated Merging Unit (MU) functionality na sumasabay sa relevant IEC 61869 accuracy (TPE/TPM class) at timing (PLL synchronization) standards.

5. Engineering Design & Integration Considerations

Thermal Management: Models na may thermal performance analysis. Power dissipation mula sa electronics na actively managed gamit ang low-power components, potential localized heatsinks, at optimized convection paths sa loob ng insulator.
EMC/EMI Robustness: Conformal coating, shielded enclosures, ferrites, at optimized grounding strategies na ipinapatupad sa internal electronics. Surge protection na sumasabay sa relevant standards (IEC 61000-4-5).
Mechanical Integrity: Structural analysis na ginawa para sa seismic loads, wind loading, ice loading, at dynamic forces sa panahon ng faults. Optimized use ng materials (composite/porcelain/SF6) na nakakatulong sa lower seismic mass.
Factory Calibration & Testing: Comprehensive calibration laban sa reference standards (optical/VTBI methods). Kabilang ang verification ng EM isolation effectiveness, timing accuracy, protocol compliance, at full-power dielectric testing.
Lifecycle & Serviceability: Disenyo para sa minimal maintenance (lalo na SF6 o solid insulation). Modular electronics na potentially accessible/testable nang walang major disassembly. End-of-life disposal pathways na inisip (SF6 recovery/recycling).

Benefits Realized through this Design & Integration Approach:

Footprint Reduction: Up to 40-50% space savings vs. separate CTs/VTs – crucial para sa retrofits at compact GIS/AIS designs.
Enhanced Accuracy & Safety: Nagwawala ng traditional CT saturation risks, improves transient response (Rogowski/CVD), reduces external connections/risks.
Simplified Installation: Single unit mounting at commissioning na significantly reduce field labor at cabling complexity.
Lower Lifecycle Costs: Reduced installation, cabling, civil work, maintenance overhead.
Digital Substation Readiness: Direct IEC 61850-9-2/3LE output na nagbibigay ng seamless integration sa modern protection, control, at monitoring systems (SAS).
Future-Proof Platform: Modular design na acommodates evolving sensor technologies at communication standards.
Reduced Environmental Impact (Solid Insulation Option): Nagwawala ng SF6 usage at associated risks.