Basler Electric BE1-11g - Manual (Page 87)

9424200994 Rev N 75
Vector Jump (78V) Protection
The vector jump (78V) element protects the generator by disconnecting it from the grid when a loss of
mains or mains failure occurs. This prevents the generator from remaining tied to the mains if the mains
returns due to an external reclose device.
Element logic connections are made on the BESTlogic
™Plus screen in BESTCOMSPlus® and element
operational settings are configured on the Vector Jump (78V) settings screen in BESTCOMSPlus. A
summary of the logic inputs and outputs and operational settings appears at the end of this chapter.
BESTCOMSPlus Navigation Path: Settings Explorer, Protection, Voltage, Vector Jump (78V)
HMI Navigation Path: Settings Explorer, Protection, Settings Group x (where x = 0 to 3), Voltage
Protection, Vector Jump 78V
Element Operation
When a loss of mains occurs, it is likely that the generator load will shift abruptly since the generator is
driving everything between the generator output and the utility breaker that removed mains power. Such a
load shift is likely to cause a speed shift, which may result in the generator being out of phase with the
mains when a reclose occurs. If the generator is out of phase and connection with the mains is
established, damage could occur.
The vector jump element trips the breaker when it detects a phase shift in the generator voltage at V
AN
,
V
AB
, or V
x
, depending on connections. A sudden change in generator phase angle often occurs when the
grid is lost. This change of phase angle results in an earlier zero crossing of the generator voltage if the
generator load decreases. It results in a later zero crossing if the generator load increases. This shift of
the zero crossing (vector jump) is expressed in degrees.
VT Source
The Source setting configures the vector jump element to monitor the Phase VT or Auxiliary VT. For an
illustration of BE1-11g terminals, refer to the
Terminals and Connectors chapter.
Pickup and Trip
The Pickup output occurs first, followed by the Trip output.
Pickup
The Pickup output becomes true when the vector shift increases above the threshold established by the
Pickup setting. In BESTlogicPlus, the Pickup output can be connected to other logic elements to
annunciate the condition, control other elements in logic, and start the fault recorder (logic element
FAULTTRIG).
Trip
The Trip output operates simultaneously with the Pickup output. In BESTlogicPlus, the Trip output can be
connected to other logic elements and to a physical relay output to annunciate the condition and to initiate
corrective action. If a target is enabled for the element, the BE1-11g will record a target when the Trip
output becomes true. See the
Fault Reporting chapter for more information about target reporting.
The Trip output is held closed for the duration established by the Trip Hold Time setting.
Element Blocking
Fuse Loss
The fuse loss (60FL) element of the BE1-11g can be used to block 78V protection when fuse loss or loss
of potential is detected in a three-phase system.
BE1-11g Vector Jump (78V) Protection