Seeing corona discharges means awareness of existing faults, both structural and electrical. Awareness of defects serves maintenance teams and asset managers in scheduling corrective activities. But, during commissioning, while systems are energized and yet not loaded and contractors are on-premises, corrective operations are done under warranty and are easy to accomplish. Moreover, at that stage, no damage is expected. The main purpose of this test is to confirm that various system components are correctly installed, and check if the system can sustain the rated voltage. During the test, the charged voltage is slowly increased from the low voltage level to the rated voltage level while testing the general operation performance of critical components. If the applied voltage exceeds a certain level corona starts flashing.