INTRODUCTION
When i wrote this, I was a site engineer at a Thermal Power Plant in India.Ask any site engineer engaged in the erection and commisioning of Thermal Power plants and he'll tell you how our days can get excruciatingly busy when we get down to work.I got my first experience of that when Unit-7 of Kota thermal power plant was synchronised on the 30th of may 2009..Almost 2 months of insane timings which finally ended up after 4 continuous night-outs on the site..Its amazing how the crescendo of work builds up here at site before those deadlines.
And i must admit,that its quite enjoyable...atleast for first timers like me..
And now that its all over,i have quite a lot of spare time and don't have anything much to do..so i decided to blog down some of my experiences..
THE BEGINNINGS
I was posted to the Kota site along with another trainee after completion of our induction training. Accomodation and food wasn't much of an issue as we were comfortably lodged in a Guest House.As i am a graduate of Electronics, i was to report to the Control and Instrumentation(C&I) department but my construction manager advised me to report to Turbine and generator(TG) department.The first few days at site were quite interesting as we were told to "go and have a luk". So we would just go with another engineer and keep asking him questions like "ye kya hai?(what is this), isse kya hota hai(what does this do)?"etc. etc.
I must tell you that a power palnt is a really big place and has just so many systems,equipments,instruments that its not possible to grasp everything by "havin a luk".But still we were gradually getting familiar with the terminologies and the sights and sounds of our workplace. After spending nearly fifteen days like this i was asked to report to the head of C&I department.
C&I is like the brain for all the brawn of the power plant.The main purpose of the whole system is to rotate the generator rotor at the precise speed to cut the magnetic flux and produce an EMF of around 15.75kV. The generator rotor rotates when the turbine rotor rotates.The turbine rotates by the force of steam on the rotor blades.The steam enters the turbine at a temperature of 540 degree C and 150 bar pressure which is generated in the boiler section..
This is quite an oversimplified view but thats what it basically is.. To ensure that the myriad of various systems function at the right time and with the right pace,it is necessary to monitor field conditions and do necessary changes wherever required..This "taking inputs and making changes" is what C&I is all about.
THE CLEARANCE FIASCO
Going back to my starting days at site,there is one particular incident i'd like to talk about.The turbine is a reasonably heavy structure with three sections .The high pressure HP turbine,The Intermediate pressure IP turbine and the Low pressure LP turbine.HP and IP come pre-assembled while the largest of the three,the LP turbine has to be assembled on site.The turbine casing is the outer part inside which the rotor is to be placed.casing comes as two semicircular halves (upper and bottom) of a cyilnder.
Design considerations make it necessary to maintain a fixed clearance between the blades and casing.Now when the rotor was placed on the casing these clearances were found to be slightly less.To adjust the clearance it was decided to file the two semicircular arcs of the casing.so two workers would sit inside the casing and scrape the metal all day long.There was no measurement technique available to determine that how much the casing has been filed already as its not possible to measure it along its whole arc.
This was a clear lack of measurement techniques and when the rotor was placed again,it was found out that the casing had been filed slightly more than required and further adjustments would be needed with the placement of casing to maintain required gaps.
I was really astounded by this hit-and-trial approach towards assembling of the machine and the main cause was non-availability of measurement technique..well it ended up quite smoothly as the turbine is now already running at around 3000 RPM but as i look back,i always feel that there must be a better way.
There are a lot of other things i saw here.
It would get quite lonely in the evenings with no friends and nowhere to go.I met people of different attitudes and behaviours.I experienced for the first time that how troublesome it can get to make people work for you,and how easy it can be at other times.
There is all this and more to share..i hope i continue to get time for this..i'll soon upload pics and everything...and we'll talk some more..
