Ji Jianwei

Research on improvement method of distributed generation optimization configuration

The influence on distribution network of the distributed generation (DG) is closely related to the location and capacity connected to the DG, therefore it is very important to study the problems of site selection and capacity determination. The reactive power optimization is considered to improve the voltage level of power grid and reduce line losses. According to the capacity of the DG, The problem about selecting site and determining capacity is decomposed into two kinds of pattern with Parallel operation and island operation, which means comprehensive target of grid losses. voltage deviation and static voltage stability margin is optimal while DG is full load. Optimal allocation model of DG is established, the constraints condition includes node voltage, the transmission current of line, the single DG capacity and the total capacity of all DG. The genetic - ant colony hybrid intelligent algorithm is put forward to calculate the location and capacity of the DG. Simulation results show that the method is effective in problem of location selecting and capacity determing of DG.

Application of ANFIS for modelling and simulation of the greenhouse environment

In order to achieve favorable greenhouse environmental conditions for plant growth, modeling and simulation of greenhouse environments is very essential. In this paper, a flexile tool which called ANFIS is used to model the greenhouse climate in the North of China. A set of published data was used to train and test this model. The values predicted by the ANFIS model were compared with the measured data. The accuracy of the model is checked using several statistical and graphical criterions. The presented method in this paper is a new approach in estimating environmental factors and faster and simpler solutions can be obtained.

Research on feeder protection strategy of distribution network connected with micro-grid

Traditional power distributed network is transformed from single power supply radial network to more than one power supply loop network, direction of the power flow is changed, Therefore action of right protection cannot be completed in the micro-grid operating in the grid-connecting mode and two kinds of operation mode switching of interconnection and lonely island. The four standard of distribution system protection namely, selectivity, reliability, sensitivity and quick action cannot be effectively meet. In paper, influence on relay protection of the micro-grid is expounded in order to solve the problem of micro power grid relay protection, according to the load sensitivity of feeder circuit, current differential protection module and inverse time over-current protection module are established, the parallel operation protection strategy is designed, the simulation results with the typical micro-grid show that performance of the proposed protection module is more rationality and effectiveness.

Research of PID Algorithm for Valve Controlled Hydraulic Motor Variable Rate Fertilizer Control System

In this system, the electromagnetic proportional valve is the actuator, and the valve controlled motor is controlled object, and the speed sensor is the feedback element, to send out the orders by industrial computer, to control the motor output speed by controller. According to the principle of the circuit and fluid mechanics, set up the mathematical model of the valve controlled hydraulic motor variable fertilization system. PID parameters tuning of system were performed by Ziegler-Nichols method, get the coefficient of increment algorithm. The step response of P, PI and PID of variable rate fertilization the system were studied by MATLAB/ SIMULINK, results show that: PID algorithm system, the overshoot was small, setting time was short, the number for oscillations was little compared with the P algorithm and PI algorithm, the dynamic performance of the system is excellent. The laboratory experiments results showed that: In the process of system operation, PID algorithm tracking speed was rapid, and steady-state error is smaller. Therefore, the electro-hydraulic proportional variable fertilization system with PID algorithm has good dynamic performance and steady state performance, and can meet the requirements of variable assignment.

Experimental Study on Valve- Controlled Hydraulic Motor Variable Rate Fertilizer System

The dynamic model of valve control hydraulic motor Variable Rate Fertilization control system was established by the mechanism analysis, applying MATLAB/Simulink to research dynamic characteristics of Variable Rate Fertilization control system. The results show rapidity and accuracy were improved, static performance was optimized. Further experiments of the PID control system show that the output stability and the control effect is excellence.

The characteristics and mathematical model of hot air drying Schisandra

The Study is focusing on investigate Schisandra by using the circulating hot air and drying device. We attain the drying characteristic curve of the Schisandra through variety of different tests. The experiments reveals the best drying results, which is when the temperature of the hot air is 60°C; the velocity of the hot air is 0.3m/s; the density of material is 15kg/m2. We established the hot air drying Schisandra model based on the Page equation by comparing three drying models created by different equations. The drying model provides reliable theoretical foundation for the design and operation of the hot air drying process of Schisandra.