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PD IEC TR 63434:2023 Low voltage switchgear and controlgear. Partial discharge voltages and PD-level in low voltage switchgear and controlgear, 2023
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- CONTENTS
- FOREWORD
- INTRODUCTION
- 1 Scope
- 2 Normative references
- 3 Terms and definitions
- 4 Basic information (physics) [Go to Page]
- 4.1 Discharge phenomena [Go to Page]
- 4.1.1 General
- 4.1.2 Homogeneous electric fields
- 4.1.3 Inhomogeneous electric fields
- Figures [Go to Page]
- Figure 1 – Temperature dependent variation of the breakdown field strength Êd of air per Equation (1), α = 0,8, θ = 20 °C, p = p0 = 1 013 mbar
- Figure 2 – Inception voltage Ui,RMS depending on the electrode radius r, R ≫ r
- Tables [Go to Page]
- Table 1 – Relationship between electrode radius r and corona inception voltage Ui,RMS
- Figure 3 – Maximum electrical field strength Ê depending on the electrode edge radius r
- Figure 4 – Paschen curve Êd = f (p × d) for air
- 4.2 Dimensioning examples [Go to Page]
- 4.2.1 General
- Figure 5 – Principle terminal / contact arrangement of a 3-pole device,capacitive voltage divider [Go to Page]
- 4.2.2 Influence of design and temperature on a series connection of clearances and solid insulation for AC voltage
- Figure 6 – Field strength in the air gap, inhomogeneous, η = 0,5 , εr2 = 4, cold state
- Figure 7 – Field strength in the solid insulation, inhomogeneous, η = 0,5, εr2 = 4, cold state
- Figure 8 – Field strength in the air gap, inhomogeneous, ƞ = 0,5, εr2 = 12at 130 °C operational temperature
- Figure 9 – Field strength in the solid insulation, inhomogeneous,ƞ = 0,5, εr2 = 12 operational temperature
- Figure 10 – Gaps and voids in a solid andcombined solid / gaseous insulation [7]
- Table 2 – Ranking of the internal field strength of different gap and void shapes [7]
- Figure 11 – Model of a void of thickness t in an insulation wallof defined thickness d [20] [Go to Page]
- 4.2.3 Series connection of clearances and solid insulation by design for DC voltage
- 4.2.4 Solid insulation – dimensioning – material characteristics
- Figure 12 – Principle arrangement of electrodes and insulation wallsof a 3-pole device
- Figure 13 – Permissible field strength for dimensioning ofsolid insulation according to Equation (18)
- Figure 14 – Breakdown at high frequency, solid insulation; d = 0,75 mm [23]
- Figure 15 – Breakdown at high frequency, solid insulation, influence of humidity; conditioning at 50 °C; 1: mica-filled phenolic, d = 0,75 mm;2: glass-silicone laminate, d = 1,5 mm [24]
- Figure 16 – Dielectric strength Êd of different types of thermoplasticinsulation material depending on the temperature
- 5 Application rules [Go to Page]
- 5.1 General
- Figure 17 – Dielectric strength Ed,RMS of PA6-GF30 in dry and moist condition (equilibrium moisture content at 23 °C/50 % RH) depending on the temperature θ (°C)
- 5.2 Partial discharge considerations
- 5.3 Measures to prevent/reduce the probability of partial discharges
- Annex A (informative)Research on partial discharge in low-voltage switchgear and controlgear [Go to Page]
- A.1 General
- A.2 Investigations on switchgear
- Figure A.1 – Example of phase resolved partial discharge measurement on a MPSD atroom temperature and at elevated operational temperatures
- Figure A.2 – PD Testing (690 V, basic insulation, 20°C)
- Table A.1 – Inception Ui and extinction Ue voltage depending onthe temperature as per Figure A.1 and Figure A.2
- Table A.2 – Maximum discharge values and number of events observed atthe test voltage as per Figure A.1 and Figure A.2
- Figure A.3 – Inception (Ui) and extinction (Ue) voltage during partial discharge measurements on motor protection switching devices (MPSD)at elevated temperatures
- Table A.3 – Ratings and design parameters of the investigatedmotor protection switching devices (MPSD)
- A.3 Reference to other products relevant for applications
- Table A.4 – Partial Discharge (PD) acceptance levels in different IEC documents
- Annex B (informative)Voltage factors when considering partial discharge effects [Go to Page]
- Table B.1 – Coordination of rated RMS voltage with partialdischarge voltage and extinction voltage
- Bibliography [Go to Page]
