Transformer differential protection

Transformer differential protection – SIPROTEC 7UT82


The SIPROTEC 7UT82 transformer differential protection has been designed specifically for the protection of two-winding transformers. 

Transformer differential protection SIPROTEC 7UT82

Features & functions

It is the main protection for the transformer and includes many other protection and monitoring functions. The additional protection functions can also be used as backup protection for subsequent protected objects (such as cables, lines, shunt reactor). In this process, you are also supported by the modular expandability of the hardware. With its modular structure, flexibility and the powerful DIGSI 5 engineering tool, SIPROTEC 7UT82 offers future-oriented solutions for protection, control, automation, monitoring and PQ basic.


Main function:

  • 1 differential protection function (standard or auto transformer) with additional stabilization; up to 2 restricted ground-fault protection functions

Usable measuring Points:

  • 2 x 3-phase current measuring points,
  • 2 x 1- phase current measuring points

Inputs and outputs:

1 predefined standard variant with 

  • 8 current transformers, 
  • 7 binary inputs, 
  • 7 binary outputs

Hardware flexibility:

  • The 1/3 base module is available with the IO103 module; it is not possible to add 1/6 expansion modules, available with large and small display

Width of housing:

  • 1/3 × 19 inches

As standard:


DIGSI 5 permits all functions to be configured and combined as required.

  • Transformer differential protection for two-winding transformers with versatile, additional protection functions
  • Transformer differential protection for phase-angle regulating transformers of the single core type
  • Universal usability of the permissible measuring points
  • Applicable from average up to extra-high voltage
  • Protection of standard power transformers, auto transformers, short lines, cables, longitudinal and shunt reactors, as well as motors
  • Increased sensitivity with near-neutral-point ground faults through a separate restricted ground-fault protection
  • Flexible adaptation to the transformer vector group
  • Controlling closing and overexcitation processes
  • Safe behavior in case of current-transformer saturation with different degrees of saturation
  • Adaptive adaptation of the operate curve to the transformer tap position
  • Arc protection
  • Graphical logic editor to create powerful automation functions in the device
  • Single line representation in small or large display
  • Integrated electrical Ethernet RJ45 for DIGSI 5 and IEC 61850 (reporting and GOOSE)
  • Up to 2 optional pluggable communication modules, usable for different and redundant protocols (IEC 61850-8-1,IEC 60870-5-103, IEC 60870-5-104, Modbus TCP, DNP3 serial and TCP, PROFINET IO)
  • Serial protection data communication via optical fibers, two-wire connections and communication networks (IEEE C37.94, and others), including automatic switchover between ring and chain topology
  • PQ-Basic: voltage unbalance; voltage changes: overvoltage, dip, interruption; TDD, THD and Harmonics

  • Reliable data transmission via PRP and HSR redundancy protocols
  • Extensive cybersecurity functionality, such as role-based access control (RBAC), protocolling security-related events, signed firmware or authenticated network access IEEE 802.1X
  • Simple, quick and secure access to the device via a standard Web browser to display all information and diagnostic data, as well as vector diagrams, single-line and device display pages
  • Time synchronization using IEEE 1588
  • Powerful fault recording (buffer for a max. record time of 80 sec. at 8 kHz or 320 sec. at 2 kHz)
  • Auxiliary functions for simple tests and commissioning



  • Protection of special transformers (phase shifter, FACTS and converter transformers, arc furnace transformers, HVDC transformers)
  • Backup protection for motor and generator differential protection applications
  • For protection of short cables and lines


  • Compact and low-cost transformer differential protection
  • Safety due to powerful protection functions
  • Data security and transparency over the entire lifecycle of the plant, saving time and money
  • Purposeful and easy handling of devices and software thanks to a user-friendly design
  • Increased reliability and quality of the engineering process
  • Cyber security in accordance with NERC CIP and BDEW Whitepaper requirements
  • Highest availability even under extreme environmental conditions by “conformal coating“ of electronic boards
  • Powerful communication components warrant safe and effective solutions
  • Full compatibility between IEC 61850 Editions 1 and 2

Downloads and services

Retrofit and enhancement services

Retrofit and enhancement services

Extend the lifespans of your energy system and thereby significantly reduce your costs of ownership with our retrofits and enhancement services for energy automation.

Power Academy training services

Power Academy training services

Our goal is to prepare you for new professional challenges in power transmission and distribution. We offer professional training courses with different training methods like Virtual Classroom Training, Classroom Training, WBTs, Webinars and Blended Learning. You can choose between open enrollment training courses, customized training courses, workshops or long-term trainings (curricula).

Energy Automation and Digital Grid Newsletter


Receive news about the Digital Grid and Energy Automation portfolio and offerings!

Energy Automation Webinars

Energy automation webinars

Learn more in one of our energy automation webinars for protection and substation automation engineers and experts.