The matching problem of solenoid valve power supply

Some time ago, a customer encountered a problem that the solenoid valve could not be opened:

The 9 solenoid valves on site are powered by the switching power supply. The voltage is a 24V switching power supply. The 9 solenoid valves are powered at the same time by using a common line, that is, a control signal is added to control the action of the solenoid valve. But why often the solenoid valve can not operate? what is the reason?

Through specific contact and communication, we learned that the cable used by the customer is 230 meters long and uses a 1.5-square wire. It is not difficult to understand why the solenoid valve cannot operate. When selecting a 24V power supply voltage, it needs to be considered. Loss, the cable is too thin, too long, the loss will be too large, when the power is supplied to the solenoid valve coil, the voltage is only 16V, which is already lower than the normally opened 20V, causing the solenoid valve coil to not operate normally, and there are 9 solenoids The valves act together, so that the voltage delivered to the solenoid valve terminal and the power of the power supply must be guaranteed.