question: why does stormy weather affect power/internet for only a couple of moments instead of completely cutting it?
comment: Most modern power grids have backups, redundancies, and protections to prevent the total loss of power. As long as a power line isn't knocked out completely, or the power station or transformers don't blow, any interruption in power cause by a nearby lightning strike or a shaky pole.will be temporary.
passages: Besides the transformers being vulnerable to the effects of a geomagnetic storm, electricity companies can also be affected indirectly by the geomagnetic storm. For instance, internet service providers may go down during geomagnetic storms (and/or remain non-operational long after). Electricity companies may have equipment requiring a working internet connection to function, so during the period the internet service provider is down, the electricity too may not be distributed.
   By receiving geomagnetic storm alerts and warnings (e.g. by the Space Weather prediction Center; via Space Weather satellites as SOHO or ACE), power companies can minimize damage to power transmission equipment, by momentarily disconnecting transformers or by inducing temporary blackouts. Preventative measures also exist, including preventing the inflow of GICs into the grid through the neutral-to-ground connection.
  
  Section::::Geomagnetic storm effects.:Communications.
   Most small generator connections require a mechanical disconnect switch, so at a minimum the utility could send a repairman to pull them all. For very large sources, one might simply install a dedicated telephone hotline that can be used to have an operator manually shut down the generator. In either case, the reaction time is likely to be on the order of minutes, or hours.
  
  Section::::Islanding detection methods.:Utility-based methods.:Automated disconnection.
   One way natural disasters impact internet connection is by damaging end sub-networks (subnets), making them unreachable. A study on local networks after Hurricane Katrina found that 26% of subnets within the storm coverage were unreachable. At Hurricane Katrina's peak intensity, almost 35% of networks in Mississippi were without power, while around 14% of Louisiana's networks were disrupted. Of those unreachable subnets, 73% were disrupted for four weeks or longer and 57% were at “network edges where important emergency organizations such as hospitals and government agencies are mostly located”. Extensive infrastructure damage and inaccessible areas were two explanations for the long delay in returning service. The company Cisco has revealed a Network Emergency Response Vehicle (NERV), a truck that makes portable communications possible for emergency responders despite traditional networks being disrupted.
   Section::::Ride through systems.
  
  Modern large-scale wind turbines, typically 1 MW and larger, are normally required to include systems that allow them to operate through such an event, and thereby “ride through” the voltage dip. Similar requirements are now becoming common on large solar power installations that likewise might cause instability in the event of a widespread disconnection of generating units. Depending on the application the device may, during and after the dip, be required to:
  
  BULLET::::- disconnect and stay disconnected until manually ordered to reconnect
  
  BULLET::::- disconnect temporarily from the grid, but reconnect and continue operation after the dip
   During the Boxing Day Storm of 1998 the reactors at Hunterston B nuclear power station were shut down when power was lost, possibly due to arcing at pylons caused by salt spray from the sea. When the grid connection was restored, the generators that had powered the station during the blackout were shut down and left on "manual start", so when the power failed again the station was powered by batteries for a short time of around 30 minutes, until the diesel generators were started manually. During this period the reactors were left without forced cooling, in a similar fashion to the Fukushima Daiichi nuclear disaster, but the event at Hunterston was rated as International Nuclear Event Scale 2.
   The first issue has been widely dismissed by many in the power industry. Line workers are already constantly exposed to unexpectedly live wires in the course of normal events (i.e. is a house blacked out because it has no power, or because they pulled the main breaker inside?). Normal operating procedures under hot-line rules or dead-line rules require line workers to test for power as a matter of course, and it has been calculated that active islands would add a negligible risk. However, other emergency workers may not have time to do a line check, and these issues have been extensively explored using risk-analysis tools. A UK-based study concluded that "The risk of electric shock associated with islanding of PV systems under worst-case PV penetration scenarios to both network operators and customers is typically 10 per year."
   When magnetic fields move about in the vicinity of a conductor such as a wire, a geomagnetically induced current is produced in the conductor. This happens on a grand scale during geomagnetic storms (the same mechanism also influenced telephone and telegraph lines before fiber optics, see above) on all long transmission lines. Long transmission lines (many kilometers in length) are thus subject to damage by this effect. Notably, this chiefly includes operators in China, North America, and Australia, especially in modern high-voltage, low-resistance lines. The European grid consists mainly of shorter transmission circuits, which are less vulnerable to damage.
   It has been suggested that a geomagnetic storm on the scale of the solar storm of 1859 today would cause billions or even trillions of dollars of damage to satellites, power grids and radio communications, and could cause electrical blackouts on a massive scale that might not be repaired for weeks, months, or even years. Such sudden electrical blackouts may threaten food production.
  
