LT Panel Temperature Rising

Are all the terminations tight? Are the cables sized correctly for each load? Is the bus-bar correctly sized for the load? Are all the cables bunched together tightly? Is the panel covered in lots of dust or sh!t?

The Temp. near busbar is 100 dgree .is there any formula to calculate the how much energy is loose in heat or otherwise the best solution is to provide duct on panel to dissipate the heat,reduces the temperature & increases the switchgears life. the busbar, cables are proper size & fully tight.

Do you clearly know what is LT panel?

Another potential solution is to use thermal imaging camera or simple noncontact infrared thermometer to view where the hotspots are and take remedial action such as proper torquing, cleaning, plating etc.

This is most likely a loose or poor contact causing localised heating. 100 deg C is too hot for the busbars, so either the busbar sizing has been done incorrectly or you have a high resistance contact problem. Ducting or other heat removal will likely not work, the problem must be fixed before a catastrophic (and expensive) thermal failure occurs.

Check these two out first, chances are (high) it is one of them. Let us know what you find.

i have checked the panel again today & found my temperature gun is showing wrong temperature due to some setting problem then i taken another one & checked the temperature at all points is between 60,65,70 & 80 dgree centigrate at some places.but my question remain the same i.e.

1.is there any harm to provide duct on the panel with exhaust fans to remove the heat.is it going to increase the lefe of switchgears.

2.How much energy is loss or in other words how much units loss due to increase in temperature.

3. what temperature should be of the bus bars at the ambient of 45 dgree centigrade temperature.

Before you do anything you should check the connections to ensure you do not have a bad (high resistance) joint or connection that could be contributing to the temperature rise. Any actions taken to cool the panel will only result in increasing the time it takes for the panel connection(s) to fail if the temperature rise is a result of a bad connection. This also high resistance crimp connections and high surface resistance between busbars or connection surfaces.

A 35 degree C temperature rise is not too bad, but coupled with a 45 degree C ambient this is just too high an operating temperature in my opinion and may well result in reduced switchgear/protection element life.

A properly-sized bus bar and panel system should not need exhaust fans. There are exceptions but I doubt this is the case for your application. This option may help if your panel and bus bar system has been sized slightly incorrectly (perhaps due to your higher than normal ambient), but this option (while it may work in some circumstances to help extend the switchgear life) is really only a last resort as it adds further complications (and will not help in all circumstances, and in fact may make things worse due to filter maintenance, fan mechanical life, temperature hotspots, panel sealing issues, etc).

Can you take the panel offline and check all the mechanical connections and surfaces (again) to see if that fixes the problem before you start to think about major design changes that may not fix the problem. It may not be, but it is a simple check and could save you a lot of expensive problems if it is a simple connection or joint issue.

If your panel is undersized for your application then you should check your switchgear documentation and the manufacturers documentation available on the internet. You should be able to find design information (including life de-rating related to temperature) there.

this is for Ashutosh's post at 10:54pm on 9th May - - -

in panel temperature limited to 80 deg Celsius is acceptable if the temperature is measured very near to the joints in Busbars or near some heat generating part like a thyristor bank or a coil ((very near" is a very relative term to be interpreted with caution, though).

if the measurements are being taken by pointing the gun to some sheet metal body parts then the actual temperature of the surrounding air is likely to be lower sill. if the temp is being measured by you on the surface of a bare conductor then it is definitely not abnormal in a Faridabad summer if the panel is in a non-ac environment. if however the temperature of 80 deg Celsius is observed on the surface of a pvc insulated busbar then you have a worry situation.

about your duct or exhaust fan idea - the exhaust fan and/or duct does not stop heat generation and therefore does not plug your energy losses - therefore you will end up spending money on installing air handling equipment without a payback on energy bills. since the temperatures are apparently within reasonable limits for in panel temperature you will not save substantially on replacement or life cycle costs of switchgear by putting exhaust fans. if you really want your panel to run a little cooler then punch louvers on cover sheets at the upper most 20% and lower most 10% of your panel. be prepared for a compromise of your IP class (ingress protection) if you do any ventilation. further - why would anyone want to expend more energy in running fans by electricity without directly saving any cost because fans will not reduce the heat actually generated in the system and sent out as losses?

about your concern for UNITs of energy lost - energy (heat) is a function of mass, specific heat and change in temperature integrated over time. the energy lost in a panel will be a summation of individual energy losses measured over time with rise in temperature and considering the diversity of materials it is almost impossible to assess directly. you may however estimate the lost energy by simple subtraction on energy readings at the points of consumption from the energy reading at the point of supply.

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on another note - do you have 3 ph power factor correction capacitors in your panel? and an unbalanced load on your bus?

100 deg in-panel temperature (Celsius) - too high because PVC insulation on wiring will get compromised - and too high because switchgear and controlgear derating will have to be done - - -

if the panel is operating at 70% load (presumably measured on an ammeter) and has all connections properly tightened (low termination point resistance) - - -

(a) check conductor sizing - there may be an abnormally high current density somewhere.

(b) obtain harmonic spectrum of load - there may be circulating currents that are not seen at the point where you measure your load.

(c) check load balance and neutral or ground circuit currents - the point of heat generation may be those conductors carrying unexpected current.

where is the LV Panel located? city?

Another thing to watch for is parallel feeders conductors. Even though the cumulative cables may be sized appropriately, a issue can arise from uneven conductor lengths where the shortest conductor carries a load that is much larger then is good for it. Particularly when the feeders are of a short lenght. I have found field installations where on short parallel feeders the difference in conductor length was as much as 35% resulting in severe overloading of the shorter conductor.

its in faridabad.

As others have said locating the source of the heat is the priority. Ventilation is just masking it.

As for energy lost, forget about it, worry about the damage being done.

Any chance of harmonics, switching loads, and/or inductive loads? Are the neutrals "HOT" temperature wise??

With todays high speed switching power supplies I have seen massive harmonic loads overheat the neutral. Yes even non magnetic ballasts, PCs and other non suspected power supplies.