Rectifiers & D.C. Power Supply Systems

Control device for rectifier sets

Untitled-3.jpgApplication

Control device for rectifier units is designed to control heavy current multi – bridge rectifier sets feeding electrolyzers. Three main design versions are available:

– for uncontrolled rectifier sets;             
– for diode rectifier sets with saturable reactors;             
– for thyristor rectifier sets.

Design

Control device is made as a double – access cabinet comprising the following functional units:

  • d.c. and a.c. input supply voltage;
  • local operative control;
  • current adjustment;
  • overcurrent and overload protection;
  • control of tape changer;
  • measurements;
  • interlocks and signals, including control of transformer, rectifier units, cooling systems and other devices incorporated by the set, considering standby facilities;
  • interface for communication with upper control level;
  • automatic ON – switching of stand – by power supply.

Main protection systems

  • overcurrent protection with opening the input power circuit breaker, when the measured current of converter transformer line or valve winding exceeds the protection set values;
  • integral overload protection of rectifier units with opening the input power circuit breaker, when the integral over time due to difference between the rectifier unit current and initial closing current of integral overload protection exceeds the preset value;
  • pulse protection of rectifier units, which opens the input power circuit breaker, when the second fuse blows;
  • opening of the input power circuit breaker, when discrete emergency report arrives from the converter transformer, rectifier unit, tape changer, overload protection devices.

Control unit based on Siemens S7 – 200 controller ensures:

  • high informative capability;
  • implementation of telecontrol and telesignalling systems in substations by organizing a local computer network on the basis of Profibus field information bus.

Control device is the lower level of three – level control system for converter substations.

The complete delivery also covers programmed control cabinets (medium level) and automated operator's working position – console (upper level).



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