Line differential protection

Line differential protection – SIPROTEC 7SD82

SIPROTEC 7SD82

The SIPROTEC 7SD82 line differential protection has been designed particularly for the cost-optimized and compact protection of lines in medium-voltage and high-voltage systems. With its flexibility and the powerful DIGSI 5 engineering tool, the SIPROTEC 7SD82 device offers future-oriented system solutions with high investment security and low operating costs.

Features & functions

Line differential protection SIPROTEC 7SD82

Features

Main function:

  • Differential protection for medium-voltage and high voltage applications

Tripping:

  • 3-pole, minimum tripping time: 19 ms

Inputs and outputs:

  • 4 current transformers,
  • 4 voltage transformers,
  • 11 or 23 binary inputs, 
  • 9 or 16 binary outputs

Hardware flexibility:

  • 2 different quantity structures for binary inputs and outputs are available in the 1/3 base module. Adding 1/6 expansion modules is not possible; housing width available with large or small display.

Housing width:

  • 1/3 × 19 inches

As standard:

Functions

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

  • Minimum tripping time: 19 ms
  • Main protection function is differential protection with adaptive algorithm for maximum sensitivity and stability even with the most different transformer errors, current-transformer saturation and capacitive charging currents
  • Directional backup protection and various additional functions
  • 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
  • Detection of current-transformer saturation
  • Arc protection
  • Automatic frequency relief for underfrequency load shedding, taking changed infeed conditions due to decentralized power generation into consideration
  • Power protection, configurable as active or reactive power 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 thermal overload protection) and operational measured values
  • Control, synchrocheck and switchgear interlocking protection
  • 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 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 (SDH networks, MPLS electrical power systems, for example using 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
  • 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

  • Line protection for all voltage levels with 3-pole tripping
  • Phase-selective protection of overhead lines and cables with single-ended and multi-ended infeed of all lengths with up to 6 line ends
  • Transformers and compensating coils in the protection zone
  • Detection of ground faults in isolated or arc-suppression-coil-ground power systems in star, ring, or meshed arrangement
  • Serial protection data communication over different distances and media, such as optical fiber, two-wire connections, and communication networks
  • Phasor Measurement Unit (PMU)

Benefits

  • Compact and low-cost line differential protection
  • 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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