Schweitzer Engineering SEL-351P, Быстрый старт

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3-20 Overcurrent, Voltage, Synchronism Check, and Frequency Elements Date Code 990430
SEL-351P Manual Técnico
= 0 (logical 0), if I
P
> pickup setting 51P1P and the phase time-overcurrent element
is timing or is timed out on its curve
Torque Control Switch Open
If the Torque Control Switch in Figure SECTION 3: .14 is open, maximum phase current, I
P
,
cannot get through to the pickup comparator (setting 51P1P) and the curve timing/reset timing
functions. For example, suppose that the Torque Control Switch is closed, I
P
is:
I
P
> pickup setting 51P1P
and the phase time-overcurrent element is timing or is timed out on its curve. If the Torque
Control Switch is then opened, I
P
effectively appears as a magnitude of zero (0) to the pickup
comparator:
I
P
= 0 A (effective)
<
pickup setting 51P1P
resulting in Relay Word bit 51P deasserting to logical 0. I
P
also effectively appears as a
magnitude of zero (0) to the curve timing/reset timing functions, resulting in Relay Word bit
51P1T also deasserting to logical 0. The phase time-overcurrent element then starts to time to
reset. Relay Word bit 51P1R asserts to logical 1 when the phase time-overcurrent element is
fully reset.
Control of Logic Point TCP1
Refer to Figure SECTION 3: .14.
The Torque Control Switch is controlled by logic point TCP1. Logic point TCP1 is controlled
by directional control (optional) and SEL
OGIC
Control Equation torque control setting 51P1TC.
If logic point TCP1 = logical 1, the Torque Control Switch is closed and maximum phase
current, I
P
, is routed to the pickup comparator (setting 51P1P) and the curve timing/reset timing
functions.
If logic point TCP1 = logical 0, the Torque Control Switch is open and maximum phase current,
I
P
, cannot get through to the pickup comparator and the curve timing/reset timing functions. The
maximum phase current, I
P
, effectively appears as a magnitude of zero (0) to the pickup
comparator and the curve timing/reset timing function.
Directional Control Option
Refer to Figure SECTION 3: .14.
See Figure 4.21 in Section 4: Loss-of-Potential, Load Encroachment, and Directional Element
Logic for more information on the optional directional control. If the directional control enable
setting E32 is set:
E32 = N
then directional control is defeated, and the directional control input into logic point TCP1 in
Figure SECTION 3: .14 is asserted to logical 1 continuously. Then, only the corresponding
SEL
OGIC
Control Equation torque control setting 51P1TC has to be considered in the control of