Siemens MJ-XL Installation And Operation Manual page 47

sections 5.1 and 5.2 for details on source-side voltage cal-
culation.
When determining power flow direction, the system
takes into account the current-to-voltage phase relation-
ship associated with the system as specified in the
<CONFIGURE> Menu (System, Utility Polarity, and I [cur-
rent] Shift parameters).
6.6.2 Forward/Reverse Operation
L
The MJ-X Control Panel accommodates power flow
reversals by alternating
"Reverse" modes. Because the microprocessor monitors
(or derives) the voltage on both sides of the regulator, it
can reverse modes by simply reversing its definition of
"source" and "load."
• In Forward Operation mode, the microprocessor
senses the "L" Bushing to determine load voltage
and controls the tap changer on the basis of the For-
ward setpoints (Voltage, Bandwidth, Time Delay, Line
Drop Compensation). During Forward Operations,
"forward" Meter data is displayed.
• In Reverse Operation mode, the microprocessor
senses the "S" Bushing (or derives the "S" Bushing
voltage from the "L" Bushing voltage and the knowl-
edge of the tap position) to determine load voltage
and controls the tap changer on the basis of the
Reverse setpoints (Voltage, Bandwidth, Time Delay,
Line Drop Compensation).
Siemens Power Transmission & Distribution, Inc.
6
MJ-XL Control Panel Automatic Mode
between "Forward" and
During Reverse Operations, "reverse" Meter data is dis-
played. The following parameters determine whether the
tap change motor is energized to raise the tap position or
to lower it:
1. Power flow direction,
2. Forward/reverse operation,
3. Out-of-band status,
4. Power flow mode (see below for details).
Tables 6.3 and 6.4 on the next page summarize the tap
change direction for each Power Flow mode
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