The Short-Circuit Testing Liaison (STL) provides a forum for voluntary
international collaboration between testing organisations. The
basic aim is the harmonised application of IEC and Regional Standards
for the type testing of electrical power equipment.
Note: STL is concerned with high voltage electrical transmission
and distribution power equipment (i.e. above 1000V a.c. and 1200V
d.c.) for which the type tests specified in Standards include
short-circuit and dielectric verification tests.
- The objectives to which Members of STL have agreed are:
- The uniform interpretation of IEC and Regional Standards related
to IEC Standards for the testing of electrical power equipment
by the preparation of STL Guides.
- The uniform presentation of test results and data in the different
documents issued by each testing organisation and the conditions
on which each document can be issued.
- The adoption of a uniform front sheet for the Type Test Certificates
issued by and under the responsibility of individual Members,
indicating that the verification tests have been performed in
accordance with the appropriate Standard and the agreed interpretations
of the relevant STL Guide.
- The harmonisation of measuring techniques and methods to be
used when performing the type
tests specified in the Standards.
3. STL GUIDES
Members of STL have agreed to co-operate in the preparation of
Guides to provide harmonised interpretation of IEC and Regional
Standards related to IEC Standards.
STL Guides will be published, given wide circulation, and made
available to other testing organisations.
STL Guides will be made available to the appropriate standardisation
bodies for consideration.
STL Guides will be revised when necessary particularly to reflect
changes in Standards.
The Members of STL hope that non-member-testing organisations
will also follow the procedures set out in STL Guides and would
appreciate mention of the appropriate STL Guide in their test
TYPE TEST CERTIFICATES
STL as a collaboration does not itself issue Certificates. Each
STL Member testing organisation or laboratory issuing a Test Certificate
is responsible for the validity and contents of that Certificate.
STL Members pledge that when testing for certification to a Standard
in respect of which an STL Guide has been issued they will test
only in accordance with the agreed interpretation of the Standard
as given in the STL Guide.
In addition, STL Members have agreed to present Certificates in
the form given in the STL General Guide.
5. GENERAL PROCEDURE
The affairs of STL are directed and controlled by a Management
Committee. Each Member organisation has one vote but may appoint
more than one delegate to each meeting. Decisions at these meetings
on general policy, preparation and publication of STL Guides and
acceptance of new Members are taken by a 2/3 majority.
STL Guides are prepared by the STL Technical Committee set up
by the Management Committee and comprising experts designated
by member organisations with a Chairman appointed by the Management
Committee. Each STL Member has the right to representation on
the Technical Committee. New applicants to STL are normally requested
to participate in the work of the Technical Committee for a period
of time prior to admission as a Member of STL. The programme of
work of the Technical Committee is decided by the Management Committee.
STL is not established for commercial purposes.
Members of STL shall inform customers and users of the agreed
Objectives and Principles of Operation of STL.
No Member of STL shall make any public statement or issue printed
publicity on the affairs of STL in relation to matters not approved
by the STL Management Committee.