The layout of four units sharing one tunnel is less frequently arranged for domestic pumped storage power stations, and it is even rarer to carry out load rejection test for four units in the same hydraulic unit at the same time. Four units sharing one tunnel is adopted in Qingyuan pumped storage power station, Guangdong province. In August 2016, after carrying out load rejection tests with single, double and three units, for the first time in China, load rejection test of four units in the same water transmission system at the same time was carried out. This paper introduces the load rejection test of Qingyuan pumped storage power station and analyzes the key test data including spiral case pressure, draft tube pressure, rotational speed, vibration and swing, etc. The results show that the two-stage closure rule of the guide vane, which is adopted now, is feasible. The maximal spiral case pressure is about 7.067 MPa when the four units reject load at the same time with 100% load while the minimal draft tube pressure is about 0.461 MPa, and the maximum rotational speed rise is 589.01 r/min. The key experimental data can meet the control standards. The vibration and the bearing temperature trend are stable, the watercourses, the units, the electrical equipment, and auxiliary systems have withstood the comprehensive test, which provide a test basis for the units to achieve full-head and full-load operation, and also have certain reference value for design of water transmission systems and real machine tests of similar power stations.

pumped storage unit, diversion system, four units sharing one tunnel, load rejection test

抽水蓄能机组, 输水系统, 一洞四机, 甩负荷试验