Decentralized system for remote real time monitoring of power transformers, reactors, circuit breakers, instrument transformers, disconnect switches and similar equipment for power plants and electric power substations, comprising intelligent sensors, installed in several equipment present in a plurality number of electric power substations or power plants, the power substations including sensor elements and electronic signals conditioning circuits to measure several variables during equipment operation, being yet able to execute maintenance Engineering Models comprising measurement procedures to obtain information for the diagnosis of the conditions of the high voltage equipment, in a microprocessor using each power substation's own measurements together with all other sensors measurements wherein the sensors have a data bank software, executed by their microprocessor, for a continuous storage of the measurements performed as well as of the maintenance Engineering Models results, being the data bank data saved in the non-volatile memory; characterized in that - the intelligent sensors have communication interfaces, that connect to a data communication network, performing through this network the interchange of measurements and maintenance Engineering Models results between sensors and establishing a communication with a central monitoring computer, informing it about the measurements figures as well as the Maintenance Engineering Models results in real time; - the intelligent sensors in case of an interruption of said communication with the central monitoring computer operate to continue saving data in a local data bank; - the central monitoring computer has a central data bank which data are kept synchronized with the local data banks placed in the sensors whenever the central monitoring computer could be able to communicate with the sensors, and in case of interruption in communications or in computer's operation, the synchronism between the data banks and central data banks is automatically reinitiated as soon as the communication would be recovered, copying from the data bank to the central data bank only the data that are in the bank and that are not in the central data bank and wherein synchronizing, in a case of a sensor substitution, the data bank in the reverse sense, comprises automatically copying the data in the data central bank to the local data bank of the new sensor; - the sensors as well as the central computer host pages in HTML language, used as remote man-machine interfaces, allowing users' access, through the communication network, to real time measurements and maintenance Engineering Models data as well as data registered in the data bank as well as in the central data bank; wherein the system is configured to allow the use of a redundant configuration, where one or more additional central computers, identical to the main central computer, operate in parallel with this, so that a failure of any of central computers (CM, CMR) will not interrupt the operation of all the others and that the central data bank as well as the interface pages are kept in operation and available for the user's access in the central computers (CM, CMR) still operating. - the intelligent sensors have communication interfaces, that connect to a data communication network, performing through this network the interchange of measurements and maintenance Engineering Models results between sensors and establishing a communication with a central monitoring computer, informing it about the measurements figures as well as the Maintenance Engineering Models results in real time; - the intelligent sensors in case of an interruption of said communication with the central monitoring computer operate to continue saving data in a local data bank; - the central monitoring computer has a central data bank which data are kept synchronized with the local data banks placed in the sensors whenever the central monitoring computer could be able to communicate with the sensors, and in case of interruption in communications or in computer's operation, the synchronism between the data banks and central data banks is automatically reinitiated as soon as the communication would be recovered, copying from the data bank to the central data bank only the data that are in the bank and that are not in the central data bank and wherein synchronizing, in a case of a sensor substitution, the data bank in the reverse sense, comprises automatically copying the data in the data central bank to the local data bank of the new sensor; - the sensors as well as the central computer host pages in HTML language, used as remote man-machine interfaces, allowing users' access, through the communication network, to real time measurements and maintenance Engineering Models data as well as data registered in the data bank as well as in the central data bank;