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, lines and capacitor banks. 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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