UNE-EN 50152-3-3:2016

Introduction
1 Scope
2 Normative references
3 Definitions
4 Service conditions
5 Characteristics and use
6 Rating and design requirements
7 Withstand conditions
   7.1 Primary side
   7.2 Secondary side
8 Ferro-resonance
   8.1 General
   8.2 Prevention of the generation
   8.3 Prevention of damages in the
       voltage transformer
   8.4 Ferro-resonance withstand test
9 Particular design and construction
   characteristics
   9.1 Pollution
   9.2 External flashover test
   9.3 Floating potentials and earthing
   9.4 Electromagnetic compatibility
   9.5 Secondary connection box
   9.6 Information to be given by the
       purchaser
   9.7 Information to be given by the
       supplier
10 Tests - General
11 Other requirements

This EN 50152-3-3 is applicable to new current transformers which are- for indoor or outdoor fixed installations in tractions systems, and- operated with an a.c. line voltage and frequency as specified in EN 50163.NOTE 1 EN 50163 specifies the a.c. traction systems 15 kV 16,7 Hz and 25 kV 50 Hz.As rails of a.c. traction systems are connected to earth and included in the return current path all phase to earth voltages will be within the tolerances as specified in EN 50163. Nevertheless phase to phase voltages may be higher e.g. in autotransformer systems.Voltage transformers are mainly used with- measurement instruments,- protective devices.This EN 50152-3-3 shall also be applied to voltage transformers other than inductive types as far as reasonably possible. Requirements of this EN 50152-3-3 prevail.NOTE 2 Combined current and voltage transformers also capacitive voltage transformers are typically not used in fixed installations.