农业工程学报
農業工程學報
농업공정학보
2014年
10期
113-121
,共9页
控制%模型%发电%微电网%运行状态
控製%模型%髮電%微電網%運行狀態
공제%모형%발전%미전망%운행상태
control%models%power generation%microgrid%operation state
为了实现微电网内各单元的协调控制,针对独立微电网设计了有功功率自主与协调控制方法。该方法基于分层控制结构,1次调整由风力分布式发电单元、光伏分布式发电单元、储能单元完成,根据电压-有功功率控制曲线自主控制。2次调整由微电网控制器完成,对风力分布式发电单元、光伏分布式发电单元、储能单元及负荷单元协调控制,实时监测储能单元的电压、有功功率,如果在2次调整允许的波动范围内,微电网控制器不下发控制指令;否则,电压越限时将储能该时刻的瞬时功率作为功率基准值实现工作曲线的平移,功率越限时,微电网控制器通过改变间歇性分布式发电单元的发电功率及投入或切除负荷完成2次调整。并建立了微电网状态转换协调控制模型,更加适用于计算机处理和工程化的实现。通过Matlab算例验证了所提出控制方法的有效性。
為瞭實現微電網內各單元的協調控製,針對獨立微電網設計瞭有功功率自主與協調控製方法。該方法基于分層控製結構,1次調整由風力分佈式髮電單元、光伏分佈式髮電單元、儲能單元完成,根據電壓-有功功率控製麯線自主控製。2次調整由微電網控製器完成,對風力分佈式髮電單元、光伏分佈式髮電單元、儲能單元及負荷單元協調控製,實時鑑測儲能單元的電壓、有功功率,如果在2次調整允許的波動範圍內,微電網控製器不下髮控製指令;否則,電壓越限時將儲能該時刻的瞬時功率作為功率基準值實現工作麯線的平移,功率越限時,微電網控製器通過改變間歇性分佈式髮電單元的髮電功率及投入或切除負荷完成2次調整。併建立瞭微電網狀態轉換協調控製模型,更加適用于計算機處理和工程化的實現。通過Matlab算例驗證瞭所提齣控製方法的有效性。
위료실현미전망내각단원적협조공제,침대독립미전망설계료유공공솔자주여협조공제방법。해방법기우분층공제결구,1차조정유풍력분포식발전단원、광복분포식발전단원、저능단원완성,근거전압-유공공솔공제곡선자주공제。2차조정유미전망공제기완성,대풍력분포식발전단원、광복분포식발전단원、저능단원급부하단원협조공제,실시감측저능단원적전압、유공공솔,여과재2차조정윤허적파동범위내,미전망공제기불하발공제지령;부칙,전압월한시장저능해시각적순시공솔작위공솔기준치실현공작곡선적평이,공솔월한시,미전망공제기통과개변간헐성분포식발전단원적발전공솔급투입혹절제부하완성2차조정。병건립료미전망상태전환협조공제모형,경가괄용우계산궤처리화공정화적실현。통과Matlab산례험증료소제출공제방법적유효성。
Usually, a microgrid is connected to a power grid as a complement that enhances the flexibility and safety of a system. However, in some cases, for example grid faults, remote rural areas, or islands away from the continent, the microgrid has to operate independently. Because of a large number of power electronic components in the microgrid, the fluctuant distributed generation, and the bidirectional power flow, the unified coordination control of the units in each case is very important for the security and stability in the operation of each standalone microgrid. Aiming at the standalone microgrid, an autonomous and coordinated control method is designed in the paper. The primary adjustment is an independent local control strategy that allows each DG unit to operate autonomously. Also, for reliability reasons, communication is avoided in the primary adjustment, similar to the conventional grid control. Hence, it is based only on local measurements, being conceived as a local control strategy. With respect to the primary adjustment, in islanded mode, the DG units need to dispatch their power to enable power sharing and voltage control, thereby ensuring a stable microgrid operation. According to the voltage and active power control curve in autonomous control, the primary adjustment is completed by wind unit controller, solar unit controller, and energy storage controller. For the fast response of energy storage devices and large random fluctuations of intermittently distributed generations in the standalone microgrid without any continuous power supply, the voltage-frequency control method is adopted in energy storage devices to allocate automatically and absorb the transient imbalance power of the system during real time operating. Meanwhile, the PQ control method is adopted in intermittently distributed generations. The secondary adjustment is completed by the microgrid controller. According to the upper and lower limits of voltage and current of energy storage, the work space of the V/f unit is divided into areas by microgrid controller for diffident suitable control. Firstly, in the stable area, such as the area 1, voltage and active power of energy storage is in bounds so no control is carried out by the secondary adjustment. Secondly, in the voltage adjustment area, such as areas 2, 3, 6, 7, 8, 9, the power reference of energy storage is replaced by a frozen output power of itself to translate droop curve, meanwhile intermittently distributed generation are at the maximum power output. Thirdly, in the power control area, if the discharge current is over the upper bound, such as areas 4, 6, 7, the procedure is performed as follows: 1) intermittently distributed generations increase power output to the maximum, 2) loading relief according to importance and power matching. If the charge current of energy storage is less than the lower bound, such as areas 5, 8, 9, the procedure is performed as follows: 1) increased loads according to importance and power matching until full loads, 2) according to priority of intermittently distributed generations, reducing the active power output. In order to make the microgrid controller achieve better management of working space, a mathematical model based on finite state machine is established for computer processing and engineering. The proposed control method is validated in simulated examples and show that microgrids can undertake power fluctuation of loads and intermittently distributed generations to achieve active power balance. The first and secondary adjustment not only realized coordinated control of wind, solar, and energy storage units to provide a valuable reference for optimization control of units, but also ensured security and stability of the standalone microgrid while also realizing hierarchical control idea.