IEEE C62.21-2003 pdf download Errata to IEEE Guide for the Application of Surge Voltage Protective Equipment on AC Rotating Machinery 1000 V and Greater
1.1 Scope
This guide covers the application of surge voltage protective equipment to ac rotating machines rated 1000V and greater. The guide does not cover motors applied in solid-state switched adjustable speed drives. Thisstandard, the first part of two parts, covers the insulation surge withstand strength of motors and generatorswith windings having form-wound multi-turn coils and the application of surge protection to form-woundmulti-turn coil motors. The second part will cover application of surge protection to generators with formwound mult-turn coils, plus insulation surge withstand strength and surge protection of single-turn coilgenerators and motors.
1.2 Purpose
This guide is intended to aid engineers at all levels of surge protection knowledge in deciding whether par.ticular machines should have surge protection. The guide may be used in estimating the surge withstandcapability and switching surge exposure of ac rotating machinery in usual, not extreme exposure, installations. The manufacturer should be contacted for specific insulation surge voltage withstand values formachinery of particular interest or importance.
For those machines that should be protected, the purpose is to provide guidance in selecting and applying theprotective devices. A simple look-up method using tables and a graph is provided for quick estimation ofsurge rise times and surge voltage levels, and for general use where accuracies in the order of 10% to 15%are acceptable. This method is based on single-phase analysis, neglecting the influence of ground modesurge propagation. A more complex method is provided by formulas to model the three-phase and groundmode propagation. The formulas can be used with calculators or personal computers.
2. References
The use of this guide may be aided when used in conjunction with the following standards. When a refer-enced standard is superseded by an approved revision, the revision shall apply.
EPCC (Electric Power Coordinating Committee, South Africa) Guide for the Application of SwitchingSurge Suppressors to Medium Voltage Motors,Aug.1992.1
IEC 60034-15: 1995, Rotating Electrical Machines, Part 19: Impulse Voltage Withstand Levels of ACRotating Machines with Form-Wound Stator Coils.
3. Definitions
For the purposes of this guide, the following terms and definitions apply. The Authoritative Dictionary ofIEEE Standards Terms (B36)° should be referenced for terms not defined in this clause.
NOTE-The following definitions are purposely not alphabetized. Rather, the terms are arranged in such as way as tofacilitate an understanding of the technical relationship between them. The terms proceed in order of technicaldependency.
3.1 rated voltage (rotating electric machinery): The rms voltage specified at the terminals of a machine, V.
3.2 rated test voltage (rotating electric machinery): The rms fundamental frequency test voltage specifiedfor the rated voltage, V, of the machine in the standard under which the machine is manufactured.
3.3 per unit (pu): The ratio of the actual value of a quantity to the base value of the same quantity
3.4 per unit surge voltage (rotating electric machinery): The ratio of a surge voltage crest magnitude tothe crest value of the machine rated voltage. For a three-phase machine, the divisor (lpu) is the crest value ofthe rated phase-to-neutral voltage and equals phase-to-phase rated voltage V times the square-root of twodivided by the square-root of three ( V2/3 ).
3.5 local surge (rotating electric machinery): A surge that originates on the same voltage system as themachine with no transformation between.
3.6 remote surge (rotating electric machinery): A surge that originates at least one voltage transformationremoved from the machine.
3.7 steep-front surge (rotating electric machinery): A voltage surge having a rise time of less than onemicrosecond.
3.8 turn insulation (rotating electric machinery): The insulation applied to provide electrical separationbetween the turns of a coil.
NOTE–In the usual case, the insulation encircles each turn. lt is sometimes referred to as turn-to-turn insulation
3.9 ground insulation (rotating electric machinery): Insulation used to insure the electric isolation of thewindings from the core and mechanical parts of a machine. It separates the turn insulation from the sur.rounding slot steel. Ground insulation is sometimes referred to as coil insulation, or groundwall insulation.
IEEE C62.21-2003 pdf download
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