GIS-SF6 230 KV Switchgear Bus-Bar Protection

We are now upgrading out 230 kv SF6 Switch gear bas-bar protection system. This needs to replace the existing protection panels with new one at the same place. Contractor has submitted the schedule indicating that at least for 2 months 230 kv switch gear bus-bar differential protection and breaker failure protection need to be bypaased to carry out the up-grading. After bypassing he will disconnect the existing wiring from each bay and loop to the new panel. Our plant has 9 TG sets (140*5 & 120*4 mw gen) connected to two bus-bars and four export lines, with bus-coupler. I would like to know, Is it allowed to run the plant with above protections bypassed?. If not, what is the alternate solution?. In other plants How they are doing this up-grading project? Who is the authority to approve the protection bypassing - Plant manager or grid controller? Expecting your suggestions and advice in this regard, Thank you.