Evaluating polymer (silicone rubber) versus porcelain housings based on pollution levels (coastal or industrial salt/dust environments). Step-by-Step Methodology for Arrester Selection
) . This shift allows for a more precise mathematical evaluation of the thermal energy an arrester can absorb during switching surges. 4. Insulation Coordination and Protection Margins
Before selecting an arrester, the user must define the environmental and electrical environment. IEC 60099-5 outlines how to account for:
is a key international standard titled "Surge arresters – Part 5: Selection and application recommendations". It provides detailed guidance for engineers and manufacturers on choosing and using surge arresters in three-phase systems with nominal voltages above 1 kV . Core Scope and Purpose iec 600995 pdf
is the maximum designated root-mean-square (r.m.s.) value of power-frequency voltage that may be applied continuously between the arrester terminals. The standard dictates that Uccap U sub c
3. Selection of Arrester Classes and Energy Handling Capability
: Historical guidance for upgrading or analyzing older gapped non-linear resistor technologies (Annex J). 2. Key Evolutionary Updates: The Third Edition (2018) iec 600995 pdf
Often considered the most reliable diagnostic indicator (Method B2 in the standard).
The technical recommendations of IEC 60099-5 are widely used in engineering practice:
Surge arresters do not just face electrical stress; they must also withstand harsh environmental conditions. The standard dedicates sections to: iec 600995 pdf
Analyze potential lightning and switching surges (referencing IEC 60099-5 guidelines).
Systems often experience temporary voltage spikes due to faults, load shedding, or ferroresonance. IEC 60099-5 provides TOV curves that plot voltage magnitude against time. Engineers must ensure the arrester's TOV capability exceeds the expected system TOV profile. D. Nominal Discharge Current ( Incap I sub n
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