Lecture 4 Unit Commitment in Power System Dr.Qi Huang School of Energy Science and Engineering UESTC
Lecture 4 Unit Commitment in Power System Dr. Qi Huang School of Energy Science and Engineering UESTC
Contents Introduction Solution of Unit Commitment Solution of Unit Commitment with Dynamic Programming 电力拿镜广城洲量写控制四川省童点实验蜜 家电
电力系统广域测量与控制四川省重点实验室 Contents Introduction Solution of Unit Commitment Solution of Unit Commitment with Dynamic Programming
Introduction The activities of human being is periodic,hence the electricity using is also periodic Daily load period,weekly load period,and seasonal load period The periodic load brings the economic problem of power generation: it is not economic to have all generator units running Definition:unit commitment is to start up and interconnection of a certain generator For economic reasons,we can shut down some generator units, according to the current or future load demand.1.e.,according to the current or future load demand,we can just keep enough generator units running to satisfy the load demand and minimize the cost of start up and shut-down. The difference between ED:the later assumes that there are N generator connecting to the power network,and just make an economic dispatch plan;the former is much more complex.One needs to determine which generator units among the dispatchable units,participate in the service,according to the current or future load demand 电力康镜广城测量与控制四川省重点实验蜜 国家电网
电力系统广域测量与控制四川省重点实验室 Introduction The activities of human being is periodic, hence the electricity using is also periodic Daily load period, weekly load period, and seasonal load period The periodic load brings the economic problem of power generation: it is not economic to have all generator units running Definition: unit commitment is to start up and interconnection of a certain generator For economic reasons, we can shut down some generator units, according to the current or future load demand. I.e., according to the current or future load demand, we can just keep enough generator units running to satisfy the load demand and minimize the cost of start up and shut-down. The difference between ED: the later assumes that there are N generator connecting to the power network, and just make an economic dispatch plan; the former is much more complex. One needs to determine which generator units among the dispatchable units, participate in the service, according to the current or future load demand
Introduction-UC example The most economic plan is to Example have only one generator consider the cost for operating running.The most economic generator! Unit1:F,(P1)=561+7.92P1+0.3z 0sT1≥00 Unit 2: F2(P2)=310+7.85P2+0.00194P,2 100≤P2≤400 Unit 3: F3(P3)=93.6+9.56P3+0.005784P32 50≤P3≤200 what combination of units is best to supply a 550 MW load? N 萼 u un 遵思 云 a ” u u” Off Off Off 0 0 Infeasible Off Off On 200 50 Infeasible Off On Off 400 100 Infeasible Off On On 600 150 0 400 150 0 3760 1658 5418 On Off Off 600 150 550 0 0 5389 0 0 5389 On Off On 800 200 500 0 50 4911 0 586 5497 On On Off 1000 250 295 255 0 3030 2440 0 5471 On On On 1200 300 267 233 50 2787 2244 586 5617 家电网
电力系统广域测量与控制四川省重点实验室 Introduction-UC example The most economic plan is to have only one generator running. The most economic generator!
Introduction 1200MW-500MW,step: 1500MW 50MW 1150 MW Peak Load 6ulpeo .>1000,3 generators 1000MW 600<P<1000, le1o1 generator 1 and 2 500MW .<600,generator 1 450 MW Min.Load 3PM 9 PM 3AM 9AM 3 PM Load Unit 1 Unit 2 Unit 3 Time of day 1200 on on on 1150 on on on 1100 on on on 1050 on on on 1500MW- 1000 on on off 950 on on off 6ulpeo 200MW Unit #3 900 on on off 1000MW 850 on on off 400MW 800 on on off Unit #2 750 on on off 700 500MW 600MW on on off 650 on on off Unit #1 600 on off off 550 on off off 500 on off off 3PM 9PM 3AM 9AM 3PM侧四具头 Time of day 家电
电力系统广域测量与控制四川省重点实验室 Introduction 1200MW-500MW，step: 50MW •>1000，3 generators •600<P<1000， generator 1 and 2 •<600，generator 1
The constraint of UC Primary constraint Enough generation output to satisfy the load demand Spinning reserve constraint Definition:interconnected backup generation capacity Functions:protect the power grid when accidental generator tripping Rule:some percent of the predicted load;or,able to supply the deficiency when the generator with maximum output is down;distributed in the network to avoid network congestion. 电力拿镜广城测量乌控制四川省重点实验蜜 家电网
电力系统广域测量与控制四川省重点实验室 The constraint of UC Primary constraint Enough generation output to satisfy the load demand Spinning reserve constraint Definition: interconnected backup generation capacity Functions: protect the power grid when accidental generator tripping Rule: some percent of the predicted load; or, able to supply the deficiency when the generator with maximum output is down; distributed in the network to avoid network congestion
Reserve example Example consider a power system consisting of two isolated regions transmission tie-lines join the regions and may transfer power up 0 to a maximum of 550 MW in either direction five units have been committed to supply 3090 MW of loading Western region Units 1.2&3 andino un (W) (W) (W) (MW)peoT e6ueyoJejul TT 550MW 1 1000 900 100 maximum Western 2 800 420 1740 380 1900 160 3 800 420 380 (in) Eastern region 4 1200 1040 160 1350 160 Eastern 1190 Units 4 5 5 600 310 290 (out) Total 4400 3090 3090 1310 3090 电力康镜广城测量与控渊四川省重点实验蜜 家电顺
电力系统广域测量与控制四川省重点实验室 Reserve example
Reserve example Example verify the allocation of spinning reserves in the system ●western region generation of largest unit:900 MW available spinning reserve local:760 MW;tie-line capacity:390 MW;eastern region:450 MW total:1150 MW load can be supplied ·eastern region generation of largest unit:1040 MW available spinning reserve local:450 MW;tie-line capacity:550 MW;western region:700 MW total:1000 MW-load can not be completely supplied lack 40 MW of spinning reserve in the eastern region commit 40 MW of new generation within the eastern region 是人W乐网翼溪别w国氢马大烈鉴 国家电网
电力系统广域测量与控制四川省重点实验室 Reserve example
Constraint of UC Constraint of thermal plant Time constraints:slow heat effect->may take some time from startup->minimum startup or shutdown time Crew constraints:cannot start up or shut down multiple generators Startup cost (heat start and cold start) C tart-up cooling 1-e d break-even banking point Coank-Hbamk!shut-dow+ fixed 0十十十十十十十 电力集院广为 01234567hm Time-dependent start-up costs
电力系统广域测量与控制四川省重点实验室 Constraint of UC Constraint of thermal plant Time constraints: slow heat effect -> may take some time from startup -> minimum startup or shutdown time Crew constraints: cannot start up or shut down multiple generators Startup cost (heat start and cold start)
Solution of Unit Commitment
Solution of Unit Commitment