MRZS-U

Performs the following functions

Control and measurement

• ­ three phase or line voltages (main channel) from TH1 installed on the busbars;
• two-line voltages of auxiliary channel from ТСН or one line voltage from TH2, set at the input;
• zero phase-sequence voltage.

Relay protection functions:

• two-stage undervoltage protection ЗНmin operates with a time delay for tripping or by signal;
• two-stage overvoltage protection ЗНmax operates with a time delay for tripping or by signal;
• maximum voltage protection of auxiliary channel operates with a time delay for tripping or by signal;
• total under-voltage protection of primary and secondary channels;
• undirected earth fault protection by 3Uo;

Automation functions:

• ACB start up;
• Startup of the normal mode restoration (NMR) scheme at ACB

Monitoring, registration and alarm functions:

­
• monitoring of serviceability of voltage circuits of main and auxiliary channels;
• emergency registrar of oscillograms 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 duration записи - 50 sec.
• discrete signal recorder:
  • 48 recent events;
  • up to 43 records in each alarm with a fixed value;
    • ­ maximal voltages (voltages of phases and voltage 3Uo);
    • ­ minimal voltages (voltages of phases and voltage 3Uo) at the moment of ЗНmin start-up.

Enhanced logic functions:

• ­ number of defined functions - 8;
• ­ number of defined triggers - 3;
• status of triggers is stored in non-volatile memory.

Enhanced logic allows to complement existing functions and create new ones.

Service functions:

• ­freely assignable inputs;
• freely assignable outputs;
• freely assignable LEDs;
• multilingual menu - 3 languages supported;
• three freely programmable 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.