INCREASING THE EFFICIENCY OF FIRE EXTINGUISHING AT OPEN ELECTRICAL SUBSTATIONS BY USING FIRE EXTINGUISHING AEROSOLS

Abstract

Formulation of the problem. Fires in electrical substations can lead to the termination of electricity supply to settlements, industries and critical infrastructure facilities. Such fires are accompanied by significant material losses. Harm the environment. The process of extinguishing them is difficult and dangerous for the personnel of fire-rescue units and employees of energy enterprises. The enemy's missile strikes on Ukraine's electric power facilities are added to the general problem. In the period from February 2022 to February 2023, there were 225 of them. When extinguishing fires caused by shelling, fire and rescue units cannot act effectively due to the risk of repeated shelling. The waiting time before the start of fire suppression can be long. During this time, the fire develops and causes significant damage.
According to statistical data, most fires in electrical substations occur in electrical transformers. In some cases, the existing fire extinguishing systems of transformers cannot achieve successful extinguishing, which leads to the spread of the fire over a larger area and increases the negative consequences of the fire.
The above problems make it necessary to increase the protection of electrical equipment of substations against fires. Equipping these facilities with effective fire extinguishing systems capable of minimising negative consequences.
The purpose of the work: To theoretically substantiate the increase in the efficiency of extinguishing fires at open electrical substations due to the use of fire-extinguishing aerosols.
Tasks. Conduct a review and analysis of the existing fire protection systems of electric substations and identify their shortcomings. Determine the necessary efficiency criteria that such systems must meet. To systematize and generalise the best experience of extinguishing fires at open power substations.
Methods. The work uses the method of analysis, comparison and generalization of scientific and technical achievements on the use of various fire-extinguishing substances and methods of extinguishing fires at electrical substations. 
Research results. It was established that the high efficiency of extinguishing the transformer with an aerosol will be ensured theoretically by such processes. At the moment of evaporation of the transformer oil, the aerosol will provide phlegmatization of the combustible medium. During the burning of transformer oil, chemical reactions in the flame will be inhibited by freshly formed finely dispersed aerosol particles (K2CO3, KHCO3, KOH, KCl, etc.) and their decomposition products (K2O, KO, etc.). Also, during the burning of transformer oil, the mirror of the combustible liquid will be protected from the thermal radiation of the flame, due to the absorption of the rays coming from the combustion zone by the particles. Lowering the temperature of the combustion zone due to heat absorption during heating, melting, evaporation and decomposition of aerosol solid particles. Stopping burning due to mixing of the combustible liquid (with sub-layer extinguishing). The long-term protective action of suspended particles of fire-extinguishing aerosol in a conditionally sealed volume is about 25 minutes, which is quite enough to prevent the further continuation of burning due to the cooling of heated enclosing structures.
Conclusions. Thus, for the effective extinguishing of fires in electrical transformers and substations, the fire-extinguishing aerosol is most suitable as a fire-extinguishing agent, which has the following characteristics: quick activation of the system (low activation inertia), high fire-extinguishing and phlegmatizing efficiency, simplicity of construction and reliability, explosion protection (explosion resistance), high intensity of fire-extinguishing agent supply, sufficient duration of fire-extinguishing agent supply, the effectiveness of application in open space, shielding ability, as well as the possibility of extinguishing fire from the outside and phlegmatization of the gas environment inside the transformer at the same time.