INSULATION COORDINATION STUDY

 S-SQUARE has an EMTP group equipped with EMTP software package and a well-documented library with IEEE, CIGRE and HV engineering books to handle insulation coordination studies for AIS and GIS substations up to 765kV. We have an impressive record of having carried out more than 40 such studies in 4 countries till date for substations and transmission lines. Our clientele includes most big names of the global electrical industry.


Insulation coordination is both an art and science. The aim of insulation coordination is to reduce the cost and disturbance caused by insulation failure to an economically and operationally accepted level. It essentially verifies the rating as well as location of lightning Arresters in substation to realize the protective margin required.
 

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The group is led by PhD scholars in HV engineering ably assisted by a group of HV engineering post graduate professionals and EMTP analysts.
 

S-SQUARE is an approved consultant of DEWA for Insulation Coordination Study on exclusive basis besides being accepted by utilities of repute across the middle east and South  America.
 

Value Addition
 

Insulation coordination study determines the selection and verification of surge Arrester at right place to limit various types of over-voltages in the system within the equipment withstand levels. Maximum over-voltage like Temporary over-voltage, switching over-voltages, lightning over-voltages and Very fast front over-voltages are determined for various operating conditions.
 

Protection of equipment from transient voltage beyond the capability of their typical insulation ratings through coordinated selection and placement of surge Arresters.
 

Insulation Coordination Methodology
 

Step 1: Select most onerous path configuration of the system for the study.

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Step 2: Collect, compile and validate data as per data questionnaire.

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Step 3: Model the components of the system - Power Transformer, GIS section - OHL section, Surge Arresters, cable, etc. & Develop network diagrams for the modelled system for EMTP analysis.

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Step 4: Study the specific requirements with respect to operational philosophy and practice and select Lightning current stroke peak and shape for carrying out Lightning impulse over-voltage performance under shielding failure and BFO conditions.

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Step 5: Decide the number of cases to be studied for Insulation Coordination exercise.

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Step 6: Run EMTP-RV analysis with Micro Tran version 3.25 to assess voltage stresses at surge impedance transition boundaries.

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Step 7: If the nominal system voltage is above 300kV, carryout SOV studies for various conditions to validate the Insulation Coordination achieved based on LIOV performance.

Step 8: Construct the wave-forms of the voltage stresses at surge impedance transition boundaries for the conditions studied.

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Step 9: Study the Alternatives of the configuration satisfying Insulation Coordination protective ratios and choose the best.

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Step 10: Study the controlling effect required and location to select type and characteristics of the surge Arresters & specify the class and energy capacity required.