Phase Overvoltage (59P) Protection; Element Operation - Basler BE1-11g Instruction Manual

9424200994 Rev U 71

Phase Overvoltage (59P) Protection

Four phase overvoltage (59P) elements monitor the sensing voltage applied to the BE1-11g. 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.
Inverse
When inverse timing is selected, a Curve setting is provided to select programmable or table curves. The
user can select integrating reset timing to make the protective element use integrated reset and emulate
an electromechanical induction disk reset characteristic. The overvoltage inverse time curve with default
constants is shown in the Time Curve Characteristics chapter.
Programmable Curves
The programmable curve can be used to create a custom curve by selecting constants in the inverse time
characteristic equation. When curve P is selected, the constants used in the equation are those defined
by the user. Characteristics for trip and reset programmable curves are defined by Equation 10 and
Equation 11. Definitions for these equations are provided in Table 21.
�������� ��������
���� = + �������� ���� =
| ���� − 1 |
���� − ����
���� ����
���� 2
Equation 10. Time Characteristics for Trip
Equation 11. Time Characteristics for Reset
BE1-11g Phase Overvoltage (59P) Protection