Lightning: The Misery Causing Mystery

 
Descending like a silvery stream from the dark heavens, lightning surely is an alluring view to behold. Yet, from the very beginning of life, humans have always feared this phenomenon,knowing the grave dangers concealed in it. Thus, it’s of paramount importance that we take proper measures to avoid the undesirable consequences of lightning strikes.

Therefore, in order to give you a proper understanding about lightning, we thought of unfolding its consequences and means of safe guarding against it, through an interview with one of the most reputed high voltage specialists in Sri Lanka, Emeritus Professor J. R. Lucas of the University of Moratuwa, Sri Lanka.

Professor, let’s start from the very basics. Could you please tell us what lightning really is?

Okay… If you go down to the very basics, it is a huge discharge.Have you heard that small pieces of paper get attracted to your comb after combing your hair, especially when the air is dry? That is due to the electrostatic charges piling up in the comb due to the rubbing action.

The same scenario occurs within thunder clouds due to air movement and charges building up inside the clouds. When the field increases beyond a certain value, about 10kV/cm, then a discharge can occur. Most of the time, these discharges take place within the cloud (a cloud, by the way, is normally few kilometers thick), between clouds or just to the air. Only about 10% of these come to the earth, and that is the lightning we are afraid of. Most lightning occurs from the negative charge centers towards the bottom of the cloud. 

Does lightning occur only during rains? 

Well, lightning and rain are not necessarily related, but in a tropical country like ours, lightning normally occurs during rain, especially when it originates from the lower part of the cloud. 

In rare instances, the thunder cloud may be a few kilometers away and you may still find that lightning occurs from those far away clouds, which you may not see.

Have you heard of the expression “lightning from the blue”? 

As a cloud is normally a few kilometers thick, when the positive chargers at its top causes lightning discharges, then it might come from fairly far away, and you may not be able to see the cloud, and you might think that the lightning is coming from the blue sky without clouds. Then again, keep in your minds that not all rain clouds cause thunder.

Sir, lightning strikes are dangerous and that’s a well-known fact. But why?

(Making a serious face)

The main reason why lightning is dangerous is due to the enormous amount of energy that it carries. You may be able to light your room lamp for a whole year from the energy of one lightning strike: And, this energy is dissipated within a small fraction of a second. Thus, the currents encountered can be of the order of twenty thousand amperes and higher, while the temperatures can be even hotter than the sun. These alone make lightning a very dangerous phenomenon.

Moreover, once lightning strikes the ground somewhere, currents start to flow through the ground, like the roots of a tree. This gives rise to a potential difference on the surface of the ground. So, if you keep your feet apart, then a potential difference (i.e. a voltage) may appear between your feet, which in turn may cause currents to flow through your body. This can be lethal. This is illustrated in the figure.

Therefore, not only a person directly struck by lightning, but people in the vicinity could also be killed. This adds to the gravity of lightning strikes. The picture obtained from the internet shows many cows dead under a tree, due to the ground potential rise caused by lightning.

On average, how many deaths are caused by the lightning strikes in Sri Lanka?

Well, that’s not an easy question to give an exact answer. Sometimes, unless directly stuck, one may not know that someone was killed by lightning, especially if he was working in the field. People might even think that he got a heart attack. So, these kinds of deaths are not reported and facts are not available. According to records, around 40-50 deaths are reported to occur every year. Including the unreported ones, it is estimated that about 70 people die per year due to lightning in Sri Lanka.

Professor, not everybody gets struck by lightning. So, based on years of your experience, can you conclude the individuals who are more susceptible to lightning strikes?

First and foremost, you must understand that normally, the probability of being hit by a lightning strike has no direct relationship with individuals as such. Anybody is susceptible to lightning strikes, depending on various facts. 

If you are the tallest object in an open field, then you are more exposed to lightning because of the higher field. That is why farmers working in paddy fields, fishermen sailing in the sea and rangers wandering in open areas, become common targets of lightning strikes. So, try to avoid open areas when there is thunder.

 

Most importantly, if there’s only one tree in an open land, never go under it for shelter, because that is the most likely place to get struck by lightning. If the tree is struck, the potential of it increases and from the tree, flash-overs might occur putting you at a grave danger.

Moreover, the use of electrical appliances, though maybe safe, is not encouraged when lightning activity is high. Because, during lightning, the potential of the plug point might go up, and anybody touching the outer metallic part of an electrical appliance might experience an electric shock. 

