No, it is definitely not the same. For several reasons:
- There is no IEC 6000 --> IEC standards tend to have a 5 digit number starting with a 6, like 6XXXX, many of them with different parts
- IEEE 519 is dealing with harmonic currents converters are injecting into the grid up to highest power levels
- There are some IEC standards addressing the same topic, but only at moderate power level, several parts of the IEC 61000 series At higher power level conditions are subject to negotiations between customer and utility
- The methods and the outcome is different
For a reasonable discussion you have to be more precise and more specific.