This paper provides a big approach for power plant automation system of Fault Detection in cooling towers on the basis of PLC and SCADA. The techniques and program which are used in this paper are helpful to detect the fault occurs inside the cooling tower of the thermal power plant. A cooling tower is also used for removing the heat from the condensate water which is flowing through the pipes of the tower so that it is called a heat removal system. Water to be cooled and then returned for use in recirculation through the system in the cooling tower. The New fault detection and fault finding system based on upcoming data from the detection sensors which are used for fault detection. In this system, a combination of PLC internal program and visualization of fault on SCADA window gives easy fault finding and clearing process. In this paper, there are two software used for finding the faulty condition (PLC - Allen Bradley- RS Logix 500 and SCADA- Wonderware Intouch .) RS Logix 500 uses ladder logic for finding the faults and Wonderware Intouch used to show faulty condition on the windows. This paper includes three types of failure of fault detection in cooling tower which are major caused in steam power Plant during operation. In this whole process SCADA is used for online visualization of faulty condition..