Attachable protective device NZPU-35 (НЗПУ-35)

Superimposed protective safety device NZPU-35


Superimposed protective device is produced for voltage class of 35 kV, climatic version «УХЛ» (moderate cold) location category 1 according to GOST 15150.

NZPU-35 is used in power industry; it is placed in open switchgears on the side of HV terminals of voltage transformers and are intended for protection of transformers ZNOL-35 and ZNOL.06-35  in  emergency conditions (short-circuit on secondary tappings of transformer). NZPU-35 should be  in vertical position (with activation flag pointing down).

Avter NZPU-35 was activated you should determine the reason of activation. If the reason for activation was unprotected transformer, than you should replace fusing element (resistor) inside NZPU-35 device. Replacement is done with the help of replacing device (hook). Before replacement, please clean internal surface of NZPU-35 device with a cloth covered with white spirit.

NZPU-35 is produced in form of dismountable aggregate (tube with sputtering, contact tips, spring) with fusing element  (resistor C2-33-M power of dispersion 0,25 Wt). Safety device has an activation indicator, which is produced in form of moving rod. Rod stroke is equal to 10±1mm.

Table 1. Technical data



Voltage class, kV


Resistance of resistor included in safety device, Ohm


Rated power of resistor, Wt




General view of device NZPU-35 (drawing)