Download Electronic lamp systems in series circuits

3
97/157/NP
Electrical installations for lighting and beaconing of aerodromes –
Electronic lamp systems in series circuits –
General safety requirements
Contents
Page
Introduction...................................................................................................................................... 4
1
Scope ................................................................................................................................... 5
2
Normative references ............................................................................................................ 5
3
Terms and definitions ............................................................................................................ 6
4
Requirements ....................................................................................................................... 8
4.1
General ................................................................................................................................. 8
4.2
Environmental conditions ...................................................................................................... 8
4.3
Degree of protection provided by enclosures ........................................................................ 9
4.4
Electromagnetic compatibility (EMC) ..................................................................................... 9
4.5
Marking ................................................................................................................................. 9
4.6
Protection against electric shock ........................................................................................... 9
4.7
Interfaces ............................................................................................................................ 11
5
Testing ............................................................................................................................... 12
5.1
Testing documentation ........................................................................................................ 12
5.2
Assemblies with direct connection to the series circuit ........................................................ 12
5.3
Type tests ........................................................................................................................... 12
5.4
Routine tests....................................................................................................................... 12
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97/157/NP
Introduction
With a few exceptions, aeronautical ground lighting is designed for series circuit technology.
Such series circuits are operated with constant current. The series circuit input voltage of the
unearthed primary circuit is tracked by a constant current regulator dependent of variations in
the load. The properties and characteristics of such constant current regulators are laid down
in IEC 61822. The maximum series circuit input voltage is limited to AC 5 000 V, tolerances
included. Due to the structure of the series circuit, i.e. a series connection of all consumers,
the usual protective organs for personal protection of an IT, TT or TN network cannot be
applied.
Aeronautical ground lighting rates among optical navigation systems and as such is subject to
special requirements with respect to availability. Insulation faults in the series circuit are thus
tolerated and do not lead to automatic shutdown of supply.
In view of the above no work of any kind shall be performed on live series circuits without
appropriate protective equipment according to IEC 61821.
In practice, it is not always easy to assign rated voltages correctly to individual consumers
and to recognize possible touch voltages in the series circuit. Here, the connections of the
familiar network are often wrongly taken for granted, i.e. constant input voltage, consumers
connected in parallel and a load-dependent current. In the usual network, the rate voltage for
consumers and the maximum touch voltage are usually smaller than or equal to the mains
input voltage. In a series circuit installation the series circuit input voltage is divided in
proportion to the internal resistances of consumers via the series circuit. The rated voltage,
i.e. the voltage between the input lines of consumers, is defined by the series circuit current
that flows through the consumer and the input impedance of the consumer. Since input
impedance depends on the design and the series circuit current is constant, the input voltage
is always the same for the consumer. Due to current control in the series circuit the series
circuit input voltage is controlled load-dependent and corresponds to the sum of all partial
voltages in the series circuit.
The internal consumer electronics is designed on the basis of the input voltage at the
consumer.
This is different for the maximum possible touch voltage against earth. Since one or more
earth faults are tolerated during operation, the touch voltage against earth can assume any
value up to the maximum series circuit input voltage depending on the location of the earth
fault and the consumer in the series circuit. The dimensioning of the dielectric strength
against earth potential shall therefore be oriented on the maximum series circuit input voltage.
Such peculiarities of the series circuit have been taken into account in the requirements for
new electronic lamp systems in this standard.
Since only few of the established equipment for personal protection are effective in series
circuit technology the protective measure “safety extra low voltage” is applied in this standard
for the supply of electronic lamp systems. This measure is common practice and can resort to
well-known and accepted methods. The introduction is especially favoured and made possible
for the first time by lower power requirements and hence lower voltage of the illuminants.
At present, electronic lamp systems normally consist of LEDs and their snubber circuit. New
technologies are intended not to be excluded by this standard.
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Scope
This standard specifies protective provisions for the operation of electronic lamp systems
powered by series circuits in aeronautical ground lighting.
The protective provisions described here refer only to secondary supply systems for
illuminants that are decoupled from the series circuit.
This standard also takes account of special operational features of aeronautical ground
lighting. It also takes account of the level of training and the requirements for maintenance
procedures according to IEC 61821.
The requirements and tests are intended to set a specification framework for system
designers, users and maintenance personnel to ensure a safe and economic use of the
systems in installations for beaconing of aerodromes.
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.
