Flexible Electronic Fiber-Optic Current Transformers

NEW ! Read our 2020 CIGRE Paper “Monitoring of asymmetric short circuit currents at a hydro power plant using electronic fibre optical current transformers. This paper presents a solution implemented by Swiss TSO Swissgrid AG, to monitor asymmetric short-circuit currents using Flexible Electronic Fibre Optical Current Transformers (F-EFOCT) and digital fault recorders.

Our Product

Flexible Electronic Fiber-Optic Current Transformers (F-EFOCT) are an alternative to Conventional Current Transformers with inductive transducers for high-precision current measurement and power quality control, in medium and high voltage systems. These innovative current transformers provide digital output according to the IEC 61850 standard for your metering and protection infrastructure. The F-EFOCT excels with a very high stability over a large temperature range, optimal performances over an increased frequency bandwidth, as well as a wide dynamic range and good performance under transient operations.

Applications for F-EFOCT

CONDIS® Instrument Transformer product range is ideal for your transition to digital substation technology. CONDIS® F-EFOCTs can be configured for the use in revenue metering, measurement of electric power quality parameters and relay protection & automation alike. Due to its adaptable current sensing head, the F-EFOCT can easily be installed at existing infrastructure such as cable terminations or generator busbars.


Blog article about the Flexible Optical Measurement System for Grid Monitoring


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Product features

Rated voltage, kV0 to 800
Rated primary current, A300 to 190'000
Accuracy class
for measurements0.05; 0.2S/2; 0.1; 0.2S; 0.5S
for protection5TPE, 5Р
Range of operating temperatures, °С
measuring sensor-60 to +70
electronic unit-10 to +40
Rated short-time thermal current
Rated dynamic currentany
Rated frequencyFrom 0 to 2500 Hz
Distance between sensor and electronic unit, mup to 1200
Power consumption, W50


StandardIEC 61850-9-2LE SV80; SV256
IEC 61850-9-2
IEC 61850-8-1
Sample rateSV80; SV256
TIMEIEEE 1588-2008 (PTPv2);
1PPS optical, electrical
RedundancyPRP; HSR