Overcurrent and feeder protection

Overcurrent and feeder protection – SIPROTEC 7SJ85

SIPROTEC 7SJ85

The SIPROTEC 7SJ85 overcurrent protection has been designed specifically for the protection of feeders and lines. With its modular structure, flexibility and the powerful DIGSI 5 engineering tool, the SIPROTEC 7SJ85 device offers future-oriented system solutions with high investment security and low operating costs.

Features & functions

Overcurrent and feeder protection SIPROTEC 7SJ85

Features

Main function:

  • Feeder and overcurrent protection for all voltage levels

Inputs and outputs:

5 predefined standard variants with

  • 4 current transformers, 
  • 4 voltage transformers, 
  • 11 to 59 binary inputs, 
  • 9 to 33 binary outputs

Hardware flexibility:

  • Flexibly adjustable and expandable I/O quantity structure within the scope of the modular SIPROTEC 5 system; 1/6 expansion modules can be added, available with large or small display, or without display

Housing width:

  • 1/3 × 19 inches to 2/1 × 19 inches

As standard:

Functions

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

 

  • Directional and non-directional overcurrent protection with additional functions
  • Protection of up to 9 feeders with up to 40 analog inputs
  • Optimized tripping times due to directional comparison and protection data communication
  • Detection of ground faults of any type in compensated or isolated electrical power systems using the following functions: 3I0>, V0>, fleeting contact, cos φ, sin φ, harmonic, dir. Detection of intermittent ground faults and admittance
  • Ground fault detection using the pulse detection method
  • Arc protection
  • Overvoltage and undervoltage protection
  • Power protection, configurable as active or reactive power protection
  • Frequency protection and frequency change protection for load shedding applications
  • Automatic frequency relief for underfrequency load shedding, taking changed infeed conditions due to decentralized power generation into consideration
  • Protection functions for capacitor banks, such as overcurrent, overload, current unbalance, peak overvoltage, or differential protection
  • Directional reactive power undervoltage protection (QU protection)
  • Detection of current and voltage signals up to the 50th harmonic with high accuracy for selected protection functions (such as peak overvoltage protection for capacitors) and operational measured values
  • Point-on-wave switching
  • Control, synchrocheck and switchgear interlocking protection
  • Circuit-Breaker Failure Protection
  • Circuit breaker reignition monitoring
  • 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)
  • 2 optional, pluggable communication modules, usable for different and redundant protocols (IEC 61850-8-1, IEC 61850-9-2, 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
  • Reliable data transmission via PRP and HSR redundancy protocols
  • Extensive cyber security functionality, such as role-based access control (RBAC), protocolling security-related events or signed firmware
  • Simple, quick and secure access to device data via a standard Web browser – without additional software
  • Phasor Measurement Unit (PMU) for synchrophasor measured values and IEEE C37.118 protocol
  • Time synchronization using IEEE 1588
  • Control of Power Transformers
  • 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

Applications

  • Detection and selective 3-pole tripping of short circuits in electrical equipment of star networks, lines with infeed at one or two ends, parallel lines and open-circuited or closed ring systems of all voltage levels
  • Backup protection for differential protection devices of all kind for lines, transformers, generators, motors, and busbars
  • Protection and monitoring of capacitor banks
  • Phasor Measurement Unit (PMU)
  • Reverse-power protection
  • Load shedding applications
  • Automatic switchover
  • Regulation or control of power transformers (two-winding transformers, three-winding transformers, grid coupling transformers)

Benefits

  • 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
  • High investment security and low operating costs due to future-oriented system solutions

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