DIN EN 55022 (VDE 0878-22),
Einrichtungen
der
Funkstöreigenschaften – Grenzwerte und Messverfahren
Informationstechnik
–
DIN EN 60529 (VDE 0470-1), Schutzarten durch Gehäuse (IP-Code)
DIN EN 61000-6-2 (VDE 0839-6-2), Elektromagnetische Verträglichkeit (EMV) – Teil 6-2:
Fachgrundnormen – Störfestigkeit für Industriebereiche
DIN EN 61140 (VDE 0140-1),
Schutz
gegen
Anforderungen für Anlagen und Betriebsmittel
elektrischen
Schlag
–
Gemeinsame
DIN EN 61558-2-4 (VDE 0570-2-4), Sicherheit von Transformatoren, Drosseln, Netzgeräten
und dergleichen für Versorgungsspannungen bis 1 100 V – Teil 2-4: Besondere
Anforderungen
und
Prüfungen
an
Trenntransformatoren
und
Netzgeräte,
die
Trenntransformatoren enthalten
DIN EN 61558-2-6 (VDE 0570-2-6), Sicherheit von Transformatoren, Drosseln, Netzgeräten
und dergleichen für Versorgungsspannungen bis 1 100 V – Teil 2-6: Besondere
Anforderungen und Prüfungen an Sicherheitstransformatoren und Netzgeräte, die
Sicherheitstransformatoren enthalten
DIN EN 61821 (VDE 0161-103), Elektrische Anlagen für Beleuchtung und Befeuerung von
Flugplätzen
–
Instandhaltung
von
Konstantstrom-Serienkreisen
für
Flugplatzbefeuerungsanlagen
DIN EN 61822 (VDE 0161-100), Elektrische Anlagen für Beleuchtung und Befeuerung von
Flugplätzen – Konstantstromregler
DIN EN 61823 (VDE 0161-104), Elektrische Anlagen für Beleuchtung und Befeuerung von
Flugplätzen – AGL-Serienkreistransformatoren
IEC 60050-195, International Electrotechnical Vocabulary – Part 195: Earthing and protection
against electric shock
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IEC 60050-826, International Electrotechnical Vocabulary – Part 826: Electrical installations
IEC 60050-851, International Electrotechnical Vocabulary – Part 851: Electric welding
IEC 60417-2, Graphical symbols for use on equipment – Part 2: Symbol originals
IEC 61000-6-4, Electromagnetic compatibility (EMC) – Part 6-4: Generic standards –
Emission standard for industrial environments
IEC/TS 61201, Use of conventional touch voltage limits - Application guide
IEC 61558-1, Safety of power transformers, power supplies, reactors and similar products –
Part 1: General requirements and tests
IEC/CISPR 11, Industrial, scientific and medical equipment – Radio-frequency disturbance
characteristics – Limits and methods of measurement
3
Terms and definitions
3.1
assembly
self-contained, closed functional unit forming an electronic lamp system together with other
assemblies
3.2
equipment
assembly operated as a consumer connected to the energy supply
3.3
basic protection
protection against electric shock under fault-free conditions
3.4
basic insulation
insulation of hazardous live parts providing basic protection
NOTE
The term “basic insulation” does not include insulation used exclusively for functional purposes.
3.5
electrically skilled person
person with relevant education and experience to enable him or her to perceive risks and to
avoid hazards which electricity can create
Elektrofachkraft ist, wer aufgrund seiner fachlichen Ausbildung, Kenntnisse und Erfahrungen
sowie Kenntnis der einschlägigen Normen die ihm übertragenen Arbeiten beurteilen und
mögliche Gefahren erkennen kann.
NOTE 1 Several years of experience/work in the relevant field of activity can be taken into account to evaluate the
technical education.
NOTE 2 For the use in aeronautical ground lighting with series circuit technology relevant electrotechnical
knowledge must be available about direct and indirect risks of this technology. Since this technology is not part of
the basic contents of a general electrotechnical education, the education and examination of knowledge must be
provided by the airport operator or his representative and be part of the recurring safety briefing.
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3.6
electrically instructed person
person adequately advised or supervised by electrically skilled persons to enable him or her
to perceive risks and to avoid hazards which electricity can create
3.7
fault protection
protection against electric shock under single-fault conditions
3.8
extra-low voltage
ELV (abbreviation)
voltage not exceeding the relevant voltage limit specified in IEC 61201
3.9
communication unit
subsystem and its components for data exchange with an external remote station
3.10
ordinary person
a person who is neither a skilled person nor an instructed person
[IEV 195-04-03]
3.11
lighting system
all components of the power supply unit and the lighting unit
3.12
lighting unit
all components used to generate light, adjust the luminous intensity, control functions and
reproduce colours
3.13
illuminant
light emitting component of the lighting unit
3.14
optical unit
all components used to guide the light produced by the illuminants
3.15
interface
electrical, optical or mechanical separation between subsystems with defined properties to
maintain given functions
3.16
SELV system
electrical system in which the voltage cannot exceed ELV:
–
under normal conditions
–
and under single-fault conditions, including earth faults in other circuits
NOTE
SELV is the abbreviation for safety extra low voltage.
