Overvoltage Protection Logic; Figure 114: Overvoltage - Single And Three Phase Tripping Mode (Single Stage) - GE P4A Technical Manual

Chapter 10 - Voltage Protection Functions
3.2

OVERVOLTAGE PROTECTION LOGIC

V> Measur't Mode
VA
VAB
V>1 Voltage Set
V>1 Time Delay
V> Measur't Mode
VB
VBC
V>1 Voltage Set
V>1 Time Delay
V> Measur't Mode
VC
VCA
V>1 Voltage Set
V>1 Time Delay
V>1 Timer Block
V> Operate mode
Any Phase
Three Phase
V 00804

Figure 114: Overvoltage - single and three phase tripping mode (single stage)

The Overvoltage protection function detects when the voltage magnitude for a certain stage exceeds a set
threshold. If this happens a Start signal, signifying the "Start of protection", is produced. This Start signal can be
blocked by the VTS Fast Block signal. This start signal is applied to the timer module to produce the Trip signal,
which can be blocked by the overvoltage timer block signal (V>(n) Timer Block). For each stage, there are three
Phase overvoltage detection modules, one for each phase. The three Start signals from each of these phases are
OR'd together to create a 3-phase Start signal (V>(n) Start), which can then be activated when any of the three
phases start (Any Phase), or when all three phases start (Three Phase), depending on the chosen V> Operate Mode
setting.
The outputs of the timer modules are the trip signals which are used to drive the tripping output relay. These
tripping signals are also OR'd together to create a 3-phase Trip signal, which are also controlled by the V> Operate
Mode setting.
If any one of the above signals is low, or goes low before the timer has counted out, the timer module is inhibited
(effectively reset) until the blocking signal goes high.
228
&
&
&
Notes: This diagram does not show all stages . Other stages follow similar principles.
VTS Fast Block only applies for directional models .
P54A/B/C/E
V>1 Start A/AB
V >1 Trip A/AB
V>1 Start B/BC
V>1 Trip B/BC
V>1 Start C/CA
V>1 Trip C/CA
1
&
1
V>1 Start
&
&
1
&
1
V>1 Trip
&
&
P54xMED-TM-EN-1