Sir, if we are in an open field during thunder, and if the field is so large such that there’s no place to run to, then what can we do to save ourselves?

In a such a situation, what you can do is to position yourself such that the effects of lightning on you is minimal.

Try to reduce contact between your feet and the ground as much as possible - keep your feet touching each other at the heel. Crouch down, lower your head and body as much as possible and cover your ears from hands.  Once you are crouched down, you might not be the tallest object around. As you are keeping your feet touching each other, the voltage difference between them are minimal (step voltage reduces and the effect from the currents running along the ground can be reduced). A lightning discharge normally encounters a considerable amount of sound. By covering your ears, the harm done to the ear drum can be reduced to a minimum.

Never lay on the ground in order to reduce your height, because that’s probably the worst thing that you can do. As the contact area with the ground goes high, so does the currents flowing through your body.

What is the safest place to stay when it is lightning?

(Thoughtfully) 
A fully enclosed metal box I might say. You are quite safe there from lightning strikes, but soon will suffocate to death and it will turn to a metal coffin.(Laughing)

(Making a serious face)

Well, my advice is to stay within a well constructed building. But make sure that you are not near to open doors, windows and not in the open areas such verandahs, balconies or courtyards.  If you cannot find a building, then the next best would be a metallic vehicle.

Some think that vehicles are much safer than buildings, because they are on top of rubber tires, which is a misconception. If lightning could have come a few kilometers from clouds, few inches are not going to make any difference.  The tires in fact help to retain charges on the vehicle body. However, fully covered metallic vehicles act as “Faraday Cages” and prevent us from being struck by lightning strikes. However, if you sit near to a window, you might experience some effects of the lightning flashes that may penetrate some millimeters in the non-metallic portions.

Most importantly, you must avoid getting in or out from a vehicle, when the lightning activity is high. This is because, the vehicle can be charged to a higher potential due to lightning and can be discharged through your body when stepping in or out. So, if you are in a vehicle, wait till all the lightning is over before you step out. If it’s urgent to come out, jump off the vehicle with both feet, without touching any part of the vehicle and be mindful not to step out one foot at a time.

Containers are said to be safe, for the same reason as that of vehicles. But practical containers, where people usually stay inside, such as those you find in construction sites, have large openings for ventilation. While containers, being metal structures, attract lightning strikes, there might be flash-overs at the openings unless a metal mesh is connected across openings. So, my advice to you is to even avoid a metal container if a substantial building is available close by when there is thunder.

Is it okay to use mobile phones and land phones when it is thundering?

When it comes to lightning, mobile phones and land phones behave very differently.

The use of land phones is not advisable as surges can come through the communication wires and harm you. However, it’s quite safe to use a mobile phone, if you do not go to the verandah or other open area to getter better reception, or it is not plugged in to a socket outlet for charging.

Sir, can we use a laptop during lightning?

Of course you can! But make sure that you have removed its power, network or any other cable. If

In short, you can use normal household appliances during lightning, as long as they don’t have any wired connection to the electricity or communication networks. That means if they are supplied by batteries.

you want to connect to the internet, use a dongle.

Professor, all this time you emphasized that we must make sure our appliances do not have wired connections, if we are using them during lightning. What is the rationale?

A good question!

Power lines and communication lines are prone to lightning strikes. Even if they are not directly struck, lightning can induce surges in them. These surges travel along these lines and eventually reach electrical equipment to harm them as well their users.

Many people think that their equipment are safe as long as they are turned off. But that is wrong.  Lightning can harm even these equipment as long as they are wired to the power or communication networks.

So, make sure that your electric appliances are disconnected at the socket outlets and no network cables are connected, if you are using them when the lightning activity is high.

Professor Lucas, we could learn quite a lot of interesting facts about lightning. Thank you very much for your cooperation!

So, this marks the end of the first part of our interview with Prof. J.R.Lucas.

Keep in touch with us to discover many other interesting facts related to lightning.

