As power companies face the task of changing out old transformers, they can be assured that the new transformers can last just as long if they are designed well and if they are continuously monitored with durable sensors.
Prabhat Jain, president of VA Transformer, gives us that hope because he knows sensors. Jain started his career in sensors and now imbeds solid-state sensors into VA Transformers. And these sensors are designed to last as long as the projected life of the transformer.
T&D World discussed Jain’s career evolution from sensor man to transformer manufacturing, and he shared the role sensors play in transformer life.
Q: So, you started your career in sensors. Was it in the power industry?
It was not in the power industry.
After graduation from Villanova, I started working for Robinson-Halpern Company based in Conshohocken, Pennsylvania that made pressure-temperature sensors. Initially I worked on a radiometer that was used by NASA for the radiation measurement – more than (85) thermocouples were used in this meter. Then I worked on a high-temperature accelerometer used in sensing vibrations in the fuel bundles in a nuclear reactor based in Hanford, Washington PWR Nuclear Plant. I also worked on high accuracy pressure transducers used in submarines in Philadelphia naval yard used for ocean depth measurements.
Q: How did you get involved in power transformers?
While working for GE, I was involved in buying specialty transformers from none other than Virginia Transformers. The corporate path of advancement seemed too slow for me, and an opportunity to head up the very same Virginia Transformers came up at the same time. I decided to take on this challenge and there was no looking back from there. In the next 20-odd years, we gradually expanded our scope through building new plants and acquisitions to supply power transformers up to 100 MVA/230 kV class to utilities and industrial customers through three plants located all around North America.
Q: I understand you bought the EFACEC larger power transformer plant in Georgia. What was the reasoning, and have you made additional investments in the facility?
Our goal was to become a domestic full line supplier of power transformers ranging from 1 MVA to 1200 MVA up to 500 kV to U.S. T&D customers. EFACEC offered that opportunity. And based on our commitment to maintain, nurture and expand the top-class facility and staff, we were the winning bidders among several others.
Let me list the investments (that run into millions) we made in the plant since the acquisition:
- Implementation of design automation to expand the engineering capacity and eliminate errors
- Addition of several design tools and simulators to augment home grown EFACEC design programs
- Capacity expansion of Core Type units by adding and modifying:
-Vertical winding machines
-Horizontal winding mandrels
-Isostatic pressure equipment
- Addition of second Test Bay for redundancy and capacity expansion
- Addition of more shop technical supervisory and engineering staff
Q: Power companies are changing out aging transformers, some of them 50 to 60 years old. Is there any hope of getting new transformers to last as long as the earlier generation?
A very good question!
A reliable transformer in general requires:
- A robust design produced by experienced & trained designers using state of the art tools and an efficient process
- Flawless Implementation of the design in the shop which in turn requires
-Trained shop technicians and experienced supervisors
-Efficient tools and technology e.g. Automatic Core stacker
-Environmentally controlled, spic & span, State of the art factory
-High quality raw material
-Efficient manufacturing process
- Continuous monitoring of critical parameters using sensors that will outlast the life if transformers and the associated service support
If a manufacturer follows these steps there is no reason why a transformer should not last for 60 years
Q: So, what sensors do you imbed in your new power transformers? How will these sensors play a role in us getting more capacity and more life out of transformers?
There are five crucial parameters we need to check to ensure the health of a power transformer: hydrogen level, moisture level, oil temperature, oil level, pressure and short circuit. We have imbedded sensors for each one of these parameters. Unlike other transformer external sensors/monitors that have set points to trip or alarm, our sensors are imbedded and integrated to furnish continuous data on these parameters to observe the trend and fix the problem before it is out of control. The data is stored for the life of transformer. The sensors themselves are solid state and designed to last as long as the projected life of a transformer. A partnership and collaboration between the customer and a supplier regarding the proper preventive actions on the readings from this monitor will ensure extended life of a power transformer.