Generator and transformer protection 25MW Synchronizing System



  • Numerical protection system (NPS) shall mean the protection terminals wherein the analog to digital conversion of the input variables takes place immediately after the input transformers and all further processing of the resulting numerical signals shall be performed by microprocessors and controlled by programs. NPS shall include all features of conventional relays, protective devices, relay panels for generator, generator transformer, unit transformer and station transformer


  • Synchronizing system mean, indicators and control devices required to ensure that, before electrical systems are paralleled, voltages, frequency (speed) and phase angle are equal and in each phase

Measuring and metering:

  • The term measuring mean indicator meters digital type installed in unit local panel and remote monitored in control system.


Generator and transformer protection 25MW Synchronizing System1

Technical Specifications

  • Protection be applicable at different generator types and power plants (Apparent power system from 0.2 MVA up to 100 MVA)
  • The implemented functions fulfill the protection requirements for direct connection and unit connection schemes
  • With the combination of 7UM62, 7UT61, and 7SJ6 protection relays and flexible redundancy concepts are feasible in protection
  • Direct read out from the relays and stored on a disk (*.zip file.)
  • Operating program DIGSI4 with online help
  • Acquisition of all relevant measured values
  • Storage of events in buffers (disturbance recording, event log and trip log buffers)
  • Flexible tripping concepts (Tripping matrix, lockout or master relay tripping)
  • Disturbance recorder with instantaneous or rms values (calculated values, every cycle; length max. 80 s(
  • The devices adjustment can be done by using integrated LC Display and keypad or, very comfortably, by using a PC and the DIGSI Software.
  • All specific data are stored in EEPROM circuits in which the information is kept also if the device is switched off. (Batteries are not necessary)
  • Insensitive to VT and CT errors, transient conditions and interferences.
  • Precise synchronizing in order to preserve the life of the equipment
  • Synchronizing be applicable at different Single line of power plants and Substations
  • Ability to select the circuit breaker for synchronizing
  • 1.5channel design at the 7VE61 (Sync-check + Paralleling function)
  • Consideration of the transformer vector group and the position of the tap changer
  • Synchronisation record (instantaneous or rms)
  • The reliability of synchron relay will be increased with additional supervision principles
Measuring and Metering:
  • Measuring system, using Transducers
  • measurement of all electrical quantities in a single unit
  • All data freely parameterisable
  • The output signal is for e.g. -10 to 0 to 10 mA,± 20 mA, 4 to 20 A, 0 to 10 V, etc.
  • Metering system, using EDMI Energy Meters
  • Quadrant splitting (4 quadrant measurement)
  • Class 0.2S / 0.5S (IEC 62053-22, IEC 62052-11)
  • Standard protocols for communication
  • More measurement quantities like single phases, U, I, VA
  • Excellent measurement behaviour (both energy directions)


  • The electrical protection, synchronizing, measuring and metering systems performs the following functions:
  • Protection of generator, main transformer, unit transformer and station transformer
  • Selective coordination
  • Reliable and fast fault clearing
  • Reliable synchronizing of circuit breakers
  • Precise electrical measuring and metering