HV Sheath bonding and parallel earth continuity conductor

[Vertemati]

Can anyone let me know whether in single point bonding ECC - earth continuity conductor - is always required as indicated in IEEE 575?

Is this true even if the 2 substations don't have transformers (or transformer neutral NOT grounded) and I don't know where else neutral in HV is grounded (neutral grounded at remote location)?

Thank you very much in advance for your support

 

[7anoter4]

If there are 2 sources then the shield open end will get not only the voltage build up of the cable
shield but the transferred potential too. A surge arrester could be provided at the open end.
If is not possible then shield both ends shall be grounded and the cable shall be derated with the shield losses.
In any case a parallel ground continuity conductor has to be provided and grounded at both end as indicated in IEEE-575 ch 5.4.3 Parallel Ground Continuity Conductor...