GE P444 User Manual

Setting
P44x/EN ST/Hb
6
MiCOM P40 Agile
P442, P444 (ST) 4-
21
Menu text Default setting
Setting range
Step size
Min Max
GROUP 1: DISTANCE SCHEMES
LOL undercurrent detector that indicates a loss of load condition on the unfaulted phases,
indicating that the remote end has just opened.
LoL: Window 0.04s 0.01s 0.1s 0.01s
Length of LOL window - the time window in which Zone 2 accelerated tripping can occur
following LOL undercurrent detector operation.
2.3 Power Swing detection and blocking (PSB) (“Power swing” menu)
Power swings are oscillations in the power flow after a power system disturbance, caused by
sudden removal of faults, loss of synchronism or power flow direction changing (as a result
of switching). Such disturbances can cause generators acceleration or deceleration adapted
to power flow, which in turn leads to power swinging.
A power swing may cause the impedance presented to a distance relay to move away from
the normal load area and into one or more of its tripping characteristics. Depending on the
setting or power swing stability, the relay should trip or not.
See section P44x/EN AP for power Swing complete description.
Menu text Default setting
Setting range
Step size
Min Max
GROUP 1: POWER SWING
Delta R
0.5 / In Ω
0
400 / In Ω 0.01 / In Ω
Power swing detection Resistive band which surrounds phase fault trip characteristic
(see section P44x/EN AP, section 4.1).
Typically, the ∆R and ∆X band settings are both set between 10 - 30% of R3Ph. This gives
a secondary impedance between 0.6 and 1.8Ω. For convenience, 1.0Ω could be set.
The width of the power swing band is calculated as follows:
∆R = 1.3 × tan(π × ∆f × ∆t) × R
LOAD
Assuming that the load corresponds to 60° angles between sources and if the resistive
reach is set so that Rlim = R
LOAD
/2, the following is obtained:
∆R = 0.032 × ∆f × R
LOAD
To ensure that a power swing frequency of 5Hz is detected, the following is obtained:
∆R = 0.16 × R
LOAD
Where:
∆R: width of the power swing detection band
∆f: power swing frequency (f
A
– f
B
)
Rlim resistive reach of the starting characteristic (=R3ph-R4ph)
Z: network impedance corresponding to the sum of the reverse (Z4) and forward (Z3)
impedances.
Delta X
0.5 / In Ω
0
400 / In Ω 0.01 / In Ω
Power swing detection Reactive band which surrounds phase fault trip characteristic
(see section P44x/EN AP…).
IN > Status Enabled Disabled or Enabled
Residual current power swing unblocking criteria activation:
Enables or disables the earth fault protection during Power Swing Blocking. When enabled,
the relay will trip when IN > ‘IN > (% Imax)’ or when IN < 0.1 × In.

GE P444 Specifications

General

Brand	GE
Model	P444
Category	Protection Device
Language	English