A distribution transformer usually fails from heat, and heat comes from load. This project instruments a transformer with load current, voltage, oil temperature and oil level sensing, estimates the winding hot-spot temperature from the measured oil temperature and load, and converts that into an insulation ageing rate using the IEEE loading guide relationship — so the dashboard reports not just that the transformer is hot, but how much life that heat is costing. That last step is what separates it from the many IoT monitoring projects that stream numbers and interpret none of them.
Not just the parts. Teams budget from a component list, then run out in week six on wire, connectors and the driver board they destroyed. These are the lines that catch them.
| Line | Cost |
|---|---|
Components and materials From the bill of materials | Rs 3,840 to Rs 18,330 |
Spares and replacements 15 % — you will destroy something | Rs 576 to Rs 2,750 |
Consumables and hardware Wire, connectors, headers, screws, heatshrink | Rs 461 to Rs 2,200 |
Perfboard and assembly | Rs 150 to Rs 400 |
Report, printing and binding Two or three bound copies, plots and the plagiarism check | Rs 400 to Rs 1,200 |
| Total | Rs 5,427 to Rs 24,880 |
| Each, split 3 ways | Rs 1,809 to Rs 8,293 |
Indicative bands last checked in August 2026 — a guide, not a quotation. Prices move and vary by seller, and anything you can borrow from the lab comes straight off the total. The 3.9 week figure assumes 9 person-weeks of work shared between 3; students past 4 add coordination rather than output, so the estimate stops improving there.
The same chain in words
Load current is measured on each phase and converted to a per-unit loading against the transformer's rated current, which is the input the thermal model needs.
Top oil temperature is measured directly. The winding hot spot runs hotter than the oil by a gradient that grows with load, so the hot spot is estimated as the top oil temperature plus a load-dependent winding gradient.
That hot-spot temperature is converted into an ageing acceleration factor using the IEEE loading guide relationship, which expresses how much faster insulation ages at any temperature compared with its reference.
The ageing factor is integrated over time, so the dashboard reports the equivalent life consumed during the day rather than a single instantaneous temperature.
Oil level, phase unbalance and overload each raise their own alert, because they are separate failure paths and lumping them into one alarm loses the diagnosis.
This is the chapter that separates an engineering project from an assembly job. Every value below carries the formula that produced it and the assumptions it rests on — check them against your own ratings before you use them, because your motor is not this motor.
I = kVA x 1000 / (sqrt(3) x V line)
25000 / (1.732 x 433) = 33.3 A. Loading is reported per unit against this figure, so it is the number every other calculation depends on.
hot spot = top oil temperature + winding to oil gradient
The gradient scales with load to a power between 1.6 and 2 depending on the cooling mode. The estimate is a model, not a measurement, and the report has to be clear about which it is — a direct fibre-optic hot-spot sensor is a different and much more expensive instrument.
FAA = exp(15000/383 - 15000/(hot spot + 273))
15000/383 = 39.164 and 15000/393 = 38.168, so FAA = exp(0.996) = 2.71. Ten degrees roughly triples the ageing rate, which is the single most useful fact in transformer loading and belongs prominently in the report.
Integrate FAA over time
This is what turns a temperature reading into a maintenance decision. A transformer that runs two hours a day at 120 C is consuming life at nearly three times the nominal rate during those hours, and that is visible in a way a temperature graph is not.
unbalance % = maximum deviation from average / average x 100
Unbalance on a distribution transformer indicates uneven single-phase loading across the phases, which causes neutral current and extra losses. It is a load management problem the operator can actually act on, which is what makes it worth alerting on.
Measure where the model assumes the measurement is taken
The thermal model is defined in terms of top oil temperature. A sensor on the side of the tank reads several degrees lower and the whole ageing calculation is then biased optimistic, which is the worst direction for a protection system to err in.
| Item | Qty | Unit cost |
|---|---|---|
Current transformers Split core, 50 A, one per phase, with burden resistors | 3 | Rs 300 to Rs 800 |
Voltage sensor modules ZMPT101B, one per phase | 3 | Rs 120 to Rs 260 |
Temperature sensors DS18B20 in a stainless probe, oil and ambient | 3 | Rs 120 to Rs 400 |
Oil level sensor Float switch, or an ultrasonic sensor above the conservator | 1 | Rs 200 to Rs 800 |
Microcontroller board ESP32 with WiFi, or with a GSM module for field use | 1 | Rs 350 to Rs 900 |
GSM module SIM800L with a 2 A supply, only if there is no WiFi | 1 | Rs 450 to Rs 1,100 |
Display 20x4 LCD with I2C backpack | 1 | Rs 250 to Rs 500 |
Alarm output Relay module and a panel buzzer | 1 | Rs 120 to Rs 350 |
Power supply 12 V SMPS with a small backup battery | 1 | Rs 350 to Rs 900 |
Weatherproof enclosure IP65 ABS box with glands, for outdoor mounting | 1 | Rs 500 to Rs 1,400 |
Test transformer Lab transformer or a demonstration model with a loading arrangement Use the machines lab transformer — instrumenting a live distribution transformer requires utility permission that a student project will not get. | 1 | Rs 0 to Rs 8,000 |
Specifications are written as ratings rather than brands, so any equivalent part works. Where a line says to borrow from the lab, do — it is usually the largest number on the page, and the total drops to Rs 5,427 at the low end without them.
