The grid connection of a high proportion of renewable energy generation increases the uncertainty in power systems. Therefore

the flexibility margin of different energy sources needs to be quantified to cope with the uncertainty change and maintain the dynamic balance of power system flexibility. In this paper

first

the flexibility characteristics of source

net

load and power and load community (PLC) are analyzed. The dynamic equilibrium relationship among them is briefly introduced. Secondly

taking into full consideration the complex output characteristics of different energy sources and combining their respective flexibility characteristics

a quantitative model of the power source flexibility margin for thermal power

hydro-power

gas power and concentrating solar power is established. A quantitative model for a power source flexibility margin in PV and wind power based on blind number theory is established. Furthermore

the calculation method of theoretical power generation capacity

which can reflect different characteristics of output power of various energy sources

is presented. The actual output power of each power source in each period is predicted. Finally

a case study shows that the model and method can consider the operating characteristics of different types of power sources

and quickly and accurately quantify the adjustable range of flexibility margins of each power source at different periods of time

which can provide an important basis for evaluating the capacity of renewable energy consumption and the optimal operation of multi-energy power systems (MEPSs).