Li Jiajue

Bio: Li Jiajue is an academic researcher from Electric Power Research Institute. The author has contributed to research in topics: Renewable energy & Electricity generation. The author has an hindex of 2, co-authored 8 publications receiving 9 citations.

Economic Benefits of Nuclear Power Plant Participating in Peak Load Regulation of Power System

Abstract: In contemporary times, the global energy crisis and environmental pollution are becoming more and more serious, and mankind is constantly exploring the sustainable development of economy, energy and environment. In this context, nuclear power as an economic, clean, environmental protection of energy, has been favored by many countries. In this paper, the necessity and possibility of nuclear power network peak Regulation are analyzed in detail, firstly, the demand and current situation of peak regulation in domestic power network are analysed, and the main measures of power network peak shaving are studied. The research shows that with the development of nuclear power and the complication of power grids, the participation of nuclear power in peak regulation will be an indispensable means for the future power generation. This paper studies the economic benefits of the power plant participating in the peak load regulation from the angle of economy, at the same time, analyzes and collates the different methods and forms of the domestic and foreign nuclear power units participating in peak shaving, and lays the theoretical foundation for the nuclear power units to participate in the power network peak shaving.

Research on Joint Planning of the Source-Grid-Load with New Energy System Energy Balance and Economy

Abstract: With the rapid development of the economy and the depletion of conventional energy sources, it is imperative to vigorously develop new energy sources. The new energy power generation industry, represented by wind power and photovoltaic power generation, has gradually become industrialized and scaled up. Its grid-connected operation effectively relieves the load pressure that the grid is subjected to. However, the output of new energy sources is random and uncontrollable. After grid connection, it will increase the uncertainty of the system and affect the stable operation of the system. Therefore, how to safely and effectively absorb intermittent renewable energy has become a major practical problem facing the new energy power system. Current research results at home and abroad mainly focus on the optimal design of the power supply on the supply side, the optimal dispatch strategy on the grid side, and the demand side. Response mechanism and planning management. Studies involving the stability and economics of power system operation and the joint planning of source and load resources are still in the preliminary stage. Therefore, the establishment of a new energy power system energy balance, economy and the joint planning model of the source and the load provide a theory for the country to promote supply-side structural reforms, formulate phased energy-saving emission reduction targets, renewable energy power supply construction standards and electricity price subsidies and other related policies.

Research on Economic Operation of Multi-source Peak-Shaving Involving Nuclear Power

Abstract: With the development of economy, large-scale access of wind power generation and other non-schedulable resources, and the difference in load peaks and valleys in the power grid have also increased year by year, making the peaking pressure of power grids with thermal power generators as the peak-shaving subject even more severe. This paper studies the operating characteristics of nuclear power units and establishes a multi-source coordinated planning model for pumped-storage-nuclear-wind power-thermal power projects. The optimization goal is to minimize the overall cost of equal annual values, and to use nuclear power's safety-adjustable domains and operations as constraints. The example shows that the model built in this paper improves the capacity of system wind power absorption, and effectively relieves the peak pressure of conventional units, and improves the economic efficiency of power system operation.

The effect of large-scale electric heating heat storage load coordinated operation on abandoned wind consumption

Abstract: Large-scale electric heating heat storage load is of great significance for eliminating wind and abandoning wind. However, power grid dispatching needs to coordinate these different types and different capacity loads so that it does not affect its own safe operation. The grid plays a bigger role. To this end, the large-scale electric heating heat storage load is divided into two categories: one is distributed small capacity; the other is centralized large capacity. The two load operation characteristics are modeled, and a coordinated operation strategy of two loads is proposed. The calculation of the actual data of a provincial power grid shows that the distributed has the characteristics of timing and fixed amplitude, and the centralized has the characteristics of dynamic adjustment. The distributed consumption is the low-level electricity, which can improve the ability to dissipate the wind and improve the peaking capacity of the power grid; most of the centralized consumption is the abandonment of wind power, but also can improve the dynamic peaking ability of the power grid.

