Abstract: Balance loop is widely used in the control system of the power plant.The purpose of balance loop is to balance the output of the equipments in pair like fans and feederwater pump.As the standard for balance loop is not available,so the design for it is variable.This article sorted all the kinds of design for balance loop which is used in different power plants,summarized the characters of different designs with hope that it can provide some reference for the late design.

Key words: balance loop, logic, design, power plant