  Section::::Geomagnetic storm effects.:Mains electricity grid.
   Telegraph lines in the past were affected by geomagnetic storms. Telegraphs used a single long wire for the data line, stretching for many miles, using the ground as the return wire and fed with DC power from a battery; this made them (together with the power lines mentioned below) susceptible to being influenced by the fluctuations caused by the ring current. The voltage/current induced by the geomagnetic storm could have diminished the signal, when subtracted from the battery polarity, or to overly strong and spurious signals when added to it; some operators learned to disconnect the battery and rely on the induced current as their power source. In extreme cases the induced current was so high the coils at the receiving side burst in flames, or the operators received electric shocks. Geomagnetic storms affect also long-haul telephone lines, including undersea cables unless they are fiber optic.
   Section::::2010–2019.:2013.
  
  Over the weekend of January 26 – February 5 ex-Tropical Cyclone Oswald caused the loss of power to over 250,000 customers in South East Queensland, Australia. Power was gradually restored over about 10 days.
  
  On February 8–9, some 650,000 homes and businesses in the northeastern US lost power as the result of a powerful nor'easter that brought hurricane-force wind gusts and more than two feet of snow to New England.
  
  On March 22, 2013, 200,000 homes in the Greater Belfast area lost power as the result of a fault with the high-voltage transmission network during a snow storm.
   Magnetic storm activity can induce geoelectric fields in the Earth's conducting lithosphere. Corresponding voltage differentials can find their way into electric power grids through ground connections, driving uncontrolled electric currents that interfere with grid operation, damage transformers, trip protective relays and sometimes cause blackouts. This complicated chain of causes and effects was demonstrated during the magnetic storm of March 1989, which caused the complete collapse of the Hydro-Québec electric-power grid in Canada, temporarily leaving nine million people without electricity. The possible occurrence of an even more intense storm led to operational standards intended to mitigate induction-hazard risks, while reinsurance companies commissioned revised risk assessments.
   The weather had resulted in localised power outages throughout the day and by around 3:50 p.m. local time, almost the entire state power grid had been cut out. Early indications were that as the transmission lines in the Mid North failed due to damaged pylons, the automatic safety features in the network isolated the generators to protect both the generation facilities and the end consumers' equipment. Over a short period, this resulted in most of the state's distribution network being powered down as the transmission network acted to protect the infrastructure.
   On 27 May 2007, the main cable television headend that distributes the TV signals for Malé fell down. The 100-foot antenna had snapped 10 feet from the top due to violent weather conditions that day. service to the neighboring islands were halted for some time due to this incident. The company was able to fix the antenna for use in Malé within 6 hours.
   Due to the extensive nature of the damage, temporary transmission towers were sent by Western Power; these towers can reach a height of 58 metres and take only one day to erect. It is expected that the towers will remain in use for 6 to 12 months while the permanent repairs are made.
  
  Section::::Consequences.
   By the morning of Friday 30 September 2016, about 10,000 properties had not yet had power restored since the blackout on Wednesday afternoon, and 18,000 more had lost power due to distribution network faults caused by continued stormy weather. An additional transmission line fault near Tumby Bay was only detected as ElectraNet tried to power up the system, and this fault prevented the power generator in Port Lincoln from being used to power the lower Eyre Peninsula.
   On April 27, one of the United States' most devastating tornado outbreaks disrupted power to most of northern Alabama; some 311 high-tension electrical transmission towers were destroyed by multiple, violent tornadoes.
  
