7SK81 Motor Protection Relay

the siprotec compact 7sk81 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 rangefrom 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:highlights-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 athe siprotec 7sk81 is a multi-functional motor protection relay. It is designed for protection of asynchronous motors of all sizes. The relays have all the required functions 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 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 sntp

function

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 valueswp,wq
• circuit-breaker wear monitoring minimum and maximum values
• trip circuit supervision
• fast measuring voltage failure