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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 inclusion
available (on demand)


Fast-operating arc fault
protection with lens-type


New modified electronic microprocessor devices series RZL-05 are used for low-cost protection, automation, control and monitoring of power distribution network elements.

Devices are designed to suit the best for feeder bay protection and automation performance in relay cubicles of switchgear bays.

Devices can be powered with DC operating voltage or AC voltage auxiliaries as well.

# Download the brochure. Protection and control devices.


  • Reliable operating under heavy ambient thermal conditions;
  • Small size;
  • Configurable inputs, outputs, LED-indicators;
  • Unified AC/DC supply source;
  • Auto-switch to current supply unit on operating voltage supply failure;
  • Digital fault-recorder, over 1 hour total record duration;
  • Two protection setting mode groups;
  • Operating parameters settings via built-in HMI and PC software tool: functions activation/deactivation, protection stages values and time delay for each stage etc.;
  • RS-485 interfaces of MODBUS data transfer protocol;
  • Real-time self-supervision;
  • Three photosensor inputs of arc-fault protection;
  • Each photosensor input independent configuration;
  • Fault recorder and event log;
  • Total fault record duration over 600 s;
  • A solid number of inputs, outputs and indicating LEDs;
  • Flexible configuration settings;
  • Remote control functions;
  • The same casing size for all types;
  • Wire connection terminals with end-position locking plug;
  • Two mutually redundant power supply units;
  • Optional current circuits low-burden redundant power supply;
  • AC/DC power supply source;
  • Binary inputs optocoupler isolations;
  • Supply inputs and all signal circuits are galvanically isolated;
  • Solid overvoltage withstand;
  • Solid ambient conditions withstand;

Technical parameters

Power supply units parameters
Operating voltage range, DC or AC 90 - 254 V
Power-on availability time 0,19 s
Operating supply interruption 0,5 s
Independent supply channels (auxiliary voltage circuits) 1
Device burden 4 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 - 125,0 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 inputs 1
Rated voltage range 1 - 130 V
Maximum continuous voltage 130 V
USB interface 1
RS485 interface 2
Data protocol Modbus RTU
Connection speed 9600, 19200, 38400 kbps
Binary input parameters
Numbers of inputs 8
Rated AC, DC voltage 230 V
Response voltage level 132 - 176 V
Response time 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 parameters
Number of binary outputs 9
Maximum DC voltage trip 300 V
Maximum AC voltage trip 400 V
Maximum AC current 8 A (16 A for K1 output)
Maximum DC LR-circuit trip current, time constant τ ≤ 20 ms 0,3 A (0,6 A for K1 output)
Mounting type (modifications) Flush/protrude
Device dimensions (WxHxD) 220x220x112 mm
LED indicators    total / configurable 18/6
Operating ambient temperature range
-40 to +55 °C
Maximum Humidity at 25 °C 98%
Insulation resistance, more than 50 MΩ
Insulation overvoltage withstand,
Instantaneous / continuous

5 / 2 kV
Weight, less then 3 kg


Function ANSI RZL-05.Mx
Protection   1 2 3 4 5 6
Overcurrent (OCP) 50/51
Switch on to fault high-speed protection 50HS
Logic Selectivity Busbar protection 68
Zero-sequence OCP (unidirectional ground-fault protection) 50N/51N
Directional ground-fault protection (directional zero-sequence power protection) 67N      
Phase conductor break protection (negative sequence or negative to positive sequence ratio current) 47
OCP/zero-sequence OCP stage activation by binary signal (current-restrained intertrip)  
Arc-fault protection (3 optofibre sensor inputs) 67
Overtemperature protection 46    
Automation functions    
Auto-reclosing 79  
Automatic underfrequency load shedding 81L
HV Breaker failure back-up 50BF
Automatic load transfer  
Automatic initial scheme restore  
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 fault recorder with 600 s total record duration  
Fault recorder on binary input activation  

Wiring Diagrams

RZL-05.M3 - wiring

Wiring diagram of external circuits to the devices RZL-05.M3

RZL-05.M6 - wiring

Wiring diagram of external circuits to the devices RZL-05.M6


RZL-05_M - dimensions

# Download the brochure. Protection and control devices.