Interviewed and presented by:   

Dilini Darmawardana
Himali Lakshika
Nisala Amarasekara

Watch Lightning strikes footballers

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Posted in: Utility and Social

Electrified Transportation - The Step towards Future: Key Note Speech Eng. Shavindranath Fernando

In 1979 when I joined CEB I was attached to Kelanitissa Power station and the Pettah power station was looked after by our staff.  There were several outgoing feeders from this power station allocated for the tram lines and trolley bus service as the Pettah Power station was primarily put up in 1902 for the Colombo Electric Tramways and Lighting Company. So here we are re opening the topic of electrification of our transport system once again more than half a century after the electrified transport system that we had Colombo operated by the Colombo Municipality was scraped. It defies me to find the reasons for these decisions as I was told by none other than Mr. H S Subasinghe former General Manager of CEB and the first Chairman of LECO, they had to canvass the tea factories during the same period to electrify their own factories scrapping the large number of mini hydro power stations that were powering them. So it is not uncommon for Sri Lankans to do one thing in one hand and undo it at the same time from the other.

In 1983, I was involved in doing some work in the energy sector and I had to analyse the CEB load profile and the demand projections. To my surprise there was an electricity demand component for railway electrification, 32 years later we are still talking about railway electrification. Railway electrification was first proposed by none other than one of our great visionary engineer D J Wimalasurendra somewhere in the early 1920s.

 

When I was small we had green colored electric trolley buses silently moving in Pettah and Fort with their characteristic horn. My grandmother used to talk about the tram cars. The rail lines laid in the middle of the roads in Colombo were still visible until recently. These tram cars were taken off the roads I believe in 1959 or so and the trolley buses too were taken off in 1964. I believe the decision to scrap them were made due to mismanagement, unionism and politics at that time and may not necessarily be for economic reasons.

 

In 1992, we in Sri Lanka Energy Managers Association organized a roundtable on transportation, I organized this event with the experts at that time, late John Diandas, Dr. Jayawardane, Prof KKYW Perera and few others including DIG (Traffic ) Mr. Perimpanayagam as main contributors. It was a very successful one at that time and some SLEMA members made even slide presentations that led to immediate leveling of some road humps that were put up near the pedestrian crossings of the universities, when everyone realized university students were not Montessori students!! Then few bus bays were also constructed on Galle road, though at that time late Mr. John Diandas was against this concept where he argued the busses should stop on the main road while private vehicles should veer away from the main line traffic giving priority to buses. I don’t think this will ever happen though it has a very rational base, perhaps until all of us travel in buses. Once again last year too SLEMA had its annual sessions dedicated for sustainable transportation.

Then in 2008 the Institution of Engineers Sri Lanka sponsored a study of railway electrification and we even got the assistance from the Institution of Engineers India to send an expert in railway electrification and I am sure Tilak who was involved in the study will dwell on. The study had very clear conclusions and a cabinet paper was drafted by the Ministry of Power and Energy and our minister at that time none other than our chief Guest signed it and sent it to the Ministry of Transport which I believe is still there to be signed by the Minister! This cabinet paper never saw the light of the day.

These are some of the attempts made by the professionals of this country to address the efficiency improvements in the transport sector. I must admit unlike in other sectors nothing much has happened in the electrification of the transport sector though it seems to be the obvious solution to many problems in this sector. I am sure those who are involved in this sector know only too well why nothing rational can be done. I do not want to go into details as they are bound to come up in the later discussion session.

So it is very opportune to talk about this topic today and I congratulate EESOC for taking the initiative.

Coming to the topic of the day, it is timely and opportune to take up this matter as a priority due to more than one reason.

• For quite some time hybrid cars are now sought after by many car users and there is very little effort to track down the energy efficiency of these cars and come out with a policy to encourage them and to see the possibility of off line supplementary charging if it can be done or if it need to be encouraged.
• For at least 10 years electric cars have been imported by enthusiasts and not really as a need, to be introduced especially for urbane commuting, for which in my own mind has a tremendous advantage of not only the efficiency gains in running on congested urbane roads but also as a measure to reduce urbane pollution from fossil fuel powered vehicles. With the current tax reductions for importation of such vehicles, it is imperative that we all in the transport and energy sector get together and address the myriad of issues that necessarily will have to be addressed as a matter of urgency.
• We also have to at the same time see the validity of imposition of increase of custom duty on hybrid vehicles in the light of the argument that it favors the electric cars, of which I am not quite convinced if it had been done with this object in mind or the real reason is something else. So I leave it to the experts to argue this out.
• The CEB has an installed capacity of around 4000MW with 900 MW of base load capacity in coal power plants and a maximum demand of nearly 2000 MW. This excess capacity can be used to meet the requirement of the transportation sector.  The load factor of the system which stands at around 68% can be improved tremendously by prudent demand side management techniques which include electrification of transport sector as well. 
• The discovery of natural gas in the Manar basin is something that need to be taken into cognizance as we have more than 600 MW combined cycle plants that can easily be powered by natural gas and their capacity too can be utilized to meet the new demand in the transport sector or natural gas can be used directly as a fuel in transport hence detail studies are required to ascertain the best use of the natural gas in the transport sector, from a techno-economic point of view.

