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Transformer TerminalRET 541, RET 543, RET 545

1MRS755543

Application

The RET 541/543/545 transformer terminals are designed to be used for the protection, control, measurement and supervision of two-winding power transformers and generator-transformer blocks in distribution networks. RET 54_ terminals can also be used in harsh environments e.g. in heavy industry, marine and offshore applications. The graphical configuration tool, based on the IEC 61131-3 standard, enables easy cre - ation of application-specific configurations and MIMIC pictures corresponding to differ - ent switchgear systems. The process status is shown on a dynamic large graphical display. Detailed information, for instance, measured values, events and application-specific alarms, are presented in the display views. The main protection function is three-phase current differential protection with stabilized and instantaneous stages for fast and selective winding short-circuit and interturn protection. Besides 2nd and 5th harmonic restraints, the stabilized stage also includes a waveform rec The RET 54_ terminals can measure two sets of three phase currents, phase-to-phase or phase-to-earth voltages, neutral current, residual voltage, frequency and power factor. Active and reactive power is calculated from the measured currents and voltages. Energy can be calculated on the basis of the mea - ognition-based blocking-deblocking feature. Reliable operation even with partially saturat-ed current transformers, that is, short operate times at faults occurring in the zone to be pro - sured power. The measured values can be indicated locally and remotely as scaled pri - - tected and high stability at external faults are achieved. Increased sensitivity can be obtain-ed by automatic adaptation to the position changes of the on load tap changer. Interpos mary values. With the condition monitoring functions the RET 54_ transformer terminal monitors e.g. trip circuits, gas pressure of the breaker and breaker wear and provides scheduled time intervals for maintenance. - ing current transformers are not needed: Any vector group matching and CT ratio correc - tions in a wide range are numerically imple - mented as well as zero-sequence current elimination, which prevents unwanted trips at earth faults occurring outside the protected area. The RTD1 card, available as an option to the RET 541 and RET 543 terminals, provides versatile analog inputs enabling e.g. tap posi - tion supervision of the on load tap changer, RTD inputs for top and bottom oil tempera In addition to the differential protection, the - Basic version terminals incorporate the fol - ture monitoring, and ambient temperature biasing for accurate thermal overload protec lowing protections: Restricted earth fault pro - - tection with stabilized numerical or high impedance principle, unbalance and thermal overload protections, three phase overcurrent and non-directional earth fault back-up pro tion. The mA outputs allow transfer of any measurement data e.g. to PLCs. - By means of the graphic HMI display, the control functions in the transformer terminal indicate the position of disconnectors, circuit breakers and tap changer locally. Local con tection with definite and IDMT characteris - tics on both sides of the transformer. - The Multi -version terminals, further includ - trol of these objects is possible via the push buttons on the front panel of the terminal. Furthermore, the terminal allows position information of the objects to be transmitted to the remote control system. Controllable objects, such as CBs, can also be opened and closed over the remote control system. ing overvoltage and undervoltage, residual overvoltage, underfrequency and overfre - quency, overexcitation, directional earth-fault, directional overcurrent and under - impedance line back-up protections fulfill the most demanding application requirements. Enhanced with the optional automatic voltage regulation function, the RET 54_ terminal can be applied as a comprehensive integrated transformer management terminal. The volt Supporting a wide range of communication protocols, including SPA, LON, IEC 60870-5-103, DNP 3.0 and Modbus RTU/ASCII, commonly used by utilities and industries, the terminals are flexibly integrated into different control systems. Connection to Profibus DP or IEC 61850 based system is possible via the interface adapters SPA-ZC 302 or SPA-ZC 400, respectively. - age regulator can be applied for a single transformer or for parallel transformers with Master-Follower, Negative Reactance or Minimizing Circulating Current principles. A special control version terminal with volt - age regulator and control functions can be applied, when integration of voltage regula - tion and protection is not allowed.
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