WEIDMANN CERTIFIED SmartSpacer®
THERMAL MANAGEMENT SYSTEM
PURPOSE OF SYSTEM
Governed by the IEEE/ANSI or the IEC Loading Guide, the transformer
upper loading limit, for normal or emergency operation, is set by the
winding hot spot and/or top oil temperature. The upper loading limit
may also be defined as a function of the allowed percentage loss
of insulation life per operating cycle. Users of power transformers
therefore need to understand the actual operating temperatures as a
function of load applied to the unit in real time as a way of maximizing
the asset value in use and minimizing the risk of overheating,
excessive loss of insulation life, and/or failure. The system is designed
to monitor and acquire key operating temperatures of the apparatus.
The data can be used to control the apparatus cooling systems and
unit loading levels. The WEIDMANN real time InsuLogix® T monitoring
system may be connected to the user’s local computer network or
SCADA system to provide necessary thermal management data to
the load dispatch center.
ELECTRIC AND DIELECTRIC REQUIREMENTS
WEIDMANN Certification for SmartSpacer® products is intended
THERMAL REQUIREMENTS
®
for use in EHV/UHV Transformer Insulation Systems. SmartSpacer®
The SmartSpacer fiber optic probe assembly will read the winding
designs can be applied in windings designed for operation up to 800
hottest-spot temperature with a tolerance of plus or minus 2ºC. Typi-
kV. The assembly, along with the fiber cable leading in and out of the
cal maximum operating hot spot temperature is 120ºC max during
assembly, shall be free of any partial discharges in use and not result
normal operation and up to 140ºC during loading beyond nameplate.
in any increased stress in the adjacent oil or insulation material. The
Maximum emergency or contingency loading temperature should not
assembly must also be capable of withstanding all required dielectric
exceed 180ºC. Measured temperatures will track the actual tempera-
tests that the apparatus may be subjected to during factory testing,
ture with a time constant of three minutes maximum.
which may include: full wave, chopped wave, front of wave, switching
surge, 60Hz applied, etc. voltages.
SmartSpacer® CERTIFICATION PROCESS
4.
Manufacturing Processes: All components including
adhesives and assemblies meet strict manufacturing
process controls in compliance with drawings and
specifications that preclude any stress concentration
factors or weakness in the transformer dielectric system.
5.
All SmartSpacer® products are shipped with a certificate of
compliance outlining that the component has met the following
five-part WEIDMANN certification process:
Quality: Strict conformance to written quality assurance
system standards are met for components and matching
sensors throughout the manufacturing, assembly,
packaging, and shipping stages. The WEIDMANN
Quality Management System is certified to the ISO 9001
Standard.
1.
Qualification and Production Testing of Smart Spacers
All WEIDMANN SmartSpacer® products are certified as individual
components that are integral to the oil-filled EHV/UHV insulation
systems found in medium and large power transformers
on the electric power grid. SmartSpacer® assemblies utilize
embedded sensors capable of communicating status or
change in thermal proporties that can indicate loss-of-life
criteria and probability of failure of power transformers.
2.
Design: The detailed design of the insulation component
and embedded sensor are compatible with normal and
emergency electrical stress limits typically found in EHV
and UHV liquid-filled power transformer winding designs,
as specified by the transformer manufacturer and operator.
Dielectric Analysis: The component, sensor, and
connection system meet the strict requirements in
compliance with 2D and 3D dielectric analysis intended
to assure compatibility with electrical field stresses that
are coordinated with the overall winding and support
insulation system design.
Verification Tests
Mechanical
Pull-out Force
Compression
Thermal
Sensor Response Time
Sensor Accuracy
Dielectric
60 Hz Withstand with PD
kV/ mm (ASTM D-149)
60 Hz Withstand
kV/ mm (ASTM D-149)
Production and Certification Tests
3.
Functional Testing: Insulation components and embedded
sensors are tested in the WEIDMANN or equivalent highvoltage laboratory to demonstrate the output metrics
and applicable tolerances required for the sensor, and
that both are suitable for use in the transformer internal
environment, in both alternating current and impulse
conditions, applicable to the BIL voltage class as specified
by the power transformer operator. (See below chart for
applicable tests.)
Incoming Sensors
Sensor Accuracy
± 2° C
After Assembly of Button in Spacer
Sensor Accuracy
± 2° C
X-ray
Free of voids
Campaign Tests*
After Fixing Sensor in Button
60 Hz Withstand with PD
6 kV/ mm (ASTM D-149)
60 Hz Withstand
8 kV/ mm (ASTM D-149)
After Assembly of Button in Spacer
60 Hz Withstand with PD
6 kV/ mm (ASTM D-149)
60 Hz Withstand
8 kV/ mm (ASTM D-149)
Compression
5000 PSI
* Once per year, in addition to Production Tests
Rev. 03.12
WEIDMANN ELECTRICAL TECHNOLOGY INC.
One Gordon Mills Way, PO Box 903, St. Johnsbury, VT 05819-0903, USA
T +800 242 6748, +802 748 8106, F +802 748 8630, www.weidmann-electrical.com
A Member of the WICOR Group