Disaster (from Greek, meaning "bad star") is a natural or man-made event,which brings sudden great misfortune and disruption in normal life including that of the power supply. It negatively affects life, property, livelihood or industry often resulting in permanent changes to human societies, ecosystemsand environment. Disasters manifest as hazards exacerbating vulnerable conditions and exceeding individuals' and communities' means to survive and thrive. We begin by understanding the impact of various types of disasters on power systems.
Types of Disasters
Disasters in the power sector can occur due to natural calamities as well as human acts. These include:
earthquakes;
floods;
storms;
cyclones;
droughts;
terrorist threats/attack and sabotage;
bomb threats and bomb explosions;
strikes;
major equipment failure.
Types of Disasters
Disasters in the power sector can occur due to natural calamities as well as human acts. These include:
earthquakes;
floods;
storms;
cyclones;
droughts;
terrorist threats/attack and sabotage;
bomb threats and bomb explosions;
strikes;
major equipment failure.
Floods along with cyclones are climate-related natural disasters, on which we have but little control. We can only try to manage them and reduce their severity only to a certain extent. Landslides / avalanches mainly occur due to geo-technical instability aggravated by lubricating and infiltrating water. The impact of these disasters and their multiplier effects on economies, national development and severity of affected infrastructures need to be adequately quantified to provide financial justification for undertaking relief measures.Events like earthquakes, floods, hurricanes, cyclones etc. have been studied statistically and scientifically and their occurrence and intensities can be predicted with a certain degree of confidence. However, there is no certainty that these events would not exceed the predicted values based on past history and cause disaster. But, if various equipment and systems of power ngenerating plant and transmission system are designed after site-specific studies, taking into account stipulations of the various codes / standards on the subjects, damage to plants and equipment can be greatly minimized.
We now discuss each of these types of disaster and their impact on the power system. In this section, we focus on natural calamities. We also highlight the pre-disaster preparedness and post-disaster activities that should be undertaken by power utilities for managing disasters.
Earthquakes
Earthquakes are one of the most dangerous and destructive forms of natural hazards. THEY STRIKE SUDDENLY WITH LITTLE WARNING. They may
occur at any time of day or on any day of the year.
Impact of Earthquakes
Earthquakes can devastate an entire city or a region of hundreds of square kilometres. A large earthquake gives rise to a series of violent motions in the ground, which set in motion the structures (e.g., buildings, roads, towers, bridges, transmission lines, etc.) on the earth’s surface. Each type of structure responds differently, depending on the type of materials it is made up of. Buildings collapse like packs of cards. They get reduced to piles of rubble in seconds, killing and injuring their inhabitants.Since the power distribution network spreads over the entire area with conductors running on metallic structures, it is most prone to the effects of the earthquake. Moreover, sensitive equipment gets activated when shaken by an earthquake and immediately interrupts power supply from the power grid. Fire is another concern immediately following an earthquake because of severed electrical lines.
We now discuss each of these types of disaster and their impact on the power system. In this section, we focus on natural calamities. We also highlight the pre-disaster preparedness and post-disaster activities that should be undertaken by power utilities for managing disasters.
Earthquakes
Earthquakes are one of the most dangerous and destructive forms of natural hazards. THEY STRIKE SUDDENLY WITH LITTLE WARNING. They may
occur at any time of day or on any day of the year.
Impact of Earthquakes
Earthquakes can devastate an entire city or a region of hundreds of square kilometres. A large earthquake gives rise to a series of violent motions in the ground, which set in motion the structures (e.g., buildings, roads, towers, bridges, transmission lines, etc.) on the earth’s surface. Each type of structure responds differently, depending on the type of materials it is made up of. Buildings collapse like packs of cards. They get reduced to piles of rubble in seconds, killing and injuring their inhabitants.Since the power distribution network spreads over the entire area with conductors running on metallic structures, it is most prone to the effects of the earthquake. Moreover, sensitive equipment gets activated when shaken by an earthquake and immediately interrupts power supply from the power grid. Fire is another concern immediately following an earthquake because of severed electrical lines.
