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Simplefied Low-Cost Protection and Control Devices
for Substations and Switchgears 1 - 45 kV




A wide range of protection
and automation functions


Combined power supply
including CT circuits unit


Backup trip via CB
current solenoids


Digital oscilloscope
Event log


Integration in


Environment temperature


User-defined logics


Fast-operating arc fault
protection with optical fibre


Microprocessor current protection devices of RZL-05.M series of three-phase execution are suitable for all cases requiring the use of non-directional protection against short circuits between phases, non-directional or directional protection against earth faults and automatic reclosure function.

# Download the catalog. Relay Protection and Automation Devices.

Nomenclature of devices of the RLZ-05.M series:

  • RZL-05.M5-B (Y) - device with non-directional OCP and directional EFP, powered by operational voltage, has backup power supply from current circuits of phases A and C.
        RZL-05.M15-B (Y) - additionally has arc fault protection with three optical fibre sensors (OFS).
  • RZL-05.M6-B (Y) - device with non-directional OCP and directional EFP, powered by operational voltage, has backup power supply from current circuits of phases A and C, and the function of unloading current circuits of circuit breaker coils (backup trip via CB current solenoids).
        RZL-05.M16-B (Y) - dditionally has arc fault protection with three optical fibre sensors (OFS).

* -B - stand out case, -Y - flush case

Hardware features

  • Convenience of mounting according to the type of installation device case (flush or stand-out case).
  • Small dimensions (device mounting depth is not more than 10 sm).
  • Non-freezing OLED display.
  • Number of analog inputs - up to 5 pcs.
  • Number of binary inputs - 8 pcs, including 2 inputs «dry» contacts.
  • Number of output relays - 9 pcs.
  • Number of assigned LEDs - 10 pcs.
  • 2 buttons of operational control of the circuit breaker.
  • Pluggable terminal blocks with locking latches.
  • Current terminals with rated current 63 A, short-term current up to 250 A.

Special characteristics

  • High operational features (guaranteed operation in difficult conditions (environment temperature is from -40 to +60 °C, mechanical fulfillment group M7, M43, earthquake resistance).
  • Universal device power supply (AC, DC, rectified AC, powered by current circuits).
  • USB interface for communication with a PC and two isolated RS-485 for communication with automatic control system (ACS).
  • Free programming of discrete inputs, outputs, LEDs.
  • Arc fault protection with current control.
  • Number of assignable function buttons is up to 10 pcs.
  • Two setting groups, control of setting sets for binary inputs or ACS.
RZL-05.M - case

RZL-05.M with flush case and stand out case


Technical parameters


Power supply units parameters
Operating voltage range, DC or AC 90 - 254 V
Power-on availability time 0,25 s
Operating supply interruption 0,5 s
Independent supply channels (auxiliary voltage circuits) 1
Device burden 6 Wt
Supply from current transformer circuits (optional) 2
Continuous current withstand 2,5 - 10,0 A
Current input parameters
Rated input current 5A
Line current inputs number 3
Measurable current range 0,3 - 150,0 A
Current thermal withstand, 1 s 10 / 400 A
Rated zero-sequence input current (3Io) 1 A
Measurable current 3Io range 0,01 - 4,00 A
Voltage input parameters
Phase voltage 100 V
Number of measured line voltage 1
Measured voltage range 1 - 150 V
Maximum continuous voltage 150 V
PC communication interface RS-485 - 2 pcs
Data protocol Modbus RTU
Connection speed via USB, RJ-485 9600...38400 bps
Binary input parameters
Numbers of inputs 8 / 6
Rated AC, DC voltage 230 V
Response voltage level 132 - 176 V
Response time not less 40 ms
Current consumption at 220 V:
- power-on current
- continuous

20 mA<
4 mA
Dry contact binary input parameters
Number of inputs 2
Dry contact circuits source voltage, DC 24 V
Binary output (relay) parameters
Number of binary outputs / programmable 8 / 6
AC voltage trip 400 V
Maximum AC current 8 A (16 A for K1 output)
DC voltage trip 300 V
Maximum DC LR-circuit trip current, time constant τ ≤ 20 ms 0,3 A (0,6 A for K1 output)
Outputs for backup trip via CB current solenoids
(M3, M6, M13, M16)
Number of outputs (relays) 2
Operating range of currents 1,2 - 150 A
Current thermal withstand, 1s 250 A
Mounting type Flush / stand out
Device dimensions (WxHxD) 220x220x112 mm
LED indicators    total / configurable 18 / 12
Operating ambient temperature range -40 to +60 °C
Maximum Humidity at 25 °C 98%
Insulation resistance, more than 50 MΩ
Insulation overvoltage withstand,
Instantaneous / continuous
2,0 kV, 50 Hz
5,0 kV pulse
Weight, less then 4,5 kg




Functions ANSI M4 M5
Backup power supply functions    
Powered by current circuits (phases of current transformer A and C)    
Backup trip coils via CB current solenoids      
Protection functions    
Overcurrent protection and current cut-off (OCP + CCO) with time delay (5 stages) 50/51
Switch on to fault high-speed protection 50HS
Logic Selectivity Busbar protection 68
Zero-sequence OCP 50N/51N
Directional earth-fault protection 67N  
Phase conductor break protection (negative sequence or negative to positive sequence ratio current) 46ВС
OCP/zero-sequence OCP stage activation by binary signal (current-restrained intertrip)  
Arc-fault protection (by binary input) with phases currents or 3I0 monitoring (3 optical fibre sensors) 50ARC (•) (•) (•)
Automation functions    
Auto-reclosing 79
Automatic underfrequency load shedding 81L
HV Breaker failure back-up 50BF
Monitoring and indication functions    
Breaker closing circuits supervision 74TCS
Protection operation alarm lockout (LED and output state save until manual reset)  
Internal malfunction alarm 30
Parameter setting groups switch on binary input activation/deactivation  
Service functions    
Non-volatile memory event log  
Non-volatile memory oscilloscope recorder with 600 s total record duration  
Oscilloscope on binary input activation  



RZL-05_M - dimensions

Wiring Diagrams


RZL-05.M1 - wiring

Wiring diagram of external circuits to the devices RZL-05.M1

RZL-05.M16 - wiring

Wiring diagram of external circuits to the devices RZL-05.M16

# Download the catalog. Relay Protection and Automation Devices.