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The anatomy of a blackout

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By Dr Tilak Siyambalapitiya

It is too early to come to conclusions on what caused the first event towards the blackout on Tuesday afternoon, why that event propagated all over the grid causing a national blackout, and why it took so long to restore electricity supply. The blackout set in around 1235; it was about 2230 when the last customer was reconnected. There is no official statement on whether the problem has been resolved, whether there were equipment damages and whether any such damages have imposed constraints to operate the grid in its normal state.

In the recent past, blackouts have occurred on 9th October 2009, 27th September 2015, 25th February 2016 and 13th March 2016. The blackout earlier this week on 17th August was the 5th blackout in recent memory.

Electric power systems are designed to receive electrical energy from power plants and deliver to customers. Unlike any other commodity, electricity cannot be stored in the form of electricity. It can be stored as water (in a reservoir), fuel (coal, oil or gas) and as chemical energy (in a battery). Wind and solar power generation have no storage whatsoever. Producing electricity from water, fuel or batteries has to be done at the same instant the customer requests the electricity supply to his light, air conditioner, water pump or the factory machine. Therefore, the key word is “dynamic equilibrium”.

That means the rate of electricity production at any moment (measured in megawatt) should be equal to the total customer demand plus the losses in the power transmission and distribution network. As long as there is a balance, all customers will get electricity supply, at the correct voltage and frequency.

Customer demand for electricity is not static. It varies all the time, based on time of day, weather, tea breaks and lunch breaks, and even as a result of TV programmes. Power system controllers also watch TV, particularly when extremely popular programmes and cricket matches are aired to raise power plant output when the match begins, be watchful during breaks, and reduce power generation when the match is over. Remember the production and the demand have to be the same all the time.

Then there are other causes. Sudden rain in a hydropower area would compel such power plants to be immediately brought into operation to save water from spilling over the reservoir. Fast moving clouds over a solar power generating area would cause electricity production from solar power to fluctuate. Electricity production from wind power plants fluctuate all the time, severely at times. These fluctuations of electricity production are somewhat predictable and can be managed, provided the amount of fluctuating hydro, solar and wind power are not very large portions of the supply. Remember the production and demand have to be the same all the time.

When any external event or an equipment failure causes that equilibrium to be lost, then we say the electricity system enters a transient state. The first reaction of the protection equipment would be to isolate the affected section of the network. Just like the fuse, the circuit breaker or the trip switch would isolate a section or all of your house, similar equipment would immediately detect the problem and isolate that faulty section. Electricity travels very fast, at the speed of light. So this isolation too, has to be done very fast, for two reasons: the faulty equipment has to be saved from damage and the fault should be prevented from causing secondary ones.

If the faulty section caused the loss of a power plant, or caused a sizeable share of customers to be disconnected, the matter will be serious, because now we have lost the balance between electricity production and demand. There would be either a shortage or a surplus of electricity production. In most situations, it is a shortage of electricity production because most problems occur within power plants or in the immediately vicinity of power plants. So, now we have less production, and it is not possible to meet the customer demand.

This is when the stored energy in the power system, in the form of rotating generators as well as rotating equipment owned by customers come to help. Any rotating mass has a stored energy. In the technical jargon (this is taught at A-levels too), the energy stored is the rotational kinetic energy. This stored energy is in the form of mechanical energy and is proportional to the size of the generator and to the square of the rotating speed. Large, fast-rotating generators (such as Norochcholai, Kerawalapititya and Kelanitissa) have larger stored energy. Large but slow rotating generators such as hydropower, have moderate stored energy. Small, slow rotating generators such as small hydro and wind power have a small amount of stored energy. Reciprocating engine-generators such as Sapugaskanda and Embilipitiya have very small stored energy. Finally, solar power has zero stored energy.

After the initial fault, such as a short circuit, the affected section is isolated by switches operating automatically and if that causes a power plant to be lost, then the remaining generators would immediately slowdown. Remember that the stored energy is proportional to the square of the speed? So when slowing down, they ‘release’ their stored energy, and convert that to electrical energy, to serve customers. This happens automatically; no operator intervention is required.

