IEEE 1732 pdf free download

IEEE 1732 pdf free download.Space Charge Measurements on High- Voltage Direct-Current Extruded Cables for Rated Voltages up to 550 kV.
4. Recommended space charge measurement methods
The space charge measurement methods recommended for space charge measurements on high-voltage direct-current (HVDC) extruded cables for rated voltages up to 550 kV are the following:
a) The pulsed electro-acoustic (PEA) method
b) The thermal step method (TSM)
For details about the PEA method, reference shall be made to CIGRE Technical Brochure (TB) 288:2006. For more details about the usage of the PEA method in the case of cable geometry, see Annex A.
For details about the TSM, reference shall be made to CIGRE TB 288:2006. For more details about the usage of the TSM in the case of cable geometry, see Annex 11.
5. Space charge measurements during the prequalification test
5.1 Introduction
Given the importance to space charge formation of cross-linking byproducts associated with the crosslinking agent dicumyl peroxide, and of anti-oxidants and molecular voltage stabilizers, and the effect of humidity (water) and the relatively rapid transmission of water through extruded insulation (in particular polyethylene and ethylene-propylene rubber), considerable care shall be exercised in performing PEA or TSM space charge measurements on HVDC extruded cables. Exposure to humid environments shall be minimized and limited strictly to the measurement duration. Constant and predefined values of cable conductor temperature. temperature gradient across insulation wall, and humidity of the surrounding environment shall he maintained during such measurements, to every extent possible. Ambient conditions during PEA or TSM measurements shall be recorded and included in the space charge measurement report.
5.2 Measurements by means of the PEA method
5.2.1 Measurement times
During the long-duration voltage test of the prequalification (PQ) test (described in CIGRE TB 496:2012, page 14, 3.4) two sequences of space charge measurements by means of the PEA method shall be carried out at the Illlowing times:
a) Before starting the long-duration voltage test of the PQ test: This first sequence of space charge measurements shall be carried out on a virgin (unaged) cable sample identical to the cable employed in the PQ test loop (see CIGRE TB 496:20 12, subclauses 1.5.2, 3.3, and 3.4); this will serve as a reference for calibrating the PEA measurement set-up.
b) Aller the completion of the long-duration voltage test of the PQ test: This second sequence of space charge measurements shall be performed on an aged cable sample identical to the cable employed in the PQ test loop and subjected to the same long-duration voltage test as the PQ test loop.
The two sequences of space charge measurements with the TSM at the times established in 5.3.1 shall not be performed on the same measured cable loop. Indeed, the TSM requires that the outer shielding layer of the measured cable is removed and the outer semiconductive layer of the measured cable is exposed: this modifies the dc-gassing rate on the measured cable ioop compared to an unmeasured PQ test loop. The two different measured cable loops for the two sequences of space charge measurements at the times established in 5.3. I shall be as tbllows:
a) A first measured cable loop, whose cable section shall be made of an unaged cable sample identical to the cable employed in the PQ test loop. On this measured cable loop—arranged with the compensation cable loop according to the TSM—double capacitor configuration—the first sequence of space charge measurements with the TSM shall be pertbrmed at the first time established in 5.3. 1.
b) A second measured cable loop, made of an aged cable sample identical to the cable employed in the PQ test ioop and subjected to the same long-duration voltage test as the PQ test loop. On this second measured cable loop—arranged with the compensation cable loop according to the TSM—double capacitor configuration—the second sequence of space charge measurements with the TSM shall be performed at the second time established in 5.3.1.
NOTE—For engineering purposes. it is permitted to let the firsi measured cable loop undergo the whole PQ test leaving the TSM measuring apparatus on it to monitor space charge evolution during the PQ test and to compare it with the measurements carried out on the second measured cable loop aflcr the completion of the PQ test.IEEE 1732 pdf download.