Siemens Siprotec 5 7SJ81 Overcurrent & Feeder Protection Relay

The SIPROTEC Compact 7SJ81 Overcurrent & Feeder Protection relay provides 4 low-power current transformer inputs and optionally 3 low-power voltage transformer inputs. Then, the same low-power current transformer (LPCT) can cover a wide range of primary rated line currents. Then, Low-power current transformers can protect objects with rated currents ranging from 20 A to 2500 A.

The following low-power current transformer (LPCT) ratios are suitable for specific primary current operating ranges:

• 300 A / 225 mV: Covers a primary operating current range of 60 A to 630 A
• 600 A / 225 mV: Covers a primary operating current range of 120 A to 1250 A
• 1250 A / 225 mV: Covers a primary operating current range of 250 A to 2500 A
• 100 A / 225 mV: Covers a primary operating current range of 20 A to 200 A

The SIPROTEC 7SJ81 functions as a multi-functional motor protection relay. It protects asynchronous motors of all sizes.

The relays provide all the functions required to operate as backup protection for a transformer differential relay. The relay offers numerous functions to respond flexibly to system requirements and to use the invested capital efficiently. Examples for this are exchangeable interfaces, flexible protection functions and the integrated automation level (CFC). Freely assignable LEDs and a six-line display ensure a unique and clear display of the process states. In combination with up to 9 function keys, the operating personnel can react quickly and safely in any situation.

Siprotec 5 7SJ81 Overcurrent & Feeder Protection Relay

This guarantees a high operational reliability.Highlights-Inputs for Low power CTs and VTs according to IEC 61869-6 (formerly IEC 60044-7 and IEC 60044-8)-Removable terminal blocks-Binary input thresholds settable using DIGSI (3 stages)-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 SNTPThe SIPROTEC Compact 7SJ81 relays can be used for line/feeder protection of high and medium-voltage networks with grounded, low-resistance grounded isolated or a compensated neutral point.

Moreover, The relays have all the functionality to be applied to a backup relay to a transformer differential relay.The SIPROTEC Compact 7SJ81 offers the highest reliability at major functionality by the synergy of reliable algorithms with newly developed hardware. The reliability is proven by the experience in the field of almost 1,000,000 SIPROTEC devices.The relay provides numerous functions to respond flexibly to the system requirements and to deploy the invested capital economically. Examples for this are exchangeable interfaces, flexible protection functions and the integrated automation level (CFC). Freely assignable LEDs and a six-line display ensure a unique and clear display of the process states. In combination with up to 9 function keys, the operating personnel can react quickly and safely in any situation. This guarantees a high operational reliability.

CONTROL FUNCTIONS/PROGRAMMABLE LOGIC

• Commands for the ctrl. of CB, disconnect switches (isolators/isolating switches)
• Control through keyboard, binary inputs, DIGSI 4 or SCADA system
• User-defined PLC logic with CFC (e.g. interlocking)

MONITORING FUNCTIONS

• Operational measured values V, I, f
• Energy metering values Wp, Wg
• Circuit-breaker wear monitoring
• Minimum and maximum values
• Trip circuit supervision (74TC)
• Fuse failure monitor
• 8 oscillographic fault records

Therefore,  SIPROTEC 5 is part of the new generation of incomparable modular, flexible, and intelligent digital field devices. In fact, With modularly designed hardware and software and its high-performance DIGSI 5 engineering tool, the SIPROTEC 5 product family of field devices are perfect for protection, control, monitoring, and measuring applications in electrical energy systems. SIPROTEC 5 offers a wide product range with modular elements for every application and requirement.