Is it illegal? Yes. Declarations in support of protection orders are ordinarily submitted under penalty of perjury. If it can be shown that she lied under oath (even a written document under penalty of perjury is "under oath"), then she could potentially face charges.
Focus on the protective order hearing (and given the situation, I'd suggest getting an attorney to handle this one), then see about having criminal charges lodged against her. Prove everything she says is false with conclusive proof via an alibi.Ask a similar question
Mr Dane has addressd all of the salient points, and like him I suggest you get an experienced criminal defense lawyer admitted to practice law in WA to handle this situation. You will have only one opportunity to try to convince the State and the Court that the basis for the OP is false, and get it dismissed. Then puruse the other issues of whether it constituted a crime such as purjury, filing a false report, etc. Good luck.
This information is offered for informational purposes only, as I am not admitted to practice law in your State. It is not intended as legal advice and you should not rely upon it to decide how to resolve this issue. No Attorney-Client relationship is intended or established by this response. You are faced with a situation where you need to consult with an experienced defense lawyer admitted to practice law in your State before you make any decisions as to how to resolve this issue.