This paper proposes a solution to implementing a coordinated optimal day-ahead dispatch in a hybrid thermal-wind-photovoltaic power system incorporating an energy storage system (ESS). Our aim is to minimize total generation cost and restrain the frequent change of ESS charging/discharging status while meeting a series of system operating constraints

including a proposed coordinated dispatch strategy for the purpose of reducing thermal power fluctuations. A novel two-stage convexification technique (TSCT) is designed and leveraged to convert the original non-convex optimal day-ahead dispatch model

without taking into account the constraints of the proposed coordinated dispatch strategy into two convex quadratic programming problems. When introducing the constraint of the coordinated dispatch strategy

the corresponding inequality constraints are transformed into a series of linear equality constraints

after which the original optimal day-ahead dispatch model can be solved by the TSCT mentioned above. Finally

numerical simulations and comparative analysis are performed on the IEEE standard test systems to verify the validity and effectiveness of the proposed model and method.