On The Unit Maintenance Scheduling Problem Of Power System Containing Wind Farms

It is of great necessity to develop renewable energy with the energy andenvironmental problem being increasingly grave. Electrical power systems consume largescale conventional energy and produce lots of CO2emission every year. Replacing theconventional thermal plants with renewable energy is a trend to reduce the consumption ofconventional energy and CO2emission. Among numerous renewable energy, wind powergets more attention because of its comparatively mature technology. However, stochasticand anti-regulating nature of wind power will make power system subject to even heavierpeak shaving pressure with the increasing amount of wind power integration. The unitmaintenance scheduling problem is an important component of power system planning.Mid-long term unit maintenance scheduling will directly affect the short term unitcommitment of power system, and then have an influence on power system’s peak shavingability. Conventional unit maintenance scheduling problem usually focuses on theeconomic and reliability problem of power system. With increasing wind powerintegration, the peak shaving problem is more and more outstanding and the unitmaintenance scheduling problem should pay attention to power system’s peak shavingability.This paper makes an explicit research on the unit maintenance scheduling problem ofpower system. Firstly, the influences that the mid-long term unit maintenance schedulingproblem has on the short term economic dispatch of power system are analyzed. Basing onthe dynamic economic dispatch model the influences of the mid-long term unitmaintenance scheduling problem has on the short term economic dispatch of powersystem is quantitatively studied. Then, a medium and long-term unit maintenancescheduling, in which the economy of maintenance, reliability and balance of peakregulation pressure is synthetically taken into account, is proposed for power grid.Considering the peak regulation ability of different types of units, an index to measurepeak regulation pressure for power grid is proposed. On this basis, a method to balance thepeak regulation pressure in maintenance scheduling is researched. According to different peak regulation abilities of units and the intensity of peak regulation pressure in differenttime intervals the unit maintenance is reasonably scheduled to balance peak regulationpressure of power grid; the constraint of maximum peak regulation of power grid is addedin constraint conditions to ensure that after the maintenance scheduling is drafted the peakregulation pressure of power grid can be kept to a reasonable level. Finally, dealing withthe unpredictable problem of mid-long term wind power, the wind power scenariosaccommodating to mid-long term unit maintenance scheduling problem is studied.The availability of the proposed models is verified by results of calculation example.