Remember these events happen all in a few seconds. Fault isolation may take about 0.1 seconds. Slowing down of generators will happen immediately and may go one for about 2 to 5 seconds. Now, slowing down of generators cannot be done all the time because they would then come to standstill and would not produce any electricity. In fact, this slowing down is allowed by about 5% of the rated speed. As the generators slow down, just like the heartbeat, the ‘frequency’ of the power supply also decreases. If the frequency, which is normally 50 cycles per second, reduces to 49 cycles per second, and stabilizes, then there will be no problem. The frequency stabilizes and then within 5 to 10 seconds, water or fuel valves of power plants will open and admit more energy into generators, which will raise the production of electricity. Then the frequency will also increase and again stabilizes at 50 cycles per second. All these happen automatically; no physical intervention is required, provided there are generators already connected to the grid, producing electricity, with spare capacity, and ‘fuel’ in store.

Sri Lanka’s power system is running with very little spare capacity, thanks to the two politicians who cancelled all the major power plants that were on the drawing boards in 2015. Politicians in Sri Lanka take pride in cancelling projects, but not for facilitating their construction. Then over 2016-2020, the country was compelled to run the existing oil power plants and purchase new oil power plants (much to the delight of some others), then the production costs went up. However, electricity prices cannot be increased because the same two politicians would not allow. So, most of the time, there is no extra fuel in the tanks to quickly raise the electricity production. In other words, spare capacity is not used, even if it is available, because keeping them spinning on partial production levels, hoping some emergency may occur, is costly. Such spare capacity, in the jargon, is known as ‘spinning reserve’.

So how does a grid go dead?

Assuming the short circuit is relieved, then if a power plant has shutdown, the ‘frequency’ drops, attempting to balance the supply and demand. What if it is unable to balance; if the gap between supply and demand is too high and if the frequency cross 49 cycles per second and goes down further? Then the second layer of protection comes into action, automatically. Customers are automatically removed from the grid in blocks, thus reducing the demand for electricity. This happens in several stages, automatically. If the gap between supply and demand is too large, up to 50% of customers may be automatically removed, in a desperate attempt to restore the balance. In most case this works, but for reasons yet to be investigated, it did not happen in this Tuesday’s blackout.

If the supply and demand cannot be balanced even after removing 50% of customers, the there is no hope. A blackout is inevitable. The ‘frequency’ may hit 47 cycles per second and then larger generators (Norochcholai, Kelanitissa) would trip automatically, for their own safety. Hydropower may hold on for a bit longer, but would not be allowed to reach even 46 cycles. One by one, all generations in the grid would shut down, automatically, for their own safety.

All this happens, typically within five seconds. For how long the grid struggled on Tuesday afternoon this week to recover is still unknown. In the 2009 blackout, it was all over in just over 3 seconds (yes seconds, not minutes).

In the 2015 blackout, the grid struggled for 3 ½ minutes before its collapse. In 2016 February blackout, the gird struggled for 8 minutes, before the final collapse.

 



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Features

Strong on vocals

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The group Mirage is very much alive, and kicking, as one would say!

Their lineup did undergo a few changes and now they have decided to present themselves as an all male group – operating without a female vocalist.

At the helm is Donald Pieries (drums and vocals), Trevin Joseph (percussion and vocals), Dilipa Deshan (bass and vocals), Toosha Rajarathna (keyboards and vocals), and Sudam Nanayakkara (lead guitar and vocals).

The plus factor, where the new lineup is concerned, is that all five members sing.

However, leader Donald did mention that if it’s a function, where a female vocalist is required, they would then feature a guest performer.

Mirage is a very experience outfit and they now do the Friday night scene at the Irish Pub, in Colombo, as well as private gigs.

 

 

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Dichotomy of an urban-suburban New Year

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Ushered in by the ‘coo-ee’ of the Koel and the swaying of Erabadu bunches, the Sinhala and Tamil New Year will dawn in the wee hours of April 14. With houses to clean, preparation of sweetmeats and last-minute shopping, times are hectic…. and the streets congested.

It is believed that New Year traditions predated the advent of Buddhism in the 3rd century BC. But Buddhism resulted in a re-interpretation of the existing New Year activities in a Buddhist light. Hinduism has co-existed with Buddhism over millennia and no serious contradiction in New Year rituals are observed among Buddhists and Hindus.

