Multiple winding transformer differential protection
SIPROTEC 5 base module with large display
The SIPROTEC 7UT87 transformer differential protection has been designed specifically for the protection of multiwinding transformers (up to 5 sides). Furthermore, it is to be used where numerous measuring points (up to 7 3-phase current measuring points) are required. Another application is simultaneous protection of two parallel transformers (additional fast backup protection). The SIPROTEC 7UT87 is the main protection for the transformer and contains many other protection and monitoring functions. The additional protection functions can also be used as backup protection for protected downstream objects (such as cables or lines). With its modular structure, flexibility and the powerful DIGSI 5 engineering tool, SIPROTEC 7UT87 offers future-oriented system solutions with high investment security and low operating costs.
Up to 3 differential protection functions with additional stabilization (in different transformer function groups); up to 5 ground fault differential protection functions.For auto transformer applications, two differential protection functions can be processed in an auto transformer function group.
Usable measuring point:
9 x 3-phase current measuring points, 5 x 1- phase current measuring points, 5 x 3-phase voltage measuring Points
Inputs and outputs:
2 predefined standard variants with 20 current transformers, 4 voltage transformers, 15 to 27 binary inputs, 22 to 38 binary outputs
Flexibly adjustable and expandable I/O quantity structure within the scope of the SIPROTEC 5 modular system.
2/3 × 19" - 2/1 × 19"
High-performance protection features guarantee safety
Data security and transparency throughout the entire life cycle of the system save time and reduce costs
Clear and easy-to-use devices and software thanks to user-friendly design
Increased quality and reliability of the engineering process
High-performance communications components guarantee safe and effective solutions
Full compatibility with IEC 61850 Edition 1 and 2
High available Ethernet communication though integrated Ethernet Redundancy Protocols PRP and HSR
Two transformer function groups can be used in SIPROTEC 7UT87. All functions can be configured freely with DIGSI 5. For the application of some of the functions, you require the appropriate number of free function points within the device. The function point calculator in the online configurator provides support in determining the required number of function points for your device.
Transformer differential protection for multiwinding transformers with versatile, additional protection functions (multi-winding transformers are typical in power converter applications (such as HVDC))
Transformer differential protection for phase-angle regulating transformers of the single core and two core types, and special transformers
Transformer protection applications with up to seven 3-phase current measuring points
Simultaneous differential protection for two parallel transformers (such as two 2-winding transformers)
Universal usability of the permissible measuring points
Applicable from average up to extra-high voltage
Protection of standard power transformers, auto transformers and motors
Typical properties of a transformer differential protection such as flexible adaptation to the transformer vector group, control of inrush and overexcitation processes, safe behavior in case of current-transformer saturation with different degrees of saturation
Voltage controller function ANSI 90V for two-winding transformers, three-winding transformers and grid coupling transformers with parallel control (master/follower, circuit reactive current minimization)
Adaptive adaptation of the operate curve to the transformer tap position
Increased sensitivity with near-neutral-point ground faults through a separate restricted ground-fault protection
Additional current and voltage inputs can be supplements for standard protection functions, such as overcurrent, voltage frequency and others
Graphical logic editor to create powerful automation functions in the device
Up to 4 pluggable communication modules, usable for different and redundant protocols (IEC 61850, IEC 60870-5-103, IEC 60870-5-104, DNP3 serial and TCP, Modbus TCP, PROFINET IO)
Redundancy protocols PRP and HSR
Cyber security to NERC CIP and BDWE Whitepaper requirements
Secure serial protection data communication, even over great distances and all available physical media (fiber-optic cable, 2-wire connections and communication Networks)
Capturing operational measured variables and protection function measured values to evaluate the plant state, to support commissioning, and to analyze faults
Phasor Measurment Unit (PMU) for synchrophasor-measured values and IEEE C37.118 protocol
Powerful fault recording (buffer for a max. record time of 80 sec. at 8 kHz or 320 sec. at 2 kHz)
Auxiliary functions for easy tests and commissioning
Flexibly adjustable I/O quantity structure within the scope of the SIPROTEC 5 modular system
Application templates are available in DIGSI for standard applications. They comprise all basic configurations and default settings.
All application templates which are described for the devices 7UT85 and 7UT86 can be used in 7UT87. The following application templates are available:
Differential protection for complete transformer (auto transformer + delta winding)
Node protection for autotransformer winding to the capture of ground faults (three-phase capture of the neutral-pointcurrent)
Overload protection, backup protection for the downstreamed power system
Circuit-breaker failure protection
Frequency- and voltage protection on the upper voltage side
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