1. An apparatus for measuring corona discharge of power facilities using a UV sensor with an optical lens, comprising: a UV sensor array including a plurality of sensors receiving UV rays emitted from an analyzing target of a power facility at a location separated a predetermined distance from the analyzing target of the power facility; an optical lens unit focusing the UV rays emitted from the analyzing target of a the power facility to the UV sensor array; a signal detector detecting the UV rays received by the UV sensor array in the form of a pulse voltage waveform signal; a UV image processor processing the detected pulse voltage waveform signal into a UV image on a screen; a real image measurement unit disposed in front of the optical lens unit and photographing a real image of the analyzing target of the power facility, wherein the real image measurement unit is inserted into and coupled to a center of the optical lens unit; a real image processor displaying the photographed real image of the analyzing target of the power facility on the screen; a matching unit combining the photographed real image of the analyzing target of the power facility with the UV image of the UV image processor; and an image/data output unit detecting a location of the corona discharge based on the combined UV image and real image.