IEC 62505-3-3 pdf download – Railway applications – Fixed installations – Particular requirements for a.c. switchgear – Part 3-3: Measurement, control and protection devices for specific use in a.c. traction systems – Single-phase inductive voltage transformers
scope
This part of lEC 62505 gives particular requirements for voltage transformers used in a.c.single-phase railway applications, fixed installations.
This International Standard applies to inductive voltage transformers used at traction voltagesand frequencies according to IEc 60850.
The main uses of these voltage transformers are:- voltage indication;
– measurement;-protection.
2Normative 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 editionof the referenced document (including any amendments) applies.
IEC 60044-2:1997, Instrument transformers – Part 2: lnductive voltage transformersIEC 60529:2001,Degrees of protection provided by enclosures (IP Code)
lEC 60850,Railway applications – Supply voltages of traction systems
IEC 62236-5，Railway applications – Electromagnetic compatibility – Part 5: Emission andimmunity of fixed power supply installations and apparatus
IEC 62497-1，Railway applications – Insulation coordination – Part 1: Basic requirements -Clearances and creepage distances for all electrical and electronic equipment
IEC 62505(all parts)，Railway applications – Fixed installations – Particular requirements fora.c. switchgear
3Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62505-1, Clause 3and in lEc 60044-2:1997 ,Clause 2, apply.
4Service conditions
Where the equipment described in this part of the standard is mounted on circuit breakers toIEC 62505-1,then the service conditions of that standard apply. Where they are separatelymounted and are used in association with switchgear then the same service conditions as theswitchgear apply.
5 Characteristics and useThe voltage transformer shall be:
a) either mounted inside the circuit breaker specified in lEC 62505-1; technical requirements
of this lEC 62505-3-3 apply together with the construction and test requirements (asapplicable) of lEC 62505-1;
b) or separately mounted, free standing; technical requirements of this lEC 62505-3-3 apply.6 Rating and design requirements
Clauses 5 and 6 of lEC 60044-2:1997 apply with the following exceptions:
ln subclause 5.1.2 the following shall be added at the end of the subclause:The secondary voltage values of 100 v or 110 V shall be preferred.
The rated ratio is given by the primary nominal voltage, as defined in lEC 60850,dividedby the rated secondary voltage.
In Clause 6 the entire subclause 6.1.1 shall be replaced by:6.1.1 Rated insulation levels for the primary winding
Voltage transformers covered by this standard shall have the same insulation ratings andtest values as the equipment into which they are installed.See Table 1 of lEC 62505-1and lEC 62505-2.Free standing voltage transformers shall meet the same requirements.Subclause 6.1.5 of lEC 60044-2 is valid unless inconsistent with 9.1 of this InternationalStandard.
7 Withstand conditions
The following requirements,additional to those of lEC 60044-2:1997, apply:7.1 Primary side
The voltage transformer shall withstand the overvoltage characteristics described inIEC 60850,Annex A.
NOTE These events occur often and special attention should be paid to protect these voltage transformers.7.2Secondary side
The voltage transformer shall withstand the current produced in secondary winding for 1 s,when its terminals are short circuited.The primary voltage shall be Umax2 for this condition.wWhere no Umax2 value is specified，Umax1 shall be used.
NOTE A rapid fuse or a miniature circuit breaker may be inserted at the load. On request, a slow-blow low-voltagefuse should be inserted between secondary winding and secondary terminals.
IEC 62505-3-3 pdf download – Railway applications – Fixed installations – Particular requirements for a.c. switchgear – Part 3-3: Measurement, control and protection devices for specific use in a.c. traction systems – Single-phase inductive voltage transformers
