Insulation coordination for Switchgear and Assembly as per IEC 60664
Rated Impulse Voltage (Uimp) for Overvoltage category — I, II, III, IV at various nominal Voltage (Ue) is suggested in IEC 60664.
Rated Impulse Voltage (Uimp) for Overvoltage category — I, II, III, IV at various nominal Voltage (Ue) is suggested in IEC 60664.
K factor of transformer is its ability to serve the nonlinear loads without temperature rise, Higher the K-factor greater the capacity to withstand harmonic heating effects.
IEC 60947 the Standard for Low Voltage Switchgear and Controlgear – ACB, MCCB, SDF, MCB, Contactor, Relay, Transfer Switch, Arc Quenching Devices.
IEC 61439, Low Voltage Power Switchgear and Controlgear ASSEMBLIES. Discrimination between TTA and PTTA eliminated by verification approach.
In Practice there wiill always difference in phase displacement between primary and secondary currents, Allowed limits are defined in IEC 61869-2.
Current transformer Accuracy class is highest permissible percentage error at rated current for that accuracy class, as per IEC 61869-2 and IS 2705.
Types of Fuse Link IEC 60269, gG, gM, gR, gS, gD, gN. HRC Fuse, Semiconductor Fuse.
Thermal Memory of CB remembers previous fault, till conductor cools – comes to Ambient temperature, if CB is closed before this it will to trip CB faster.
Temperature rise is defined as the average temperature rise of the ASSEMBLY above the Ambient Air Temperature, with Rated Current load for 8 hours.
Reference Ambient Air Temperature is one third (1/3) of sum of Maximum Air Temperature “Current + Daily Average + Annual Average + 10°C”. As per IS 9676.
Arc Flash is light and heat produced as a result of Arc Fault, due to low impedance path, which causes electrical explosion or discharge.
Internal Arc Protection ensures Personal and ASSEMBLY protection under arcing conditions due to low impedance path, cause of electrical explosion.
Utilization Categories indicate the type of Load and Duty Cycle of the load basis which selection of Switchgear should be done for the intended application.
Utilization Categories indicate the type of Load and Duty Cycle of the load basis which selection of Switchgear should be done for the intended application.
ANSI standard Device Numbers and Acronyms, for Intelligent Electronic Device – IED Protection Relays / microprocessor based controllers / Numeric relay.
Protection degree provided by Assembly against mechnical impact, according to IEC 62262, is defined by IK code.
Protection degree provided by Assembly against ingress of solid foreign particals and liquid is indicated by the IP code.
Thermal Classification of Electrical Insulating Materials, basis Permissible Temperature Rise above Ambient Temperatuer and Hotspot.