Deep wall submersible pump supporting cable technical requirements

The specifications of the power cable with the deep well submersible pump are determined by the heating and voltage drop of the cable. In addition to the need to control a certain current density to limit the temperature rise of the cable, the longer the length of the cable, the greater the voltage drop of the cable, the starting performance of the motor, running performance and reliability of the greater impact. Therefore, the same well with the diving motor, when equipped with deep well submersible pump head is different, with cable length is different, the requirements of the cable cross-section is not the same. In accordance with GB / T 2816 "well submersible pump" standard, the water temperature is 25 ℃, the current rating, the cable voltage drop should not be greater than 5% of the rated voltage. Which can be obtained when the power supply voltage of 380V, different power wells with a diving motor with a certain size of the cable when the maximum allowable length. When the grid supply voltage is higher and more stable or the capacity of the power supply transformer is relatively large, the voltage is high, more stable, the well with the diving motor with the same length of the allowable length of the cable can be appropriate as appropriate The cable cross-section is properly reduced to reduce the cost of cable configuration). The maximum allowable length of the cable fitted with the submersible motor is shown in Table 2-2.
When the deep well submersible pump head is very high, the motor down the well, with a long cable length, and the transformer power quality is poor, the motor is very difficult to start: the starting current is very large, long cable voltage drop, The voltage drops a lot, the starting current is further increased, the cable voltage drop is larger, the starting torque is lower, resulting in a vicious cycle, not only the motor start difficult, forced start may cause the motor winding damage. At this time, in addition to the provisions of Table 2-1 in accordance with the provisions of the cable, it is best to increase the transformer supply voltage.