Simply put, the power supply system provides electricity for many users. For example, a substation has cement plants, coal mines and flour mills. The maximum load of these three plants cannot appear at the same time. For example, in March, the maximum load of cement plant 1 1,000 kw appeared on No.4, the maximum load of coal mine/2,000 kw appeared on No.5, and the maximum load of flour mill 1 1,000 kw appeared on No.7. Then the maximum load of this month is definitely not the sum of the maximum values of these three plants. In order to calculate the maximum load, a synchronization rate is needed, which is estimated by statistics. In this case, the maximum load in March may be 34,000 kilowatts, so the synchronization rate is 3.4/(1+2+1) = 0.6 = 60%.