IEEE 1018:2013 pdf free download – IEEE Recommended Practice for Specifying Electric Submersible PumpCable-Ethylene-Propylene Rubber Insulation
8.2.5.1 DC withstand test
Finished armored cable should be tested in air by dc withstand test according to the values shown inTable 6.Each phase conductor should be tested individually. Adequate electrical ground should beprovided by grounding the armor,lead sheath if present, and the phase conductors not being tested at thetime. The negative polarity should be applied to the conductor under test. The test duration should be 5 minafter reaching test voltage.
8.2.5.2 AC withstand test
Finished armored cable should be tested in air by ac withstand test at power frequency according to thevalues shown in Table 6.Each of the phase conductors should be tested. The armor，and the phaseconductors not being tested at the time, should be grounded during the test. The test duration should be 5min after reaching test voltage.
8.2.6 DC test conductance leakage readings
All power cables should be tested and meet the minimum test requirements for factory testing ofconductance leakage readings per Table 7 through Table 10 at the prescribed dc test voltage level listed inTable 6.The leakage values are based on bulk resistivity factor of 6100 M2· km (20 000 MQ ·kft).Referto API RP 11S6 for the calculation method.
9.2 Temperature
Conductor operating temperature as a function of well temperature and current flow is shown in Figure B.1to Figure B.16.10These figures are based on Neher-McGrath calculations in an air-filled pipe. lt isrecommended that 140 °C(284 °F) be used as the maximum conductor operating temperature for EPDMinsulation with a nitrile jacket. Conductor temperatures for cables with EPDM jacket or lead sheath may berated up to 232 °C (450 °F).For temperatures rated over 232 °C (450 °F), cable suppliers should beconsulted.
9.3 Safety factor
The Neher-McGrath calculations are based on the limit of performance for the material under idealconditions.Because of real constraints in operating environments and the experience of the industry, it isnecessary to restrict the temperature or current limits. The ampacity of the cable contains a safety factorthat is 0.9 of the Neher-McGrath calculated value based on cable in air-filled buried pipe.
9.4 Conductor size
The conductor size depends on the length of the cable(D) in meters (feet), the current (1), the conductorresistivity (p), the ambient well temperature (T) in degrees Celsius(Fahrenheit), and the voltage drop (V).The voltage drop is generally restricted to 5%.
The conductor resistivity is corrected for ac resistance and for temperature.The unit for resistivity is ohmsquare millimeter per meter (ohm circular-mil per foot). The basic value for bare copper resistivity is0.017241 (10.371), and it is 0.017965 (10.810) for coated copper.
voltage stress: It may be thought of as the electrical pressure being applied to the insulation in an effort toburst through the material and short to ground. It could be thought of as analogous to water pressure in apipe, where the higher the pressure, the harder it tries to burst through.For an electrical insulation material,the resistance to bursting through is known as the dielectric breakdown strength. It is usually expressed interms of volts/millimeter (or volts/mil) required to puncture a sample of known thickness.
With electrical stress, the further away(outward) from the conductor one moves,the lower the stressbecomes. Formulas are used to calculate the electrical stress levels. They assume that the cable insulation issurrounded by a shield (i.e., lead sheath) or other adequate source of ground potential.The electrical stresslevel (S) may be calculated by Equation (8).