Good day
In Power BI, I want to calculate the time difference and display it in hh:mm:ss. I have a field named “New” and a field named “At_Incident” which I want the difference to display as hh:mm:ss. Screenshot as below.

I have already calculated the columns in H, M and S separately.
The formula for TimeTaskDiff_H is:
TimeTaskDiff_H = DATEDIFF(unit_task_timestamps[NEW], unit_task_timestamps[AT_INCIDENT], HOUR)

the same for M and S.

To display a column as hh:mm:ss I used the below formula:

Duration = 
// Duration formatting 
// * @konstatinos 1/25/2016
// * Given a number of seconds, returns a format of "hh:mm:ss"
//
// We start with a duration in number of seconds
VAR Duration = [TimeTaskDiff_S]
// There are 3,600 seconds in an hour
VAR Hours =
    INT ( Duration / 3600)
// There are 60 seconds in a minute
VAR Minutes =
    INT ( MOD( Duration - ( Hours * 3600 ),3600 ) / 60)
// Remaining seconds are the remainder of the seconds divided by 60 after subtracting out the hours 
VAR Seconds =
    ROUNDUP(MOD ( MOD( Duration - ( Hours * 3600 ),3600 ), 60 ),0) // We round up here to get a whole number
// These intermediate variables ensure that we have leading zero's concatenated onto single digits
// Hours with leading zeros
VAR H =
    IF ( LEN ( Hours ) = 1, 
        CONCATENATE ( "0", Hours ),
        CONCATENATE ( "", Hours )
      )
// Minutes with leading zeros
VAR M =
    IF (
        LEN ( Minutes ) = 1,
        CONCATENATE ( "0", Minutes ),
        CONCATENATE ( "", Minutes )
    )
// Seconds with leading zeros
VAR S =
    IF (
        LEN ( Seconds ) = 1,
        CONCATENATE ( "0", Seconds ),
        CONCATENATE ( "", Seconds )
    )
// Now return hours, minutes and seconds with leading zeros in the proper format "hh:mm:ss"
RETURN
    CONCATENATE ( H, CONCATENATE ( ":", CONCATENATE ( M, CONCATENATE ( ":", S ) ) )
    )

I however get the following error:
Cannot convert value ‘::’ of type Text to type Date.

any assistance would be appreciated. I should mention I am new to Power BI and DAX.

I’ve tried the below code:

Duration = 
// Duration formatting 
// * @konstatinos 1/25/2016
// * Given a number of seconds, returns a format of "hh:mm:ss"
//
// We start with a duration in number of seconds
VAR Duration = [TimeTaskDiff_S]
// There are 3,600 seconds in an hour
VAR Hours =
    INT ( Duration / 3600)
// There are 60 seconds in a minute
VAR Minutes =
    INT ( MOD( Duration - ( Hours * 3600 ),3600 ) / 60)
// Remaining seconds are the remainder of the seconds divided by 60 after subtracting out the hours 
VAR Seconds =
    ROUNDUP(MOD ( MOD( Duration - ( Hours * 3600 ),3600 ), 60 ),0) // We round up here to get a whole number
// These intermediate variables ensure that we have leading zero's concatenated onto single digits
// Hours with leading zeros
VAR H =
    IF ( LEN ( Hours ) = 1, 
        CONCATENATE ( "0", Hours ),
        CONCATENATE ( "", Hours )
      )
// Minutes with leading zeros
VAR M =
    IF (
        LEN ( Minutes ) = 1,
        CONCATENATE ( "0", Minutes ),
        CONCATENATE ( "", Minutes )
    )
// Seconds with leading zeros
VAR S =
    IF (
        LEN ( Seconds ) = 1,
        CONCATENATE ( "0", Seconds ),
        CONCATENATE ( "", Seconds )
    )
// Now return hours, minutes and seconds with leading zeros in the proper format "hh:mm:ss"
RETURN
    CONCATENATE ( H, CONCATENATE ( ":", CONCATENATE ( M, CONCATENATE ( ":", S ) ) )
    )