Jie Zhao

Dynamic characteristics analyse of pressurized water reactor Nuclear Power plant based on PSASP

The large capacity nuclear power plants have been widely constructed in recent years to cope with social economic development and electrical energy demands. Consequently, it is necessary to be aware of nuclear power plant (NPP) dynamic characteristics in order to study the transient and midterm dynamic process of power system. Due to lacking suitable NPP model which is described the detail characteristics of the Nuclear Power Unit in the power system simulation, at first, the paper presents functional description of nuclear power plant. Then a detailed pressurized water reactor (PWR) plant overall model for medium-term and long-term power system transient stability is proposed based on PSASP through user-defined modeling program. In the end, dynamic response characteristics of pressurized water reactor is presented. The simulation results are obtained.

Piecewise Model and Parameter Obtainment of Governor Actuator in Turbine

The governor actuators in some heat-engine plants have nonlinear valves. This nonlinearity of valves may lead to the inaccuracy of the opening and closing time constants calculated based on the whole segment fully open and fully close experimental test curves of the valve. An improved mathematical model of the turbine governor actuator is proposed to reflect the nonlinearity of the valve, in which the main and auxiliary piecewise opening and closing time constants instead of the fixed oil motive opening and closing time constants are adopted to describe the characteristics of the actuator. The main opening and closing time constants are obtained from the linear segments of the whole fully open and close curves. The parameters of proportional integral derivative (PID) controller are identified based on the small disturbance experimental tests of the valve. Then the auxiliary opening and closing time constants and the piecewise opening and closing valve points are determined by the fully open/close experimental tests. Several testing functions are selected to compare genetic algorithm and particle swarm optimization algorithm (GA-PSO) with other basic intelligence algorithms. The effectiveness of the piecewise linear model and its parameters are validated by practical power plant case studies.

Modeling and Dynamic Analysis of Nuclear Power Plant Reactor Based on PSASP

In this paper, we propose a dynamic mathematical model for nuclear power plant (NPP) reactor, and give an implementation in Power System Analysis Software Package (PSASP) through a user-defined program. NPP is modeled with a bipartite model that consists of the neutron dynamics module and thermodynamics module. Through the simulation results of NPP reactor under different disturbances, a conclusion can be drawn that the temperature effect and poisoning effect are crucial to the self-stability of reactor, which is not only the basis of safe operation of the nuclear power plant but also the aim of the designing. The simulation validated the proposed NPP reactor model, and it can be packaged with the other parts of the NPP detailed model in PSASP for further usage in dynamic calculation of the power system. Index Terms—NPP reactor, modeling, self-stability, PSASP. modified and new codes need to be added and debugged carefully via the compute languages which is used for the implementation. In this paper, a reactor model suitable for the high-dynamic analysis was proposed, in which the constant pressure sta- bilized was simplified, and the fuel/coolant temperature ef- fect and poisoning effect were considered to model the true characteristics of reactor more accurately. And we give an implementation of the proposed model in PSASP, a mature and powerful software for steady-state/transient/small-signal stability analysis. Although there is a mature database of models for nearly all electrical devices for PSASP, nuclear unit model is still lacking in the available commercial power system simulation software. And the reactor model can be packaged in the PSASP with the other parts of the NPP models to complete the database. And it can be easily invoked by other researchers for diverse dynamic analysis without modifying the existing program or adding new codes. Based on the program, the basic characteristics of the reactor were studied.

Research and Analyse for Pressurized Water Reactor Plant into Power System Dynamics Simulation

The nuclear power plants are being constructed and operated widely in recent years. Consequently, it is necessary to study nuclear power plants (NPPs) dynamic characteristics and power system dynamics simulations with nuclear plant after NPPs has been introduced into power system. At first, the paper presents functional description of NPP. Then a detailed and new models of generating plant with PWR have been developed in PSASP through user-defined modeling program for medium- term and long-term power system transient stability analyse. In the end, the results for power system dynamics simulation with nuclear plant are presented.

