Multiple winding transformer differential protection
SIPROTEC 5 base module with large display
The transformer protection device SIPROTEC 7UT87 is an universal protection, control and automation device on the basis of the SIPROTEC 5 system. It is especially designed for protection of multiple winding transformers (up to 5 sides). Further it is to be used there, where a numerous of measuring points (up to 7 3-pole current measuring points) are required. Another application is simultaneously protection of two parallel transformers (additional fast backup protection).The SIPROTEC 7UT87 is the main protection for the transformer and includes a numerous other protection and monitoring functions. In addition the protection functions can also be used as backup protection for following protected objects (for example cable, line). It also supports modular availability of the hardware.
The device supports all SIPROTEC 5 system characteristics. It enables futureoriented system solutions with high investment security and low operating costs.
Up to 2 differential protection with add-onstabilizations (in different function group transformer);
Up to 5 differential ground-fault protection functions
For autotransformer applications two differential protection functions in a function group autotransformer can be used.
Usable measuring point:
9 three-pole current measuring Points,5 one-pole current measuring points,5 three-pole voltage measuring Points,one-pole voltage measuring points
Inputs and outputs:
2 predefined standard variants with
20 current transformers,
4 voltage transformers
15 to 27 binary inputs,
2 to 38 binary outputs
Flexible adaptable and expandable I/O-quantity structure within the scope of the modular SIPROTEC 5-building blocks
Width of housing:
1/3 x 19'' to 2/1 x 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 degree of overall safety and security based on thor-ough implementation
High-performance communications components guar-antee 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 protection for multiple winding transformers with multifunctional, additional protection functions (Multiple winding transformers are typical with power converter applications (e.g. HVDC))
Transformer differential protection for single-core phase-shift transformers and special transformers
Transformer protection applications with up to 7 3-pole current measuring point
Concurrent differential protection for two parallel transformers (e.g. two two-winding transformers)
Universal usability of the admissible measuring points
Usable from medium up to extra-high voltage
Protection of standard power transformers and autotransformers
Typical properties of a transformer differential protection such as flexible adaptation to the transformer vector group, consideration of inrush and overexcitation processes, safe behavior in the case of current transformer saturation with different degrees of saturation
ANSI 90 V voltage control function for two-winding transformers, three-winding transformers and system coupling transformers
Adaptive adjustment of the trip characteristic to the transformer tapping
Increased sensitivity in the case of ground faults close to neutral through a separate ground fault differential protection
Further current and voltage inputs can be added for standard protection functions such as overcurrent, voltage, frequency, etc.
Up to 4 pluggable communication modules usable for different and redundant protocols (IEC 61850, IEC 60870-5-103, IEC 60870-5-104, DNP3 (serial+TCP), Modbus RTU Slave)
Ethernet redundancy protocols PRP and HSR
Cyber Security in accordance with NERC CIP and BDEW whitepaper
Powerful automation with CFC (Continous Function Chart)
Safe serial protection data communication also across large distances and all available physical media (fiber optic, two-wire connections and communication networks)
Measurement of relevant operating variables
Phasor Measurment Unit (PMU) for synchrophasor-measured values and IEEE C37.118 protocol
Powerful fault recording
Help functions for simple tests and easy commissioning
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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