Control cables shield grounding practices

[ters]

There seem to be a lot of controversy out there re control cables shield grounding practices in HV switchyards (110 kV and above). I refer to control and protection cables that run between various yard apparatus to yard junction (marshalling) boxes and/or cables that go from apparatus and/or junction boxes to relay buildings.

Some recommendations are leaning towards the idea that only one end should be grounded preventing so shield current that may flow in case of system disturbance (short circuits, over-voltage spikes, etc). Others say that it may be better in some cases (such as CVT connections) to ground shields at both ends which will cause shield currents to flow in case of a disturbance (such as high frequency surge discharge) but in the other hand it will tend to equalize potentials on both ends of the cable preventing so a danger potential difference that may develop on two grounding loops, whereas one is being exposed to, for example, high frequency surge discharge through a CVT capacitor and the other one (at the relay building) is far away from that disturbance.

Is there a prevailing method/standard out there (the question excludes cables for SCADA/RTU, 4-20 mA and similar analog signals and related stuff that are always grounded at one end only). Or this questions is something like: would you like to have a real wheel drive car that tends to over-steer or a front wheel drive one that tends to under-steer…

 

[stevenal]

IEEE 525:

"When shielded control cable is
used, grounding the shield at both ends is recommended. Care should be exerted in keeping the shield intact, as
a broken or separated shield can greatly reduce the shield efficiency.
If only one end of the shield is grounded, large transient shield-to-ground and conductor-to-ground voltages may be
present at the ungrounded end.