Relematika’ s transformer PAC devices TOR 300 DPT provide users with superior main and backup protection as well as control functionality which allows for quick clearing of severe internal faults. Available maintenance on request functionality enhances overall safety and protection reliability by reducing fault clearing time and lowering potential incident energy levels. Three independent zones and event recording feature help reduce troubleshooting time, maintenance requirements and overall costs.

TOR 300 DPT devices provide all necessary main and backup protection functions for two or three- winding transformers and autotransformers on all voltage levels (UHV\EHV\HV\MV). They can protect and control, in addition to their main functionality, also complete (auto)transformer installations, including their bus arrangement, circuit breakers as well as fault current limiting reactors.

Back up distance and overcurrent protections may be incorporated into the TOR 300 DPT device or installed into the cabinets as TOR 300 DIS devices.

Transformer differential protection

Restrained and unrestrained transformer differential protection algorithms operate reliably for internal faults in a protected transformer and all types of short circuits on its leads. Additional measures, applied within its algorithm secure dependable operation for external faults, magnetizing inrush currents, open-phase conditions, and different transient events in power system. Operation of built-in CT supervision function increases the minimum operating differential current and this way prevents unnecessary operation due to high load currents.

Compensation of winding connection groups and fine numerical equalization of currents from different transformer windings, including continuous equalization of tap-changer position, can be easily configured in TOR 300 DPT. The second and fifth harmonics together with current waveform blocking are available to prevent unwanted operations during magnetizing current inrush and transformer overexcitation. CT circuit supervision prevents unnecessary operation during different faults in CT secondary circuits.

Additional functionality

Flexible hardware and software as built in TOR 300 DPT devices permit simultaneous implementation of three separate differential zones and up to five protection sides, which permits also differential protection of transformers with split windings as well as restricted earth fault protection of directly earthed windings.

Buchholz protection (BP) is designed for protection from faults inside the transformer tank accompanied by gas emission. It is connected to circuits of leakage current relay, tripping and alarm elements of Buchholz relay. At tripping command, BP initiates  tripping at all sides of protected element with dissabled autoreclosing, and starts breaker failure protection on all corresponding breakers.

Some additional functions supervise and protect transformer against different faults, like:

Voltage control functionality can be added to the same TOR 300 DPT device together with main and back-up protection functions or installed in the same PAC cubicle as a separate TOR 200 R 63 device. In such case it is possible to control voltage on two transformers at the same time.

Protected objects

Main functions

Main advantages

If required, TOR 300 DPT devices as well as TOR 300 for any other application can be provided within assembled, tested and pre-configured PAC cabinets and fully adapted to your specific project. Also, it is possible to combine main (TOR 300 DPT) and backup (TOR 300 DIS) IEDs in one relay protection cabinet.