  On June 30, Chennai suffered a major power outage that affected many parts of the city for more than 15 hours.
  
  Starting on July 11, Cyprus suffered a half-week power outage, affecting all cities on the Greek part of the island. The outage was caused by an explosion next to the Vassilikos power plant, shutting down the plant.
   On February 2, in Texas, forced outages at two major coal-fired power plants and high electricity demand due to cold weather caused rolling blackouts affecting more than one million customers.
  
  On February 3, Cyclone Yasi hit communities in North Queensland, Australia. The cyclone winds reached 300 km/h (186mp/h) and caused widespread damage through many communities. 170,000 homes lost electricity.
   Disruption of the gas supply during Cyclone Dagmar in 2011 left Royal Dutch Shell's Ormen Lange gas processing plant in Norway inoperable after its electricity was cut off by the storm. This left gas supplies in the United Kingdom vulnerable as this facility can supply up to 20 percent of the United Kingdom's needs via the Langeled pipeline. However, the disruption came at a time of low demand. The same storm also saw the Leningrad Nuclear Power Plant also affected, as algae and mud stirred up by the storm were sucked into the cooling system, resulting in one of the generators being shut down. A similar situation was reported in the wake of Storm Angus in 2016 (though not linked specifically to the storm) when reactor 1 at Torness Nuclear Power Station in Scotland was taken offline after a sea water intake tripped due to excess seaweed around the inlet. Also following Storm Angus the UK's National Grid launched an investigation into whether a ship's anchor damaged four of the eight cables of the Cross Channel high voltage interconnector, which would leave it only able to operate at half of its capacity until February 2017.
   Planned outages of the link are required occasionally to carry out maintenance that is not possible while the system is live. Maintenance outages are planned well in advance to minimise the effects – they are usually carried out in summer when national electricity demand is at its lowest, and on only one pole at a time, with the other pole remaining in operation providing half of the full two-pole capacity, using the earth electrodes providing a path for return current through the ground.
  
  Notable faults and outages on the HVDC Inter-Island link:
   In order to prevent damage, each station along the network is protected with circuit breakers or fuses which will turn off power in the event of a short circuit. This presents a major problem when dealing with transient events. For instance, a tree limb blown off a tree during a windstorm that lands on the power line may cause a short circuit that could cause damage. However, the fault could quickly clear itself as the limb falls to the ground. If the only protection system is provided by breakers at distribution substations, large areas of the distribution network could be blacked out while repair crews reset the breakers. Reclosers are programmed to automate the reset process and allow a more granular approach to service restoration. The result is increased availability of supply.
   A second way natural disasters destroy internet connectivity is by severing submarine cables—fiber-optic cables placed on the ocean floor that provide international internet connection. A sequence of undersea earthquakes cut six out of seven international cables connected to that country and caused a tsunami that wiped out one of its cable and landing stations. The impact slowed or disabled internet connection for five days within the Asia-Pacific region as well as between the region and the United States and Europe.
   Section::::2010–2019.
  
  Section::::2010–2019.:2010.
  
  On January 30, two separate transmission lines were hit by lightning, blacking-out the Australian city of Darwin and the nearby cities of Katherine and Palmerston starting at about 6:00 am. Power was restored to all areas by 4:30 pm.
   Section::::Restoring power after a wide-area outage.
   There are large opportunities owing to technology miniaturization (accelerometers, digital signal processing for embedded data treatment, telecommunications, etc.) and new developments in weather forecasts (which are nowadays much more accurate and require less computational power than only a few years ago), including for these last, up to 72 hours ahead. Availability of this equipment and data for a reasonable cost helps to develop new sensors and systems which may be implemented into the EMS (energy management system) of national or local dispatching. These dynamic line rating sensors may sometimes warranty up to 30% more power transit in the monitored lines, depending on wind speed which is actually and locally evaluated by appropriate sensors using intelligent data processing.
  
raw_presuppositions: Power and internet do not go down anymore.
raw_corrections: Power and internet can still go down, but power grids have backups.