Basler Electric BE1-11t - Manual (Page 65)

9424200995 Rev H 53
Phase Overvoltage (59P) Protection
Four phase overvoltage (59P) elements monitor the sensing voltage applied to the BE1-11t. An element
can be configured to protect against overvoltage when the phase voltage increases above a defined level.
The four, identical overvoltage protection elements are designated 59P-1, 59P-2, 59P-3, and 59P-4.
Element logic connections are made on the BESTlogic
™Plus screen in BESTCOMSPlus® and element
operational settings are configured on the Overvoltage 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, Overvoltage (59P)
HMI Navigation Path: Settings Explorer, Protection, Settings Group x (where x = 0 to 3), Voltage
Protection, Overvoltage 59P
Element Operation
Overvoltage protection can be used to prevent large transformer and equipment damage when an
overvoltage condition exists. For example, an overvoltage condition could occur when the tap changing
control fails.
Modes of Protection
Three modes of protection are available. The One of Three mode activates protection when one of the
three phases of voltage increases above the Pickup setting. The Two of Three mode activates protection
when any two of the three phases of voltage increases above the Pickup setting. The Three of Three
mode activates protection when all three phases of voltage increase above the Pickup setting.
Voltage Response
The overvoltage element can be set to monitor VPP or VPN. This is determined by the 27/59 Mode
parameter of the phase VT connections found on the System Parameters/Sensing Transformers settings
screen in BESTCOMSPlus. For more information on the VTP setup for PP or PN voltage response, see
the
Configuration chapter.
Timings
The timing mode can be set for definite or inverse. For details on the inverse time curve, refer to the Time
Curve Characteristics chapter.
Pickup and Trip
The Pickup output occurs first, followed by the Trip output.
Pickup
The Pickup output becomes true when the measured voltage increases above the voltage 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).
Assertion of the Pickup output initiates a timer that begins timing to a trip. The duration of the timer is
established by the Time Delay (definite timing) or Time Dial (inverse timing). A Time Delay or Time Dial
setting of zero (0) makes the 59P element instantaneous with no intentional time delay.
If the pickup condition subsides before the element delay or calculated inverse time expires, the timer and
Pickup output are reset, no corrective action is taken, and the element is rearmed for any other
occurrences of overvoltage.
BE1-11t Phase Overvoltage (59P) Protection