IMSDS

EDP D as a DSO as significant number of unattended substations that require inspections and maintenance operations in order to maintain their operational capabilities. Due to this large number of substations, currently around 400, scheduling and performing maintenance and inspections activities is a very time intensive process which can lead to the detection of defects in an advanced state. In electrical installations hotspots and insulation breakage are key aspects in for predictive maintenance, since the evolution of these defects can lead to service interruptions in the worst case, degrading the quality of service. Currently EDP D performs thermography and corona discharge inspections on an annual basis in order to identify hot spots and insulation breakage in substations. The ability to detect in real time these abnormal situations enables predictive maintenance, preventing future component failures. In terms of corona discharge analyses the inspections are also performed annually using specialized and quite expensive UV cameras. With a current policy of replacing ceramic based insulators by polymer based ones, corona discharge importance ramped up, due to the production of corrosive chemicals: ozone, nitrogen oxides which in presence of water vapor yield nitric acid. These corrosive materials shorten the life span of high voltage polymer based insulators leading to insulation breakage. Theft is also a concern, due to the unattended nature of substations, causing equipment damage that could cost millions of euros. Thus, the use of automated intrusion detection system is required to mitigate these situations. This paper presents an autonomous integrated inspection system to be installed in substations, including thermal and corona inspection, as well as intrusion detection. The development of this system came from the market absence of a solution that could integrate all of the components, considering the DSO requirements: low cost, autonomous and with minimal intervention from the operator. The thermography sub-system monitors in real time in the substation environment using infrared cameras installed in pan and tilt units. The corona discharge detection sub-systems is based on an ultrasonic detector, able to capture the ultrasound emitted by a corona discharge and measure in real time the existence and evolution of the corona defect on the installed equipment. Depending on the signal emitted by the corona discharge, the software classifies its severity. When compared with UV cameras based inspection, ultrasonic technology is a low cost and effective technology. The surveillance sub-system is able perform intelligent motion and intrusion detection, being able to tracking the substation area with the implementation of virtual barriers and trigger an alarm notification depending on the detected intrusion. Moreover, there is the capability of tracking the intruding body in the image element and between several cameras. When an abnormal condition is detected, a specific alarm is triggered for the appropriate maintenance procedure to be performed. This system was validated in a distribution substation where the system performed with very good results.