Siemens MJ-XL Installation And Operation Manual page 38

5
Reading and Interpreting MJ-XL Control Panel Data
displayed. Pressing the Ù key displays the last metered
data item. An example for displaying min/max time and
date stamps is shown below:
Action
View Vcomp data item
in <METER> Menu.
Press Max/Min key once.
Press the Save key
before timeout.
Press the Ú key.
5.3.2 Viewing the <METER> Menu Data
Table 5.1 summarizes the <METER> Menu data items.
The remainder of the section defines the data items in
detail.
Table 5.2 Meter Data Items
<METER> MENU DATA ITEMS
1
Vld Measured rms regulator load voltage
1
Vs Measured rms regulator source voltage
1
Vcomp Regulator load voltage corrected for line
drop using LDC parameters
1
Measured rms load current
Ild
1
PF Power factor
1
KVA Apparent regulator power load
1
KW Real power measured at the regulator
1
KVAR Reactive power measured at the regulator
1
Freq Line frequency
2
KWhr Forward and Reverse Real energy
2
KVARhr Forward and Reverse Reactive energy (lead
& lag)
1. Instantaneous, Max, and Min values
2. Time-cumulative value — no Max/Min
Vld (Load Volts)
The Vld data item displays the rms load voltage. The value
displayed is either the basis voltage (nominal 120 V) or the
system primary voltage. (See Meter Volts as defined in
the <CONFIGURE> Menu Meter Volts data item, Chapter
4.)
Vs (Source Volts)
The Vs data item displays the rms source voltage. The
value displayed is either the basis voltage (nominal 120 V)
or the system primary voltage. (See Meter Volts in the
<CONFIGURE> Menu, Chapter 4.)
Vcomp (Line Drop Compensation Volts)
The Vcomp data item displays the rms voltage present at
the theoretical load center. This is the voltage the micro-
processor compares with the voltage setpoint to deter-
mine when tap changes are required. The value displayed
is either the basis voltage (nominal 120 V) or the system
primary voltage. (See Meter Volts in the <CONFIGURE>
Menu, Chapter 4.)
Ild (Load Current)
The ld data item displays the rms regulator current in
I
amperes. Note: the Current Transformer is typically
located in the Load Bushing lead. Therefore, under reverse
34
Display Shows
Vcomp = 121.2 F
Vcomp = 124.3 Fmax
061798 21:26:45
Vld = 122.5F
power flow conditions, load current includes regulator
excitation current which could be approximately 10%
higher or lower than actual load current.
PF Lead, PF Lag (Power Factor)
This is the present line power factor, derived from the fun-
damental frequencies only, using the relationship
PF =
Volts * Amps
Three values are recorded for Power Factor: instanta-
neous, maximum (most leading), and minimum (most lag-
ging or least leading).
kVA (Apparent Power)
The kVA data item displays the present kVA load on the
regulator. The CT of a regulator is always located in the
"L" bushing lead. The MJ-X
5.3.
Regulator kVA Load
Table 5.3
Regulator Type Forward Power
Flow
ANSI A Straight kVA = Vld x
ANSI B (Inverted) kVA = Vld x
Note: For reverse power flow,
into the regulator and will differ from actual
load current by the amount of excitation cur-
rent of the regulator.
kW (Real Power)
The Forward and Reverse kW data items display the real
portion of the present kVA load on the regulator.
Real Power = kW = Real Power =
The kW is displayed as a positive quantity when power
flow is into the load, or as a negative quantity when power
flow is into the source.
kVAR (kVAR)
The kVAR data item displays the reactive portion of the
present kVA load on the regulator.
Reactive Power = kVAR = ReactivePower
=
+ = lagging, - = leading
Siemens Power Transmission & Distribution, Inc.
Watts
L
calculates the kVA per Table
Reverse Power
Flow
ld kVA = Vs x ("L")
I I
ld kVA = Vs x ("L")
I I
ld is current flowing
I
n
1 n
1 ∑
Vn(t) x n(t) I
kW -- - Vn(t) x In(t)
n
n
1
1
n
1
n
1 ∑
V(t) x (t+90º)
kVAR V(t) x I(t+90°) I
= -- -
n
n
1
1