If you are working or some protocol which is not part of NS-2 then you have to install that protocol using some particular patches. ( As you are saying you are working on WSN, i am sure the protocol you are working on is no part of NS2).
First, do a fast survey on published papers where authors used simulators to simulate WSN especially power consumption.
Second, if you find the most used simulator for example ns-2, then determine which version was used, because there are many versions of ns-2. Check if the simulator needs to install some patch to support your technique. You should contact the authors who used the simulator to confirm the version of the simulator and any needed patch.
Third, each simulator has its limitations and requirements such as knowledge of
c++, tcl, and Linux environment in ns-2. And check if there is any active community on Internet that supports users and answers the enquiries.