Study on the Energy Dispatch Strategy of PV Power Plant

LIU Shu-ping，MA Jiao-jiao

Abstract: Now the energy efficiency of the PV power plant is low. For this case, this paper presents a PV power plant energy scheduling strategy.It includes new grid scheme and scheduling algorithm.Through the establishment of PV power station network model and the method of computer simulation of its scheduling algorithm, this paper describes its realization way, and then proves that the scheduling strat? egy is correct and the effectiveness of improving energy conversion rate. At the same time, the PV power station scheduling strategy aslo re? duces the environmental pollution, and alleviates the energy crisis and environmental crisis.

Key words: photovoltaic power plant; grid-connected mode; scheduling algorithm; energy efficiency

中圖分類號：TP302文獻標識碼：A文章編號：1009-3044(2012)23-5697-04

1 Introduction

Solar energy as the one kind of emerging of green energy, with its inexhaustible, an inexhaustible, clean no pollution, no area limits on the unique advantages, become the focus of attention, and are widely used in many fields. And it is the highest, most technical content strate? gy for the future development of the new energy. Solar photovoltaic power plant achieves the use of renewable energy, its first advantages is to save the electricity grid in order to save increasingly scarce one-time resources, while reducing pollution emissions, which is a kind of social benefits.

2 Analysis of Present Study

The solar photovoltaic power plant energy controls include the maximum power point tracking control, battery charge and discharge con? trol, inverter control, off-grid and grid-connected control. These controls have carried out a detailed study in a large number of papers.

But the study of solar energy scheduling problem is less at present, so this article will focus on this issue. The reasons are as follows: First, solar energy is infinite and scattered, so at present the utilization of solar energy is still low. Second, renewable energy power plants are often built in the places far away from the concentration area of electric energy consumption. This requires energy dispatching.

3 The new grid mode of pV power plants

Grid-connected solar photovoltaic power generation system includes: solar cell components, controller, battery, inverter, the user that lighting load. Among them, solar cells and batteries as power system, controller and inverter to control protection system, load for system ter? minal

Photovoltaic power station will be Internet with each other in the future. It can not only meet the need of local load at ordinary times, but also can reserve power. When the other sites appear electricity shortage, we can make a remotely scheduling, to compensate electricity short? age site.

This paper presents a new type of photovoltaic power plants grid-connected mode. It is different from the traditional grid is that conven? tional photovoltaic power station grid-connected mode is connected with the national grid, while the new type of photovoltaic power plants grid-connected mode is that each site connected to each other, based on the conventional photovoltaic power station grid-connected mode. When the power of a site is low, it dispatches the power from other site that electricity rich at first. Until this mode cannot satisfy the meet, it was connected to the national grid. At the same time, when the power of all site are relatively abundant, it can feedback to the national grid. This grid-connected management energy mode realizes the solar energy scheduling.

New grid-connected mode of photovoltaic power plant includes two levels, namely, senior and junior. Junior grid-connected mode uses a star connection, that is, a dispatch centre is connected with various PV power plant site, so that each site are connected to other through the dispatch centre, realizing the circulation of energy flow. Junior grid topology is shown in Figure1.

Senior grid-connected mode is that make each junior dispatch abstract into a site again, then the site after abstract connected to each other. Each junior dispatch centre connected to each other, unified by a senior dispatch centre. Connecting according to the following routing rules: a, it should first be connected to the site from which nearest; b,compared the power between the load with the new site, if it was at the