Insulation Coordination
Overvoltage assessment and insulation-level coordination.
Coordinate insulation and protection
NEWATT evaluates switching, lightning and temporary overvoltages and coordinates insulation levels and surge-arrester selection.
Study scope
Switching overvoltages
Switching surge magnitudes are assessed across the network from circuit breaker and capacitor switching operations, establishing the switching overvoltage levels that equipment insulation needs to withstand with adequate margin under normal operating scenarios.
Lightning overvoltages
Lightning surge levels and the resulting basic insulation level requirements are assessed for equipment at every point in the network exposed to direct or induced lightning transients, following the protective margin principles set out in IEC 60071.
Ferro-resonance
We screen for ferro-resonance conditions that can arise from the interaction between transformer magnetising characteristics and system capacitance under specific switching configurations, since ferro-resonance can produce sustained overvoltages that conventional surge protection isn't designed to address.
Arrester selection
Surge arrester ratings and locations are selected from the insulation coordination study's protective margin requirements, confirming arrester protective levels provide adequate margin below equipment withstand across the full range of switching and lightning transients identified.
How we deliver
Standards
Studies are performed to IEC 60071 insulation coordination methodology, with IEEE guidance applied where relevant to the project's region or equipment standards, establishing required withstand levels and protective margins at every voltage level.
Software
Insulation coordination studies draw on PSCAD, EMTP or DIgSILENT transient simulation results as the basis for overvoltage magnitudes, ensuring the coordination margins calculated are grounded in the project's actual modelled transient behaviour, not generic assumed levels.
Outcomes
The study delivers basic insulation level and arrester rating recommendations for every voltage level and location assessed, giving the procurement team a clear, standards-referenced basis for equipment insulation and surge protection specification.