The local New Year is a complex mix of Indigenous, Astrological, Hindu, and Buddhist traditions. Hindu literature provides the New Year with its mythological backdrop. The Prince of Peace called Indradeva is said to descend upon the earth to ensure peace and happiness, in a white carriage wearing on his head a white floral crown seven cubits high. He first plunges, into a sea of milk, breaking earth’s gravity.

The timing of the Sinhala New Year coincides with the New Year celebrations of many traditional calendars of South and Southeast Asia. Astrologically, the New Year begins when the sun moves from the House of Pisces (Meena Rashiya) to the House of Aries (Mesha Rashiya) in the celestial sphere.

The New Year marks the end of the harvest season and spring. Consequently, for farming communities, the traditional New Year doubles as a harvest as well. It also coincides with one of two instances when the sun is directly above Sri Lanka. The month of Bak, which coincides with April, according to the Gregorian calendar, represents prosperity. Astrologers decide the modern day rituals based on auspicious times, which coincides with the transit of the Sun between ‘House of Pisces’ and ‘House of Aries’.

Consequently, the ending of the old year, and the beginning of the new year occur several hours apart, during the time of transit. This period is considered Nonegathe, which roughly translates to ‘neutral period’ or a period in which there are no auspicious times. During the Nonegathe, traditionally, people are encouraged to engage themselves in meritorious and religious activities, refraining from material pursuits. This year the Nonegathe begin at 8.09 pm on Tuesday, April 13, and continues till 8.57 am on 14. New Year dawns at the halfway point of the transit, ushered in bythe sound of fire crackers, to the woe of many a dog and cat of the neighbourhood. Cracker related accidents are a common occurrence during new year celebrations. Environmental and safety concerns aside, lighting crackers remain an integral part of the celebrations throughout Sri Lanka.

This year the Sinhala and Tamil New Year dawns on Wednesday, April 14, at 2.33 am. But ‘spring cleaning’ starts days before the dawn of the new year. Before the new year the floor of houses are washed clean, polished, walls are lime-washed or painted, drapes are washed, dried and rehang. The well of the house is drained either manually or using an electric water pump and would not be used until such time the water is drawn for first transaction. Sweetmeats are prepared, often at homes, although commercialization of the new year has encouraged most urbanites to buy such food items. Shopping is a big part of the new year. Crowds throng to clothing retailers by the thousands. Relatives, specially the kids, are bought clothes as presents.

Bathing for the old year takes place before the dawn of the new year. This year this particular auspicious time falls on April 12, to bathe in the essence of wood apple leaves. Abiding by the relevant auspicious times the hearth and an oil lamp are lit and pot of milk is set to boil upon the hearth. Milk rice, the first meal of the year, is prepared separate. Entering into the first business transaction and partaking of the first meal are also observed according to the given auspicious times. This year, the auspicious time for preparing of meals, milk rice and sweets using mung beans, falls on Wednesday, April 14 at 6.17 am, and is to be carried out dressed in light green, while facing east. Commencement of work, transactions and consumption of the first meal falls on Wednesday, April 14 at 7.41 am, to be observed while wearing light green and facing east.

The first transaction was traditionally done with the well. The woman of the house would draw water from the well and in exchange drop a few pieces of charcoal, flowers, coins, salt and dried chillies into the well, in certain regions a handful of paddy or rice is also thrown in for good measure. But this ritual is also dying out as few urban homes have wells within their premises. This is not a mere ritual and was traditionally carried out with the purification properties of charcoal in mind. The first water is preferably collected into an airtight container, and kept till the dawn of the next new year. It is believed that if the water in the container does not go down it would be a prosperous year. The rituals vary slightly based on the region. However, the essence of the celebrations remains the same.

Anointing of oil is another major ritual of the New Year celebrations. It falls on Saturday, April 17 at 7.16 am, and is done wearing blue, facing south, with nuga leaves placed on the head and Karada leaves at the feet. Oil is to be applied mixed with extracts of Nuga leaves. The auspicious time for setting out for professional occupations falls on Monday, April 19 at 6.39 am, while dressed in white, by consuming a meal of milk rice mixed with ghee, while facing South.

Traditionally, women played Raban during this time, but such practices are slowly being weaned out by urbanization and commercialisation of the New Year. Neighbours are visited with platters of sweetmeats, bananas, Kevum (oil cake) and Kokis (a crispy sweetmeat) usually delivered by children. The dichotomy of the urban and village life is obvious here too, where in the suburbs and the village outdoor celebrations are preferred and the city opts for more private parties.

