Bring a pot of lightly salted water to a boil in a saucepan and cook carrots in the boiling water until just tender, about 15 minutes. Drain. Transfer carrots to a serving dish and keep warm. Whisk sugar, cornstarch, salt, and ginger in a saucepan until thoroughly combined; turn heat to medium and whisk in orange juice. Bring to a simmer, whisking constantly, and cook until sauce is smooth and thickened, about 3 minutes; stir in butter. Pour sauce over carrots, stir to coat, and serve.