None of these blocks you — they are learnable inside a semester. Each one you do not have costs a couple of weeks, so count them into your plan.
Anything marked required is a blocker, not a difficulty. Arrange the access before you commit to the project, not after.
Use these when your guide says the scope is too small, or when you want something in the results chapter that nobody else in your batch will have.
The structure below is what a project report is marked against, with the mistake that costs marks in each chapter. There is no template to download and there will not be one: the writing is your work, and a site that did it for you would be helping you cheat rather than helping you pass.
A mini project report runs to about 40 to 50 pages, and the literature survey is usually brief. Guides expect one clear objective, met and measured. A final year report is normally 60 to 90 pages with a substantial literature survey, and many departments expect a paper submission alongside it.
The full report guide — front matter, conventions and page countsOne paragraph covering what the problem is, what you built, and what the result was. Written last, even though it appears first.
Loses marks: Describing the problem and the method but never stating a result. If there is no number in your abstract, it is not finished.
Why the problem matters, the context it sits in, and a clear statement of the objectives your project set out to meet.
Loses marks: Objectives written so vaguely that nobody can tell at the end whether they were met. Write objectives you can tick off in the conclusion.
What has already been done, what each approach achieved, and the specific gap your work addresses.
Loses marks: A list of paper summaries with no comparison and no gap. The survey exists to justify your design choice, so end it by saying what you chose and why.
The system as a whole: the block diagram, what each block does, and the signal or power path between them.
Loses marks: A block diagram copied from a datasheet or another report. Draw yours to match what you actually built, including the parts that are inconvenient.
Every component value and rating, with the formula, the assumptions and the arithmetic that produced it. This is the chapter that distinguishes an engineering project from an assembly job.
Loses marks: Component values with no justification. If a resistor is 10 kOhm, the report must say why it is not 1 kOhm.
The circuit as built, the PCB or wiring, the flowchart, and the parts of the code that carry the actual logic.
Loses marks: Twenty pages of pasted source listing. Include the flowchart and the few functions that matter, and put the full listing in an appendix.
What you measured, in tables and graphs, compared against what you predicted in the design chapter — including where they disagreed.
Loses marks: Photographs of the working model presented as results. A photograph is evidence that it exists, not evidence that it works. Results are measurements.
Whether each objective was met, what the measured performance was, and what the honest next step would be.
Loses marks: Future scope written as a wish list of unrelated features. It should follow from a limitation you actually hit.
Every source in a consistent style, plus datasheets, full code listings and the complete bill of materials.
Loses marks: Citing a blog or a video where a datasheet or a standard exists. Cite the primary source for anything you relied on.
The demonstration is half the assessment. These are the questions this project invites, and the answers are written the way you would give them out loud.
Because the insulation is cellulose paper, and its degradation is a chemical process whose rate follows an Arrhenius relationship with temperature. Chemical reaction rates rise exponentially with temperature, so a modest increase produces a large increase in ageing rate. The usual working rule is that every six to eight degrees roughly halves the remaining life.
The hot spot is the hottest point in the winding, and it is what actually determines insulation ageing. Oil circulates and carries heat away, so the oil is cooler than the copper that is heating it. The difference between them is the winding to oil gradient, and it grows with load because the losses that create it rise with the square of current.
It is estimated from the measured top oil temperature plus a load-dependent winding gradient, following the IEEE loading guide. Directly measuring it needs a fibre-optic probe installed inside the winding at manufacture, which is done on large power transformers and essentially never on distribution units. The report presents it as a model output with its assumptions stated.
How fast the insulation is ageing right now compared with the reference condition. A factor of one means the transformer is consuming one hour of life per hour of operation; a factor of three means three. Integrated over a day it converts a temperature record into equivalent life consumed, which is a maintenance and loading decision rather than a number on a gauge.
Because it is a different failure path. Falling oil level means a leak or severe overheating, and it directly threatens both insulation and cooling, since the windings must stay immersed. It develops independently of load, so folding it into a general alarm would lose the specific diagnosis that lets someone act on it.
It indicates that the single-phase loads are unevenly spread across the three phases. That produces current in the neutral, extra losses in the transformer, and uneven heating between the windings. It is also one of the few things an operator can actually fix cheaply, by redistributing the connections, which is what makes it worth alerting on.
Normally taken as a B.E. mini project (5th/6th sem) or B.E. final year project (7th/8th sem) project. If yours is a different course, the extensions above scope it up and the simpler half of the design scopes it down — the arithmetic does not change. Back to all projects.