User-Defined Modeling of Pressurized Water Reactor Nuclear Power Plant Based on PSASP and Analysis of its Characteristics

Established the mathematical modules of pressurized water reactor (PWR) nuclear power plant (NPP) for the studying of the interactions of the power system and the nuclear power plant after its connecting to system, then set up the user-defined model of PWR NPP using the user-defined modules of the Power System Analysis Software Package (PSASP). Calculate the dynamic traits of PWR NPP without regulating system of reactor and responses to faults in single machine infinite bus system. The results showed the self-stabilization and self-regulation of PWR NPP due to the negative feedbacks of fuel temperature and coolant temperature and the small interaction between power system and NPP if the fault of power system can be eliminated quickly which proved the validity of the model. The model can be used to calculate the influences of the NPP induced by disturbances of voltage or frequency of the system also the influences of the system induced by the change of the output of the NPP after NPP connecting to the power system.

Reliability Evaluation of NPP’s Power Supply System Based on Improved GO-FLOW Method

NPP’s power supply system is repairable and there is common cause failure between the components. The repair rate is introduced and total signaling is considered in the improved GO-FLOW method, aimed at reliability analysis for NPP’s power supply system. Traditional GO-FLOW operators’ algorithms are improved. Comprehensively considering the effect of total signaling flow in the power supply system, the equivalent reliability parameter model and common cause failure probability model of multimodal repairable components are constructed. The improved GO-FLOW model of NPP’s power supply system is set up. Based on the proposed model, components’ reliability parameters are computed. The failure probability time-varying trend in thirty years, respectively, of NPP’s offsite power source and power supply system, is simulated and analyzed. Compared with calculation results of dynamic fault tree analysis method, the validity and the simplicity of the improved GO-FLOW method are verified. The effectiveness and applicability of the improved GO-FLOW model for NPP’s power supply system are proved by simulation examples.

Dynamic Model of Kaplan Turbine Regulating System Suitable for Power System Analysis

Accurate modeling of Kaplan turbine regulating system is of great significance for grid security and stability analysis. In this paper, Kaplan turbine regulating system model is divided into the governor system model, the blade control system model, and the turbine and water diversion system model. The Kaplan turbine has its particularity, and the on-cam relationship between the wicket gate opening and the runner blade angle under a certain water head on the whole range was obtained by high-order curve fitting method. Progressively the linearized Kaplan turbine model, improved ideal Kaplan turbine model, and nonlinear Kaplan turbine model were developed. The nonlinear Kaplan turbine model considered the correction function of the blade angle on the turbine power, thereby improving the model simulation accuracy. The model parameters were calculated or obtained by the improved particle swarm optimization (IPSO) algorithm. For the blade control system model, the default blade servomotor time constant given by value of one simplified the modeling and experimental work. Further studies combined with measured test data verified the established model accuracy and laid a foundation for further research into the influence of Kaplan turbine connecting to the grid.

Hydro Turbine Nonlinear Model Parameter Identification Based on Improved Biogeography-Based Optimization

The nonlinear model of hydro turbine considering the elastic water column was proposed, and the improved biogeography-based optimization (IBBO) algorithm was applied to identify parameters of this model. The cosine species migration model and the elitist reservation strategy were introduced into the algorithm to improve operating efficiency. Based on measured data, comparison of the effects of different identification methods was presented, including the IBBO algorithm, genetic algorithm (GA) and particle swarm optimization (PSO). The results demonstrated that the IBBO algorithm can be applied in parameters identification of hydro turbine nonlinear model, and it has the advantages of faster convergence and higher precision.

The Balance of Power System Peak Load Regulation Considering the Participation of Nuclear Power Plant

Nuclear power plants (NPP) have to face urgent requirement of participating in peak load regulation of power grid. The peak load regulation performances of NPP were researched. Based on the calculation and analysis on peak load regulation cost and benefit of NPP, the location, criterion and peak balance algorithm of NPP participating in peak regulation were proposed. Results of the actual research show that NPP possesses better ability of peak load regulation and the cost is lower, so NPP can participate in daily peak load regulation, which will improve both security and flexibility of power grid and enhance the efficiency of resource configuration. However, the depth and speed of peak load regulation by NPP are restricted by security and economy.