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Modular universal protection relay SIPROTEC 7SX85
SIPROTEC 7SX85 - the modular universal protection device impresses with high performance and an extensive function library. One device type covers all protection, control and automation tasks in medium voltage, distribution and transmission grids with 3-pole tripping and offers many advantages in terms of investment and operation.Always the right device – tailored like you need it and pay only for what you applyMartin Berndsen, Director Sales, Energy Automation
The equation for the universal protection device SIPROTEC 7SX85 is: Hardware + required functions.
Choose the right device HW and complement it with functions according to your needs. In this way the specific device is always precisely tailored according to the respective application.
SIPROTEC 7SX85 at a glance
Highlights
- Always the precisely tailored functionality in the device. Pay only for what you apply!
- Protection and control of feeders, lines, transformers, motors, generators, and capacitor banks
- Modular design with a high number of IOs
- Virtual testing with SIPROTEC DigitalTwin
- IoT connectivity for easy access to your device data and associated fast response times
- Multiple and pluggable communication interfaces

Profile of the universal protection relay SIPROTEC 7SX85
Benefit in your daily work
- Device variance can be significantly reduced
- Reduced number of spare parts
- SIPROTEC 7SX85 can be ordered and put on stock with minimum functionality – reduces capital employed
- Additional functionality can be ordered on-demand and paid when required – within minutes
- Device order can be done before engineering is finalized
- Full flexibility until start of commissioning
- Easy functional extension when grid conditions or applications are changing after installation
- Universal protection can replace type specific SIPROTEC devices
Three aspects of the SIPROTEC 7SX85 universal protection relay
The new modular SIPROTEC 7SX85 universal protection device leverages the full potential of the comprehensive and powerful SIPROTEC 5 system platformStefan Werben, product manager SIPROTEC 5
How is it done?
When selecting a device, use one of the 3 predefined hardware variants and assemble your desired device from the hardware catalog and add the required functionality:
- Up to 443 binary inputs, 225 binary outputs and 64 analog inputs
- Load the required functions from the extensive SIPROTEC 5 function library into the device configuration simply by dragging and dropping them with DIGSI 5
- Possible main protection functions: overcurrent protection, distance protection, line differential protection, transformer differential protection, motor and generator protection, and capacitor protection
- The range of functions that can be used in the device is determined by the specified function class
- If required, simply extend the function point class in a few minutes via the new SIPROTEC Function Point Manager application.
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SIPROTEC Function Point Manager
SIPROTEC Function Point Manager manages function point budgets and assigns function points to SIPROTEC 5 and SIPROTEC 5 Compact devices to extend their functionality.
Major Functions
Protection:
Directional and non-directional overcurrent protection of feeders, with additional functions
Distance protection for overhead lines and cables, with a wide variety of pickup methods
Differential protection of overhead lines and cables of all lengths with up to 6-line ends fed from one or more sides
Transformer differential protection for two- and multi-winding transformers with versatile, additional protection functions
Motor protection against short circuits, all kinds of thermal overload, unbalances, and instabilities, and blocked or idle driving conditions
Protection of generators, power units and synchronous motors
Detection of ground faults of any type in isolated or arc-suppression-coil grounded power systems
Protection functions for capacitor banks, such as current-unbalance, peak overvoltage, overcurrent, overload, or differential protection
Arc protection
Overvoltage and undervoltage protection, with all methods
Frequency protection and frequency-change protection
Power protection, with all methods
Automation, control, and monitoring:
- Automatic frequency unloading for load shedding in case of underfrequency, considering changed feed-in conditions due to decentralized power generation
- Synchronization of generators (power plant units) with the power grid or synchronization of 2 power grids for up to 4 synchronization points
- Automatics, controls, synchrocheck and protection against switching faults
- Voltage controller function for two-winding transformers, three-winding transformers and grid coupling transformers
- Phasor Measurement Unit (PMU)
Benefits
Your benefit with only 1 universal device type
- Optimization of investment and operating costs
- Time and cost savings during project planning
- Significant reduction of logistics and spare part costs - Full flexibility until shortly before commissioning, easy function adjustment via the function point manager
- For grid operators: easy adaptation when network conditions change after commissioning, e. g. use as line differential protection instead of distance protection
- For industrial applications: simple addition of necessary motor or frequency protection functions to the feeder protection.
- For energy producers: Easy adaptation of device functions when connecting regenerative feeders
- Migration of existing device specific application templates and parameterizations (7SA86, etc.)
- Optimally suited for retrofit applications