Embed Size (px)
Citation preview
What about type tested assemblies?
The tested switchboard,complying with IEC 60439-1
2
IEC standards are based on the consensus and knowledge find among the best experts in the world.
They provide minimum requirements and test procedures for safe and reliable installation allowing a high availability of the electrical energy
3
To gather and protect the control and protective devices together with electrical and mechanical connections against external influences.
To inform the end-user on the state of his installation. To protect the switchboard user against the main risk of
accidents (direct contact protection, indirect contact protection and fire risk).
To evolve with the activity
Protection for individuals Electrical power distributionInstallations monitoringand control
What is a switchboard used for ?
4
It is a question of balance between: the needs of safety and availability the constraints of reliability and maintenability of the
installation.
Safety
Maintenability
Reliability Availability
The LV electrical switchboard has to be safe and available
5
One general standard : IEC 60439-1 type-tested assemblies (TTA) and partially type-
tested assemblies (PTTA)
Four related standards: IEC 60439 -2 busbar trunking systems (busways) IEC 60439 -3 distribution boards (<250A, unskill people) IEC 60439 -4 assemblies for construction sites (ACSs) IEC 60439 -5 cable distribution cabinets (CDCs)
IEC 60439 series Low-voltage switchgear and controlgear
assemblies
What about the main features?
The tested switchboard,complying with IEC 60439-1
7
Scope : Low-voltage switchgear and controlgear assembly, TTA or PTTA, whose rated voltage is 1000 Vac or 1500 Vdc.
TTA : type-tested assemblies conforming to an established type or system without deviations likely to significantly influence the performance, from the typical ASSEMBLY verified to be in accordance with this standard. A full range of representative configurations have been tested.
PTTA : partially type-tested assemblies, containing both type-tested and non type-tested arrangements provided that the latter are derived (e.g. by calculation) from type-tested arrangements which have complied with the relevant tests. Some limited configurations may be tested.
Definition : A combination of one or more low-voltage switching devices together with associated control, measuring, signalling, protective, regulating equipment, etc., completely assembled under the responsibility of the manufacturer with all the internal electrical and mechanical interconnections and structural parts
IEC 60439-1, what about the scope?
Either a TTA or a PTTA equipment meeting IEC 60439 afford the same quality level
8
Meeting IEC 60439-1 requirements means : a minimum level of safety for people and equipment to include the low-voltage switchgear and controlgear
assemblies for the power distribution and control precise requirements for
- service conditions (temperature...)
- construction requirements (IP, IK, forms,...) precise test procedures
IEC 60439-1: one worldwide standard for all the professionals of switchboards.
Conformity to IEC 60439 provides an insurance on switchboard realization quality
The IEC 60439-1 standard gives general rules for switchboards construction
Safety
Maintenability
Reliability Availability
9
external design (open-type, dead front, enclosed, busway)
place of installation (indoor - outdoor)
conditions of installation with respect to mobility (stationary - movable)
degree of protection (for outdoor IP 3X)
type of enclosure (e.g metallic or plastic)
method of mounting (fixed or removable)
measures of protection of persons
form of internal separation (to be detailed, agreement between customer and manufacturer)
types of electrical connections of functional units (to be detailed, agreement between customer and manufacturer)
Classification according to IEC 60439-1
10
IEC 60439-1 : Functional unit
Definition : Part of an assembly, comprising all the electrical and mechanical elements that contribute to the fulfilment of the same function
Example : drawer in a Motor Control Centre switchboard .
Incoming
Outgoing
Auxiliary
Functional unit
11
In most installations, no particular partitioning is needed, electrical switchboard of the form 1 type is acceptable.
However this is no longer true without a front plate or other equivalent mean. The user shall not access to living parts.
Following forms 2, 3 and 4 introduce additional partitioning within the switchboard
Form 2: partitioning of busbars Form 3a and 3b:
- functional units separated from each other and separated from the busbars
- connecting terminals separated from busbars Form 4a and 4b:
- functional units separated from each other and separated from the busbars
- connecting terminals separated from each other and separated from busbars.
V. FormsIEC 60439-1 proposes different type
of secured forms adapted to each situation
12
Form 1 Form 2a Form 3a Form 4a
Form 2b Form 3b Form 4b
IEC 60439-1 The forms of internal separation
1. Maintenance people should not be in a dangerous situation, e.g. parts not under maintenance should not create dangerous situation in parts under maintenance
2. Maintenance in one part should not create a dangerous situation in another part e.g. a screw or a tool falls in another part
3. Danger in one part should not expand to other parts e.g. an arc in one part should not influence other parts
13
Types of electrical connections of functional units (FU)
F = Fixed
D = Disconnectable
W = Withdrawable
Identification connections are codified with these 3 letters referring to :
1st : main incoming circuit 2nd : main outgoing circuit 3rd: auxiliary circuits
Electrical connections for functional units
B
What about test procedure ?
The tested switchboard,complying with IEC 60439-1
15
There are two type of tests:
7 type tests are performed by the manufacturer on one or several configurations:
n°1 temperature rise limits n°2 dielectric properties n°3 short-circuit withstand n°4 protective circuit effectiveness n°5 clearances and creepage distances n°6 mechanical operation n°7 degree of protection.
