DC network protection relay
DC network protection relay can be applied in order to supervise the AVR value or RMS value of DC current or voltage Example applications are: synchronous motor excitation circuit supervision, ground faults detection systems in DC network, auxiliary voltage network supervision. The device belongs to the mZAZ family of protection relays whose integrates the functions of measuring, protection, control and recording.

Manuals, diagrams, technical details


Product description

Protection set

76 overcurrent (AVR), time-delayed, two-stages
50/51 overcurrent (RMS), time-delayed, two-stages
59 overvoltage (AVR), two-stages
59 overvoltage (RMS), two-stages
27 undervoltage (AVR), two-stages
62 external protection

Main features

  • Two measuring inputs (IDC, UDC)
  • Two binary inputs for external protection purposes or to block selected protection functions or to acknowledgment of relay pick-up signalling
  • 7 programmable relay outputs
  • BZ “watchdog” contact for device failure signalling purposes or lack of aux. voltage signalling purposes
  • 4 settings banks
  • Trip pulse forming
  • SMiS software enabling full operation of the device by PC computer
  • Indicating of key device statuses
  • Measuring of current input values
  • Event recorder
  • Samples and magnitudes values recorder
  • Last disturbance parameters recorder
  • Self-control of proper operation of relay
  • Real time clock
  • Remote communication with PC computer or with supervise and control system in RS-485 standard
  • Protection against unauthorized access
  • Digital technology ensures high accuracy, stability and dependability of the relay

SMiS software provided with each device allows to: protection functions configuration, read and write of protection settings, acknowledgment of relay pick-up signal and browsing relay recorded data.


Rated measuring current Idcn Idcn=1A or Idcn=5A
Rated measuring voltage Udcn 100V
Auxilliary voltage (24V, 48V/60V)DC,
(110V, 230V)DC/AC
Control voltage acc. to aux voltage
Setting ranges of threshold values:
– current threshold value (0,20÷20,00) Idcn
or (0,05÷5,00) Idcn
– voltage threshold value (0,05÷1,20) Udcn
– operating time (0,00÷99,99)s
Relay operation time for current protection <30ms
Relay operation time for voltage protection <100ms
Accuracy of current inputs if I=IDCn 1%
Accuracy of voltage input if U=UDCn 0,5%
Accuracy of time measuring 1% ±10ms
Burden in current measuring inputs ≤0,5W
Burden in voltage measuring inputs ≤1W
Burden of supply module ≤6W
Continuous measured current 4Idcn
Thermal withstand (1s) 80Idcn
Dynamic withstand 200Idcn
Continuous measured voltage  1,2Udcn
Thermal withstand (10s) 1,5Udcn
Relay outputs data:
Max. breaking capacity by 250V DC
– resistive load 0,3A
– inductive load of L/R ≤40ms 0,1A
Max. breaking capacity by 250V, 50Hz
– inductive load, cosϕ=0,4 3A
Continuous contact carry 6A
Ambient temperature (operation) (253÷328)K/(-20÷55)°C
Ambient temperature (storage) (248÷343)K/(-25÷70)°C
Relative humidity ≤80%
Ingress Protection degree IP40
Weight ~0,7kg
Dimensions (height x width x depth) 75 x 100 x 120 mm
Electromagnetic compatibility according to EN 60255-26
Insulation according to EN 60255-27

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