Digital protection and control relay for MV asynchronous and synchronous motor
CZAZ-UM/UM+ is a complex solution ensuring protection and control of MV motor (both synchronous and asynchronous type as well). The device provides reliable and selective protection of the motor and also safe operation of motor feeder, taking into account breakers configuration and all neccessery bay interlocks and automation functions. Rich protection function library allows to use different measuring criterions in order to detect abnormal motor operation.

Manuals, diagrams, technical details


Product description

Protection set

87 Differential protection for motors against internal faults
50/51 Instantonous and definite-time overcurrent protection against phase-to-phase faults
50/51 Overcurrent protection with option of 3 inverse-time characetersistics or definite-time
50/51 Additional two overcurrent functions in order to fullfill busbar protection or breaker failure function
51 Definite-time overcurrent dedicated to protect synchronous motor against loss of synchronism
51N Ground fault overcurrent protection, inverse time characteristic
67N Ground fault directional protection
46 Current unbalance protection
49 Thermal overload protection, two time constant thermal model
48/66 Motor start-up supervision
51LR Overcurrent, against locked rotor
51 Overcurrent, against motor stall
37 Undercurrent, against motor idle
27/59 Under and overvoltage protection
· Three temperature inputs in 4-20mA loop to protect motor against overheat or to measure temperature
· Rotor cage supervision ensuring detection of failure of one bar or ring (only CZAZ-UM+)
· Cable insulation failure detector
· Arc Flash Detector


Rated current In 1A albo 5A
Rated voltage Un 100V
Rated frequency fn 50Hz
Rated auxilliary voltage Up 110V or 220V DC
Burden in measuring inputs ≤0,5VA/input
Burden in supply module ≤25W
Pick-up time ≤40ms
Continuous thermal withstand of current inputs 2,2In
1 sec thermal withstand of current inputs 80In
Dynamic withstand of current inputs (10 ms) 200In
Continuous voltage withstand of voltage inputs 1,2Un
10 sec voltage withstand of voltage inputs 1,5Un
Relay outputs data:
Max. breaking capacity by U=250V DC
– resistive load 0,3A
– L/R ≤ 40 ms 0,12A
Max. breaking capacity by U=250V AC, 50Hz
-inductive load of cosϕ=0,4 3A
Continuous contact carry 5A
Operating temperature range (263÷328)K/(-10÷55)°C
Relative humidity ≤80%
Ingress Protection degree IP40
Weight 6,5kg
Dimensions (height x width x depth)
– surface mounting 223 x 337 x 260 mm
– flush mounting 288 x 145 x 305 mm
– metal enclosure – surface mounting 337 x 223 x 260 mm
– metal enclosure – flush mounting 298 x 256 x 258 mm
Electromagnetic compatibility according to EN 50263
Insulation according to EN 60255-5

Main features

  • Unified and universal hardware and software allowing adaption of the relay to protected objects
  • Two realisations of HMI:
    • graphic display for visualisation current bay state. It enables to simultaneously display: mimic diagram, several selected measured values and other states. Alphanumeric display also available
    • 7” touch screen with resolution of 800 x 480
  • specialised bay controller with biult-in logic to provide safe maintance of bay both in local and remote control mode. Proper control functions are coverd by continuous controlling of switch positions and blocking signals from protection functions. The relays cooperate with substation automation system. The functioning of switch control covers:
    • Circuit breaker position and charging control – by 3 dedicated binary inputs
    • Control voltage supervision
    • Trip circuits supervision
    • operational and test command for closing the circuit breaker
    • operational and trip command for opening the circuit breaker
    • position control of disconnector, earthing switch and changeover switch – whatever installed in switchgear bay
  • Programmable bay controller with programmable logic which allows to add extra logic circuits and more complex protection circuits (busbar protection or breaker failure logic). Possibility to control bay switches (with proper blocking system of opening and closing commands). Programmable logic is set by simple and user friendly graphic interface:
    • 21 binary inputs and 16 logic inputs controlled by communication port
    • 14 output relays
    • tens of signals generated by biult-in unit logic (pick-ups and trip signals from protection functions, faulty position of switches signals, substation control system signals, trip circuit supervision signals etc.)
  • possibility to design user logical circuits and time delays using Boolean operators (AND, OR and NOT), multifunctional timers and other automation functions (eg. technological protection, auto-reclose automation, underfrequency load shedding). Possibility to display logic states on LCD, record in event recorder or send to remote control system
  • Set of biult-in bay diagrams or possibility to build user custom bay diagram
  • Output circuits allowing to direct control of bay switches, including two trip outputs with trip circuit supervision function
  • 8 (CZAZ-U) or 11 (CZAZ-UM) analog inputs (phase currents, phase to phase voltages, residual current, residual voltage – CZAZ-U and -UM and set of currents for differential protection – only CZAZ-UM)
  • Measuring of current electrical values (phase currents, residual current, phase or phase to phase voltages, residual voltage, active and reactive power, active and reactive energy in both directions, power factor)
  • Recordings of disturbances and events:
    • recording of approx. 150 unique events in memory of 500 records
    • disturbance recorder saves 8 waveforms and 16 binary signals
    • recording of maximum and minimum value of voltage, current or frequency and time of duration of last fault
    • trips counter and sum of tripped currents counter
  • Visual signalling (LED diodes) of key relay conditions (PWR, OK, TRIP)
  • 8 or 16 user programmable LED diodes for signalling other logical values
  • system of self control and autotest, signalling improper relay status
  • screwless terminals for current inputs, pluggable terminals for other circuits
  • communication with PC computer or SCADA system by RS 232/485 port or by fiber optic. Offered communication protocols: MODBUS RTU, MODBUS ASC, IEC 60870-5-103

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