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Option 1- No good! You will increase potential ground , reducing personal security Option 2- Good!Add in a high resistance ground (<10A) at the generator frame.

subtransmission utilities in Brazil use 69kV supplied by source in delta grounded by zigzag grounding transformer step down transformer are 230/69kV or 138/69kV YNd

I guess less expensive will be Ynd11 with zig-zag grounding transformer.

attached assistance to set transformer protectionhttp://files.engineering.com/getfile.aspx?folder=e35b0af0-3e41-464c-aab8-24e5f9ef26a9&file=Yd5.png

Marmite, below my interpretation of your post for setting relay Siemens Transformer Relay Parametrization (extract): 270 Rated Frequency 60 Hz 271 Phase Sequence L3 L2 L1 313 Starpoint of Side 1 is Earthed 314 Transf. Winding Connection Side 1 Y (Wye) 323 Starpoint of Side 2...

Marmite: "You would need to check the LV connections as well. If A&C are crossed on the secondary the same as they are on the primary then your transformer will act as a Yd7. If not then you are just changing the phase rotation." LiteYear: "crossing A & C on the primary of a Yd5 will, provided...

Sorry for my ignorance. What do you mean: Check the OP?

current differential scheme is a unit-protection. distance relaying needs telecommunication to be a unit-protection. I did not understand David post.

I had experience with circuit breaker SF6-50 Hz 230kV replacing 230kV breaker SF6-60 Hz. The only type test that it is not tended refers to maneuvers with capacitive loads.

DTR2011, This protection do not close or avoid close breaker; it opens breaker after wrong synchronization.

-Dedicated protection against wrong synchronization Despite all the prevention measures used in synchronization circuit: synchronism check, synchroscopy, automatic synchronizer, dead-line bar alive, etc, the synchronization information wrong that occurred in Brazilian plants reached the level of...

guys, you’re right! I wanted to summarize the introduction but I ended up writing nonsense! Forget my comment. I guess there is a thread about this logic diagram; I posted to show Shlim another protection relay. I just wanted to introduce a protection against wrong, poor, bad synchronization in...

Once I participated in a project of 230kV outdoor substation, we change it to 345 kV outdoor substation because high altitude region. Finally we discover utility only used indoor 230 kV SF6 substation. The priority is to discover the BIL used by utilities of high altitude region.

miltonboss, the reference is classical book of Insulation Coordination!!! ?????

ERRATA There is no protection relay specific to prevent the breaker from closing, because you have to close breaker to detect the synchronization criteria not satisfied for good synchronization. We have a dedicated very fast and selective protection for wrong synchronization occurred after...

There is no protection relay to prevent the breaker from closing, because you have to close breaker to detect the synchronization criteria not satisfied for good synchronization. We have a dedicated very fast protection for wrong synchronization occurred after breaker closed. See logic...

%% example % REF: Insulation Coordination for Power Systems Andrew R. Hileman chap.16 - 2.8 Effect of Altitude CFO = 20; % mm/kV withstand specific creep at sea level a = 2; % altitude in km m=0.5; % standard insulators m=0.8; % for fog type insulators tau = 1.03 *...

Why surge capacitor? I guess 3 surge arresters between input phases and ground is enough.

I have seen induced current would be present on an adjacent de-energized line grounding by disconnecting switch that runs parallel to another line that is energized. both lines are 345kV. Line energized with 890A loading with 35km in parallel with 50A induced current at de-energized grounding...

ERRATA! Assume your solar powerplant is connected to a big system. If ground fault current of 18.16pu occurs at connection point it means that contribution current of powerplant is only 1.14pu and (18.16-1.14)=17.02pu is the contribution of the system. 1.14pu is the current contribution...