Method of monitoring of a dielectric state of high voltage equipment with capacitive insulation, including condensive bushing, current transformers and potential transformers wherein a leakage current of the insulation is directly and continuously monitored by a monitoring system, comparing it to a limit value, scheduled by the user, that, if exceeded, will excite an alarm for serious deterioration in the isolation, characterized in that the monitoring system performs following steps: - counting the time period in which the current exceeds that limit value, suppressing any alarm emission until the counting has reached a scheduled temporization value scheduled by the user; - allowing an alarm emission after the counting has reached the scheduled temporization value, and, if the leakage current returns to a value under the scheduled limit during the counting operation, the time counting is interrupted and annulled; - checking the consistency of the leakage current measurement through a comparison of the alteration in the individual leakage currents (3FA, 3FB, 3FC) against the alteration in the vector sum of the leakage currents (3FA, 3FB, 3FC), and calculating the vectorial difference between the alteration suffered by individual leakage current and the alteration suffered by the sum current; - if the vectorial difference is smaller than the scheduled limit value, the monitoring system determining that the detected alterations are valid and correct, and allowing the emission of deteriorated insulation alarms, and if the vectorial difference is greater than the limit scheduled value the monitoring system is configured to determine that the detected alterations are not valid and to block the deteriorated insulation alarms emission; and - counting the time where said vectorial difference is above the scheduled limit value, emitting a monitoring system failure alarm if the counting reaches a temporization value previously fixed, the monitoring system being also configured and arranged to interrupt and annul the time counting should the vectorial difference return to a value under the limit one. - counting the time period in which the current exceeds that limit value, suppressing any alarm emission until the counting has reached a scheduled temporization value scheduled by the user; - allowing an alarm emission after the counting has reached the scheduled temporization value, and, if the leakage current returns to a value under the scheduled limit during the counting operation, the time counting is interrupted and annulled; - checking the consistency of the leakage current measurement through a comparison of the alteration in the individual leakage currents (3FA, 3FB, 3FC) against the alteration in the vector sum of the leakage currents (3FA, 3FB, 3FC), and calculating the vectorial difference between the alteration suffered by individual leakage current and the alteration suffered by the sum current; - if the vectorial difference is smaller than the scheduled limit value, the monitoring system determining that the detected alterations are valid and correct, and allowing the emission of deteriorated insulation alarms, and if the vectorial difference is greater than the limit scheduled value the monitoring system is configured to determine that the detected alterations are not valid and to block the deteriorated insulation alarms emission; and - counting the time where said vectorial difference is above the scheduled limit value, emitting a monitoring system failure alarm if the counting reaches a temporization value previously fixed, the monitoring system being also configured and arranged to interrupt and annul the time counting should the vectorial difference return to a value under the limit one.