Place peeled and cut potatoes in a large saucepan and add enough water to cover by 1- inch. Bring to a boil over medium-high heat, then reduce heat to medium and let simmer for 8-10 minutes or until potatoes are tender. Drain potatoes and transfer to a large mixing bowl.
Add chopped hard boiled eggs, pickle relish, red onion and celery; stir to combine.
In a mixing bowl, whisk together vinegar, yogurt, sugar, mustard, salt, pepper and onion powder until well combined. Pour mixture over potato mixture and gently stir to combine.
Refrigerate for at least 1 hour before serving.