Research On Time Process-Oriented Power System Static Security Analysis And Daily Generation Scheduling

At present, the economic operation of power system, such as the daily generation scheduling, is calculated based on the sections with equal time intervals. The changing trend of load curve is not considered thoroughly. There are still benefit margins for the economic operation of power system. Furthermore, the economic operation scheme usually is established under the condition of intact power network. The security of power network with the losing of one element and the corresponding correction control are lacking of further study. However, the expense brought by one emergency commonly is higher that the benefit gained by economic operation of several years. And enough attention should be paid to the N-1 security of power system. With the constant renewal of measuring approach, the improvement of state estimation method and the development of load forecasting technique, much denser and more accurate data will be provided for calculation. If the data is fully utilized, the economy and security of power system definitely will be promoted. Based on the abundant measuring and forecasting data, the paper makes some study on the power system static security analysis and optimization with the time-process oriented method. The economy of power system is guaranteed while the security is promoted.Firstly, the basic theory and method of time-process oriented idea are presented. The improved agglomerative hierarchical clustering (IAHC), which synthetically considers the static security and economy of power system, is put forward to partition the time process preliminarily. IAHC takes into account the operation characteristics of power system, that is, all the data sections are in time sequence and the load injections distribute widely. And it is prior to the traditional partition method with equal intervals. The index to pick up the maximum section, the minimum section of each process is defined. And the way to get the mean section is introduced. The maximum and the minimum section are closely related to the security of power system in the process. The mean section of each process shows the load level that is much closer to the real operation state of power system.Secondly, based on the time processes partitioned by IAHC and the characteristic sections extracted, the time-process oriented static security analysis is expatiated. The fictitious maximum section of every sub-process is distilled. Multi-level contingency selection and ranking method is implemented on the fictitious maximum section. And the serious contingencies of each sub-process are selected and ranked rapidly. While the N-1 static security is specified as constraint, the time processes are further partitioned according to the principle that the control schemes are feasible in the whole interval.Thirdly, in allusion to the deficiency that the traditional daily generation scheduling roughly consider the load changing trend, the paper presents a novel daily generation scheduling that takes the load variation rate into account with time-process oriented method. During the periods of gentle load variations, the time processes partitioned by IAHC are fewer and last longer. And the mean sections extracted are closer to the actual load level of power system. By contrast, during the periods of abrupt load variation, there are more time processes with shorter time duration. And the mean sections depict in detail the load behavior in the pick-up and drop-down process and provide sufficient buffer time for power system to get through the critical peak and valley loads. Based on bottle neck analysis, the full-stage optimal algorithm is applied to make the daily generation scheduling. Compared with the traditional one, the method proposed attains better optimization effect without increasing any computational workload. Meanwhile, the active outputs of generation units are smoother in every time process and it is easier to coordinate with the automatic generation control (AGC).At last, time-process oriented static security analysis and daily generation scheduling are considered integratedly. And a multi daily generation scheduling (MDGS) method is brought forward. MDGS takes the N-1 static security into account and establishes the predetermined correction schemes of the serious contingencies forecasted. The security of power system is promoted while the economy is satisfied.The time-process oriented method adequately mines the measurement and forecasting data and makes careful analysis on the changing tendency of power system. In allusion to the changing state, the relative economic operation and correction control schemes are constituted. Under the condition of secure operation, the economic benefit of power system is increased.