• Description
  • Protection set
  • Ordering method
  • Catalog

Area of application

iZAZ400 is a series of powerful, communication-enabled digital multifunctional relays with up to 12 measurement inputs. These devices are characterised by high accuracy and reliable operation. They can be used in automatic control systems as comprehensive protection devices for MV bays (incoming, bus coupler, outgoing, transformer, engine, measurement, etc.), high voltage bays, and small generators. Automatic controls for automatic frequency load shedding, automatic reclosing, automatic voltage load shedding, busbar protection, automatic reserve switching, return transfer switch, automatic transfer switch as well as breaker failure protection are supported in applicable hardware and software configurations.

iZAZ400 can be used as a five zone distance protection with polygonal or circular characteristics and single-phase automatic reclosing functions, telecom and reverse current port, short circuit locator, and power swing interlock. iZAZ400 can also be used as a differential protection of medium and high voltage lines as two semi-sets with dedicated fibre connection.

Apart from the protection and automatic control function, the devices are used for measurements, recording, emergency control and signalling. Methods of communication with the relay include: two RS-485 serial ports (optional COM2 in the fibre variant), a wire or fibre LAN connection and a USB port on the control panel. Thanks to the modular design, the hardware configuration can be optimally customised to the requirements of the protected facility. A 7-inch colour touch display ensures legible presentation of the bay synoptic system with essential measurements and additional information. The operation logic is easily and freely programmable via a graphic editor, which enables legible and transparent implementation of various applications, both typical and dedicated, including specific requirements for a given facility. Bay controller enables the control of circuit-breaker and switching devices, while maintaining the required functional interlocks.

The universal hardware and software enable easy and intuitive changing of the configuration and adaptation to various facilities. With the application base developed by the manufacturer, default solutions can be used. Moreover, it is possible to modify the configuration to match the specifics of the protected facility, and the user needs. The modification of the configuration can include adding protective functions or automatic controls and the change of logic-time dependencies (e.g. means of controlling diodes on the panel, signalling on the display, controlling signalling relays and means of emergency control).

The iZAZ400 relay was adapted to work with the flash sensor for arc protection.


The device is equipped with three different recorders enabling the analysis of phenomena occurring in the protected facility.

Event recorder – basic status recorder creating a chronological event log with a resolution of 1 ms. Circular buffer with a capacity of 500 events. It records protective device excitations, reactivations and operations as well as status changes of binary inputs, automatic controls, and other events generated from the internal logic. Names and comments can be edited for all events, which allows application adaptation and facilitates the analysis of events by the user.

Actuation recorder – enables quantitative analysis of the interferences. This recorder allows the review of interference time and threshold parameters of analogue signals measured from the moment of excitation to the reactivation of the function after its operation. The type and amount of recorded data depend on the nature of the function, e.g. for overcurrent protection it is the interference duration and maximum current value in this period. This recorder enables quick assessment of the event by presenting information on criterion values associated with the interference, giving the user the opportunity to verify settings. For a typical record of three analogue values (e.g. maximum current, voltage), the internal circular buffer allows recording up to 200 records.

Disturbance recorder – a set of recorders of analogue and binary waveforms with criterion recorder function enabling full analysis of interfering phenomena. The device allows programming of up to two fully independent configurable recorders. The function of criterion recorder offers the opportunity of recording any of the criterion values available in the device (analogue and binary). The standard settings of pre-run, post-run and maximum recording time enable proper shaping of the log window for the phenomenon of interest. In order to optimize the recording of long term low-frequency phenomena, it is possible to lower the sampling rate with the option of controlling rarefaction of the recorder log using a chosen binary signal (e.g. circuit-breaker open, start-up status, etc.). The capacity of the internal buffer depends on the number of active recorders, programmed analogue and binary channels, and the maximum duration of the individual recording. For a single recorder, 8 analogue channels, and 64 binary channels, it is possible to record a 1000-second file.

Functional characteristics

  • An extensive set of protective functions and automatic controls
  • Extensive list of available measurements, such as measurement of all currents and voltages, and calculated values (e.g. power and energy, frequency, temperature from the model)
  • Programmable controller with a legible graphic interface enabling the implementation of various logic-time dependencies on the basis of all signals available in the device
  • Counters enabling diagnostics of the working status of the bay (including: number of protection device operations, automatic control operations, trips, cumulated counter of circuit-breaker currents)
  • Operation logic easily programmable using a graphic interface
  • Recorder of configurable and system events
  • Actuation recorder
  • Disturbance recorder with the function of the criteria recorder
  • Capability of saving the recording files to an external FLASH (USB) memory
  • Indicator of qualitative energy coefficients: THD, frequency, number of voltage losses, dips
  • Up to 12 measuring inputs (hardware-configurable)
  • Up to 36 (4 IO modules) output relays, fully programmable
  • Up to 48 (4 IO modules) programmable binary inputs for visualizing the switching device status and interoperating with external protection devices
  • 16 programmable, two-colour signalling diodes on the control panel
  • Extended autotest system with warning signalling
  • Real time clock with sync capability
  • Communication with a PC or parent system via RS-485 or LAN (wire or fibre) interface and standard mini-USB port at the front panel
  • Control panel with a legible 7-inch colour graphical touch display, navigation and numerical keyboard with a standalone mounting capability
  • Standard package of application software - iZAZ Tools (including iREC software for disturbance recordings analysis)
  • Digital technology ensuring high stability, accuracy and reliability of operation
  • Protection against unauthorised access (setting or configuration modification)
  • Works with flash sensors (up to 3 in parallel) for arc protection on the basis of current and voltage criterion

