IEC 61869-14:2018 provides all requirements specific to current transformers to be used in DC applications (DCCTs), whatever the technology used. The output signal can be analogue or digital. It is applicable to newly manufactured current transformers used for measuring, protection and\/or control applications in DC power systems with a rated voltage above 1,5 kV. The general configuration of a single-pole low-power instrument transformer is described in Figure 601 of IEC 61869-6:2016. The DCCTs intended for current measurement in the transistor branch of the VSC valve (referred to as CT4a and CT4b in Figure 1403 and Table 1402) are not covered by this document, and will be considered in a future revision. IEC 61869-14:2018 applies to current transformers intended to be used in DC applications with at least one of the following functions: \u2022 measure DC current (with significant harmonics); \u2022 withstand DC voltage. Depending on the position on the DC system, different kinds of application exist, which are briefly described below, together with the approximate voltage or current wave shape.<\/p>\n
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| 2<\/td>\n | National foreword <\/td>\n<\/tr>\n | ||||||
| 5<\/td>\n | Annex ZA(normative)Normative references to international publicationswith their corresponding European publications <\/td>\n<\/tr>\n | ||||||
| 7<\/td>\n | English CONTENTS <\/td>\n<\/tr>\n | ||||||
| 9<\/td>\n | FOREWORD <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | INTRODUCTION Figures Figure 1401 \u2013 Example of LCC scheme <\/td>\n<\/tr>\n | ||||||
| 13<\/td>\n | Figure 1402 \u2013 Typical scheme for VSC \u2013 symmetrical monopole Tables Table 1401 \u2013 Current and voltage in current transformers for LCC application <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | Figure 1403 \u2013 Typical scheme for VSC \u2013 asymmetrical monopole or bipole <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | Table 1402 \u2013 Current and voltage in current transformers for VSC application <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | 1 Scope 2 Normative references 3 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | Figure 1404 \u2013 Typical step responses of a system <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | 5 Ratings <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | Table 3 \u2013 Partial discharge test voltages and permissible levels <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | Figure 1405 \u2013 Accuracy limits of a DCCT Table 1403 \u2013 Limits of ratio error for DCCT (classes from 0,1 to 1) <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | 6 Design and construction <\/td>\n<\/tr>\n | ||||||
| 26<\/td>\n | Table 7 \u2013 Static withstand test loads <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | Table 8 \u2013 Arc fault duration and performance criteria <\/td>\n<\/tr>\n | ||||||
| 28<\/td>\n | Table 1404 \u2013 Markings of terminals <\/td>\n<\/tr>\n | ||||||
| 29<\/td>\n | Table 1405 \u2013 Rating plate marking for common rating plate Table 1406 \u2013 Rating plate marking for each secondary converter <\/td>\n<\/tr>\n | ||||||
| 30<\/td>\n | 7 Tests Table 1407 \u2013 Rating plate marking for auxiliary power supply <\/td>\n<\/tr>\n | ||||||
| 31<\/td>\n | Table 10 \u2013 List of tests <\/td>\n<\/tr>\n | ||||||
| 35<\/td>\n | Figure 1406 \u2013 Polarity reversal test profile <\/td>\n<\/tr>\n | ||||||
| 37<\/td>\n | Figure 1407 \u2013 Measurement of the step response time <\/td>\n<\/tr>\n | ||||||
| 42<\/td>\n | Annex 14A(informative)Equivalent thermal current in CTs for DC application 14A.1 General 14A.2 Current harmonic content Figure 14A.1 \u2013 Typical waveform of current flowing in the primary conductor for LCC applications <\/td>\n<\/tr>\n | ||||||
| 43<\/td>\n | 14A.3 Losses in primary conductor due to harmonic content Table 14A.1 \u2013 Typical harmonic current values (800 kV LCC) <\/td>\n<\/tr>\n | ||||||
| 44<\/td>\n | Figure 14A.2 \u2013 The two terms that make up the total losses in the primary conductor <\/td>\n<\/tr>\n | ||||||
| 45<\/td>\n | 14A.4 Thermal test with AC current Figure 14A.3 \u2013 Additional losses in conductors due to typical current harmonics Figure 14A.4 \u2013 Power-frequency losses in conductors compared to DC losses <\/td>\n<\/tr>\n | ||||||
| 46<\/td>\n | Annex 14B(informative)Proposed rated insulation level applicable tocurrent transformers for DC application Table 14B.1 \u2013 Proposed rated primary terminal insulation levels for current transformers for DC application <\/td>\n<\/tr>\n | ||||||
| 47<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Instrument transformers – Additional requirements for current transformers for DC applications<\/b><\/p>\n |