Looks like these are synonyms that mean change, alteration. Is there any difference in usage?
In most cases, these two words are interchangeable (when used in meaning "change, alteration"). "Изменение" is more universal and common, so if you have doubts, use "изменение". The difference between these two words is rather small, but it exists. I'll try to explain it according to my personal experience:
"Перемена" sounds stronger, "bigger". For "great changes" both words are OK, but for "minor changes" you are likely to use "изменения", not "перемены".
"Изменение" tends to be more concentrated on process of changing, while "перемена" - on result. For example, "watch the temperature changes" - "наблюдать за изменениями температуры", not "переменами". But "strive for changes" - "добиваться перемен" or "добиваться изменений", both variants are possible.
To summarize, "перемена" is closer to "revolution", while "изменение" - to "evolution (which sometimes includes revolutions, as well)".
Word перемена has a few different meanings (cf. change as money, not related to any alteration, for example).
Besides generic "change", перемена may also mean
Set of dishes (i.e. course)
Set of clothes / underware
A break in a school
Otherwise these words are mostly the same, except people tend to use изменение / измениться if talking of slight changes, and перемена / перемениться as big changes. But that's not really a must.