Siemens MJ-4 Series User Manual

5 Reading and Interpreting MJ-4A & MJ-4B Control Panel Data
40 Siemens Energy, Inc.
displayed. Pressing the ¿ key displays the last metered
data item. An example for displaying min/max time and
date stamps is shown below:
Action Display Shows
View Vcomp data item Vcomp = 121.2 F
in <METER> Menu.
Press Max/Min key once. Vcomp = 124.3 Fmax
Press the Save key 061798 21:26:45
before timeout.
Press the À key. Vld = 122.5F
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.
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 Ild data item displays the rms regulator current in
amperes. Note: the Current Transformer is typically
located in the Load Bushing lead. Therefore, under reverse
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
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-4 calculates the kVA per Table 5.3.
Note: For reverse power flow,
Ild is current flowing
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.
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.
+ = lagging, - = leading
Freq (Line Frequency)
The Freq data item displays the line frequency in Hertz
(present, max, min).
Table 5.2 Meter Data Items
<METER> MENU DATA ITEMS
Vld
1
Measured rms regulator load voltage
Vs
1
Measured rms regulator source voltage
Vcomp
1
Regulator load voltage corrected for line
drop using LDC parameters
Ild
1
Measured rms load current
PF
1
Power factor
KVA
1
Apparent regulator power load
KW
1
Real power measured at the regulator
KVAR
1
Reactive power measured at the regulator
Freq
1
Line frequency
KWhr
2
Forward and Reverse Real energy
KVARhr
2
Forward and Reverse Reactive energy (lead
& lag)
1. Instantaneous, Max, and Min values
2. Time-cumulative value — no Max/Min
Table 5.3 Regulator kVA Load
Regulator Type Forward Power
Flow
Reverse Power
Flow
ANSI A Straight kVA = Vld x Ild kVA = Vs x I(“L”)
ANSI B (Inverted) kVA = Vld x
Ild kVA = Vs x I(“L”)
PF =
Watts
Volts * Amps
Real Power = kW =
1
n
n
1
Vn(t) x n(t)
I
Reactive Power = kVAR =
1
n
n
1
V(t) x (t+90º)
I

Siemens MJ-4 Series Specifications

General

Brand	Siemens
Model	MJ-4 Series
Category	Control Panel
Language	English