 

 

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New Year games: Integral part of New Year Celebrations

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Food, games and rituals make a better part of New Year celebrations. One major perk of Avurudu is the festivals that are organised in each neighbourhood in its celebration. Observing all the rituals, like boiling milk, partaking of the first meal, anointing of oil, setting off to work, are, no doubt exciting, but much looked-forward-to is the local Avurudu Uthsawaya.

Avurudu Krida or New Year games are categorised as indoor and outdoor games. All indoor games are played on the floor and outdoor games played during the Avurudu Uthsava or New Year festival, with the whole neighbourhood taking part. Some of the indoor games are Pancha Dameema, Olinda Keliya and Cadju Dameema. Outdoor games include Kotta pora, Onchili pedeema, Raban geseema, Kana mutti bindeema, Placing the eye on the elephant, Coconut grating competition, Bun-eating competition, Lime-on-spoon race, Kamba adeema (Tug-o-War) and Lissana gaha nageema (climbing the greased pole). And what’s an Avurudhu Uthsava sans an Avurudu Kumari pageant, minus the usual drama that high profile beauty pageants of the day entail, of course.

A salient point of New Year games is that there are no age categories. Although there are games reserved for children such as blowing of balloons, races and soft drinks drinking contests, most other games are not age based.

Kotta pora aka pillow fights are not the kind the average teenagers fight out with their siblings, on plush beds. This is a serious game, wherein players have to balance themselves on a horizontal log in a seated position. With one hand tied behind their back and wielding the pillow with the other, players have to knock the opponent off balance. Whoever knocks the opponent off the log first, wins. The game is usually played over a muddy pit, so the loser goes home with a mud bath.

Climbing the greased pole is fun to watch, but cannot be fun to take part in. A flag is tied to the end of a timber pole-fixed to the ground and greased along the whole length. The objective of the players is to climb the pole, referred to as the ‘tree’, and bring down the flag. Retrieving the flag is never achieved on the first climb. It takes multiple climbers removing some of the grease at a time, so someone could finally retrieve the flag.

Who knew that scraping coconut could be made into an interesting game? During the Avurudu coconut scraping competition, women sit on coconut scraper stools and try to scrape a coconut as fast as possible. The one who finishes first wins. These maybe Avurudu games, but they are taken quite seriously. The grated coconut is inspected for clumps and those with ungrated clumps are disqualified.

Coconut palm weaving is another interesting contest that is exclusive to women. However men are by no means discouraged from entering such contests and, in fact, few men do. Participants are given equally measured coconut fronds and the one who finishes first wins.

Kana Mutti Bindima involves breaking one of many water filled clay pots hung overhead, using a long wooden beam. Placing the eye on the elephant is another game played while blindfolded. An elephant is drawn on a black or white board and the blindfolded person has to spot the eye of the elephant. Another competition involves feeding the partner yoghurt or curd while blindfolded.

The Banis-eating contest involves eating tea buns tied to a string. Contestants run to the buns with their hands tied behind their backs and have to eat buns hanging from a string, on their knees. The one who finishes his or her bun first, wins. Kamba adeema or Tug-o-War pits two teams against each other in a test of strength. Teams pull on opposite ends of a rope, with the goal being to bring the rope a certain distance in one direction against the force of the opposing team’s pull.

Participants of the lime-on-spoon race have to run a certain distance while balancing a lime on a spoon, with the handle in their mouths. The first person to cross the finish line without dropping the lime wins. The sack race and the three-legged race are equally fun to watch and to take part in. In the sack race, participants get into jute sacks and hop for the finish line. The first one over, wins. In the three-legged race one leg of each pair of participants are tied together and the duo must reach the finish line by synchronising their running, else they would trip over their own feet.

Pancha Dameema is an indoor game played in two groups, using five small shells, a coconut shell and a game board. Olinda is another indoor board game, normally played by two players. The board has nine holes, four beads each. The player who collects the most number of seeds win.

This is the verse sung while playing the game:

“Olinda thibenne koi koi dese,

Olinda thibenne bangali dese…

Genath hadanne koi koi dese,

Genath hadanne Sinhala dese…”

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