Coordinated Optimization of Electric-Thermal System for Renewable Energy Clean Heating

Abstract: In recent years, Using renewable energy is the trend of world energy development. The volatility of renewable energy is increasing along with its installed capacity magnfying, resulting in abandoned wind, light and other issues, impacting renewable energy consumption seriously. In order to solve this problem, trading the abandoned wind and light and using them supply based on power market means under the existing scheduling system can effectively promote the elimination of renewable energy, reduce the consumption of fossil fuels such as coal, and protect the environment. China's renewable energy has been growing rapidly. However, the phenomena of wind and solar power curtailment because of the lack of the peak load regulating capacity in power system, CHP(Combined Heat and Power)operating on the principle of power determined by heat”, the mismatch between installed capacity of renewable energy and the demand for electricity, the lack of local consumption capacity, the unbalance between renewable energy power generation and grid construction, and the transmission capacity restrictions, still exist, which brings serious challenge to power system economic operation. The randomness, variability and uncertainty of renewable energy power generation further increase the difficulty of grid connected consumption. To solve the problem of renewable energy consumption, measures should be taken from the aspects of generation, grid, load, storage, power market and other areas. Focusing on the issue of renewable energy consumption, the following research was carried out: considering using the multi-energy complementary strategy improve the ability of renewable energy consumption, the integrated electricity-heat energy system which is coupled by CHP units and power-to-heat equipment is researched and a combined heat and power dispatch considering the energy storage characteristics of the heating network is formulated. In the optimal dispatch model which comprehensively takes into account the complementary characteristics of electrical system and the system-temperature dynamics equation considering transmission delay in the pipelines is used to reflect the energy storage characteristics of the heating network. In addition, the transmission loss in the pipelines, the user flexible demand for thermal energy and other heating network constraints are taken into account in the model. The simulation indicates that the proposed model can coordinate the generation, grid, load in the system and realize optimal matching of heat and power thus improve the renewable energy consumption ability.

Dispatching optimization model of gas-electricity virtual power plant considering uncertainty based on robust stochastic optimization theory

Abstract: With the rapid development of renewable energy, virtual power plant technology has gradually become a key technology to solve the large-scale development of renewable energy. This paper focuses on the stochastic dispatching optimization of gas-electric virtual power plant (GVPP). Based on this, wind power plant, photovoltaic power generation and convention gas turbines are used as the power generation side of GVPP. Power-to-gas (P2G) equipment and gas storage tank can realize the conversion and storage of electricity-gas energy. Price based demand response and incentive based demand response are introduced into the terminal load side to regulate the user’s electricity consumption behavior. GVPP bilaterally connects power network and natural gas network, which realizes the bidirectional flow of electricity-gas energy. Firstly, taking the maximization of economic benefits as the objective function, combined with the constraints of power balance, system reserve and so on, a dispatching optimization model of GVPP participating in multi-energy markets is constructed to determine the operation strategy. Secondly, wind, solar and other clean energy have the characteristics of random and fluctuation, which threaten the stable operation of the system. Therefore, a stochastic dispatching optimization model of GVPP considering wind and solar uncertainty is established based on robust stochastic optimization theory. Thirdly, the evaluation indicators of GVPP operation is determined, which can comprehensively evaluate the economic benefits, environmental benefits and system operation of virtual power plant. Finally, in order to verify the validity and feasibility of the model, a virtual power plant is selected for example analysis. The results show that: (1) After the implementation of price based demand response and incentive based demand response, the system load variance changes from 0.03 to 0.013. Through the comparison of load curves, it is found that demand response can play a role of peak-shaving and valley-filling and smooth the power load curve; (2) Stochastic optimization theory can overcome the uncertainty of wind and solar by setting different robust coefficients Γ which reflects the ability of the system to withstand risks; (3) The optimization effect after introducing the P2G subsystem makes the amount of abandoned clean energy close to zero. The operation risk of system is reduced, and the carbon emissions are reduced by 370 m3 too. The market space is expanded from electricity market mainly to natural gas market and carbon trading market.

