MRZS-Т

Performs the following functions

Control and measurement

• low-side three phase currents with a frequency of 50 Hz with a nominal value of Iн = 5 A in the range of 0.1 to 30 Iн;
• three phase currents of the middle side with a frequency of 50 Hz with a nominal value Iн = 5 A in the range from 0.1 to 30 Iн (for three winding transformers);
• high-side three phase currents with a frequency of 50 Hz with a nominal value Iн = 5 A within the range of 0.1 to 30 Iн;
• three phase voltages;
• current direct sequence low side;
• current of the negative side reverse sequence;
• current zero sequence low side;
• current direct sequence high side;
• high side reverse sequence current;
• high side zero sequence current;
• three phases of differential current;
• three phases of the second harmonic of the differential current;
• three phases of the fifth harmonic of the differential current;
• three phases of the aperiodic component of the differential current;
• direct sequence voltage;
• negative sequence voltage;
• voltage zero sequence;
• angles between all analog line measurements;
• network frequencies;
• active power with a sign;
• reactive power with a sign;
• full power;
• power factor.

Relay protection functions:

• differential current protection and differential current cutoff with braking from the maximum phase current of the sides of the higher, middle and lower voltage.
• The characteristics of the deceleration curve (base points, slope coefficients) are specified when parameterizing.
• Differential current protection with braking.
• Any of the stages can be executed with voltage start using extended logic elements.
• Alignment of the rated currents of the sides of the high, medium and low voltage is provided.
• The switching circuit does not depend on the connection group of the transformer windings, the device recalculates the values and angles of currents according to the connection group number.
• The ability to enter harmonic blocking to prevent false triggering when the transformer is overexcited.
• Ability to enter aperiodic locking;
• four-stage overcurrent protection (OCP), has the following stages:
• 1 stage with definite time delay (current pinch-off), or with the possibility of a voltage triggering, or directional OCP with an independent time delay;
• 2 stage with definite time delay with the possibility of voltage triggering or with a time-dependent delay (in accordance with IES 255-4 types A, B, C, RТ-80, RТV-1 characteristics), or directional OCP with an independent time delay;
• 3 stage with a definite time delay (overload protection) with the possibility of voltage triggering or directional OCP;
• 4 directi stage with a definite time delay (overload protection) with the possibility of voltage triggering or onal OCP.
• Works on currents of high or low side
• blocking of OCP from magnetizing current surges
• two-stage undervoltage protection voltage with the ability to control the current and the inclusion of the launches of organs by AND or OR. It operates on high or low side voltage.
• two-stage overvoltage protection with the inclusion of launching bodies by AND or OR. It works on the voltage of the high or low side.
• two-stage non-directional protection against ground faults based on the calculated 3Io (equivalent to the RTZ-51 relay). Operates on either high or low side currents
• zero-sequence voltage protection 3Uo according to the rated voltage of the zero sequence. Works on the voltage of the high or low side.
• four-stage directional ground fault protection according to design 3Io (GFP) with the possibility of simultaneous operation in two directions with different sets of settings. Works on currents of high or low side.
• two-stage negative phase-sequence protection (NPSP), reacts to the ratio of negative sequence current to direct sequence current. Works on currents of high or low side.
• transformer gas protection, It reacts to the state of discrete inputs from the closing contacts of the gas relay and, after operation, acts on shutdown or signal.
• transformer thermal protection, It reacts to the state of discrete inputs from the closing contacts of the thermal relay and, after operation, acts on shutdown or signal.
• universal protection (8 ps.) with the ability to start on all currents, voltages andc apacities indicated in the section “Control and measurement”. In this case, the fault detector can operate both on the excess of the setpoint and on a decrease below the setpoint.
• determination of the nature of the damage (external or internal) by the angle between the vectors of the currents of the reverse sequence;
• two device circuit-breaker failure protection (CBFP) with current control. It acts on the adjacent connection. Works on currents of high or low side. The start of the CBFP is carried out when the protection is triggered or through a digital input. Every CBFP has two steps in response time.
• two functions for monitoring switching circuits on and off with independent settings
• the de-shunting function of two current circles

Automation functions:

• ­ two functions circuit breaker control.The circuit breaker can be switched on and off both from the device and via a discrete input (pulsed). If there is a command to cut off the circuit breaker, the on signal is blocked;
• ­ trigger (need for checkback);
• interlocking from multiple switching of the breaker.

Monitoring, registration and alarm functions:

• monitoring of the serviceability (symmetry) of the current circuits (from the phase failure of the feeder)
• circuit breaker closing and opening monitoring;
• ­ emergency registrar of oscillograms of currents with recording of discrete signals:

• parameterizable duration of pre-emergency and emergency recording;
• ­ resolution capability of the recorder by analog signals - 1,25 ms;
• ­ total recording time - 50 s.

• ­ discrete signal recorder:
• ­ 30 recent events;
• up to 43 records in each event;
• statistics recorder: records the last 400 changes of all discrete signals.

Enhanced logic functions:

• ­ number of defined functions - 16;
• ­ number of defined triggers - 4;
• ­ status of triggers is stored in non-volatile memory;
• ­ transfer functions;
• ­ logical elements AND, OR, NOT, EXCLUSIVE-OR.
• Enhanced logic allows to complement existing functions and create new ones.

Service functions:

• freely assignable inputs;
• freely assignable outputs;
• freely assignable LEDs;
• four groups of settings for all protections;
• multilingual menu - 3 languages supported;
• six freely programmable buttons with the ability to operate in key mode;
• switch control buttons;
• work with an external computer is carried out through the USB port.

Interfaces and communication protocols:

• ­ Interface RS 485 - Communication protocol Modbus RTU;
• ­ Interface USB;
• ­ Interface by choice:
  • Interface Ethernet (RJ-45)- Communication protocol IЕС 61850 (optional);
  • Interface Ethernet (optic) - Communication protocol IЕС 61850 (optional).

Short-circuit current auxiliary power supply. If the power supply of the device at the power input of 220 V (or 110 V) The device can be powered from current transformers of phases A and C. In this case, the magnitude of the current must be 4 A or more for one of the phases or for the total of two phases.

Power supply of two discrete inputs from an internal source (DIP)