[IEV 826-12-31]
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3.17
SELV equipment
SELV assembly connected to a SELV energy supply as a user in a SELV system
3.18
(electrically) protective separation
separation of one electric circuit from another by means of:
–
double insulation or
–
basic insulation and electrically protective screening or
–
reinforced insulation
3.19
safety extra-low voltage
SELV (abbreviation)
[IEV 851-15-08]
AC voltage the r.m.s. value of which does not exceed 50 V or ripple-free DC voltage the value
of which does not exceed 120 V, between conductors, or between any conductor and
reference earth, in an electric circuit which has galvanic separation from the supplying electric
power system by such means as a separate-winding transformer
[IEC 61558-1, definition 3.7.16 MOD]
NOTE 1 Maximum voltage lower than 50 V AC or 120 V ripple-free DC may be specified in particular requirements,
especially when direct contact with live parts is allowed.
NOTE 2 The voltage limit should not be exceeded at any load between full load and no-load when the source is a
safety isolating transformer.
NOTE 3 Ripple-free qualifies conventionally an r.m.s. ripple voltage not more than 10 % of the DC component; the
maximum peak value does not exceed 140 V for a nominal 120 V ripple-free DC system and 70 V for a nominal 60
V ripple-free DC system.
3.20
power supply unit
all components for the supply and transfer of energy used to operate a lighting unit in a series
circuit
4
Requirements
4.1
General
Electronic lamp systems for use in aeronautical ground lighting shall be designed for the
power supply in a 6,6 A series circuit. The maximum ratings of the series circuit supply are
given by the constant current regulators according to IEC 61822.
If the lamp systems are designed for other current or voltage ranges, such information shall
be given by the manufacturer on the type plate.
4.2
Environmental conditions
Electronic lamp systems shall be designed for continuous indoor operation without derating,
under the following environmental conditions:
–
temperature range from −25 °C to +55 °C;
–
relative humidity from 10 % to 100 %;
–
altitude from sea-level to 1 000 m;
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4.3
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Degree of protection provided by enclosures
The degree of protection against contact with conducting parts or the ingress of solid objects
and liquids shall be indicated by the IP coding according to IEC 60529.
When installed, enclosures of individual assemblies shall comply with the requirements in
normal operation at aerodromes.
4.4
Electromagnetic compatibility (EMC)
4.4.1
Limits of electromagnetic emission
Lighting systems shall comply with the requirements given in the EMC generic standard
IEC 61000-6-4, Emission standard for industrial environments. The limits of electromagnetic
emission shall comply with IEC/CISPR 11, class B.
4.4.2
Limits of immunity
Lighting systems shall comply with the requirements given in the generic standard for
industrial environments IEC 61000-6-2. The immunity limits and methods of measurement of
IEC/CISPR 22 shall be complied with.
4.5
Marking
Each assembly shall be marked with a name plate. The name plate shall be captively
attached to a visible part of the enclosure. If the enclosure is too small for a name plate to be
attached the assembly shall be marked with an unambiguous type designation.
The name plate shall contain the following information:
–
Unambiguous type designation of the manufacturer
–
Name of the manufacturer of the assembly
–
Nominal input voltage and nominal input current
–
Nominal output voltage and nominal output current
–
Maximum output of a current supply unit
–
Marking of the assembly as class III (SELV) with symbol original 5180 of IEC 60417-2
(Roman III within rhombus)
The SELV marking shall be attached in a way that it is clearly visible for maintenance
personnel where it is in the normal installation position. If variants of the installation position
are allowed the SELV marking shall be attached in more than one place to ensure visibility, if
applicable.
4.6
Protection against electric shock
4.6.1
Basic requirements
Hazardous live parts shall not be accessible and accessible conductive parts shall not be
hazardous live
–
neither in normal use without fault, nor
–
under single fault conditions.
4.6.2
Protective measure to be applied
A SELV system shall be provided as a protective measure on the secondary side of the series
circuit. The protective mechanisms of the SELV system shall not be lost if a single fault
occurs.
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For this purpose
–
limitation of voltage in a circuit (the SELV system) and
–
protective-separation of the SELV system from all circuits other than SELV and PELV and
–
simple-separation of the SELV system from other SELV systems, from PELV systems and
from earth
shall be provided.
Intentional connection of parts to a protective conductor or to an earth conductor according to
IEC 61140 is not permitted.
In locations where protective screening is used for the purpose of protective separation the
protective screen shall be separated from each adjacent circuit by basic insulation intended
for the highest voltage present.
If internal circuits produce a voltage value higher than the value that is allowed for SELV this
part of the circuit shall be separated safely. If such parts with a higher voltage value are
accessible when repair work is done on the open enclosure, the working instructions shall
contain respective warnings.
All external interfaces of the SELV system shall not exceed the SELV level. This applies for
loaded and unloaded interfaces.
Operational earthing of active parts of the SELV system is not allowed.