Thermal-Oxidative Aging Effects on the Dielectric Properties of Nuclear Cable Insulation

Abstract: In order to satisfy demands of cable insulation for nuclear power, a low-smoke, halogen-free flame retardant and better cryogenic property insulation was prepared. The effect of thermal-oxidative aging on the dielectric properties was researched in this paper. The changes of chemical structure and thermal-oxidative stability caused by aging were characterized by Fourier transform infrared spectroscopy and a differential scanning calorimeter. The results showed that, the oxidative-induced stability reduced as complex products accumulated during aging. The dielectric properties including polarity, conductivity and breakdown at different aging stages were measured. For comparison, tensile testing was performed. The parameters related to conductivity changed notably, and were comparable with the changes in mechanical properties.

Modeling and Stability Analysis of Parallel Inverters in Island Microgrid

Abstract: The island microgrid is composed of a large number of inverters and various types of power equipment, and the interaction between inverters with different control methods may cause system instability, which will cause the power equipment to malfunction. Therefore, effective methods for analyzing the stability of the microgrid system have become particularly important. Generally, impedance modeling methods are used to analyze the stability of power electronic converter systems. In this paper, the impedance models of a PQ-controlled inverter and droop-controlled inverter are established in d-q frame. In view of the difference of output characteristics between the two control methods, the island microgrid is equivalent to a double closed-loop system. The impedance model of the parallel system is derived and the open loop transfer function of the system is extracted. Based on the generalized Nyquist criterion (GNC), the stability of parallel system working in island microgrid mode is analyzed using this proposed impedance model. The simulation and experiment results are presented to verify the analysis.

Evaluating peak-regulation capability for power grid with various energy resources in Chinese urban regions via a pragmatic visualization method

Abstract: With the development of renewable energy and the increase of peak–valley load difference, amounts of power grids in Chinese urban regions present great insufficiency of peak-regulation capability in recent years. It is necessary to evaluate the peak-regulation capability of power grid quantitatively and discuss the available measures to maintain the sustainable operation of urban power grid. This paper proposes a visualization method for evaluating the peak-regulation capability of power grid with various energy resources, which visualizes the peak-regulation supply by the cumulative histogram with typical unit on–off state combinations (UOSCs). In the proposed method, a cluster center-based extracting method is developed to reduce the number of UOSCs significantly and improve the visualization of histogram. Compared with the traditional optimization model-based methods, the proposed method is more pragmatic because it features high efficiency and is intuitive to applied. Numerical experiments based on a 5-unit system and the practical East China Grid (ECG) in Chinese urban regions are carried out to verify the validity of the proposed method. Further, two typical peak-regulation problems in ECG are analyzed by the proposed method and four measures with policy guidance are discussed to enhance the peak-regulation capability of ECG. • A visualization method of evaluating peak-regulation capability is proposed. • Effective clustering method reduces the number of unit on–off state combinations. • Two typical peak-regulation problems in Chinese power grid are analyzed. • Four measures are discussed to enhance the peak-regulation capability.

A Power and Energy Joint Optimization Model and Its Application for Long-term Large-range Wind Power Accommodation

Abstract: In order to solve wind power accommodation problem in China,this paper proposes to take advantage of clean energy's long-term seasonal fluctuation characteristics over annual or monthly period,or to utilize the complementary nature of power supply and load characteristics in different regions.By building power and energy joint optimization model for long-term large-range wind power accommodation to minimize system operating costs,key problems like temporal-coupling power and energy joint optimization modelling problem,multi-generation,generation and transmission coordinative optimization modelling problem are solved.In addition,quantified decision making for long-term large-range wind power accommodation is achieved by using mixed integer programming(MIP).The model is tested with a practical example of a regional grid power system.The numerical example shows that the model can coordinately optimize different types of generating units and transmission lines in a long period,and improve the accommodation level of wind energy.