HT Room No Ventilation

HT = ??

HT means high trannsmission having range 132 to 400 KV

Go back to the Engineer that issued the instruction, and ask.

I'm just take over this place and frankly speaking i do not have much more experience. Thats why i'm looking for your opinions. i try to contact the engineer, closed this windows 15 years ago but his contacts no more in use.

I think you need to describe your situation in more detail. Somewhere your HT must be transformed to LT; where does that happen? Is the transformer actually in the HT room, or does it have a separate room with only the infeed cables in the HT room? Or some other combination?

Sorry for the less info. There is a transformer room beside the HT room.(Transformer room got well air circulation system with ventilation fans). HT room inside only switchboards. Below the HT room there is a cable chamber also.( infeed cables to transformer room)

HT room located ground floor.

Below the under ground cable chamber.

just beside the HT room is transformer room.

Do you think air floor in HT room causing any damage by humidity? Please take a note this HT room opposite is sea. its about 100m away.

Hang on, are you saying you have a school building with a 132 to 400 KV indoor transformer on site?

Surely this transformer is not just for powering the school site (the normal procedure is to step the transmission level voltage down to a lower 11-33kV distribution level voltage at a substation).

Is this some sort of University with VERY high power requirements for test or research labs or something? Or perhaps the HT transformer feeds the old school and then loops out to feed the local area at the lower voltage also.

What's the transformer type, construction, output voltage and power rating?

Can you please provide more information (including country location, transformer details and even school details if possible) on this rather interesting nightmare (I mean application).

In the end the answer is likely in your local electrical and transmission transformer standards and codes, but they are country and application specific and what you describe is very uncommon from my point of view.

Last week a small Civic Cat entered in HT room of Electricity board. He found a path to enter inside the panel (through gap with cable entry). he want to warm herself as there was severing cold outside. But unfortunately she came in contact with live bus and the result was complete blackout for 12 hrs.

Now the ENGINEERS are busy to close/seal all openings to panels & HT room.

Believe me, it is a true story.

whats the fuss about cat havong a 12 h blackout

I just put my cat out..................It was on fire!

This may help you. Normally an HT room, (HT/HV-132kv and above, MV/MT 1kv to 132kV), is positive air pressured with air flow. So a flow in and a vent out. It helps to keep the room 'dust free', and free of fumes which may build up over time. The dust can cause a potential flash over of phases and tracking on conductors. Their would be a filter on each in flow and out flow. If you have cable trenches in the room, the air flow helps keep the trenches clear of any heavy gas which may, be present in the room. An air flow will also help keep the heating from the equipment down slightly. And before anyone jumps down my throat here, everytime a switch is operated or trippped out, gases will be present in the room and they need to be vented off. They usually end up in the trench or the lowest part of the room. If there are batteries present in the room, which there should not be, the ventilation will help keep the gases from the charging batteries at a minimum level. (Old school building!). But, you do need to calrify if you have HT or LV equipment in the room as well as any tranformers. I have doubts that in a school you have 132kV. Perhaps 11kV or lower transformed down to 440V, so please make sure you know what voltage you have. It is marked on the switchgear or transformer for easy reference. If you have LV, 440V, the room should still have some sort of ventilation and fliters to keep dust out the room. Hope this helps you.

Actually my English is poor.

I mean to say that, based on our past experience, sometimes we keep all windows and ventilators closed to prevent entry of lizards, dove etc in the HT room.

In all honesty this is a simple issue to solve. Pull out the window, install an expanded metal mesh in a frame. The frame has a nylon 66 filter, about 50mm thick. Another expanded metal mesh is installed, sandwiching the filter material. Make a second one for the door of the switch room. Install rodent protection mesh on the switchgear, normally a fly screen type mesh. (around the cable entries and gland plates), or use a sheet metal to fill in the gaps around the cable entries. Rodent proofing is not new and not rocket science, neither is installing a vent system for HV/LV rooms. Even use acrylic, bakelite sheeting if need be to rodent proof the gear. It works in Africa, I see no reason it wont work where you may be. If it wants in, it will get in and it will cook, no matter what you do. Try having a large bird fly over, and close to your OH Lines and see what happens to it when it craps mid-flight, between phases. The last thing going through its mind is indeed, its arse. You still have not stated your whereabouts nor actual voltage you are working with. If in doubt, employ me. Cheers.

Everything is relative. HT is short for High Tension, not Transmission, because "tension" is a literal translation to English of the term for "voltage" in some languages.

In same said countries, "High" with regards to voltage is also not the same as the IEEEE definition of "High Voltage". In general, the use of the term "HT" with regards to switchgear and motors etc. in places that regularly use that term is what the rest of us refer to as "Medium Voltage", meaning above 1000V and below 100kV. This is most likely 3.3kV switchgear.

Without knowing the original justification for sealing the windows, it is not necessarily a good idea to introduce outside unconditioned air to MV switchgear rooms. You will also introduce humidity and the possible deadly combination of high humidity, cold air and warm bus bars, which can cause flash-over.

I must know this room by a different name..........ht??