Basler BE1-11m, Instruction Manual, Page: 89 / 610

9424200996 14-5
BE1-11 m Inverse Overcurrent (51) Protection
Figure 14-2. 51 Phase Pickup Level Compensation
𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝑃𝑃𝑃𝑃𝐴𝐴𝑃𝑃𝐴𝐴𝑃𝑃 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐴𝐴 =
𝑆𝑆𝐿𝐿𝑆𝑆𝑆𝑆𝑃𝑃𝑆𝑆𝑆𝑆 𝑉𝑉𝑉𝑉𝐴𝐴𝐴𝐴𝐴𝐴𝑆𝑆𝐿𝐿 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐴𝐴
𝑅𝑅𝐿𝐿𝑆𝑆𝐴𝐴𝑅𝑅𝐴𝐴𝑃𝑃𝑆𝑆𝐴𝐴 𝑃𝑃𝑃𝑃𝐴𝐴𝑃𝑃𝐴𝐴𝑃𝑃 𝑆𝑆𝐿𝐿𝐴𝐴𝐴𝐴𝑃𝑃𝑆𝑆𝑆𝑆
× 51 𝑃𝑃ℎ𝐴𝐴𝑆𝑆𝐿𝐿 𝑃𝑃𝑃𝑃𝐴𝐴𝑃𝑃𝐴𝐴𝑃𝑃 𝑆𝑆𝐿𝐿𝐴𝐴𝐴𝐴𝑃𝑃𝑆𝑆𝑆𝑆
Equation 14-3. Restraint Pickup Level
Phase VT Configuration
The 51/27R function can be set to monitor either Vpp or Vpn depending upon the Phase VT Connection
settings. See the Configuration chapter for details on how to set the phase VT connections. Table 14-2
shows which voltage measurements are used by each 51 element for each possible phase VT connection
and 51/27 voltage monitoring mode setting.
Table 14-2. Phase VT Connection Cross Reference
Phase VT Connection 51/27 Mode 51A 51B 51C
4W Vpp Vab Vbc Vca
4W Vpn Van Vbn Vcn
3W Vpp Vab Vbc Vca
AN Vpn Van
Vbn* Vcn*
BN Vpn
Van*
Vbn
Vcn*
CN Vpn
Van* Vbn*
Vcn
AB Vpp Vab
Vbc* Vca*
BC Vpp
Vab*
Vbc
Vca*
CA Vpp
Vab* Vbc*
Vca
* Calculated value. See the
Configuration
chapter for more information.
Element Blocking
Fuse Loss
The fuse loss element (60FL) can also be set to supervise the 51/27R function. It is possible to set the
60FL element to automatically prevent misoperation on loss of sensing voltage. When the 51/27R
function is set for control and a 60FL condition is detected, the inverse overcurrent elements will be
disabled. When the 51/27R function is set for restraint and a 60FL condition is detected, the inverse
overcurrent elements will remain enabled but the pickup will not be adjusted from 100% of its setting. See
the
Fuse Loss (60FL)
chapter for more information.
Protective elements blocked by 60FL should be set so that trip times are 60 milliseconds or greater to
assure proper coordination of blocking.