Study On The Control Strategy Of The Third Frequency Adjustment With The Participation Of The Nuclear Power

The power system must ensure the quality of electrical energy, frequency is one of the most important operating parameters. To avoid the frequency deviation exceeding the limit, there are three frequency adjustment methods:the primary frequency adjustment, the second frequency adjustment and the third frequency adjustment. The third frequency adjustment deals with load fluctuations with large fluctuations and time scales of hours. It’s the base of theother two frequency adjustment methods, and its completion will directly determine the pressure of the adjustment methods, then affecting the stability of the entire system frequency. So, it seems that the third frequency adjustment plays a vital role in maintaining the balance of active power in the power system.China began to carry out the "Up Greatly Press Small" power Construction Policy in 2006. This policy is to improve the utilization of coal energy, and give full play to the effectiveness of thermal power units. So, inefficient small-capacity units with high loss have been shut down and high-capacity units with low loss is close to full capacity operation, resulting in a serious shortage of capacity of the third frequency adjustment units. What’s more, as a clean and efficient way of generating, the wind power parallels in more and more frequently. However, the randomness and uncertainty of the output make the system equivalent load volatility increasing and bring greater pressure to the third frequency adjustment. Considering the above circumstances, it’s needed to look for new forms of energy generation units to be involved in the third frequency adjustment. Developing the fossil energy supply to solve the problem is irrational and uneconomic. As a result, making use of the frequency adjustment characteristic of the non-fossil energy supply is the effective method.After analyzing the characteristics of various types of non-fossil energy supply, this paper concludes that only nuclear power is likely to ease the pressure of the third frequency adjustment. Then, this paper proposes the idea of the introduction of nuclear power, and develops the control strategy in which thermal power and nuclear power can be well coordinated. The control strategy should be called "’Wind decomposition, Unit grouping" Firstly, this paper analyzes the rapid development of nuclear power and the features of other forms of energy generation. According to the fairness of frequency adjustment task and the inability of other types of power generation to participating in the third frequency adjustment, it’s necessary to introduce the nuclear power to the third frequency adjustment. Then, make in-depth study of working principle of nuclear power plants and power adjustment characteristics. Proposing the implementation of tou power price is to use the price leverage to ensure the economic interests of the unit involved in frequency adjustment. As a result, come to a conclusion that the introduction of nuclear power to the third frequency adjustment is with technical feasibility and economic viability. Secondly, explore the control thought and strategy of rational use of nuclear resources to participate in the third frequency adjustment. Under the premise of meeting the economic and security requirements, coordinating thermal power with nuclear power to get the best adjustment results is needed. By analyzing the volatility characteristics of wind power output, it can be concluded that wind power equivalent load contains two different kinds of components. The first component has high fluctuations but do not change frequently. The second component dose not have high fluctuations but change very frequently and randomly. The proposed "Wind decomposition" strategy separates the two components. Then compare the control performance in nuclear power plants and thermal power plants. The "Unit grouping" strategy is proposed to make full use of the advantages and characteristics of each two unit and to track the two load components separately. At last, do the case analysis by building a simulation system. Comparing system frequency quality, the second frequency adjustment unit output and tie-line exchanging power in three strategies to illustrate that the "Wind decomposition, Unit grouping" strategy can guarantee the stability of the system frequency in the case of the introduction of wind power.