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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Typical defects for fluid-impregnated and extruded cable systems are listed in Annex C. Takada [B33]; Dissado, et al. Permission to photocopy portions of any individual standard for educational classroom use can 40.02 be obtained through the Copyright Clearance Center. Normative references The following referenced documents are indispensable for the application of this document i. For a sinusoidal waveform the rms is 0.
VLF cable testing – Wikiwand
During the test cycle the leakage current may be monitored and recorded if the necessary equipment is available. The tangent delta TD at 0. 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. Once the test ranges of frequencies and voltages have been defined, the active bridge automatically measures the complex dielectric constant and the tangent delta at each voltage and ieef by measuring accurately the voltage across and the loss and capacitive currents in the cable under test with a voltage divider and an electrometer.
Negative slope loss decreasing with Isolated loss regions such as lossy accessories or heavily water length treed regions within a large proportion of low loss cable 5.
During the test cycle the leakage current may be monitored and recorded. If no PDs are observed up to the withstand voltage, the voltage is maintained at this level for a maximum of 30 min unless PDs occur. The segregation is straightforward and can be accomplished by inspection of the empirical distributions; to date it has not been found necessary to use any optimization tools.
More importantly, it must be understood that, for different insulations, installations, and cable 400.2, tangent delta, differential tangent delta and tangent delta stability figures of merit can vary significantly from each other. Note, however, that the data in Figure G. Cables, Medium and High Voltage. The variation of tangent delta with test voltage is also sensitive to insulation aging.
The issues encountered include: Generally, the measured loss is increased under this circumstance; however, the precise impact on the loss is not clear. If more engineering information is required, failures during the ramp up and hold portions can be collected separately ieew follows: Comments on standards should be submitted to the following address: However, there is a benefit in recognizing the probabilistic nature of the criteria.
Table 8 —Interpretation of the slopes of the tangent delta vs. The mechanisms for the increase or decrease in tangent delta are not fully understood at this time, but the greater the change in tangent delta the more severe is the insulation aging. In order to get the ueee performance, standards and guidelines have been developed which address the specific 40.2 requirements for new and service-aged extruded and laminated dielectric cable insulations.
For more information, visit 4002 However, there is a trade-off between gathering additional information about the cable under test and going to elevated voltage levels, with the associated higher risk that the cable may fail as the voltage is increased.
There are risks associated with high-voltage testing and diagnostics. NOTE—There have been no cases documented of partial discharge detectable in the field from water trees. Oeee users ifee find the ranges provided in Table H. The tangent delta stability refers to the variation of tangent delta with time at constant voltage. In addition the variation of tangent delta with time at a particular voltage TDTSusually over a period of some minutes, can be measured and from which the mean and standard deviation of the readings can be calculated.
Patents Attention is called to the possibility that implementation of this standard may require use of subject matter covered by patent rights. Additional diagnostic tests, such as leakage current measurements that measure the extent of insulation losses, are recommended. Lower and upper TD and differential TD limits are individually applied. Leee thermoset polymer used as electrical insulation in 400.
A thermoplastic polymer used as electrical insulation in cables. Therefore, both the loss and capacitive currents can be plotted separately as a function of voltage and frequency. Click here to sign up. If the test object survives, the test it is deemed to have passed the test. 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.
In this case then it is rather straightforward to develop the confidence limits for the 40.2. At least one end of the cable must be accessible.
The values may change as additional data iee accumulated. In addition, should a failure occur under test, the resultant fault current and collateral damage to the cable and surrounding assets may be limited. The 80th and 95th percentiles were guided by the cusps or split points in the distributions of data see the distribution for mineral-filled EPR shown in Figure H.
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Definitions and requirements for on-site tests. Authorization to photocopy portions of any individual standard for internal or personal use is granted by The Institute of Electrical and Electronics Engineers, Inc. A significant investment with respect to electric power systems is underground cables. The revision of this document has clearly demonstrated the benefits of iee establishing the methodology date driven, consistent percentiles, percentile estimates, etc.
Published 31 May Obviously the 95th percentile Action Required is the level that is most sensitive to this issue as this is at the 4000.2 of the data distribution. If a circuit is considered as important, e.
In withstand testing, Gnerlich [B11]the test object must survive a specified voltage applied across the insulation for a specified period of time without breakdown of the insulation Hampton, et al.
Tree-like growths, consisting of non-solid or carbonized micro-channels, that can occur at stress enhancements such as protrusions, contaminants, voids, or water trees subjected to electrical stress.