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Analogies

Cascading Power Failures Explained

Posted on 4 min read

Early on Saturday morning, a power transmission cable snapped somewhere near Nairobi city. The resulting effect was a nationwide blackout in Kenya and Uganda. How did one cable send two countries into darkness?

It is something complicated if you do not understand the power distribution, but we can make it simple for you via an analogy.

Analogy

Let’s assume that on average, one person can lift 40 kg of weight. Some can do 70 while other only can manage 10kg, but the average always comes to 40 kg.

You need to move your house from one point of your farm to another, and you need to hire some people to do it. You estimate that the house weighs 1000kg, and this translates to 25 people if each of them is to carry 40kg. Remember you are moving the whole house as one unit (it happens).

In some parts of the world, we can always move with our houses

Since you know that something could go wrong during the lifting, you will need to have more than 25 people to do the work as failure of one man could cripple the whole operation. However, getting too many extra people will cost you more than is necessary, so you opt to go with 27 people. One person will always be free to help lift any side when people are overwhelmed while 26 will always be working.

When it is time to move the house, everything goes on as planned. At one point one man stumbles and the standby guy moves in quickly. Everything is going on according to the plan.

At another point one guy hurts his leg and you are left with 26 people doing the lifting. This is still safe since you only need 25 people for the work.

But then, something unusual happens. One man who is very strong slips. He was carrying about 70 kg of the weight, and when he stops doing the work, every person around him feels the extra burden. To rescue him, his neighbor stops lifting and helps him move out of the way before he is ran over. The others near him stop moving and try to get everybody else to stop moving so that there is no accident. In the confusion that follows, there is an imbalance and the only safe thing to do is to put the house down so that everyone can recollect themselves.

This stops the whole operation for 10 minutes as everyone realigns themselves and work resumes.

How can such a scenario be prevented? Majorly by having more people so that there can be more tolerance to imbalances. However, this increases the cost and it will not help you when all the people holding one side encounter a unexpected obstacle. They will still have to put the house down.

The other option is to divide the house into equal pieces and let every person carry a 40 kg piece. This is would work, but remember some people can only lift 10 kg while others 70 kg. You will spend a lot of time either cutting unequal pieces and marching them to each person’s capacity, or alternatively you might need to pair up the people with less capacity, thus increasing the number of people you need.

What Happened

The electricity distribution system is called a grid, and involves several electricity generators being connected together into one network so as to serve people all over the country. In Kenya, we have different sources of electricity such as hydroelectric power plants, geothermal, wind, solar and other sources of power, including imports from Uganda.

This interconnection helps keep the load stable even if one source of power fails. It also helps maintain optimum supply such that if demand is low, some sources such as the expensive thermal (diesel) powered plants can be switched off.

Part of the failed cable
Kenya Power engineers at work

The grid has various high voltage lines evacuating power from where it is generated to where it is needed, with Nairobi being the main consumer of power while most generation takes place in remote places such Olkaria and Seven Forks.

In the even that one major power lines fails or a generator is knocked offline, the system adjusts to both to compensate for the changes and to protect the system. However, beyond a certain threshold, the whole system can be overwhelmed, and this time it did.

The line that failed was carrying a significant share of the total system loading, and it affected the whole system which had to shut down.  Getting everything back to work is not as easy as a switch flip. It takes time, and in this case some repairs.

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The story of two fish

Posted on 2 min read

Two fish were swimming when they saw a piece of meat dangling before them.

The younger fish darted toward it with an open mouth. The older fish cried out,

 

“Stop!”

“You can’t see it, but there is a hook inside that meat. It is connected by an invisible line to a pole outside the water. There is a man holding the pole.

THE TRUTH is, if you eat the meat, the hook will catch in your jaw and the man will pull you out of the water. He will cut you open with a knife, roast you on a fire and eat you. Then he will throw your remains to his cat.”


The young fish stopped. The two swam away. But when the young fish was alone, he thought to himself, 

“Let me investigate the truth myself how accurate these lousy claims are.”


He went back to the meat, swam around it, above and below it. He swam as far as he could in widening circles around the meat.

After a long search, he said to himself, 

“I’ve looked far and wide, and I haven’t found any sign of a man, a pole, a knife, a fire or a cat. In fact, I’ve found nothing outside this water we live in” I have come to realise my truth.

“These must just be stories made up to limit our freedoms.”


He went back to the meat and ate it.

The hook caught in his jaw, he felt himself being yanked out of the water.
For sure He saw a pole, a man and a knife, and a little further, he saw the man’s cat sleeping in a shade, but at that point his knowledge of the TRUTH was useless.



