Weather forecast for September in Greece

A strong explosion occurred in the Kumondulu high-voltage substation in Asperopigos, a suburb of Athens, causing a fire. There was a power outage in Athens and its surrounding areas, affecting nearly one million residents.

Some nearby residents said:? At that time, we heard a loud noise and went out to have a look. We found that the substation had been swallowed up by flames and the explosion was loud. We are also afraid, because we don't know what happened. But the firemen arrived at the scene soon. ? Greek police and fire department estimate that the explosion and fire may be caused by short circuit of transformer in substation. The substation belongs to Greek independent transmission operation company. According to the announcement issued by the company, after the fire broke out in Kumondulu substation, the staff intervened in time, so the transmission systems in Attica and Peloponnesus quickly returned to normal. More specifically, Attica's power supply network was restored within 40 minutes, and the Peloponnesian power supply network was re-operated within 55 minutes.

Since then, the fire has been controlled. This time, * * * dispatched 25 firefighters and 10 fire engines to participate in the fire fighting, and two other special fire engines also went to the surrounding area for support. In addition, the Greek Ministry of Civil Defence dispatched four water tank fire engines at the first time to assist the Greek police and the national emergency center. However, due to the power failure in Athens and the surrounding Attica, there were 18 elevator shutdown accidents in Kalidia, Ani, Cesari, Kelamikos, Rona, Petra, Gaglio, Cretisini and Cori Dallos, and the fire brigade also launched rescue.

The Greek special disaster management department then went to the scene to determine whether the clouds generated after the explosion were toxic. At present, there are still firefighting forces on standby at the scene to prevent re-ignition. The Greek weather forecast also issued a notice about the toxicity of clouds, warning citizens (especially those with heart and lung diseases) to close windows to avoid breathing difficulties.

Knicks, Deputy Minister of Civil Protection of Greece? Hadarias ordered the Greek police and fire brigade to form a joint team to investigate the specific cause of the substation fire. Costis, Minister of Environment and Energy? President and CEO of Hadjidakis, Manos, an independent transmission operation company in Greece? Manu Sachis went to the scene. After the explosion, the alarm mechanism was also activated in the Ropigos refinery near Aspell. Up to now, the accident has not caused any casualties. According to preliminary information, the accident may be caused by the failure of the protection mechanism of the automation system. It is reported that this is also the third accident that happened in Greece in recent years.

Transformer is a kind of power equipment which uses electromagnetic induction principle to convert alternating current energy into different parameters such as voltage and current. In oil-immersed transformer, the iron core and winding are immersed in the oil tank filled with insulating oil to strengthen insulation and improve cooling and heat dissipation conditions. When there are serious faults such as overload, short circuit and insulation damage in the transformer, the insulating oil is subjected to high temperature or arc, which is decomposed by heating to produce a large amount of hydrocarbon mixed gas, which makes the internal pressure of the transformer rise sharply, and then leads to the structural damage of the transformer oil tank (primary transformer explosion).

After a transformer explosion, insulating oil, mixed gas and oil mist are released violently through the rupture of transformer oil tank. Insulating oil leaks from the transformer, forming a liquid pool on the ground, which is ignited to cause a pool fire. However, when the leaked pyrolysis product mixed gas and oil mist are mixed with air and ignited, a secondary explosion will occur. When these situations occur in closed or crowded areas, it may lead to a very strong explosion, which will threaten people and equipment and bring serious social and economic losses.

The normal operation of power equipment will generate heat due to the action of current and voltage, mainly including the heat generated by current effect and the heat generated by voltage effect. When there is a defect or fault in power equipment, the temperature at the defect or fault will change abnormally. This will cause local heating of the equipment. If these hidden dangers are not found and stopped in time, it will eventually lead to equipment failure or accident, which will seriously expand into power grid accident.

Power equipment heating faults can be basically divided into two categories, namely, external faults and internal faults, and their basic characteristics are as follows:

1) External heating fault: infrared rays are radiated to the surroundings in the form of local overheating, and the thermal faults of various bare joints and connectors present thermal field distribution centered on the fault point. Therefore, whether there is a thermal fault can be intuitively judged from the thermal map of the equipment, and the location and severity of the fault can be accurately determined according to the temperature distribution.

2) Internal heating fault: The heating process is generally long. In order to stabilize heating, solid, liquid and gas in contact with the fault point form heat conduction, convection and radiation. In this way, the heat generated by internal fault is continuously transferred to the equipment shell, thus changing the thermal field distribution on the external surface of the equipment.

Power production includes power production and transmission and distribution of power plants. The inefficiency of these two links makes it difficult to improve the capacity of the power industry, and accidents occur from time to time.

The problems in production mainly focus on poor infrastructure. Old equipment, low energy conversion efficiency, frequent accidents.

Due to the aging of transmission network infrastructure, substations and power grids in other areas lack automation systems to monitor the operation status of key equipment, so the risk of power outage and continuous low voltage is increasing.

For example, the leakage of transformer liquid or the failure of internal insulation will lead to overheating of equipment, which will lead to failure, but most power supply companies are not equipped with automatic thermal detection systems that can detect these failure points.

Regardless of the cause of the failure, a major substation failure may evolve into a series of concurrent failures, which may lead to large-scale failures of banking facilities, security systems, manufacturing plants, food refrigeration, communication networks and traffic control systems. Undoubtedly, the relevant power supply companies may suffer huge income losses and increase a lot of costs to restore the normal operation of the system.

The infrastructure of power supply companies is gradually aging, and the risk of power outage and continuous low voltage is increasing. Continuous low voltage refers to the voltage drop in power supply, so it is named because low voltage usually leads to dim lights, and power supply companies are also facing expensive unplanned maintenance and soaring costs.