IEEE 400.2 PDF
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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Examples of the various waveforms shown in Annex B are as follows: However, they are included here to provide some guidance to engineers encountering these insulation systems in the field. The dearth of data leads to the issue faced at the 95th percentile where the data would suggest an upper limit atwhile the distribution argues for As a general rule the more severe the defects, the lower the ac dielectric strength. Every detectable partial discharge generated during the testing time is recorded in a computer-based system by magnitude and location of its origin.
Many users will find the ranges provided in Table H. IEEE develops its standards through a consensus development process, approved by the American National Standards Institute, which brings together volunteers representing varied viewpoints and interests to achieve the final product. Printed in the United States of America. 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 of a balance of interests.
These tests are described in 5. Any person who would like to participate in evaluating comments or revisions to an IEEE standard is welcome to join the relevant IEEE working group at http: There are two main wave shapes presently in use, the sinusoidal and cosine-rectangular waveforms. It is intended that the technique-specific guides provide the definitive information on voltages, times and criteria.
A safety ground cable must connect all test instrument cases with system ground. While other wave shapes are available for testing of cable systems, recommended test voltage levels have not been established.
Monitoring the future performance of tested circuits will help to strengthen or modify the correlations as more data are collected. The charging current at a very low frequency of 0. A thermoplastic polymer used as electrical insulation in cables. Implementers of IEEE Standards documents are responsible for determining and complying with all appropriate safety, security, environmental, health, and interference protection practices and all applicable laws and regulations.
Insulation formed in layers typically from tapes of either cellulose paper or polypropylene or a combination of the two.
For new cable systems, the differential tan delta DTD is expected to be small, i. Definitions, acronyms, and abbreviations The columns in Table 4 to Table 7 are arranged in the order of sensitivity of the measurements to insulation deterioration, 40.2.
Whenever possible, ieeee systems are treated in a similar manner to individual cables. Tables of test voltage levels are included for installation, acceptance, and maintenance tests on cable systems up to 69 kV.
VLF cable testing – Wikiwand
Tree-like pattern of electro-oxidation that can occur at stress enhancements such as ionic contaminants, protrusions, or voids in polymeric materials subjected to electrical stress and moisture. For new cable systems, the voltage sensitivity of the tangent delta, the differential tangent delta DTDis expected to be small, as should the temporal stability of tangent delta at constant voltage TDTS.
If PDs occur, the voltage is maintained for an additional 30 s to 60 s and then slowly reduced until the PDs extinguish. The values in Table 4 to Table 7 were derived from empirical cumulative distribution functions CDF for the data consisting of data points obtained for aged cable systems, iree in utilities from North America, i.
In these cases it has been found that reasonable estimates can be developed with sample sets of the order of separate entries. Remember me on this computer. The measurement of the test voltage should be made with an approved measuring system as described in IEC Therefore, both the ueee and capacitive currents can be plotted separately as a function of voltage and frequency.
As already mentioned, this document has, for consistency across insulation classes, selected the 80th and 95th percentiles as the critical levels. When the cable or cable system passes the VLF voltage test, the test voltage is regulated to zero, the cable or cable system and test set are discharged and the cable or cable system is grounded.
After ieer fault has been located and repaired, the circuit should be retested. Some comments on data interpretation and subsequent performance after simple or monitored withstand test are given in Annex F. Therefore, caution is recommended in interpretation of results. Cables ,Medium, and High Voltage.
The intervals will be correspondingly longer at lower frequencies. A convenient way to determine and represent this is through the confidence limits associated with fits of statistical distributions. If there is a significant increase in tangent delta during the test with increasing voltage from 0.
In equipment 400.2 allows the voltage to reach the test voltage in the first cycle the ramp is a quarter cycle of the voltage waveform and the instantaneous breakdown voltage is recorded. These are set out below, using the filled insulation, and its sub-classes, as an ieeee. If the accessory or cable insulation is sufficiently degraded a breakdown can occur. The cable system may be repaired and the insulation retested until it passes the withstand test.
Generally, the measured loss is 4000.2 under this circumstance; however, the precise impact on the loss is not clear.