Siemens Siprotec Compact 7SD80 Line Differential Protection

The 7SD80 Line differential protection relay has been conceived for selective line protection of power cables and overhead lines up to 24km for all kind of star point configurations. The implemented phase comparison algorithm is a fast and stable method for line protection in industry and distribution grids. The protection interface communication of 7SD80 Line differential protection relay is carried out directly without external equipment over copper wires, optical fibers or both in redundancy.The wide scope of non-directional and directional functions can be applied miscellaneously as emergency functions as well as backup functions. For instance, the 7SD80 enables simplified and cost saving concepts for meshed grids and busbar protection by means of reverse interlocking. Fast and selective tripping is guaranteed even if the communication fails between the relays.

The scope of functions includes protection functions as well as functions for control and monitoring.The interoperable connectivity to substation control systems is given by standard protocols like IEC61850. The general concept of redundancy for protection and its communication gets completed by Ethernet redundancy protocols (PRP, HSR, RSTP) and thus increases the total system availability. Integrated functions for commissioning help and easy settings lead to short commissioning times.

Detail Protection interface communication Data exchange of the differential protection function takes place by means of digital communication via integrated two-wire interface and / or an integrated fiber-optic interface. By parallel use of both options, communication redundancy can be realised, therefore.Communication via the protection interface can further be used to send an inter-tripping command to the circuit-breaker at the opposite end, and to exchange at the same time up to 16 freely assignable binary signals between the 7SD80 relays.

7SD80 Line differential protection Relay Benefits: 

Conformal coating available (NEW)

-Pluggable current and voltage terminals

-Binary input thresholds settable using DIGSI (3 stages)

-Secondary current transformer values (1 A / 5 A) settable using DIGSI

-9 programmable function keys

-6-line display

-Buffer battery exchangeable from the front

-USB front port

-2 additional communication ports

-Integrated switch for low

-cost and redundant optical Ethernet rings

-Ethernet redundancy protocols RSTP, PRP and HSR for highest availability

-Relay-to-relay communication through Ethernet with IEC 61850 GOOSE

-Millisecond-accurate time synchronization through Ethernet with SNTP

-Short commissioning times by an easy parameterization and integrated commissioning help for protection and communication

-Integrated interfaces for exchanging differential protection data (fiber-optic up to 24 km/ 15 miles and/or two-wire copper cables up to 20 km/ 12 miles)

-Integrated monitoring function of the protection interface, both in the commissioning phase and in running operation

-Addressability of the protection devices for the differential protection communication in order to detect an accidental interchange of the communication cables in case of parallel cables

-Integrated non-directional and directional time

-overcurrent protection

-Transmission of a circuit-breaker inter tripping signal and 16 further binary signals to the opposite end

-Result: The 7DS80 is ideal for distances to 24 km/15 miles, for ring systems and as an application for differential protection.

Hardware-4 current transformers-0/3 voltage transformers-3/5/7 binary inputs (thresholds configurable using software)-5/8 binary outputs (2 changeovers)-1 live-status contact-Pluggable current and voltage terminals-Conformal coating available (NEW)

Siemens 7SD80 PROTECTION FUNCTIONS

• Differential protection, line (87L)
• 3I0 differential protection ( 87N L)
• Ground-fault differential protection for systems with resonant or isolated neutral ( 87Ns L)
• Definite time-overcurrent protection with delay for phase ( 50 TD (3 stages))
• Definite time-overcurrent protection with delay for earth (50N TD (3 stages))
• Inverse time-overcurrent protection (phase) ( 51)
• Inverse time-overcurrent protection (ground) ( 51N)
• Inrush current detection
• Circuit-breaker failure protection (50BF)
• Trip-circuit supervision (74TC)
• Lockout (86)
• Circuit-breaker intertripping scheme (85 DT)
• External trip initiation
• Undervoltage/overvoltage protection (27/59)
• Underfrequency/overfrequency protection (81 U/O)
• Directional time-overcurrent protection (phase) (67 (3 stages))
• Directional time-overcurrent protection (ground) (67N (3 stages))
• Automatic reclosing (79)
• Flexible protection functions for current, voltage, power, cos?, frequency
• Thermal overload protection (49)

PROGRAMMABLE LOGIC

• Commands (e.g. for the control of circuit-breakers, disconnect switches, grounding switches, etc.) through:
  – keyboard
  – binary inputs
  – DIGSI 4
  – communication interface
• User-defined PLC logic with CFC (e.g. interlocking)

MONITORING FUNCTIONS

• Operational measured values V, I, f
• Energy metering valuesWp,Wq
• Circuit-breaker wear monitoring
• Minimum and maximum values
• Trip circuit supervision
• Fast measuring voltage failure ?fuse-failure-monitor?
• 8 oscillographic fault records

COMMUNICATION INTERFACES

• System/service interface
  – IEC 61850 Edition 1 and 2
  – IEC 60870-5-103
  – MODBUS RTU
  – DNP 3.0
  – PROFIBUS-DP
  – Ethernet redundancy protocols RSTP, PRP and HSR
• Service interface
  – USB front interface for DIGSI 4
  – RS232/RS485 (instead of the system interface)
• Protection interface
  – Fiber-optic connection and/or
  – Two-wire connection

HARDWARE

• 4 current transformers
• 0/3 voltage transformers
• 3/5/7 binary inputs (thresholds configurable using software)
• 5/8 binary outputs (2 changeover)
• 1 live-status contact
• Pluggable current and voltage terminals
• Conformal coating available (NEW)

Perfectly suited for protection in distribution systems and industry, with minimal space requirement. SIPROTEC Compact devices provide a comprehensive range of functions in a surprisingly compact and space-saving housing. Whether as main or as backup protection, a single SIPROTEC Compact device provides protection functionality for every conceivable fault. And it can do even more – it supports the control, automation, and monitoring functions in the substation.