基于全過程仿真的城市電網(wǎng)中長期電壓穩(wěn)定軌跡特征及防控策略研究
發(fā)布時間：2018-09-11 20:29
【摘要】：隨著我國大規(guī)模超/特高壓交直流互聯(lián)電網(wǎng)的快速發(fā)展,各種電力系統(tǒng)新設備和新技術不斷投產(chǎn)和應用,系統(tǒng)的動態(tài)行為變得更加復雜,這使得發(fā)生在暫態(tài)過程之后的中長期動態(tài)穩(wěn)定問題日趨突出并逐步受到電力系統(tǒng)研究人員的高度重視。發(fā)電機過勵磁限制器和有載調(diào)壓變壓器等慢速動態(tài)元件的動態(tài)特性是影響大容量高比例受電城市電網(wǎng)中長期動態(tài)穩(wěn)定水平的關鍵因素。構(gòu)建適用于中長期動態(tài)過程的穩(wěn)定判據(jù)及安全穩(wěn)定控制措施以防止城市電網(wǎng)電壓崩潰就顯得尤為重要。本文基于北京市電力公司科技項目“北京電網(wǎng)全過程動態(tài)穩(wěn)定及對策研究”,以環(huán)狀分區(qū)運行的特大型城市電網(wǎng)為研究對象,分析了中長期過程中慢動態(tài)元件動作對系統(tǒng)運行點在系統(tǒng)動態(tài)PV曲線上的遷移特征及主要電氣量的影響。研究過程中把負荷功率隨負荷端電壓和系統(tǒng)頻率變化而改變的負荷特性現(xiàn)象進行了分析,分別研究了靜態(tài)負荷模型和動態(tài)負荷模型負荷特性對中長期電壓穩(wěn)定的影響,揭示了過勵磁限制和有載調(diào)壓動作引起系統(tǒng)中長期電壓失穩(wěn)機理,并在此基礎上定義了中長期動態(tài)穩(wěn)定控制判據(jù)及裕度計算方法,提出了相應的多手段改善中長期穩(wěn)定水平的控制策略。最后通過對北京電網(wǎng)的全過程動態(tài)仿真分析驗證了穩(wěn)定判據(jù)及控制策略的有效性。本文所做工作及得出的主要結(jié)論如下:1)研究了采用的不同負荷模型對仿真的影響,受端系統(tǒng)在慢動作元件動作時受不同負荷模型影響有不同形態(tài)的遷移軌跡。包含有阻抗和馬達負荷的綜合動態(tài)負荷模型系統(tǒng)在慢動作元件動作時的運行點遷移特性滿足同阻抗-馬達負荷所占比例相關的線型疊加原理,經(jīng)過仿真分析驗證馬達負荷所占比例越大運行點遷移軌跡曲線斜率越大。2)全過程動態(tài)仿真中慢動作元件動作后系統(tǒng)穩(wěn)定與否同狀態(tài)遷移后系統(tǒng)運行點所在遷移后PV曲線上的位置直接相關。以發(fā)生狀態(tài)遷移后的PV曲線極限功率點B所對應的遷移前系統(tǒng)運行點A作為中長期動態(tài)穩(wěn)定的臨界點,能夠確保慢動元件動作導致的運行點遷移過程后系統(tǒng)運行點能夠繼續(xù)穩(wěn)定運行于遷移后PV曲線。3)快速響應切負荷措施對慢動元件如過勵限制和有載調(diào)壓引起的系統(tǒng)中長期穩(wěn)定性問題都有良好的優(yōu)化效果。切負荷措施的及時響應是確保策略有效的關鍵。及時響應的切負荷動作能夠保證系統(tǒng)運行點在慢元件動作之前回復到穩(wěn)定臨界點以內(nèi),進而防止因運行點遷移至動作后PV曲線失穩(wěn)區(qū)而引發(fā)的電壓崩潰。在仿真過程中證實了恒阻抗模型和馬達模型均在有載調(diào)壓動態(tài)中表現(xiàn)出了明顯的負調(diào)壓特性。因而在系統(tǒng)重載、動態(tài)無功支撐不足以及運行點接近穩(wěn)定臨界點時閉鎖有載調(diào)壓可以有效防止受端電壓崩潰。
[Abstract]:With the rapid development of large-scale ultra-high voltage / ultra-high voltage AC / DC interconnected power grid in China, the dynamic behavior of the system becomes more and more complex, with the continuous production and application of new equipment and new technologies in various power systems. This makes the long-term dynamic stability problem after the transient process become more and more prominent and gradually received great attention by the power system researchers. The dynamic characteristics of low-speed dynamic components such as generator over-excitation limiter and on-load voltage regulating transformer are the key factors that affect the long-term dynamic stability of large capacity and high proportion of urban power grid. It is very important to construct the stability criterion and safety and stability control measures to prevent the voltage collapse of urban power network. Based on the scientific and technological project of Beijing Electric Power Company, "dynamic Stability and Countermeasures of Beijing Power Grid", this paper takes the super-large urban power grid running in the ring zone as the research object. The effects of slow dynamic component movement on the migration characteristics and main electrical quantities of the system running point on the dynamic PV curve of the system are analyzed in the medium and long term process. In the course of the study, the load characteristics of load power varying with load terminal voltage and system frequency are analyzed, and the effects of static load model and dynamic load model on medium and long-term voltage stability are studied respectively. The mechanism of medium and long term voltage instability caused by over-excitation limitation and on-load voltage regulation operation is revealed. On this basis, the medium and long-term dynamic stability control criterion and margin calculation method are defined. The control strategy of multi-means to improve the level of medium-long-term stability is put forward. Finally, the effectiveness of stability criterion and control strategy is verified by dynamic simulation of Beijing power grid. The main conclusions of this paper are as follows: 1) the effects of different load models on simulation are studied. The moving characteristic of the running point of the integrated dynamic load model system with impedance and motor load satisfies the linear superposition principle related to the ratio of impedance to motor load. The simulation results show that the larger the proportion of motor load, the bigger the slope of the moving trajectory curve. 2) in the whole process dynamic simulation, whether the system is stable or not after the slow motion element moves is the same as the system running point after the moving state. The position on the PV curve is directly related. The system operating point A corresponding to the limit power point B of the PV curve after the state transition is taken as the critical point for long-term dynamic stability. It can ensure that the system running point can continue to run stably in the PV curve 3 after the slow moving element moves.) the system can respond quickly to the system caused by the slow moving element such as over-excitation restriction and load voltage regulation. The medium-and long-term stability of the system has a good optimization effect. The timely response of load cutting measures is the key to ensure the effectiveness of the strategy. The timely response load shedding action can ensure that the operating point of the system returns to the stable critical point before the slow component action, and then prevents the voltage collapse caused by the point moving to the unstable zone of the PV curve after the operation. In the process of simulation, it is proved that both the constant impedance model and the motor model have obvious negative voltage regulation characteristics in the on-load voltage regulation dynamic. Therefore, when the system is overloaded, the dynamic reactive support is insufficient and the operation point is close to the stable critical point, the latch load voltage regulation can effectively prevent the terminal voltage from collapsing.
