The SIPROTEC Compact 7SJ81 provides 4 low-power current transformer inputs and optionally 3 low-power voltage transformer inputs. With the same low-power current transformer (LPCT) a wide range of primary rated line currents can be covered. Objects with rated currents in the range from 20 A to 2500 A can be protected when using low-power current transformers.
The following low-power current transformer ratios are suitable for the following primary current operating ranges
300 A/225 mV for a primary operating current range of 60 A to 630 A
600 A/225 mV for a primary operating current range of 120 A to 1250 A
1250 A/225 mV for a primary operating current range of 250 A to 2500 A
100 A/225 mV for a primary operating current range of 20 A to 200 A
SIPROTEC 7SJ81 is a multi-functional motor protection relay. It is designed for protection of asynchronous motors of all sizes. The relays have all the functionality to be applied as a backup relay to a transformer differential relay.
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.
Highlights
Inputs for Low power CTs and VTs according 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 SNTP