GE F650 Instruction Manual page 223

5.4 PROTECTION ELEMENTS
The block time allows blocking the element operation during a set time after the coupling breaker closure. For this purpose
it is necessary to connect the breaker bay using a 52B type contact. The purpose of this setting is to avoid spurious trips
caused by overloads after the breaker closure.
Power calculations depending on the VT connection:
1- WYE VT connection, or only one transformer in phase-to-ground connection:
2- DELTA VT connection, or only one voltage transformer in phase-to-ground connection:
V
=
P
5.4.9.2 DIRECTIONAL POWER ELEMENT (32)
a) ELEMENT DESCRIPTION
The Directional Power element responds to three-phase active power measured from the feeder associated to the F650.
This element can be selected to operate according to the power threshold adjusted in the corresponding setting. This
element is ideal for reverse power applications (F32 REV) or forward power (F32 FWD), depending on the selected setting.
The relay measures the three-phase power for wye or delta connections.
5
The element has an adjustable characteristic angle and minimum operating power as shown in the Directional Power
Characteristic diagram. The element responds to the following condition:
P cos(ϕ) + Q sin (ϕ) > SMIN
where: P and Q are active and reactive powers as measured per the F650 convention, ϕ is the angle set at the 32 setting
(DIR POWER ANGLE) in degrees in steps of 0.01º, and SMIN is the minimum operating power.
The element has two independent (as to the pickup and delay settings) elements. Both elements can be used for alarm and
trip, and they can be set separately to provide a mixed power protection.
The Directional Power Characteristic is shown in the following diagram.
5-76
ϕ
= ∗ ∗ +
P V I cos
a a a
V
ab ϕ bc
∗ ∗ +
I cos ( - 30)
a a
3 3
Figure 5–17: POWER DIRECTIONAL CHARACTERISTIC
F650 Digital Bay Controller
ϕ
∗ ∗ + ∗ ∗
V I cos V I
b b b c c
V
ϕ ca
∗ ∗ + ∗
I cos ( - 30)
b b
3
DIR POWER ANGLE
5 SETTINGS
ϕ
cos
c
ϕ
∗
I cos ( - 30)
c c
GEK-106310AB