I will try to help you better. Although Samsung TVs are known for power supply problems. Its not common with Plasma TVs and your symptoms.
Plasma TVs have boards called the "Y" boards - there is the Y-sustain board and Y-driver boards. The Y-driver boards provide the "high voltage" to the plasma display as well as a portion of the video signal.
When these board detect a fault, they issue a shutdown command, that removes the Vs and Va voltages (shuts them off) from the power supply - on many units these are controlled by a relay and that is what you are probably hearing.
I do not have the service manual for you specific model, but these boards are usually located on the left side of the TV. A large ribbon cable will go to the Y-driver boards (there are usually two). You can remove one of the ribbon cables at a time to see if the TV will shutdown - if it doesn't, then its the Y-driver board. You will only have half of a screen when you do this.
Sometimes the Y-sustain board can do the same, but it depends on the design.
You will need some basic trouble shooting skills and a volt meter to proceed further - or have it serviced. A service tech should be able to isolate the problem easily. The boards are replaced in this case.
Ask if you have any follow up questions.