Operation: CP1SD/T/L Version
CENTRON® Polyphase Meter Technical Reference Guide
65
The following is an example of the data available in the Toolbox
Mode. This example is for
a Form 9S meter wired for a 4-Wire Wye system:
Phase A Display
(Left Element)
Phase B Display
(Center Element)
Phase C Display
(Right Element)
Voltage Phase
Angles
PhA 0.0° V
PhB 120.5° V
PhC 240.3° V
Phase Voltage
PhA 120.2 V
PhB 115.5 V
PhC 119.3 V
Current Phase
Angles
PhA 9.0° A
PhB 117.8° A
PhC 246.0° A
Phase Current
PhA 6.8 A
PhB 10.2 A
PhC 9.8 A
Diagnostic Counters
1
d1 000 d2 000 d3 000 d4 000
d5A 000 d5B 000 d5C 000 d5T 000
1 The diagnostic counters are incremented each time a diagnostic error occurs.
If the magnitude of a phase voltage or current is zero or too low to measure accurately, a
dashed line (---) will appear in the value location. The corresponding angle will also indicate
dashed lines. Accurate measurement is considered to be 0.5% of class rating for the current:
CL 20 = 10 mA
CL 200 = 1 Amp
CL 320 = 1.6 Amps
By following the definitions of the SiteScan system and the information on the Toolbox
display, the above example can be graphically plotted into the phasor diagram shown in the
figure above.
By simply viewing the phasor diagram, several facts about the site become clear:
There are no wiring problems currently at the site.
Both A and C phase currents lag while B phase current leads its voltage.
The site is wired with ABC phase rotation.
By graphically plotting the Toolbox Mode display information, many metering site
problems are easily diagnosed. Problems such as cross-phasing of voltage or current
circuits, incorrect polarity of voltage or current circuits, and reverse energy flow of one or
more phases can be found quickly. The load emulator scrolling in the direction of energy
flow for each phase will also aid in checking for reverse energy flow. Other problems, such
as loss of phase voltage, incorrect voltage transformer ratio, current diversion, or a shorted
current transformer circuit, can be determined through the Toolbox Mode.
While some of these problems may occur at the time of meter installation, others may
happen at any time after the meter is installed. Since it is impossible to continuously watch
the Toolbox Mode information, the SiteScan on-site monitoring system has been designed
to continuously monitor the site. The occurrence of any diagnostic condition can be logged,
as well as display error codes on the LCD.
