Control of earthing

 

Condition:

•The earthing is documented.

•A reference value exist.

•The earthing point is connected to a protected object (joint, busbar, other point objects).

•For control of maximum allowed earth fault voltage, the earthing point must be classified (1A, 1B, etc.).

•The earthing control calculation can only be done if they are connected to a medium voltage object. Low voltage earth point can be calculated if data is available.

 

Create an earthing with both LV/MV earth values

 

Earth point data for calculation

Reference values.

Earthing classification.

Earthing combined J/*.

 

Connect the earthing with protected object

Must be a point object, for instance a bus bar or a bay.

Can not be a cable or device.

Tools > Eartching relations > Protective earthing.

 

Verify that the earthing is connected to its protected object

 

Right-click on a earthing symbol or the bus bar and select Related objects....

 

Result

 

Calculated earth fault voltage, and the maximum exposed earth fault voltage can be seen in the result presentations.

 

Maximum allowed earth point resistances.

If codelists and conditions for calculations exists an extra report will be generated containing maximum allowed earth resistance values for different earthing classes. The report is presented with the maximum earth fault resistance for the earth fault current at 0 Ohm and high Ohm earth fault.