Sulod nga Rogowski Coil + Low-Power CT (LPCT) Integrated GIS Broadband Current Measurement Solution

17yrs 700++ staff 108000m²+m² US$150,000,000+ China

Background: Sa mga DC transmission converter stations, malalaking electric arc furnaces, ug uban pang mga kalibutan nga may severe harmonic pollution ug high transient conditions, ang tradisyonal nga electromagnetic current transformers (CTs) sa loob sa Gas-Insulated Switchgear (GIS) naghahadlok sa significant challenges: ang limited frequency bandwidth nagdudulog sa distortion sa high-frequency ug transient signals; ang measurement accuracy wala masukod sa mga requirement sa harmonic analysis ug protection; ug ang external merging units (MUs) mogasto og dako ug komplikado.

Solution: Kini nga solusyon innovatively integrates Rogowski coils ug Low-Power Current Transformers (LPCTs) sa loob sa GIS enclosure, gisama sa local digitization technology, na naghatag og accurate full-band measurement gikan sa near-DC hangtod sa high frequencies, ug direct digital output compliant sa IEC 61850 standard.

Technical Highlights:

Dual-Sensor Fusion Technology:

Rogowski Coil: Responsible for capturing broadband/high-order harmonics/transient currents. Ang absence niini sa magnetic saturation nagtubag sa linear response sa ultra-wide bandwidth gikan sa 0.1 Hz hangtod sa 2 MHz, accurately capturing fast transient processes sa converter stations (e.g., commutation failures) ug high-order harmonics up to several hundred times generated by arc furnaces.
Low-Power CT (LPCT): Responsible for high-accuracy measurement and protection of power frequency fundamentals. Nakamit niini ang accuracy class as high as 0.2S, ensuring stable, reliable, ug standard-compliant current measurement sa fundamental frequency (50/60Hz) ug nearby low-order harmonic conditions, meeting the requirements for energy metering ug protection signal sources.
Intelligent Fusion: Ang data processing unit performs intelligent synchronization ug calibration sa duha ka signal paths, achieving seamless stitching sa entire frequency band (0.1 Hz to 2 MHz), outputting a unified, high-precision current data stream.

On-Sensor Digitization:

Sampling: Integrates the high-performance AD7606 ADC chip (16-bit resolution, 200 kSPS sampling rate) directly at the CT mounting flange side.
Output: Ang digitized data is transmitted via optical fiber, compliant sa IEC 61850-9-2LE protocol standard, replacing the traditional external merging unit (MU).
Advantages: Completely eliminates attenuation, noise interference, ug grounding issues introduced by long-distance analog signal transmission; significantly simplifies the system structure; enhances signal quality ug anti-interference capability.

Extreme Anti-Interference Design (Key Reliability Assurance):

Fusion Unit (MU Module) Structure:

Enclosure: High-stiffness cast aluminum housing provides mechanical strength ug basic electromagnetic shielding.
Core Shield Layer: Employs Permalloy (magnetic permeability μ ≥ 10⁴), forming an ultra-high permeability magnetic shielding path. Ang shielding capability niining materyales para sa low-frequency strong magnetic fields far exceeds that of ordinary aluminum housings or silicon steel sheets, making it the ideal choice for the harsh electromagnetic environment inside GIS.

Application Scenarios:

High-Voltage Direct Current (HVDC) Converter Stations: Accurately measures steep wave front (extremely high di/dt) transient currents ug characteristic harmonics (e.g., 12k±1 orders generated by 12-pulse systems) produced during converter valve switching, ensuring stable ug efficient operation of the DC control and protection system.
Large Electric Arc Furnaces / Rolling Mills and other Impact Loads: Precisely captures load rapid start/stop, short-circuit currents, ug the generated wide-spectrum harmonics (2nd to 50th order and beyond), providing high-fidelity data for power quality analysis, harmonic mitigation, ug relay protection.
Smart Substations: Meets the stringent requirements for current data bandwidth ug accuracy from new advanced applications such as Condition-Based Monitoring (CBM), Phasor Measurement Units (PMU), ug broadband protection.

Core Advantages:

Ultra-High Accuracy Across Full Bandwidth: Comprehensive error strictly controlled within ±0.5% across the entire measurement band (0.1 Hz - 2 MHz), simultaneously meeting high-accuracy power-frequency metering (0.2S class) ug high-frequency/transient measurement needs.
Breakthrough in Bandwidth Limitations: The Rogowski coil's ultra-wide frequency response (0.1 Hz - 2 MHz) covers DC components, extremely low-order harmonics up to high-frequency RF interference, unattainable by traditional CTs.
Significant Cost and Space Savings: Eliminates the external Merging Unit (MU) ug associated cabling, installation space, reducing overall system equipment procurement, installation, ug maintenance costs by approximately 30%. The GIS main structure becomes more compact.
Strong Anti-Interference & Reliable Operation: The combination of a cast aluminum housing ug Permalloy magnetic shielding provides exceptional electromagnetic protection, ensuring long-term stable ug reliable operation in the harsh GIS environment.
Seamless Digital Grid Integration: Native IEC 61850-9-2LE optical fiber digital output, fully compatible with modern digital substation architecture, simplifying secondary wiring.

Key Performance Parameter Overview

Indicator Category	Measurement Parameter	Performance Value	Core Significance
Measurement Bandwidth	(Rogowski)	0.1 Hz - 2 MHz	Covers transients & high-frequency harmonics
Measurement Accuracy	(LPCT @ Power Freq)	0.2S Class	Meets precision metering & protection requirements
Measurement Accuracy	(Full Bandwidth Composite)	< ±0.5%	Ensures high precision across the entire domain
Digitization	Sampling (ADC)	16-bit / 200 kSPS (AD7606)	High-precision on-sensor digital conversion
Digitization	Output Protocol	IEC 61850-9-2LE (Fiber)	Seamless access to digital substations
Anti-Interference	Shielding Material	Permalloy (μ ≥ 10⁴)	Resists strong internal GIS electromagnetic interference