Why do power grids fail?

Just as we write this article, the country is slowly reeling back from nearly a five-hours long blackout caused by a national power grid failure. Many parts of Dhaka, Sylhet and Chittagong were completely out of electricity since 2 PM local time and concerned officials from the Bangladesh Power Development Board (BPDB) and the Power Grid Company of Bangladesh (PGCB) claimed that the transmission line malfunctioned somewhere in the country's eastern region, causing the power plants to "trip" one after another. 

What, now, is a "trip"? Why do "trips' happen and how does a power grid fail? There can be many reasons and unfortunately, we are yet to get a clarification from the authorities. Nonetheless, we try to take a look at the many ways a power grid can fail.

What is a trip and why do blackouts happen

What happens in an electricity grid, is that to meet the grid's fluctuating power needs, hundreds of power plants must produce electricity. 

In unfortunate cases, other units must step in to fill in the gaps left by failing generators, high-voltage transmission lines, or power plants. This typically does not cause issues. However, when there is a high demand for electricity, a few isolated grid failures can set off a chain reaction that leaves millions of people without power.

When the load is dangerously high, parts of the power grid can "trip" and shut off, just like a circuit breaker. As a result, the load is transferred to other areas of the grid network, which may then shut down as a chain reaction, resulting in a blackout.

As for the reasons why plants may fail, one of the many reasons why a power plant may fail is due to bad weather. But bad weather can be probably ruled out since the weather was a decent breezy one today. Other reasons include distribution failures, transmission failures, and supply shortages. 

Distribution failures

The most frequent kind of power outage, distribution failures typically only affect a small area. This kind of failure can be caused by a variety of factors, including natural, man-made, and unfortunate accidents like a car crashing into an electric pole. Distribution system outages typically only affect a small number of neighbourhoods. However, these outages can occasionally, and for extended periods of time, affect whole cities.

Transmission failures

Although transmission failures are much less common than distribution failures, they can still have very serious repercussions. Weather is a major factor in many transmission system failures, but other factors like equipment failure, computer issues, and human error can also result in this kind of outage. Again, transmission-related outages are comparatively infrequent. However, due to the fact that transmission systems are frequently interconnected across numerous states and even countries, transmission system failures can cause significant power outages if they are not properly managed.

Supply shortages

When there is simply not enough electricity to meet demand, these outages take place due to supply shortages. Due to rising import costs, the government recently suspended all diesel-powered power plant operations. The diesel-powered plants generated about 6% of Bangladesh's total electricity, so their closures reduced output by as much as 1500 megawatts.