Independent Insulation Group Sweden AB

About us

Independent Insulation Group (I²G) consists of twelve employees with over two hundred years of combined power industry experience. Three of us have a PhD in high-voltage engineering or electrical engineering, while the other seven 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:

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System studies

Modelling of components and network for static, dynamic and EMT type studies
Load flow and short-circuit calculations
Insulation coordination, calculation of lightning, switching, and temporary overvoltages
Series compensation studies
Investigation of sub-synchronous oscillations, such as sub-synchronous control interaction (SSCI)
Calculation of frequency dependent impedance

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Power-generating modules

Modelling of plant for static and dynamic studies
Design studies
Grid code compliance studies as per RfG, EIFS 2018:2, etc., and requirements from network operator
Development of testing plan and support during testing
Short-circuit calculations and protection coordination
Failure investigations
Power quality measurements and analysis

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Power Quality

High-bandwidth measurements ensuring sufficient accuracy even at high frequencies and voltages
Analysis of power quality events
Analysis of harmonic propagation and complex resonance conditions
Support in development of large-scale measurement program
Development of technical requirements and methods for allocation and validation of disturbance levels

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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 in-house developed software
Calculation of lightning, switching and temporary overvoltages for overhead lines, substations, and cable systems
Overvoltage calculations for live-line work

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Performance verification

Development of new test methods
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

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Overhead line design

Design of AC and DC overhead lines concerning EMF and corona effects using in-house developed software
Design of overhead line transposition schemes and tower grounding systems using in-house developed software
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

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Other services

Calculation of induction effects for overhead lines and cable systems
Reliability calculations for substations, overhead lines, and cables systems
Dynamic current rating calculations for overhead lines
Methods for de-icing of overhead line conductors
Maintenance and diagnostic methods for line and substation insulators
Independent failure investigations of insulators, cable accessories, and other high-voltage components
Customized workshops covering our services and experiences from recent projects