About us

Independent Insulation Group (I²G) consists of eight employees with more than one hundred seventy years of combined power industry experience. Three of us have a PhD in high-voltage engineering, while the other five have a Master of Science or similar in electrical engineering, materials engineering or physics. We participate actively in international CIGRE/IEC working groups and have published a total of around 250 articles.

Our vision is that I²G will be the Nordic region's leading competence company for high voltage technology and power systems.

Our services

I²G offers independent consulting services within the following technical areas:
Insulation dimensioning
  • Measurement and evaluation of pollution levels (ESDD and NSDD) in specific environments
  • Creation of laboratory-based flashover performance curves for insulators under conditions of pollution or ice
  • Statistical dimensioning of AC and DC outdoor insulation using our specialized software Insulator Selection Tool (IST) and Line Performance Estimator (LPE)
  • Calculation of lightning, switching and temporary overvoltages for overhead lines, substations, and cable systems
  • Overvoltage calculations for live-line work
Performance Verification
  • Development of new test methods
  • Testing specifications for laboratory tests on insulators in simulated environments
  • Access to STRI's high-voltage laboratory for environmental testing of insulators in conditions of rain, pollution, ice, snow, or salt fog
  • Access to STRI's high-voltage laboratory for ageing tests on composite insulators
  • Evaluation of performance of insulators in service or in laboratory tests
  • Calculation and verification of electric fields on insulator surfaces and hardware
  • Live inspections of apparatus, insulators, conductor joints and other auxiliaries with IR/UV-camera
Overhead line design
  • Design of AC overhead lines with regard to EMF and corona effects using our specialized software EMF/AN Calculator (EAC)
  • Design of DC overhead lines with regard to electric field and corona effects
  • Design of overhead line transposition schemes and tower grounding systems using our Tower/Pole Earthing program (TPE)
  • Evaluation of step and touch voltages
  • Voltage uprating of lines and substations
  • Conversion of lines from AC to DC operation
  • Development and verification of new tower designs
System studies
  • Power quality measurements and analysis, including measurements of high-frequency harmonics and analysis of complex resonance conditions
  • Calculation and analysis of temporary overvoltages due to low-order harmonic resonances, e.g. in the presence of long AC cables
  • Connection studies for production units (solar, wind, etc.) including static and dynamic calculations in line with grid code requirements such as RfG/EIFS 2018:2
  • Short circuit calculations and protection coordination
We offer the following softwares for licensing:
  • IST (Insulator Selection Tool) for selection and dimensioning of AC and DC insulators
  • LPE (Line Performance Estimator) for dimensioning of AC and DC overhead lines with respect to transient overvoltages and insulation performance in conditions of pollution and ice
  • EAC (EMF/AN Calculator) for calculation of electric and magnetic fields, and audible noise levels, in the vicinity of AC lines.
  • TPE (Tower/Pole Earthing program) for calculation of overhead line tower grounds, transposition schemes, and induction effects. Evaluation of step and touch voltages.
  • I-line for steady-state and dynamic current rating of overhead lines
Other services
  • Calculation of induction effects for overhead lines and cable systems using our Tower/Pole Earthing program (TPE)
  • Reliability calculations for substations, overhead lines, and cables systems
  • Dynamic current rating calculations for overhead lines using our specialized software I-line
  • Methods for de-icing of overhead line conductors
  • Maintenance and diagnostic methods for line and substation insulators
  • Independent failure investigations of insulators, cables accessories, and other high-voltage components
  • Customized workshops covering our services and experiences from recent projects

Our team

Our team has more than one hundred seventy years of combined power industry experience.
Igor Gutman
Igor Gutman

010-151 08 53


Jan Lundquist
Jan Lundquist

010-151 08 52


Andreas Dernfalk
Andreas Dernfalk

010-151 08 54


Peter Sidenvall
Peter Sidenvall

010-151 08 56


Christian Ahlholm
Christian Ahlholm

010-151 08 55


Oscar Lennerhag
Oscar Lennerhag

010-151 08 51


Johan Lundengård
Johan Lundengård

010-151 08 57


Magnus Speychal
Magnus Speychal

010-151 08 58



Meet some of our clients.


Contact us via email or phone and we will get back to you as soon as possible.
Storgatan 5 771 30, Ludvika, Sweden
E-mail: info@i2g.se Phone: +46 (0)10-151 08 50

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