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| Impact of Earthquakes |
Cyclones
Cyclones are among the most awesome events that nature can produce, and pose a major threat to lives and property in many parts of the world. A cyclone’s destructive work is done by the high wind, flood-producing rains, and associated storm surges. The cyclonic storm dominates the ocean surface and lower atmosphere over tens of thousands of square kilometres.Devastating floods from extremely heavy rainfall often accompany tropical cyclones.
Impact of Cyclones
Cyclones can lead to tremendous loss of life, property and infrastructure,particularly, in the vulnerable human settlements. Their vulnerability is determined by the exposure to the storms, the degree to which the houses and other structures can be damaged, and the likelihood that secondary effects could occur. Safety is also compromised by the damage to or destruction of public installations and facilities, such as water and electrical plants, hospitals, and police stations. The impact of cyclones on the power utility is immediate interruption of supply from the power grid due to network disruption by cyclonic winds. Fire is another concern immediately following a cyclone because of severed electrical lines.
Cyclones are among the most awesome events that nature can produce, and pose a major threat to lives and property in many parts of the world. A cyclone’s destructive work is done by the high wind, flood-producing rains, and associated storm surges. The cyclonic storm dominates the ocean surface and lower atmosphere over tens of thousands of square kilometres.Devastating floods from extremely heavy rainfall often accompany tropical cyclones.
Impact of Cyclones
Cyclones can lead to tremendous loss of life, property and infrastructure,particularly, in the vulnerable human settlements. Their vulnerability is determined by the exposure to the storms, the degree to which the houses and other structures can be damaged, and the likelihood that secondary effects could occur. Safety is also compromised by the damage to or destruction of public installations and facilities, such as water and electrical plants, hospitals, and police stations. The impact of cyclones on the power utility is immediate interruption of supply from the power grid due to network disruption by cyclonic winds. Fire is another concern immediately following a cyclone because of severed electrical lines.
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| Cyclones are devastating |
Floods
Floods caused by overflowing rivers result from heavy rains or from the melting of winter snow, or from both. Floods in rivers differ from flash floods in their extent and duration. Flash floods are of short duration in small streams,while floods in rivers take place in river systems whose tributaries may drain large geographic areas and encompass many independent river basins.Floods on large river systems may continue for periods ranging from a few hours to many days. Flood flows in large river systems are influenced primarily by variations in the intensity, amount, and distribution of precipitation. Thecondition of the ground − amount of soil moisture, seasonal variations in vegetation, depth of snow cover, and imperviousness due to urbanization − directly affects runoff. Silting, soil conditions, absorption capacity of the watershed, and the capacity of streams to carry runoff have an effect on the extent of the flooding.
Impact of Floods
Floods are natural hazards that are not, in and of themselves, disasters, but they can transform a vulnerable situation into a disaster. The vulnerability of a human settlement is determined by its exposure to flooding. The primary effects are power failure, electrocution and short circuit due to water logging iflooded areas as well as around the substation grids. In Table, we summarise the impact of natural calamities on power utilities.
Floods caused by overflowing rivers result from heavy rains or from the melting of winter snow, or from both. Floods in rivers differ from flash floods in their extent and duration. Flash floods are of short duration in small streams,while floods in rivers take place in river systems whose tributaries may drain large geographic areas and encompass many independent river basins.Floods on large river systems may continue for periods ranging from a few hours to many days. Flood flows in large river systems are influenced primarily by variations in the intensity, amount, and distribution of precipitation. Thecondition of the ground − amount of soil moisture, seasonal variations in vegetation, depth of snow cover, and imperviousness due to urbanization − directly affects runoff. Silting, soil conditions, absorption capacity of the watershed, and the capacity of streams to carry runoff have an effect on the extent of the flooding.
Impact of Floods
Floods are natural hazards that are not, in and of themselves, disasters, but they can transform a vulnerable situation into a disaster. The vulnerability of a human settlement is determined by its exposure to flooding. The primary effects are power failure, electrocution and short circuit due to water logging iflooded areas as well as around the substation grids. In Table, we summarise the impact of natural calamities on power utilities.
