Causes of power system failure

Top 6 Causes for power system failures

1- Underground cables

Electrochemical treeing of underground power cables is one of the alarming causes for the downscaling of power system reliability.
Treeing is a process in which the dielectric strength of an insulating material perishes as a result of moisture penetration while the electric field is still in operation.Once the dielectric strength of the insulating material weakens considerably, a lightning strike or even a switching can destroy the insulation.

 

Solution for this is one can considerably reduce electrochemical treeing by installing surge protection devices on the electric poles, which are capable of transitioning voltage transients into the ground. Alternatively, one can also purchase cables that are treeing resistant.

2-Transformer breakdowns

Transformers are one of the most important components of a distributed power system and can pose a lot of complicacies if they breakdown. Though voltage transients and faults can impose a lot of stress on the transformers and its windings, overloading the transformer seldom leads to a breakdown. However, they can considerably weaken the thermal insulation and accelerate the ageing process of a transformer.

Different types of transformer faults

3- Lightning

When air’s dielectric strength is exceeded by the voltage produced between the clouds and earth, lightning strikes occur. The strikes thus generated carry a mammoth 30,000 Amperes of current which can virtually destroy almost any kind of power system.

In addition to this, during the lightning strikes, multiple electric discharges of varying magnitudes are induced into the power system, which can make matters even worse. This is why; the lightning strikes are of a major concern to the power utilities that operate in high altitude areas and mountains.

4-Tree contact

Trees that grow very near to the electric poles can pose a lot of threats. They can fall on vital electrical erections during heavy storms, drop branches on conductors, couple two conductors together and can also provide access to various animals that can cause disturbances to the power supply.

This is the reason why most power distribution companies invest a lot of time and money in trimming dangerous trees as a part of preventive maintenance.

5-Birds and squirrels snakes

Birds

Most of the animal faults on the transmission lines and substations that are air-insulated are caused due to birds. Nesting birds tend to build nests on the transmission towers and the materials they use to build their nests can induce fault currents, moreover, birds excretion may limit the performance of insulators

Squirrels

Squirrels can cause major upsets as far as the reliability of a power system is concerned. These upsets are even more in woods and places where there are a lot trees.

Squirrels are known not only for leaping on to the electric poles, but chewing on the transmission lines, forming a bridge between the phase conductors and earth.

Snakes

Snakes can also cause major upsets in substations as well as underground cables. This is because they squeeze their way out through tight spaces and can climb most structures with ease. They climb on to the poles in search of food like birds and mice.

The real concern about these snakes is their length. They can easily bridge two conductors leading to short-circuits and subsequently, power failures.

6-Insects

Fire ants can also be responsible for some serious power outages. They build their homes in critical places such as pad mount equipment. The materials used to build their nests can degrade the dielectric strength of an insulating system by eating away the insulating material

It can be a challenge for the power utility personnel to locate and destroy these nests, before the actual damage is done.

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