Independent Insulation Group Sweden AB

About us

Independent Insulation Group (I²G) consists of seven former STRI employees with more than one hundred twenty years of combined power industry experience. Three of us have a PhD in high-voltage engineering, while the other four have a Master of Science or similar in electrical engineering, materials engineering or physics. We participate actively in international 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 optimal solutions concerning insulation dimensioning for reliable 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
Wind farm connection studies including static and dynamic calculations
Short circuit calculations and protection coordination

Software

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