In depth and well coordinated studies are needed if we are not to make any more mistakes and nullify what  one arm of the government does with the other. I would like to place on record that, at a seminar conducted by the UGC few weeks ago on the findings of Natural Gas, policy on petroleum and electricity sector was discussed. Politics aside, I categorically mentioned that the biggest mistake we have done in the energy sector in Sri Lanka was the separation of the ministries of Petroleum, Power and the renewable energy as I believe it so. Fortunately now all the relevant sectors in Energy are brought together. So if we are to take any initiative on electrification of the transport sector there should be constant dialog between these two sectors and unified policy initiatives should be adopted with absolute commitment from all concerned. 

I am not going to dwell on statistics or forward any definite blueprints how this should be done as there is enough expertise in this room to do that. Further I am not in any way an expert in transport. However, as a person who was involved in promoting Integrated Energy Planning in the 1980’s with Prof. Mohan Munasinghe in his team, all I can say is there is an ideal opportunity for us to start this effort once again at least with the transport sector for efficiency gains in both sectors.

In the years gone by we had steam locomotives powered by coal, spewing thick black smoke depositing coal soot and dust all along the rails lines that ran in the most beautiful part of the country. Those days we were not bothered about environmental pollution. Now we have Coal power plants with all the environmental safeguards. We have no black fumes, SOx and NOx pollutions are under control. We have a clean and an efficient source of energy, electricity available 24x7 throughout the country with load factors that can be improved that will yield enormous economic benefits. So what are we waiting for? There is an obvious choice an ideal win-win situation waiting to be exploited for greater good of the country.  This will be a case of shifting the fuel for transportation back again to coal shifting away from oil, but this time in a much more efficient and an environmentally friendly and a sound manner.

Moreover we all know there are two predominant transport rush hours in the morning and in the afternoon more towards the evening hours, We have to take advantage of this phenomenon that suits well with the electricity daily demand curve which takes a dip in those times. This should be used with prudence to derive the economic benefit to both sectors and the country at large by electrifying railways and even introducing electric trolley buses.

However, individual charging of smaller motor vehicles need to be regulated with proper power quality standards and tariff making to take advantage of the low price of electricity that the CEB should be able offer to fill the valleys in the daily power demand curves. This can be easily done with proper planning and studies.

In the CEB we have looked at vehicle charging centers before the electric vehicles are brought to the country in large scale. There is an urgent need to get on with the pilot projects that we in CEB were contemplating. This will help CEB to come up with proper standards for charging centers and also a proper tariff to encourage charging of these vehicles in the off peak hours.

We are also well aware of the sliding costs of solar pV panels of which the prices have come down significantly due to large scale pV manufacturing plants that have come up in China. We must take advantage of this now and even solar powered charging centres can be made popular, but all these need careful evaluation before we embark on any one of them. With the large potential of wind to be developed in the country in the future we would be in a position to power the transport of our country to a great extent on Coal and renewable energy sources from today’s 100% Oil base.

We do not lack the expertise on the maters I have raised today. We also have with us Ministers who are committed to do what is right and prudent. We don’t need expertise unlike in building complex power plants or other infrastructure like harbours and air ports. Some decisions can be made with rudimentary studies while others like railway electrification may take few more months of detail studies to carry out the feasibility and detail designs etc. But we all agree this is an urgent need. The country has wasted so much of time we have made mistakes in the past very expensive mistakes starting from scrapping electrified transportation we once had, delaying the Coal power project for no apparent reason, delaying the railway electrification for reasons best known for very few. These are some such very expensive mistakes. The need of the hour is for us all to get together and do what is right.

As I always say to quote from the Bible: “knowing what is right to do and not doing is a sin” Let us not collectively sin by prolonging this discussion any more let us map out a strategy together.

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Posted in: EESoc Panel Discussion - 2015