Family of MV protection relays
CZAZ-SN relays are complex protection devices dedicated to particular elements of MV power grid. The relays are equipped with specialised bay controller. All types of protection relays are simillar design which ensures high accuracy, stability and dependability. CZAZ-SN relays are replaced by new type of relay (CZAZ-U) so its not recommended to use them i new projects. Types of CZAZ-SN relays:
  • CZAZ-CR              - protection of coupling bay
  • CZAZ-L                 - protection of MV line
  • CZAZ-PR              - protection of voltage measuring bay
  • CZAZ-PZ              - protection of incoming feeder
  • CZAZ-T1/T2/T3 - protection of MV/LV transformer
  • CZAZ-TSE            - economical version of transformer protection

Manuals, diagrams, technical details


Product description

Protection set

Depending on type of relay, different set of protection functions from the list below are implemented:

50/51                    Instantonous and definite-time overcurrent protection against phase-to-phase faults

51                           Definite-time or inverse time overcurrent protection

51/67                    instanteneous or definite-time dedicated for long lines against phase-to-phase faults, with directional interlocking in CZAZ-L+ (67)

51/67                    overcurrent against phase-to-phase faults with two possible operation modes:

– definite-time overcurrent with directrional interlocking

– inverse-time overcurrent

51N/27                 inverse-time overcurrent against ground faults with option of interlocking by residual undervoltage

51N/67N             against ground fault with option to choose one of the following operation modes:

– two-stages overcurrent (51N)

– inverse-time overcurrent (51N)

– directional overcurrent (67N)

– admittance-based directional protection

50N/51N             ground overcurrent, definite-time, two-stages

51N                       ground overcurrent, inverse-time

21N                       admittance-based against ground faults protection

67N                       directional ground overcurrent

59N                       ground overvoltage

27                           undervoltage, definite-time, two-stages

59                           overvoltage

81                           overfrequency

62                           external

79                           auto-reclose automation

Arc Flash Detector (optionally)

coordination with UFLS and AR after UFLS automation

coordination with transformer Bulcholtz protection

Main features

  • bay controller with standard control operation mode implemented which ensures safe in both local and remote modes based on breakers position supervisingAdditional functions:- busbars protection

    – CB failure function

    – cooperation with ATS function

    – Switch Onto Fault function

    – cooperation with station failure/alarm signalling system

    Cooperation with breakers function ensures:

    – supervising of CB postition

    – Trip Circuits Supervising functions

    – Open command and Close command

    – Disconnector and Earthing switch postion supervising

    Up to 24 binary inputs and 10 relay outputs in order to fullfil functions listed above.

    – 8 programmable relay outputs

    – 5 binary inputs for cooperation with external protections

    – 2 TRIP purposes relay outputs allowing to direct connection with CB coils and with Trip Circuit Supervision function

    – 7 measuring inputs (phase currents, phase-to-phase voltages, residual current/voltage)

    – Measuring of current electrical vaules (phase currents, zero-sequence current, phase-to-phase voltages, active power, reactive power, active energy counter, power factor)

    – Event and disturbances recorders

    – ab. 70 unique events register with capacity to memorise up to 500 events

    – disturbance recorder of sampling frequency 1000 Hz (7 analog signals and 16 binary signals)

    – parameters of last disturbance recorder: maximum current during disturbance and duration of disturbance

    – number of protection operations counter and sum of tripped current counter

    – optical visualisation of most important states of protected object (8 LED diodes)

    – autotest and autocontrol system

    – screw terminals for current inputs and pluggable screwless terminals for other circuits

    – autonomic communication by local Human Machine Interface

    – remote communication with PC computer or supervising system

You need more information?

Contact our Sales Department and talk to our expert about the details.
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