9424200994 Rev N 75Vector Jump (78V) ProtectionThe vector jump (78V) element protects the generator by disconnecting it from the grid when a loss ofmains or mains failure occurs. This prevents the generator from remaining tied to the mains if the mainsreturns due to an external reclose device.Element logic connections are made on the BESTlogic™Plus screen in BESTCOMSPlus® and elementoperational settings are configured on the Vector Jump (78V) settings screen in BESTCOMSPlus. Asummary 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), VoltageProtection, Vector Jump 78VElement OperationWhen a loss of mains occurs, it is likely that the generator load will shift abruptly since the generator isdriving everything between the generator output and the utility breaker that removed mains power. Such aload shift is likely to cause a speed shift, which may result in the generator being out of phase with themains when a reclose occurs. If the generator is out of phase and connection with the mains isestablished, damage could occur.The vector jump element trips the breaker when it detects a phase shift in the generator voltage at V AN,VAB, or Vx, depending on connections. A sudden change in generator phase angle often occurs when thegrid is lost. This change of phase angle results in an earlier zero crossing of the generator voltage if thegenerator load decreases. It results in a later zero crossing if the generator load increases. This shift ofthe zero crossing (vector jump) is expressed in degrees.VT SourceThe Source setting configures the vector jump element to monitor the Phase VT or Auxiliary VT. For anillustration of BE1-11g terminals, refer to the Terminals and Connectors chapter.Pickup and TripThe Pickup output occurs first, followed by the Trip output.PickupThe Pickup output becomes true when the vector shift increases above the threshold established by thePickup setting. In BESTlogicPlus, the Pickup output can be connected to other logic elements toannunciate the condition, control other elements in logic, and start the fault recorder (logic elementFAULTTRIG).TripThe Trip output operates simultaneously with the Pickup output. In BESTlogicPlus, the Trip output can beconnected to other logic elements and to a physical relay output to annunciate the condition and to initiatecorrective action. If a target is enabled for the element, the BE1-11g will record a target when the Tripoutput 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 BlockingFuse LossThe fuse loss (60FL) element of the BE1-11g can be used to block 78V protection when fuse loss or lossof potential is detected in a three-phase system.BE1-11g Vector Jump (78V) Protection