The maximum SELV shall not exceed the following values:
–
50 V AC for sinusoidal AC voltages in the 15 to 100 Hz range,
–
71 V peak value for non-sinusoidal AC voltages and
–
120 V DC for direct voltages with a maximum harmonic content of 10 % of the direct
voltage effective value.
4.6.3
Protective separation from the primary series circuit
The power supply unit of the electronic lamp systems with the SELV system shall provide a
galvanic, safe separation from the primary part of the series circuit.
The power supply unit can be used in series circuits of maximum 30 kVA and 6,6 A series
circuit rated current. The partial voltage in the series circuit occurring at the input of a single
power supply unit through its power input at series circuit nominal current results in the rated
voltage of the power supply unit and shall not exceed 1 000 V. The dielectric strength shall
comply with the maximum series circuit voltage.
Protective separation between the primary and the secondary winding of a transformer shall
be achieved according to IEC 61140 by means of:
–
basic insulation and supplementary insulation, each rated for the highest voltage present,
i.e. double insulation, or
–
reinforced insulation rated for the highest voltage present, or
–
protective screening with the protective screen being separated from each adjacent circuit
by basic insulation rated for the adjacent circuit voltage, or
–
a combination of these provisions.
If conductors of the separated circuit are contained together with conductors of other circuits
in a multi-conductor cable or in another grouping of conductors, they shall be insulated,
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individually or collectively, for the highest voltage present, so that double insulation is
achieved.
SELV and non-SELV circuits shall not be carried in one common cable.
If any component is connected between the separated circuits, that component shall comply
with the requirements for protective impedance devices according to IEC 61140.
4.6.4
Assemblies in the SELV system
If assemblies in the SELV system are connected to the power supply unit by means of an
external interface they shall be designed as class III equipment according to IEC 61140.
Electric interfaces shall be designed for at least 50 V AC and 120 V DC.
Assemblies of class III equipment shall have no equipment for the connection to a protective
conductor.
In no case provisions for the connection of active parts to earth potential shall exist.
An earthing connection of the enclosure of an assembly may be provided if earthing is
necessary for other functional reasons than personal protection.
NOTE
An earth connection may be necessary e.g. to integrate a fire enclosure into a lightning protection system.
4.6.5
Use of class III equipment
Class III equipment for use in beaconing systems shall be used only in SELV or PELV
systems.
4.7
Interfaces
4.7.1
Supply unit
The supply of the lighting system is made by the series circuit. All subsystems having a direct
galvanic connection to the primary series circuit shall comply with IEC 61823 (AGL series
transformers).
If the supply of a series circuit or another voltage supply is intended with a nominal voltage of
up to 1 000 V AC, the dielectric strength can be determined according to IEC 61558-2-4.
4.7.2
Connections
Connections between SELV assemblies shall be unambiguously identifiable in the mated and
unmated condition as SELV connection by the maintenance personnel.
It shall not be possible to connect SELV equipment to non-SELV equipment via connections.
Connectors shall be marked as a SELV component with a permanently visible graphic
symbol 5180 according to IEC 60417-2 (Roman III inside rhombus) The marking shall be long
lasting and visible all around.
The live side shall be equipped with the socket. Consumers shall be equipped with the plug.
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5
Testing
5.1
Testing documentation
97/157/NP
The manufacturer shall give a detailed test instruction for each assembly.
The test instruction shall contain each component test and the sequence of component tests.
For each component test the exact tolerances shall be specified for successful testing.
If the component test is required by a standard the relevant standard and the section of the
standard shall be indicated.
For each component test the test arrangement including the environmental conditions shall be
specified for the test.
The manufacturer shall provide the following test information to the operator of the units upon
request:
–
type and sequence of all component tests of the type and routine test as far as these are
relevant for electrical safety and mechanical strength;
–
tolerances for such type tests;
–
results of the type test for the component tests.
5.2
Assemblies with direct connection to the series circuit
All applicable tests of dielectric and mechanical strength shall be carried out on power supply
units having a galvanic connection to the series circuit on one side according to IEC 61823.
The applicable tests for safety isolating transformers according to IEC 61558-2-6 shall be
carried out.
5.3
Type tests
All tests according to 5.2 shall be carried out as type tests.
The test has been passed if all electrical and mechanical requirements have been fulfilled.
The test shall be documented with all single results and a clear description of the structural
condition of units.
If an assembly is modified in a way that this has an effect on the safety or basic function the
type test shall be repeated.
5.4
Routine tests
After production the manufacturer shall submit each assembly to a visual inspection, a nondestructive dielectric test according to the applicable parts of IEC 61558-2-6 and a functional
test. The functional test shall contain the basic functions and compliance with the maximum
permitted output voltage for supply units.
The manufacturer shall document the type and scope of tests in the test instructions.