ION9000 VT wiring and meter config Question

[EE103]

I am looking for confirmation that the ION9000 is correctly wired and configured for voltage readings with the below configuration. The system in question is a 3-phase, 3-wire system with a neutral bond via low resistance ground. The phase-to-phase voltage is 34.5kV and the VT ratio is 34500:120. With the below configuration, ION setup gives the warning "PT Primary/nominal mismatch."

Metering Setup - Basic
PM1 Volts Mode: 4W-WYE

PM1 PT Prim: 34500.0
PM1 PT Sec: 120.0
Nominal Voltage: 19918.58

[Mehran_Mehrnia]

Hi @EE103 

Nominal Voltage refers to the primary power system RMS voltage (line-to-line voltage for Delta
systems and line-to-neutral voltage for Wye systems).

In Wye system as shown in the image above, the PT primary and secondary are referenced to the Neutral, therefore, the PT primary is considered as VL-N which is supposed to be 19918.58(34500/√3).
The Nominal voltage is 19918.58 while the PT primary is entered as VL-L which is 34500.

Best Regards,

-Mehran

L3 Expert Advanced metering

[Charles_Murison]

Hello @EE103 ,

A lot will depend on what the outputs of the VT are. Is the VLL output on the secondary side 120V Line to time, or 120V Line to Neutral? Depending on the answer to this you may have different options.

If VT output is 120 V Line-to-line, then options include ignoring the warning, there is nothing wrong with your settings. Just not a common way to configure a meter, which is why ION Setup is giving a warning. Another option is to change the PT settings. PT Ratio is 287.5 (34500/120), have PT Primary =19838, PT Secondary =  69. This way the nominal voltage is close to the setting in PT Primary.

If VT output is 120V Line-to-Neutral, then may need to check your PT primary setting as I think there is likely a mistake.

If you read meter's voltage values for Line-to-Line or Line-to-Neutral, do you see your expected values?

Regards,

Charles