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Post by jtroglin on Aug 1, 2011 12:34:07 GMT -5
Anyone have any suggestions/experience with how to meter high volt systems?
I am currently trying to meter a 12 kv system. I have seen it done and have been told to use a 208/25 HVC Class 3000 meter from Emon. I believe in the one I saw in the past they used multipliers in the software to adapt to the voltage and amperage.
Any help would be appreciated.
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Post by Rick Blanchard on Oct 10, 2011 14:05:19 GMT -5
E-Mon’s Class 3000 Meter utilizes unique 2 volt Current Sensors for acquiring the amperage data from the electrical load(s).
Since, like standard CTs, they are rated for operation on 600 volts maximum, it is necessary to install them on the secondary
side of special CTs rated for use with high voltage circuits. The standard 5 amp output on the high voltage CT secondary is
converted to the meter’s required 2 VAC input by passing the secondary wire through E-Mon’s 25 amp Current Sensor five
(5) times.
The voltage inputs to the E-Mon meter are provided from high voltage PTs (potential transformers) which lower the voltage
to 120 for connection to the meter’s voltage input terminals. The three PTs are wired in a WYE configuration that will provide
the reduction from “X” to 120 volts. (see the drawing). The PTs are selected for the specific high voltage being monitored. As
an example, in a 4160 volt application, the correct PT would be 2400:120 (X=4160/1.732). The phase voltage is divided by
1.732 to determine the voltage for a PT wired in a WYE connection.
The Class 3000 meter will require multipliers for the voltage, the amperage, and the power. The PT and CT ratios will
determine the multipliers. Voltage readings will be multiplied by the PT ratio. (example: 2400/120 = 20) The amp readings
will be multiplied by the CT ratio compared to the 25 amp rating of the Current Sensor. (example: a high voltage 100 amp CT
would be 100/25 = 4) The power readings would be multiplied by the PT ratio times the CT ratio. (example: 20 x 4 =80)
* If the high voltage CT is equal to one of E-Mon’s standard sizes (25, 50, 100, 200, 400, 800, 1600, 3200), the
meter could be set up for the CT size which will eliminate the CT multiplier and give a direct reading for amps. The
multiplier (volts ratio) would then only be required for the voltage and power readings.
If E-Mon Energy software is used with the Class 3000 high voltage meter, the pulse value in the software can be adjusted to
provide the correct power readings.
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