IEC 60034-18-42-2017 pdf free.Rotating electrical machines – Part 18-42: Qualification and acceptance tests for partial discharge resistant electrical insulation systems (Type 1) used in rotating electrical machines fed from voltage converters.
This Technical Specification defines criteria for assessing the insulation system of stator/rotor windings of single or polyphase AC machines which are subjected to repetitive impulse voltages, such as pulse width modulation (PWM) converters, and expected to withstand partial discharge activity during service. It specifies electrical qualification and acceptance tests on representative samples which verify fitness for operation with voltage-source converters.
This document does not apply to:
— Rotating machines which are fed by converters only for starting.
— Electrical equipment and systems for traction.
NOTE Although this Technical Specification deals with voltage-source converters. It is recognised that there are other types of converters that can create repetitive impulse voltages. For these converters, a similar approach to testing can be used if needed
2 Normative references
The following referenced documents are indispensable for the application of this document For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 60034-18-1. Rotating electrical machines — Functional evaluation of insulation systems — Part 18-1: General guidelines
IEC 60034-18-32, Rotating electrical machines — Functional evaluation of insulation systems — Part 18-32: Test Procedures for form-wound windings — Electrical evaluation of insulation systems used in machines up to and including 50 MVA and 15 kV
IEC!TS 60034-18-4 1, Rotating electrical machines — Part 18-4 1: Qualification and type tests for Type I electrical insulation systems used in rotating electrical machines when fed from voltage converters
IEC 60216-3, Electrical insulating materials — Thermal endurance properties – Part 3: Instructions for calculating thermal endurance characteristics
IEC/TS 61251, Electrical insulating materials — AC. voltage endurance evaluation — Introduction
IEC 61800-4, Adjustable speed electrical power drive systems — Part 4: General requirements — Rating specifications for ac. power drive systems above 1 000 V a.c. and not exceeding 35kV.
Modern converter output voltage rise times may be in the 50 ns to 2 000 ns range due to power semiconductor switching characteristics. The voltage appearing at the terminals of a converter-driven machine depends upon several characteristics of the power drive system (see IEC 6 1800-4). such as
• operating line voltage of the converter
• architecture and control regime of the converter
• filters between the converter and machine
• length and characteristics of the cable between them
• design of the machine winding
• grounding system
In order to apply this Technical Specification to the qualification and testing of the insulation system of a winding, it is necessary to specify the required parameters of the voltage appearing at the machine terminals (Clause 6). In the case of 2-level or other U converters. depending on the rise time of the voltage impulse at the converter output and on the cable length and machine impedance, the impulses generate voltage overshoots at the machine terminals. This voltage overshoot is created by reflected waves at the interface between cable and machine or converter terminals due to impedance mismatch. The voltage appearing at the machine terminals when fed from a 3-level converter is shown in Figure 2 The figure shows one cycle at the fundamental frequency.IEC 60034-18-42 pdf download.