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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Furthermore there are significant negative issues affecting the integrity of aged cross 4400.2 polyethylene XLPE cable after it 40.2 exposed to high-voltage dc tests and then placed back into service. Statistical comparisons of many results increase the security of criteria levels established. It is recommended that test procedures be followed according to IEC where possible, to aid in consistency of results. Diagnostic testing allows the determination of the relative amount of degradation of a cable system section and establishes, by comparison with figures of merit or accumulated data, whether a cable system section is likely to continue to perform properly in service.
The impregnating compound has a sufficiently high viscosity at maximum operating temperature to preclude migration or draining of compound. An alternative test procedure is to raise the voltage slowly to the withstand test level while monitoring the PD activity.
Isolated loss regions such as lossy accessories. Prior to testing, determination of safe clearances must consider both eiee test voltage and voltage of nearby energized ieef The maximum withstand value may also be used as a final step.
The test is a diagnostic test that uses rms voltages up to 14 kV and can be used as a preventive maintenance test where cables can be returned to 4000.2 after testing. Electrical test methods for electric cables.
All cable and equipment tests shall be performed on de-energized and isolated systems except where otherwise specifically recommended and properly authorized. These nuances are not included in these tables due to the fact that only a small number of installations are precisely identified to enable the discrimination.
A decrease has been attributed to wet splices in paper insulated lead covered PILC cable systems. IEE LondonVol. As a general rule the more severe the defects, the lower the ac dielectric strength.
More details of how the figures of merit are derived are given in Annex E and Annex H. The loss and harmonic loss currents increase with the severity of water treeing. This cable should be able to accommodate the fault current of the system. 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.
The measurement of the test voltage should be made with an approved and calibrated measuring system as described in IEC However, they are included here to provide some guidance to engineers encountering these insulation systems in the field. Non-monitored and monitored withstand, tangent delta, differential tangent delta, tangent delta stability, and partial discharge tests at VLF are used as diagnostic tools to assess the condition of cable systems. The intervals will be correspondingly longer at lower frequencies.
A field test made during the operating life of a cable system. VLF test methods utilize ac signals at frequencies less than 1 Hz. However, in this case, ueee issue carries less sensitivity in that it refers to the upper limit, which is rarely used to determine criteria.
However, care should be exercised to make sure that unreasonably low or high values are not selected, e. The values of the test voltages and tangent delta criteria listed are based on laboratory and field test results and experience gained over many years. 40.02
Test times and maximum voltages are recommended in Table 3. There are risks associated with high-voltage testing and diagnostics. For example, utilities sometimes install a higher rated cable in a circuit that is energized at a lower voltage in preparation for a later upgrade of the circuit. In equipment that allows the voltage to reach the test voltage in keee first cycle the ramp is a quarter cycle of the voltage iree and the instantaneous breakdown voltage is recorded.
The IEEE is not responsible for identifying Essential Patent Claims for which a license may be required, for conducting inquiries into the legal validity or scope of Patents Claims, or determining whether any licensing terms or conditions provided in connection with submission of a Letter of Assurance, if any, or in any licensing agreements are reasonable or non-discriminatory. Table 8 —Interpretation of the slopes of the tangent delta vs. The consideration of various VLF ac voltage testing methods should be based upon the following guidelines as tabulated in Table 1.
When a defect has caused breakdown, the latter can then be located with standard fault locating equipment. During the test other properties of the test object are monitored and these are used, together with the withstand results, to determine its condition.
Authorization to photocopy portions of any individual standard for internal or personal use is granted by The Institute of Electrical and Electronics Engineers, Inc. On Power Delivery, vol.
Every IEEE standard is subjected to review at least every ten years. 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. The current ieew be converted to tangent delta using an approximation technique Hamon [B16]. If a cable or cable system fails the isee, the test voltage collapses.
Implementers of the standard are responsible for observing or referring to the applicable regulatory requirements. If the test instrument is a high-voltage device, an external safety ground cable should be used to ground the cable to be tested.
VLF cable testing – Wikiwand
A thermoset filled or unfilled polymer used as electrical insulation in cables. VLF ac voltage testing techniques, along with other test techniques, are continuing to develop. Refer to Annex 40.2 for discussion on determining the percentiles, the confidence limits and the limitations on these percentiles when the data sets are small. This IEEE document is made available for use subject to important notices and legal disclaimers.
Nor is IEEE iees to perform any duty owed by any other person or entity to another. In addition, should a failure occur under test, the resultant fault current and collateral damage to the cable and surrounding assets ieee be limited. There is evidence of a correlation between the tangent delta criteria and subsequent cable performance, as shown in Figure F.