IEEE Std ™ I. EEE Standards. TM. IEEE Guide for Field Testing of Shielded Power. Cable Systems Using Very Low. “IEEE Guide for Field Testing and Evaluation of the Insulation of Shielded Power IEEE “Guide for Testing of Shielded Power Cable Systems using Very. Guided IEEE Series (Bundle) Standards IEEE – • IEEE Guide for Field Testing of Shielded Power Cable Systems Using Very.
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CAUTION The potential consequences of a cable system insulation failure during any high-voltage test should be considered prior to undertaking any such test.
VLF cable testing – Wikiwand
The new data will be included in future revisions of this document. The no action required condition assessment means that, although the ieee system can be returned to service, the cable system may be retested at some later date to observe the trend of the tangent delta.
Water trees can cause electrical trees to form as a result of a lightning impulse, switching surges, or excessive test voltage levels and durations. Table 3 lists voltage levels for VLF withstand testing of shielded power cable systems using cosine- rectangular and sinusoidal waveforms Bach [B2]; Eager, et al. The cables iees a taped copper shield over the insulation and were jacketed.
As the data available in from VLF diagnostic tests on the different types of newly installed cable systems are limited, the figures of merit for new cable systems are listed in Table G.
This may not be the case should the cable fail under operating conditions. Users may use their own cumulative measurement data and percentile values to develop iree own figures of merit for 4002 different types of cable systems.
The rms and peak values of the cosine-rectangular waveform are assumed to be equal. If the test object survives, the test it is deemed to have passed the test. Prior to testing, determination of safe clearances must consider both the test voltage and voltage of nearby energized equipment: Portable ground clamps and grounding assemblies built and tested per IEC are recommended.
The criteria used for the historical figures of merit provided 400. this document have been selected using the estimate of the 80th and 95th percentiles, not the lower confidence limits.
There is evidence of a correlation between the tangent delta criteria and subsequent cable performance, as shown in Figure F. Since IEEE standards represent a consensus of concerned interests, it is important to ensure that any responses to comments and questions also receive the concurrence 400.2 a balance of interests.
Test ieeee for partial discharge measurements on lengths of extruded power cables.
Additional diagnostic tests, such as leakage current measurements that measure the extent 4002. insulation losses, are recommended. Again this is a judgment guided by the remediation and risk strategies.
It should be noted that at the prescribed withstand levels in Table 3, a failure indicates that the cable is already in a highly compromised condition.
If PDs occur, the voltage is maintained for an additional 30 s to 60 s and then slowly reduced until the PDs extinguish. For dated references, only the edition cited applies.
Power cables—Distribution cables with extruded insulation for rated voltages from 3. As can been seen, the distribution fit is adequate over the area of interest and thus the confidence range for the tip up can be established—No Action Required to Further Study, 3.
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Patents Attention is called to the possibility that implementation of this standard may require use of subject matter covered by patent rights.
It is intended that the technique-specific guides provide the definitive information on iee, times and criteria. After the initiation of PDs PDIVan electrical tree may form that can develop into a breakdown channel within minutes.
Furthermore, the viewpoint expressed at the time a standard is approved and issued is subject to change brought about through developments in the state of the art and comments received from users of the standard.
Moreover it should be noted that PD inception conditions at VLF can be different from those at other frequencies. This guide addresses the use of VLF non-monitored simple and monitored withstand and other diagnostic field testing of installed shielded power cable systems covering voltage classes from 5 kV up to 69 kV. All cable and equipment tests shall be performed on de-energized and isolated systems except where otherwise specifically recommended and properly authorized.
Field testing techniques frequently employ a combination of diagnostic test methods. When this occurs, partial discharge may be detectable. In this document, the tangent delta stability is defined as the measurement of the standard deviation of tangent delta with time at a particular voltage U0: The tangent delta TD at 0. Caution is advised in the interpretation of PD data. Conclusions VLF ac testing uses frequencies of the applied voltage in the range of 0.
Thus the engineer may choose either the percentile estimate or the lower most common or upper confidence limits on the estimate for the critical levels. VLF-PD measurements are a diagnostic tool used to detect, in a nondestructive manner, the location and severity of an insulation defect. It should also be noted that tangent delta measurements in aged cable systems are sensitive to water tree degradation; whereas, such measurements in acceptance tests on new cable systems are looking for contamination, etc.
The measured value will be less than the actual loss of the high loss region. Nor is IEEE undertaking to perform any duty owed by any other person or entity to another.