3 routine tests are performed by the panelbuilder on each particular switchboard:
n°8 general inspection n°9 insulation/dielectric test n°10 protection measures.
The tests of standard IEC 60439-1
B They guarantee that the switchboard complies with the necessary standard requirement
16
The aim of these tests is to confirm the switchboardcharacteristics.
The 7 type tests are carried out on the most difficult and unfavourable system configurations. The assembled and cabled switchboards are made up of their usual components, connection system…, equipped with switchgear and assemblied and installed according to industrial standards.
The tests are conducted either in approved laboratories (Asefa, Kema, Lcie,…), or in a manufacturer laboratory.
The 7 type tests performed by the manufacturer
17
Guarantees the safety and reliability of the switchboard, by avoiding problems such as:
connection damages reduction in insulation performances risk of burn for maintenance operators electronic components damages faulty operation of the devices: inopportune release.
How to proceed: to measure the temperature of each equipment, after a
delay allowing a stabilized temperature, when each circuit is used at its rated power and when the complete switchboard is loaded with an appropriate diversity factor
Result to be obtain temperature rise shall not exceed what the different
equipment can withstand the temperature of accessible surfaces has to be checked
Test n°1 (8-2-1): temperature rise limitsTest performed by the manufacturer
18
Guarantees the switchboard safety and reliability,to avoid problems such as:
electrical arc generation insulation performance decreasing connection damages
Withstand impulse voltage test and an ac test are performed
Test n°2 (8-2-2): dielectric propertiesTest performed by the manufacturer
19
This test simulates an incident which could occur on site. Withstanding the short-circuit currents is:
to avoid danger (rupture and projections of components, arc generation and propagation outside the switchboard,...)
it also means the installation can be quickly put back into operation after the incident.
Relationship between peak current (Ipk) and short-circuit current (Icw):
Ipk = Icw x n
RMS value of short-circuit current kA eff/1s (Icw)
n Ipk (kA)
Icw 5 1.5 Ipk 7.5
5 < Icw 10 1.7 8.5 < Ipk 17
10 < Icw 20 2 20 < Ipk 40
20 < Icw 50 2.1 42 < Ipk 105
50 < Icw 2.2 110 < Ipk
Test n°3(8-2-3): short-circuit withstandTest performed by the manufacturer
20
The effectiveness of the protective circuit is verified by two tests:
resistance measurement of the connection between the exposed conductive parts and the protective circuits
short-circuit withstand performed between the protective conductor and the nearest phase conductor.
Test n°4(8-2-4): effectiveness of the protective
circuitTest performed by the manufacturer
21
Clearance control: shortest distance between two conductive parts.
Creepage distance control: shortest distance along the surface of an insulating material between two conductive parts.
Test n°5 (8-2-5): clearance and creepage distancesTest performed by the manufacturer
22
Endurance of material, guaranteeing the longevity of the various mechanisms.
The standard requires 50 operating cycles.
Test n°6(8-2-6): mechanical operationTest performed by the manufacturer
23
The tests carried out define the capacity of an equipped switchboard to:
protect persons against contact with live parts protect equipment against penetration of solid objects
and liquids
Test n°7 (8-2-7): degree of protection (IP, IEC
60529)Test performed by the manufacturer
1st digit: protection of persons protection against solids.
2nd digit: protection against liquids.Note: in case of only protection of persons is needed, the 2 IP digits are replaced by x.Example: IPxxB.
Additional letter (optional): protection of persons against contact with live parts:
A: protect againts access of the back of the hand B: protect against access of fingers Ø 12 mm C: protect against access of a tool Ø 2.5 mm D: protect against access of a tool Ø 0.1 mm.
IP
24
3 routine tests performed by the panelbuilder: n°8 general inspection n°9 insulation/dielectric test n°10 protection measures.
The 3 tests performed by the panelbuilder
These 3 routine tests can be easily and rapidly performed by the panelbuilder:
overall inspection according to the mounting instructions and technical documents (right device ratings, tightening torques)
insulation checking by a dielectric test checking of protective measures and of the electrical
continuity of the protective circuits. They complete the 7 manufacturer type tests and guarantee
professionnalism and responsability of panelbuilder.
25
Check of mechanical actuating elements, interlocks,... effectiveness.
Check of proper laying of conductors and cables and proper mounting of device.
Check of connections adequate contact, especially screwed and bolted connections.
Test n°8(8-3-1): general inspectionTest performed by the panelbuilder
26
No arc flash-over or insulator perforation must be observed between the live parts each other and between the live parts and the conductive structural parts.
Test n°9(8-3-4): insulation resistance/(8-3-2):
dielectric testTest performed by the panelbuilder
27
Checking of protective measures and of the electrical continuity of the protective circuits for metallic assemblies.
Test n°10(8-3-3): protective measuresTest performed by the panelbuilder
What about the benefits?
The tested switchboard,complying with IEC 60439-1
29
Specifiers/consultants: the certainty to prescribe a switchboard which ensures
the level of safety required by the user
Panel-builder / Installer: confidence in products and swichboards systems,
following the standard increase efficiency, easy to show conformity
Manufacturer: products tested in real configurations detailed instructions for fautless construction.
The benefits from IEC 60439-1
IEC 60439-1 provides minimum requirements and test procedures for safe and reliable installation allowing a high availability of the electrical energy
