Siemens MJ-5 Installation And Operation Manual page 42

5
Reading and Interpreting MJ-5 Control Panel Data
will be displayed. Pressing the ▲ 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 Change/Save key
before timeout.
Press the ▼ 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
1. Instantaneous, Max, and Min values
Time-cumulative value — no Max/Min
2.
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 in 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
microprocessor compares with the voltage set point to
determine 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.
Vld,Vs and Vcomp is calculated voltage based on Basis
Voltage and U2 secondary or P2 secondary.
V= Raw Voltage * Basis Voltage/Secondary voltage.
Raw voltage – Voltage at Test terminal, Basis Voltage –
refers config setting, Secondary –U2 sec or P2 Sec.
Siemens Industry, Inc.
Display Shows
Vcomp = 121.2 F
Vcomp = 124.3 Fmax
061798 21:26:45
Vld = 122.5F
Ild (Load Current)
I
The ld 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
fundamental frequencies only, using the relationship
Three values are recorded for Power Factor: instantaneous,
maximum (most leading), and minimum (most lagging 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-5 calculates the kVA per Table
5.3.
Table 5.3 Regulator kVA Load
Note: For reverse power flow,
into the regulator and will differ from actual
load current by the amount of excitation current
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 (Reactive Power)
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).
I
ld is current flowing
38