INCREASED CONTACT RESISTANCE IN ELECTRICAL NETWORKS AS A CAUSE OF FIRES

Problem statement. The article focuses on the actual problem of increased fire hazard of power grids of old buildings in Odesa and Lviv, which is associated with an increase in electrical load and the presence of areas with high transient resistance (TR). Based on the analysis of electrophysical parameters, a method for assessing the state of power grids is proposed, which allows timely detection of emergency areas with HTR.Research methods. To detect areas with increased transient resistance (TR) in hidden low-voltage power grids (up to 1000 V inclusive), we propose to use a diagnostic approach based on the analysis of the ratio between the input electrical power supplied to the consumer load and the power directly consumed by this load. The methodology involves comparing the input and output voltages with the calculation of the fire hazard factor, which determines the input power to output power ratio, i.e. the proportion of energy that does not reach the load and is lost to heating.Results. An increase in the fire hazard factor indicates an increase in losses in the network, which, in turn, may indicate a decrease in the cross-section of conductors, oxidation of contacts, or areas with critical transient resistance. Experimental studies of the power distribution network with areas of high transient resistance confirm the effectiveness of this approach for diagnosing hidden networks with voltages up to 1000 V. A photo of the experimental setup for determining the emergency state of a hidden electrical network is shown. Scientific significance. The proposed approach makes it possible to prevent the emergence of fires in intra-building electrical networks and reduce the risk of fires caused by the thermal effect of electrical energy, that is, to minimize the possibility of fires in buildings, in particular in historical heritage sites.