~Anonymous
 

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Parable of the Life-saving Station

Posted on 2 min read

On a dangerous seacoast where shipwrecks often occur, there was once a crude little life¬saving station. The building was just a hut, and there was only one boat, but the few devoted members kept a constant watch over the sea, and with no thought for themselves went out day and night tirelessly searching for those who were lost. Some of those who were saved and various others in the surrounding area wanted to become associated with the station and gave of their time, money, and effort to support its work. New boats were bought and new crews trained. The little lifesaving station grew.
Some of the members of the lifesaving station were unhappy that the building was so crude and poorly equipped. They felt that a more comfortable place should be provided as the first refuge of those saved from the sea. They replaced the emergency cots with beds and put better furniture in the enlarged building.
Now the lifesaving station became a popular gathering place for its members, and they decorated it beautifully because they used it as a sort of club. Fewer members were now interested in going to sea on life-saving missions, so they hired lifeboat crews to do this work. The lifesaving motif still prevailed in the club’s decorations, and there was a liturgical lifeboat in the room where the club’s initiations were held. About this time a large ship wrecked off the coast, and the hired crews brought in boatloads of cold, wet, and half-drowned people. They were dirty and sick. The beautiful new club was in chaos. So the property committee immediately had a shower house built outside the club where victims of shipwrecks could be cleaned up before coming inside.
At the next meeting, there was a split among the club membership. Most of the members wanted to stop the club’s lifesaving activities as being unpleasant and a hindrance to the normal social life of the club. Some members insisted upon life¬saving as their primary purpose and pointed out that they were still called a life¬saving station. But they were finally voted down and told that if they wanted to save the lives of all the various kinds of people who were shipwrecked in those waters, they could begin their own lifesaving station. So they did.
As the years went by, the new station experienced the same changes that had occurred in the old. It evolved into a club, and yet another lifesaving station was founded. History continued to repeat itself, and if you visit that seacoast today, you will find a number of exclusive clubs along that shore. Shipwrecks are frequent in those waters, but most of the people drown.
Dr. Theodore O. Wedel

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Is there life after birth?

Posted on 2 min read

Two twins were talking in the womb:
Tell me, do you believe in life after birth?
Of course. After birth comes life. Perhaps we are here to prepare for what comes after birth.
Forget it! After birth there is nothing! From there, no one has returned! And besides, what would it look like?
I do not know exactly, but I feel that there are lights everywhere … Perhaps we walk on our own feet, and eat with our mouth.
This is utterly stupid! Walking isn’t possible! And how can we eat with that ridiculous mouth? Can’t you see the umbilical cord? And for that matter, think about it for a second: postnatal life isn’t possible because the cord is too short.
Yes, but I think there is definitely something, just in a different way than what we call life.
You’re stupid. Birth is the end of life and that’s it.
Look, I do not know exactly what will happen, but Mother will help us…
The Mother? Do you believe in the Mother? !
Yes.
Do not be ridiculous! Have you seen the Mother anywhere? Has anyone seen her at all?
No, but she is all around us. We live within her. And certainly, it is thanks to her that we exist.
Well, now leave me alone with this stupidity, right? I’ll believe in Mother when I see her.
You can not see her, but if you’re quiet, you can hear her song, you can feel her love. If you’re quiet, you can feel her caress and you will feel her protective hands.

Written in Hungarian by Útmutató a Léleknek, translated by Miranda Linda Weisz.

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if Humans had Horns…

Posted on 3 min read

What if human beings had horns?

It sounds evil and weird, but I think by now it would be normal. We would be used to it until it sounds normal.

I would remember the beautiful horns my grandfather had. Maybe we would know people by the shape of their horns. Life would be quite different. We would outdo each other in beautifying our horns. Monks would be dehorned. Hats and caps would be perforated to give rooms for horns. Vehicles would be taller to accommodate horns. Roads would not have bumps, to prevent horn damage when matatus hit bumps at high speed.

Horn Business

There would be a multi-billion dollar industry dedicated to care of horns. Here are a few examples of a few shops you would find in a mall:

  • Horn-Cure: for the longest horns
  • The Nairobi Horn House: replacing broken horns
  • Horn-First: …if your horns have refused to grow
  • The Horns: for all your horn needs

Parliament would be a risky place to be elected to (for Hornarable Members). Occasionally, we would hear that a MCA was gored during a motion to impeach a governor.

Over every door post, there would be a clear warning written ‘Mind your horns’. In addition to dermatologists, we would have hornologists who we would pay a lot of money to have a horn-canal treatment, for painful horns.

Reindeers would be an endangered species, from horn poachers. Artificial horns would be a thriving business. Beds would be at least ten feet long. Diving would be prohibited in swimming pools, except for monks. Rugby players would be charged with first degree murder. The world would be hornited.

No longer would we depict the devil as a being with horns, but we would brand him with a very prominent tail, to distinguish him from humans.

Female Horns

Fashion trends would be a bit different. Some would consider long, straight horns to be a sign of beauty, while others would think the curved horns are the best. We would occasionally complain about the rising cost of horn polish whenever we visit the hornbill (not a bird, but a business name or a profession). Assuming that female horns would be smaller, or shorter/smoother/colourful than male horns, we would have a movement and a handful of NGOs trying to fight for the equality of horns. They would argue that all horns are equal, and children should be allowed to have their horns the way they want. Socialites would have horn surgery to ensure that their horns look exactly like elephant tusks, while instead of a Mohawk, we would have people donning one horn like a rhino (I won’t mention Sonko).

Luckily, Humans Don’t

Fortunately, we don’t have horns. Genesis tells me that it is because God did not create us with horns, while evolutionists claim that either horns fell off our heads according to the law of natural selection, or we did not develop them because they were not necessary (an insult to zebras). As far as I am concerned, God created me without horns.

What if human beings had tails?    

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