SU135323A1 - Polarized electrical drainage to protect underground metallic structures from corrosion - Google Patents

Description

Existing highly sensitive electrical drainage to protect underground metal structures from corrosive destruction under the influence of stray currents (for example, PED-AKH-54M, PED-AKHOrggas) require connection to the lighting mains of the main drainage contactor, which complicates installation and operation; in addition, the drainage operation is made dependent on the constancy and uninterrupted supply of external energy. Operating drainage without an external power source (for example, PED-45, UPDU-57) include the drainage circuit only when a certain potential difference is reached, which is many times greater than drainage with an external power source.

The proposed polarized electrical drainage is characterized by the fact that an intermediate relay is supplied to it, which is powered by batteries and is simultaneously a contactor closing the drainage electrical circuit. Intermediate relay is activated when a polarized relay is triggered. Such performance increases the sensitivity of the device.

The scheme works as follows. When a potential difference appears on the drainage terminals, sufficient for the polarized RP relay to operate, the latter closes the circuit of the intermediate PR relay, which, in turn, connects the drain with the 1PR contacts. With a further increase in the potential difference, the main drainage contactor CD is activated, which turns on the main contacts of the 1KD drainage and at the same time turns off the auxiliary 1PR by de-energizing the NR relay by the contacts of 2KD. When the voltage rises to a certain value, for example, +1.5 V, the blocking relay of the RB switches on and the 1RB contacts breaks the circuit of the polarized relay, which is necessary because of the overheating of the RP relay coil.

By reducing the potential difference to the magnitude of the voltage holding the core of the blocking relay RB, the latter includes