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| Impact of Natural Calamities on Power Distribution Utilities and Their Roles Calamity |
Disaster Preparedness Measures
A trigger mechanism must be established by the utility to initiate the action for mitigation of disaster, as soon as information is received about any calamity which is likely to occur or has occurred. An illustrative check list of who has to do what should be prepared by each organisation for each of its sections, in case of emergency. The rescue operation for any disaster has to start right from the warning received from the Intelligence, meteorological organisations or any other State / Central agency. The rescue operation should concentrate on life safety as the prime objective followed by attending to the injured and stopping the disaster from spreading further.Utilities should undertake the following general disaster preparedness measures:
• developing a disaster preparedness plan to sequence the activities and responsibilities of each department;
• training for first aid and trauma and maintaining stocks of medical supplies;
• establishing emergency communication systems as well as messages to the public regarding matters of health, safety, and security.
• reviewing the location of critical facilities such as hospitals, important buildings, communications installations, and other structures;
• formation of teams for search and rescue operations and teams for disaster assessment; and
• preparing plans and equipment for alternative electric supply as necessary.
The role of the utilities also includes creating public awareness, preparedness planning, economic mitigation, search and rescue activities, establishing the distribution network of relief, disaster assessment, structural surveys and bringing the power distribution to normal service level.The focus should be on education and planning of the utility personnel. Conducting Public Awareness Programmes on a regular basis is equally important. The people living in the surroundings can play a vital role in the event of a disaster. Utilities should make the general public aware about potential hazards likely to occur in project area. Emphasis may be laid on the following aspects:
• Fixing permanent notice boards at all suitable places in the area displaying information related to assisting agencies, important telephone numbers,etc.
• Taking help from local youth organisations, voluntary organisations, educational institutions for spreading awareness about the safely measures and rescue operations in the event of a disaster.In addition, some specific measures need to be taken for earthquakes, cyclones and floods. These are described below.
Earthquake-preparedness activities:
• Identification of safe sites where people living in areas threatened by landslides in secondary tremors could be relocated.
• Reviewing and upgrading the structural soundness of facilities that are essential for the operation of disaster response, such as grids, buildings,communications installations, etc.
•Preparing plans for clearing streets on a priority basis to provide emergency access.
Additional activities for cyclone and flood-preparedness:
• Developing early warning and evacuation procedures for people under threat.
• Dewatering pump and barrier walls in cable trenches to prevent the water from entering the substation.
We now present the post-disaster activities to be undertaken if any of these natural calamities occur in an area.
Post-disaster Activities
A number of lessons for post-disaster activities have been learnt from experience. The response should include activities outlined in the preparedness stage, but the initial emphasis during the post-disaster period should be on search and rescue of victims, providing emergency medical assistance and relief to survivors. An exercise has to be commenced in parallel to conduct damage and needs assessment and respond to the crisis.The various activities in response to a disaster should include:
• evacuation of affected people from the area;
• provision of temporary lodging in case staff is left in office;
• provision of short-term basic life amenities such as food and water to the disaster-affected people and the stranded office staff;
• exchange of information in terms of event description, its severity and action plan;
• field/site surveys, damage assessment;
• identification of resources needed and their deployment viz., technical experts, human resources, equipment, spare parts and other materials;
• early restoration of power supply;
• re-establishing communications to quickly get information to the public about what they should do and where they can go for services;
• making contact with remote areas;
• providing construction related materials for reconstruction of damaged infrastructure;
• repair and reconstruction of “lifelines” − electrical services;
• technical, material, and financial assistance for the repair and reconstruction of offices and systems;
• financial assistance to emergency operation teams to enable their participation in recovery efforts; and
• post event investigation and analysis and strategy for the future.
Specific post-disaster and emergency activities after cyclones and floods are:
• dewatering;
• water purification; and
• epidemiological (which relates to the origin, nature, pathology and prevention of epidemic diseases) surveillance.
