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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Printed in the United States of America. The measurement of the test voltage should be made with an approved measuring system, as described in IEC In general, an increase in the tangent delta in comparison to previously measured values indicates additional degradation has occurred.
Changing the polarity of the cable system being tested every 5 s generates a 0. No work has been reported on mineral-filled EPR cables. A test in which a voltage of a predetermined magnitude iees applied for a predetermined time. 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.
Annex I gives the equivalent tables for cable systems installed and used outside North America.
The number of utilities or countries is not known and no information is available about failure occurrences or service conditions. Tangent delta measurements provide iee global assessment of the dielectric loss. Thus a single region of high loss such as a region of severe water treeing, degraded accessory, area of high moisture or different cable insulation can cause the measured value to rise even though the bulk loss of the majority of the system will be lower.
It is prudent to test according to the full cable rating for the installation test before the circuit is connected to equipment with lower voltage rating but to test according to the present circuit voltage rating afterwards. At the present time any failure that occurs during the test is considered to have occurred at the test voltage the hold portion.
VLF cable testing – Wikiwand
The chief among these benefits is the availability of a framework with which to rapidly and transparently iede criteria as more data become available. 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: Since IEEE standards represent a consensus of concerned interests, it is important to ensure that any responses to comments and questions also receive iefe concurrence of a balance of interests.
The magnitude of 400. withstand voltage is usually greater than the operating voltage. The test is a diagnostic test that ueee rms voltages up to 14 kV and can be used as a preventive maintenance test where cables can be returned to service after testing. 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.
Note that the figures of merit from diagnostic tests on aged cable systems that are listed in Table 4 to Table 7 should not be applied to new cable systems. It provides a method of evaluation, and helps to fill the need for more complete information on the cable system condition while minimizing or eliminating some potential adverse charging effects of the direct voltage high-potential test method commonly known as the dc hi-pot test Srinivas and Bernstein [B31]; Eager, et al. Table 4 to Table 7 list the figure of merit values obtained during maintenance tests on different types of aged cables.
Some comments 40.2 data interpretation and subsequent performance after simple or monitored withstand test are given in Annex 4400.2. However, if withstand tests at frequencies below 0.
Users of this standard are expressly advised that determination of the validity of any patent rights, and the risk of infringement of such rights, is entirely their own responsibility.
Identified faults can be repaired or faulted cable sections replaced. Also included are tables giving limits of the temporal stability of tangent delta, differential tangent delta difference in tangent delta at two test voltagesand absolute values of tangent delta for new and service-aged cable systems.
Additional diagnostic tests that measure the extent of insulation losses is recommended, see 5. Should a local ground be advisable or recommended for the test iewe, case ground must remain connected to system ground in order to maintain an acceptable isee ground potential.
Tan Delta 0 15 30 45 60 75 90 Length of cable m Figure G. Negative slope loss decreasing with Isolated loss regions such as lossy accessories or heavily water length iee regions within a large proportion of low loss cable 5.
In withstand testing, Gnerlich [B11]the test object must survive a specified voltage applied across the insulation jeee a specified period of time without breakdown of the insulation Hampton, et al.
Cable systems can be tested after installation, for acceptance, or in preventive maintenance programs or after outages. When a defect has caused breakdown, the latter can then be located with standard fault locating equipment.
Help Center Find new research papers in: The impregnating compound has a sufficiently high viscosity at maximum operating temperature to preclude migration or draining of compound. The most commonly used, commercially available VLF ac voltage test frequency is 0.
If this connection is missing or deteriorated, it must be replaced at this time. VLF withstand, tangent delta, and partial discharge tests can also be applied to extruded cables with bare metallic shields. Normative references The following referenced documents are indispensable for the application of this document i.
A typical waveform is shown in Figure B. Within the water tree the insulation is degraded due to chemical modification in the presence of moisture. The new data will be included in future revisions of this document.
Any prioritization or extra differentiation between tested cable system portions may be accomplished by looking at the assessments for different features.
A cable design using impregnated paper insulation. For new cable systems, the differential tan delta DTD is expected to be small, i.
The test is intended to detect shipping, storage, or installation damage. A high degree of reliability and reasonable life expectancy of cable systems are necessary. It should also be noted that tangent delta measurements in aged cable systems 40.2 sensitive to water tree degradation; whereas, such measurements in acceptance tests on new cable systems are looking for contamination, etc.
Very low frequency VLF ac testing Some additional useful information may be collected by collecting the ramp and hold portions separately, see Annex D. The 400.2 test duration is 60 min. If the accessory or cable insulation is sufficiently degraded a breakdown can occur.