IEEE 1264:2015 pdf free download – IEEE Guide for Animal Deterrents for Electric Power Supply Substations
4.2 Problems
There are various reasons why animals enter substations. For example, cats enter substations forwarmth,woodpeckers create holes for shelter and to store food, and birds build nests on equipmentand structures，Raccoons and snakes try to reach bird nests for young birds and eggs. Squirrels,especially during weaning cycles,migrate through unfamiliar territory. Predators, such as foxes, entera substation looking for rodents and other nocturnal animals that make homes in vaults, equipment, andstructures.
Animals in substations cause a variety of problems， such as faults, which can result in power outages,reduced equipment life, or severely damaged equipment.They may even pose a variety of safety andhealth hazards due to animal waste, and safety to personnel who come upon the animal unexpectedly.
Squirrels，raccoons，snakes， and other creatures that climb fences，structures and equipment mayeventually come into contact with energized parts of equipment or conductors, thus causing outages anddamage.Rodents chewing through power and control cable insulation can also cause outages and damage.
Birds build nests in substation structures and equipment, sometimes using conductive material such aswire or magnetic tape that can fall or be carried into contact with insulators or bushings. Some birds havewing spans that can bridge phase-to-phase distance and cause an outage.Bird droppings can also be a majorproblem. Being communal, many congregate in a relatively small area. Their droppings accumulate onelectric hardware quickly, causing insulator or bushing flashovers and possible equipment damage.
4.2.1 Outages
Animal-related outages run the gamut from momentary disturbances to long-term outages.Majorportions of substations can be tripped off line, including transmission circuits.
ln addition to the inconvenience caused by an outage and the cost of repair,revenue could be lost untilservice has been restored.Outages，sustained or momentary，reduce the long-term confidence of allcustomers and could be a critical factor for commercial and industrial customers. These problems canbecome serious if they are recurring in a particular substation or class of substations.
The majority of animal-related faults start as phase-to-ground faults, which may become phase-to-phase faults.Due to reduced clearances, these faults typically occur at 15 kV and below, but can also occur at highervoltages.
4.2.2 Equipment damage
The equipment susceptible to animal-related damage includes power transformers, capacitors, breakers,reclosers, surge arresters，voltage and current transformers, regulators, switchgear, potheads, switches,bushings, insulators, and bus conductors.
Flashovers cause costly damage, which in many cases is so severe that equipment or components must bereplaced. The equipment most commonly damaged by animal intrusions are bushings and bus insulators.Damage to bus insulators usually requires replacement of the insulators.Damage can includc burmnedglazing,tracking,chipping, and even total fracture. Besides the direct damage to the insulators, the fault cancause stress in other equipment such as transformers, breakers, etc., which reduces the life of the equipmentand somctimes results in complcte cquipment failure.
4.2.3 Safety/health hazards
Animals in substations can be safety hazards for operations and maintenance personnel.Althoughdirect cncounter between personnel and the animals that invade substations is unlikely，anyconfrontation can be hazardous. Additionally，animals can cause health hazards，particularly due toaccumulations of animal wastes.
Safety is a concern when personnel confront live animals.Snakes that climb onto equipment and structuresmay not be seen until a person is close. Bees or other insects that nest in the substation may attack, as may thoseanimals that have been cornered in vaults, troughs, or any other cnclosure.
Odorous emissions from animals，such as skunks can be quite unpleasant.Animal wastes can causeunsanitary conditions for workers. Bird droppings are the most common problem, especially where largeflocks of pigeons, ravens, starlings, etc., have roosted within a substation.