In the next section, we discuss the disasters stemming from human actions.But before studying further, you may like to consolidate the information presented so far.
A trigger mechanism must be established by the utility to initiate the action for mitigation of disaster, as soon as information is received about any calamity which is likely to occur or has occurred. An illustrative check list of who has to do what should be prepared by each organisation for each of its sections, in case of emergency. The rescue operation for any disaster has to start right from the warning received from the Intelligence, meteorological organisations or any other State / Central agency. The rescue operation should concentrate on life safety as the prime objective followed by attending to the injured and stopping the disaster from spreading further.Utilities should undertake the following general disaster preparedness measures:
• developing a disaster preparedness plan to sequence the activities and responsibilities of each department;
• training for first aid and trauma and maintaining stocks of medical supplies;
• establishing emergency communication systems as well as messages to the public regarding matters of health, safety, and security.
• reviewing the location of critical facilities such as hospitals, important buildings, communications installations, and other structures;
• formation of teams for search and rescue operations and teams for disaster assessment; and
• preparing plans and equipment for alternative electric supply as necessary.
The role of the utilities also includes creating public awareness, preparedness planning, economic mitigation, search and rescue activities, establishing the distribution network of relief, disaster assessment, structural surveys and bringing the power distribution to normal service level.The focus should be on education and planning of the utility personnel. Conducting Public Awareness Programmes on a regular basis is equally important. The people living in the surroundings can play a vital role in the event of a disaster. Utilities should make the general public aware about potential hazards likely to occur in project area. Emphasis may be laid on the following aspects:
• Fixing permanent notice boards at all suitable places in the area displaying information related to assisting agencies, important telephone numbers,etc.
• Taking help from local youth organisations, voluntary organisations, educational institutions for spreading awareness about the safely measures and rescue operations in the event of a disaster.In addition, some specific measures need to be taken for earthquakes, cyclones and floods. These are described below.
Earthquake-preparedness activities:
• Identification of safe sites where people living in areas threatened by landslides in secondary tremors could be relocated.
• Reviewing and upgrading the structural soundness of facilities that are essential for the operation of disaster response, such as grids, buildings,communications installations, etc.
•Preparing plans for clearing streets on a priority basis to provide emergency access.
Additional activities for cyclone and flood-preparedness:
• Developing early warning and evacuation procedures for people under threat.
• Dewatering pump and barrier walls in cable trenches to prevent the water from entering the substation.
We now present the post-disaster activities to be undertaken if any of these natural calamities occur in an area.
Post-disaster Activities
A number of lessons for post-disaster activities have been learnt from experience. The response should include activities outlined in the preparedness stage, but the initial emphasis during the post-disaster period should be on search and rescue of victims, providing emergency medical assistance and relief to survivors. An exercise has to be commenced in parallel to conduct damage and needs assessment and respond to the crisis.The various activities in response to a disaster should include:
• evacuation of affected people from the area;
• provision of temporary lodging in case staff is left in office;
• provision of short-term basic life amenities such as food and water to the disaster-affected people and the stranded office staff;
• exchange of information in terms of event description, its severity and action plan;
• field/site surveys, damage assessment;
• identification of resources needed and their deployment viz., technical experts, human resources, equipment, spare parts and other materials;
• early restoration of power supply;
• re-establishing communications to quickly get information to the public about what they should do and where they can go for services;
• making contact with remote areas;
• providing construction related materials for reconstruction of damaged infrastructure;
• repair and reconstruction of “lifelines” − electrical services;
• technical, material, and financial assistance for the repair and reconstruction of offices and systems;
• financial assistance to emergency operation teams to enable their participation in recovery efforts; and
• post event investigation and analysis and strategy for the future.
Specific post-disaster and emergency activities after cyclones and floods are:
• dewatering;
• water purification; and
• epidemiological (which relates to the origin, nature, pathology and prevention of epidemic diseases) surveillance.
In the next section, we discuss the disasters stemming from human actions.But before studying further, you may like to consolidate the information presented so far.
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