Automatic control and protection set depends on the analogue channel configuration and is limited by the maximum number of software configuration objects of the iZAZ400. In the software variant, the set is chosen from a basic application library and it is possible to configure a dedicated, individual group of required protective functions. The following standard hardware versions of the analogue input configurations are available (up to 12 analogue inputs):

A - optimal: I13f, 3Io, I3, U13f, U2, 3Uo
B - maximum: I13f, I23f, 3Io, U13f, U2, 3Uo
Z - impedance: I13f, 3Io, U13f, U2, 3Uo 
D - differential: I13f, I23f, I33f, I43f
S - voltage: Ut1, Ut2, Us13f, Us23f

Other, individual hardware configurations can be also manufactured. The details on the availability of functions in certain hardware variants are listed in Table 1 of the Product Data Sheet.

Protective function and automatic control library

  • Overcurrent (50/51)
  • Inverse time overcurrent (51)
  • Peak overcurrent (wide frequency range) (50/51)
  • Inverse time overcurrent (49R)
  • Thermal overcurrent (49M)
  • Negative sequence overcurrent (46)
  • Inverse time negative sequence overcurrent (46)
  • Undercurrent (37)
  • Directional overcurrent (67)
  • Overvoltage (59)
  • Peak overvoltage (wide frequency range) (59)
  • Undervoltage (27)
  • Residual overvoltage (59N)
  • Negative sequence overvoltage (47)
  • Positive sequence undervoltage (27D)
  • Rate of voltage change (59S/27S)
  • Incremental rate of voltage change (59SA/27SA)
  • Integral rate of voltage change (59SI/27SI)
  • Ground fault overcurrent (50N/51N)
  • Ground fault inverse time overcurrent (51N)
  • Ground fault directional - MV (59N/67N)
  • Ground fault directional - HV (59N/67N)
  • Earth-fault admittance, non-directional (21N)
  • Earth-fault admittance, directional (0÷90), capacitative (21N)
  • Frequency (81H/81L)
  • Rate of frequency change (81S)
  • Incremental rate of frequency change (81SA)
  • Overexcitation (24)
  • Directional power supervision, against reverse power (32R)
  • Directional power supervision, against load rejection (32L)
  • External (62)
  • Load-jam motor rotor (51LR)
  • Starting-time supervision (48)
  • Strartup monitoring (66)
  • Rotor stall monitoring (51LR)
  • Phase-sequence voltage (47)
  • Loss-of-excitation (40/27)
  • Underimpedance, circular (21)
  • Against accidental switching of a non-excited generator (50/27)
  • Loss-of-synchronism (RMS current pulsations) (51S)
  • Differential for generator, transformer, generator-transformer block with interlock from 2 h and 5 h (87G/87T/87B)
  • Differential for line (two semi-sets) (87L)
  • Distance, five zone, polygonal or circular (21)
  • Short circuit locator function (LMZ)
  • Power swing detection function (68/68T)
  • Earth-fault differential REF (IL1+IL2+IL3-3Io) (64REF)
  • Earth-fault of rotor (64R)
  • Earth-fault of stator 100% (3h difference) (64S)
  • Against synchronism loss / pole slip (78)
  • Power factor monitoring tgφ (55)
  • Automatic underfrequency load shedding
  • Automatic reclosing (79)
  • Automatic transfer switch
  • Automatic planned transfer switch
  • Automatic control for automatic voltage load shedding
  • Local breaker failure (50BF)
  • Synchrocheck (25)
  • Tester for rotor cages of inductive motors
  • Detection of cable insulation failures

The order should contain the following information: device name, analogue channel configuration, rated current/measurement voltage, auxiliary supply voltage and the protective function set variant as well as the communication port and control panel configuration.

Order examples:

iZAZ400-P-XXAA- XP-A51-220-220-A1 - iZAZ400 type multifunctional relay: with control panel, two 12 input/9 output I/O modules for 220V DC, optimal version of analogue channels (I13f, 3Io, I3, U13f, U2, 3Uo), current channels with transformers rated at 5A, voltage channel with a transformer rated at 100 V, LAN, COM1, wire COM2, rated auxiliary voltage: Upn = 220 VDC / 230 VAC, control voltage Usn = 220 VDC. Protective function set variant according to A1.

iZAZ400-X-PAXK-FF-C1X-110-110-C2 - iZAZ400 type multifunctional relay: without the control panel, one 12 input/9 output I/O module for 110V DC (6 inputs 6x1, 3 relay outputs, 3 reed relay outputs), one 12 input/9 output I/O module for 110V DC and one module with inputs in 4–20 mA standard, minimum version of analogue channels (I13f, 3Io, I3), current channels with transformers rated at 1 A, fibre LAN, wire COM1, fibre COM2, rated auxiliary voltage: Upn = 110 VDC, control voltage Usn = 110 VDC. Protective function set variant according to C2.

Details on the ordering methods can be found on the pages of the Product Data Sheet.