【學位授予單位】：華北電力大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TM727.2;TM712
[Abstract]:With the rapid development of large-scale ultra-high voltage / ultra-high voltage AC / DC interconnected power grid in China, the dynamic behavior of the system becomes more and more complex, with the continuous production and application of new equipment and new technologies in various power systems. This makes the long-term dynamic stability problem after the transient process become more and more prominent and gradually received great attention by the power system researchers. The dynamic characteristics of low-speed dynamic components such as generator over-excitation limiter and on-load voltage regulating transformer are the key factors that affect the long-term dynamic stability of large capacity and high proportion of urban power grid. It is very important to construct the stability criterion and safety and stability control measures to prevent the voltage collapse of urban power network. Based on the scientific and technological project of Beijing Electric Power Company, "dynamic Stability and Countermeasures of Beijing Power Grid", this paper takes the super-large urban power grid running in the ring zone as the research object. The effects of slow dynamic component movement on the migration characteristics and main electrical quantities of the system running point on the dynamic PV curve of the system are analyzed in the medium and long term process. In the course of the study, the load characteristics of load power varying with load terminal voltage and system frequency are analyzed, and the effects of static load model and dynamic load model on medium and long-term voltage stability are studied respectively. The mechanism of medium and long term voltage instability caused by over-excitation limitation and on-load voltage regulation operation is revealed. On this basis, the medium and long-term dynamic stability control criterion and margin calculation method are defined. The control strategy of multi-means to improve the level of medium-long-term stability is put forward. Finally, the effectiveness of stability criterion and control strategy is verified by dynamic simulation of Beijing power grid. The main conclusions of this paper are as follows: 1) the effects of different load models on simulation are studied. The moving characteristic of the running point of the integrated dynamic load model system with impedance and motor load satisfies the linear superposition principle related to the ratio of impedance to motor load. The simulation results show that the larger the proportion of motor load, the bigger the slope of the moving trajectory curve. 2) in the whole process dynamic simulation, whether the system is stable or not after the slow motion element moves is the same as the system running point after the moving state. The position on the PV curve is directly related. The system operating point A corresponding to the limit power point B of the PV curve after the state transition is taken as the critical point for long-term dynamic stability. It can ensure that the system running point can continue to run stably in the PV curve 3 after the slow moving element moves.) the system can respond quickly to the system caused by the slow moving element such as over-excitation restriction and load voltage regulation. The medium-and long-term stability of the system has a good optimization effect. The timely response of load cutting measures is the key to ensure the effectiveness of the strategy. The timely response load shedding action can ensure that the operating point of the system returns to the stable critical point before the slow component action, and then prevents the voltage collapse caused by the point moving to the unstable zone of the PV curve after the operation. In the process of simulation, it is proved that both the constant impedance model and the motor model have obvious negative voltage regulation characteristics in the on-load voltage regulation dynamic. Therefore, when the system is overloaded, the dynamic reactive support is insufficient and the operation point is close to the stable critical point, the latch load voltage regulation can effectively prevent the terminal voltage from collapsing.
【學位授予單位】：華北電力大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TM727.2;TM712
【參考文獻】
相關期刊論文 前10條
1 王晶;李衛(wèi)星;李志民;孫勇;;計及發(fā)電機動態(tài)的多端口網(wǎng)絡等值及中長期電壓穩(wěn)定監(jiān)視[J];中國電機工程學報;2015年18期
2 宋瑋;劉桂林;吳國e，
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