Users who have been actively using power plans in Windows 7 probably know that Windows doesn’t allow you rename the default power plans (Power saver, Balanced & High performance). Although one can always create new plans, many users like to personalize by renaming default ones.
If you are looking for a way to rename these power plans, here is how to rename power plans in Windows 7 using a simple command.
1. Launch elevated Command Prompt. To do this, type cmd in start menu search box and then press Ctrl + Shift + Enter. Alternately, navigate to All programs, Accessories, right-click on Command Prompt and then select Run as administrator.
2. Type Powercfg List in the Command Prompt to know existing power plans and their GUIDs.

3. Now type the following command & hit enter to rename a power plan:
Powercfg –Changename GUID Newname
In the above command, replace GUID with the power plan’s GUID that you have obtained in the above step and Newname with your custom name. For example:

4. That's it!