The concept of the deployment of Smart Grids and digital substations (DSS), which implies replacement of conventional grid components with digital alternatives, brings up the subsequent task – to develop digital and combined instrument current and voltage transformers rated at 35 kV and 110 kV. 

The transducers of optical type are recognized as having the best market potential.

Complex Optical Voltage/Current  transducer KRISMARS-CT/VT


  • Optical current sensor 
  • Optical voltage sensor
  • Optoelectronic unit with the standardized output signal + Merging Unit for digital substation applications

Project status:Research & Development

Operating principle:

  • Magneto-optical (Faraday) effect
  • Electro-optical effect of electro-gyration

Features and benefits: 

  • No magnetizing and magnetic saturation effect
  • No piezoelectric effect
  • No ferromagnetic resonance
  • Phase-to-phase measurements

Design for DSS applications: IEC 61850-9-2LE output

Equipment for testing and calibration: Reference sets produced by Mars-Energo

Specifications (to be provided)



Operating voltage range 

0.4 ... 35 kV

Voltage grade

6  to 35 kV

Frequency range

10 ... 6000 Hz

Rated primary current

100 ... 5000 A

Accuracy class

0,2S; 0.5S 

Thermal and electrodynamic resistance

100; 150 kA

Output signal: 

  • Analogue  



  • Digital



A; 4 V

100; 100√3 V

According to iEC 61850-9-2LE

 Fiber guide length between the optical sensor and optoelectronic unit 

  Up to 200 m

 Dimensions and weight (no more than)

  • Optical sensor (35 kV)
  • Optoelectronic unit


900х400 mm,15 kg

134х215х450 mm, 3 kg

Power supply (optoelectronic unit)

220 V; 50 Hz


Block diagram