Insulation Coordination Study
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 realise the protective margin required.
SEN EDS has a DIgSILENT software package and a well-documented library with IEEE HV Engineering books to handle Insulation Coordination Studies for AIS and GIS substations up to 400kV.
About Insulation Coordination
- The primary goal of the Insulation Coordination Study is to align the insulation levels of the Switchgear equipment with the protection. Overvoltage’s arising from events such as cable energization, reenergization, fault application/clearing, and capacitor bank switching are examined in the Insulation Coordination Study to determine the suitable size and placement of surge arresters.
- The modelling and analysis adhere to the guidelines outlined in IEC 60071 and the IEEE standard “Modelling Guidelines for Switching Transients”, as detailed in the report prepared by the Switching Transients Task Force of the IEEE Modelling and Analysis of System Transients Working Group. The network is meticulously modelled to incorporate all equipment stray capacitance value.
Study Criteria for Insulation Coordination:
- Insulation Coordination is a methodical process that involves determining optimal insulation levels for various components within a Power System network. This procedure includes the careful selection of an insulation structure capable of withstanding the anticipated voltage stresses on the system or equipment, coupled with the appropriate choice of surge arresters. The primary objective of this study is to confirm the adequacy of insulation levels for Cables, Gas-Insulated Switchgear (GIS) Equipment, and Transformers. This validation is carried out with regard to voltage stresses resulting from actions such as the Switching Of Conductor (energization/re-energization), Transformer operations (energization), and occurrences of faults.
Insulation Coordination Methodology
- Temporary Overvoltage (TOV):
- Short Duration Power Frequency Withstand Voltage Study:
- Unsymmetrical Cable Faults
- Lightning Overvoltage
Theoretical Background Analysis
- Shielding Failure
- Back Flashover
