COSI-CT
The COSI-CT optical current sensor brings a new level of accuracy to sensing over the range between 1 Arms and 63 kA rms.
The reduced size and weight are attractive benefits compared to conventional oil-filled equipment, allowing placement in compact substations or in retrofit applications where space may be limited.
A lightweight dry-type insulator and window head design allow pedestal mounting or suspension from a rigid bus.
Its broad dynamic range makes this CT particularly suited for both high-precision metering and protection applications at the same time.
The accurate measurement of DC and AC to 100th harmonic and the measurement of phase angle is a must for new Smart Grid applications.
The standard digital interface will ensure smooth integration of COSI-CT in the digital substation application.
PERFORMANCE FEATURES
- Accuracy exceeds ANSI/IEEE Class 0.15S/IEC Class 0.2S for metering and IEC Class 5P/IEEE 10% for protection
- Wide dynamic range
- Bandwidth from DC to 100th + harmonic
- No magnetic core saturation
- Excellent phase accuracy
- Digital Interface and analog output
INTRINSICALLY SAFE, ENVIRONMENTAL FRIENDLY
- No oil, gas or SF6
- No hazardous open secondaries
- No violent failure
BASIC FARADAY EFFECT
In Faraday Effect current sensors, the current flowing through a conductor induces a magnetic field that affects the propagation of light traveling through an optical fiber encircling the conductor.
A linear state of polarization rotates in the presence of a magnetic field because the field produces a circular birefringence in the glass. Birefringence refers to an optical material with two indices of refraction.
METERING AND PROTECTION ACCURACY
The COSI-CT design permits measurements to be made with the highest possible accuracy and stability. To address stringent revenue metering applications, its performance exceeds IEC Class 0.02S and IEEE Class 0.3 accuracy (optional 0.15%) with a dynamic range that extends from 1 A to 4800 A.
The COSI-CT has ultra-accurate and stable phase measurement, which is critical for intertie metering. For protection applications, the COSI-CT exceeds IEC Class 5P accuracy ratings and IEEE 10% accuracy ratings.
FAST FAULT RESPONSE
- Extreme fast and accurate response
- COSI-CT actually measures the dynamic current
- No distortion due to core saturation, no need for TPY - TPZ specs, yet no danger for secondary equipment
WIDE DYNAMIC RANGE
Accuracy specification is maintained over a broad dynamic range - from 0.2% to 150% of rated current (extended metering range sensor) and up to 171 kA (protection range sensor). Broad dynamic range allows elimination of separate high and low range CT’s.
WIDE BANDWIDTH
Accurate waveform reproduction up to 6 kHz allows full power quality analysis of harmonics and transients with no sensor-imposed limitations.
DRY TYPE INSULATOR SEISMIC STABLE
Field-proven lightweight composite insulator reduces transportation costs, substation support structure requirements, and installation equipment demands. The lightweight design also allows location in seismically active areas.
CHOICE OF CONNECTION OPTION
New window head design allows a variety of connection options including standard NEMA pads, up to 300 mm rigid bus, or flexible cable pass thru, allowing optimal selection for ease of installation and reliability.
GREEN DESIGN
The COSI-CT insulator contains no oil, SF6 or other gas. There is no internal mechanism for violent failure to endanger personnel or adjacent equipment. There are no environmental concerns or gas to recycle. With an optical design there are also no open secondary concerns.
LOW MAINTENANCE
The COSI-CT has no active components at line potential, eliminating the need for costly outages to maintain the electronics. Since there is no insulating oil or paper there are no complex maintenance procedures. The polymeric insulating column employs silicone rubber sheds that do not require liveline washing.
SMART GRID READY WITH DIGITAL INTERFACE
The standard digital interface will ensure smooth integration of COSI-CT into digital substation applications the accurate measurement of harmonics and phase angle is a must for new Smart Grid applications.
