Transformer set-up in Device management

[Former Member]

Hi Experts,

I'm trying to analyze set-up of transformer in IS-U DM. I have following questions:

1) To calculate Billing Factor CT/PT ratio and Transformation ratio are used. What is the significance of both these ratios? How they are practically available in transmission of electricity?If transformation ratio is there, will it not suffice the calculation of billing ratio alone?

2) Is only technical installation of transformer sufficient for calculating billing ratio?

3) What will happen if there are 2 CT & 2 PT transformers available. How the billing ratio is calculated?

[Former Member · Accepted solution]

Hi Vinod,

1. PT/CT ratio = Primary current / Secondary current or Primary voltage / Secondary voltage. This is maintained at winding group.

Transformation ratio is maintained either at register or device or device category.

During run-time, billing ratio = ( PT / CT ratio ) / transformation ratio.

2. Yes, technical installation of CT/PT is sufficient. However, you need to install CT/PT devices followed by Meter. So, that ratios are considered.

3. If there are 2 CTs and 2 PTs at a device location, then you will also have two meters. You need figure it out which CT/PT belongs to which meter.

Hope this helps.

Regards,

Avinash

[Former Member]

Hi Avinash,

Thanks for your valuable inputs.

I need some information on the below question.

How they (PT/CT and transformation ratio) are practically available in transmission of electricity? I mean if PT/CT ratio of transformer is available then why does meter need to have transformation ratio.

Regards,

Vinod.

[Former Member]

Hi Vinod,

In transmission division, electricity is transported at high voltage and it cannot be measured directly by meters. CT/PT are devices used to scale large primary currents/voltages - to a smaller, easy to measure, secondary

currents / voltages.

Once current and voltage are brought down to smaller values, it is measured by meters. Since, we are measure secondary part, we need to apply transformation ration in order to calculate actual primary values.

Hope you are able to follow. Please let me know if you need any details.

Regards,

Avinash

[Former Member]

Hi Avinash,

Thanks for your valuable inputs.

Regards,

Vinod