Compressor suction liquid carrying judgment method and device and unit

The invention discloses a method and device for judging suction liquid carrying of a compressor and a unit. The method comprises the steps that the suction temperature and the condensation temperature are monitored in real time; according to the suction temperature and the condensation temperature, an exhaust superheat degree set value is calculated; and when the exhaust superheat degree is smaller than the exhaust superheat degree set value, it is determined that the compressor runs with liquid. According to the method, the exhaust superheat degree set value is calculated according to the actual operation condition of the unit and serves as the basis for judging the suction liquid of the compressor instead of using the fixed exhaust superheat degree set value, so that the suction liquid of the compressor can be judged more accurately; the problem that a protection mode with liquid cannot be rapidly entered under the conditions of high pressure difference and wide operation range is avoided, and the problem t