How to Safely Install Fire Detection Systems in Live High-Tension Transformer Bays?

Dear Friends,

The below contents were received from a professional group and we need your valuable comments. We have been advised to work on live high-tension transformers (400/220 kV, oil-filled transformers) for the installation of a fire detection system. The total work duration will be 7 days in 3 transformer bays. Shutdown is practically not possible due to production requirements.

Installation of scaffolding is too risky as we need to ensure that no manpower or manual handling activities are involved. Working using a manlift is also a high-risk activity, especially when working above the live transformer (2 meters from the transformer body). The clearance from the completely insulated bus bar lines (400 kV) will be less than 1 meter when the manlift is in operation.

We consider this operation to be too risky and have refused to perform the installation under live conditions. Can anyone help with a proper risk assessment or provide standards that are applicable or generally followed in the Gulf regions?

Regards,
Ashokkumar.P

Dear Ashokkumar.P,

First of all, welcome to the forum and thanks for bringing up this topic for discussion.

Let me provide my comments on the topic:

You mentioned that "clearance from the completely insulated busbars lines (400 kV) will be less than 1 meter when a man lift is under operation," so this falls under the limited approach boundary. You may allow entry of qualified persons with the required PPE and highly insulated tools to work in such a location as per NFPA 70E. Please refer to the attachment for specific details. Additionally, you can find a lot of details regarding NFPA 70E online.

However, my suggestion regarding this scenario is not to take such a high risk. When the plant is under shutdown for any maintenance, proceed with this task. The installation of a fire detection system is not a critical job that needs to be done while the plant is operational, as it could affect your plant's performance. Please consider this.

I am attaching a case of an electrical accident that occurred due to a lack of shutdown.

The only work that we can consider doing in a live electrical circuit is checking, and even that should be done under the supervision of a competent person with the required protection.

I hope this information is helpful to you.

Keep participating and sharing your expertise with us.

Regards,

Dipil Kumar V

Dear Mr. Ashok Kumar P, please find the attached file. Awaiting comments on the issue from other members too.

Regards,
Dipil Kumar V