Study on Risk Dispatch Model of Hydropower Station in the Market Environment

In the power market environment, due to the uncertainty of the reservoir inflow and the pool purchase price, it is very important to research power generation risk dispatch of hydropower plants, taking into consideration the benefits and risk control of both sides. This paper investigates power generation risk dispatch of hydropower plants in the market environment, and proposes a mathematical model which considers maximization of benefits and risk control, reflects control willingness of risk and benefits, resolves it with the PSO algorithm, finding more economic and reasonable results. The feasibility and validity of the model and resolving methods are verified by an example.     

Power Market Development with Considerations of Characteristics of China Power Sector

1. IntroductionThe global structure reconstruction and reform centered withelectric power market has brought the sense of crisis to thetraditional and conservative electric power industuy. Apparently,the challenges and chances exist at the same time. At present,China is undergoing full-scale social reforms. Thedetermination of the government and electric power industryitself to deepen the system reformation is very firm. The majorpurpose of the reform is to introduce competition and increaset…     

China''''s Electric Power Reform:Different Economics and Challenges

China's traditional power industry model and power market reform The Chinese government initiated the electric power market reform in December 2002. The reform has since de-integrated the old State Power Corporation into five state-owned power generation companies and two grid companies, established the State Electricity Regulatory Commission, created regional wholesale markets and started experimental wholesale compe- tition.Further de-integrationbetweentransmissionanddistribution and ret…     

Electricity Price Forecasting Based on AOSVR and Outlier Detection

Electricity price is of the first consideration for all the participants in electric power market and its characteristics are related to both market mechanism and variation in the behaviors of market participants. It is necessary to build a real-time price forecasting model with adaptive capability; and because there are outliers in the price data, they should be detected and filtrated in training the forecasting model by regression method. In view of these points, this paper presents an electricity price forecasting method based on accurate on-line support vector regression (AOSVR) and outlier detection. Numerical testing results show that the method is effective in forecasting the electricity prices in electric power market.     

Primary Study of Power-Exchanging Transaction Model Among Price-Varied Power Plants in Practical Conditions

At present, electricity price to grid of domestic power plants is priced by the national administration based on the policy of “one power plant with one electricity price to grid,” which is difficult to realize real bidding for access to grid in practice in a short term. This paper presents one kind of power-exchanging transaction model among price-varied power plants, which will be beneficial to price-varied power plants without any loss of profits of them and guarantee state-owned assets profits in minimum loss with no promotion of average price limit by power plants. Under ideal conditions, the computation results showed the sufficiency and necessity of power-exchanging transaction and maximum similarity with the requirements of optimized resources disposition in economics. The presented model is shown to be full of practicability and has been used in some part of power market.     

Status and Functions of Regional Power Grid Corporations

In line with power institutional reform and formation of the state power grid, status and roles of regional power grid corporations experienced several variations and are now being incessantly marginalized and weakened. The reform of turning regional grid corporations into regional headquarters of State Grid Corporation may be a better choice beneficial to group operation, intensive development and precise management. This article can be regarded as the author＇s personal opinion.     

Power Tariff Reform and Energy Constraint in China

Power tariff reform and power restructuring should be coordinately advanced. In the period of the power tariff reform, attention should be fully given to possible demand growth, investment characteristics and environment pressure when taking transitional measures. In the stage, focal point of the reform is to establish a rational system of sales price to power network. Moreover, it is necessary to raise the electricity price for household consumption. The highly-centralized system of state-owned power enterprises is the root-cause of some basic problems in the power industry. The system would cause a great power overproduction, squeeze out private and foreign investment and constrain efficiency improvement. Effective energy strategy and planning are a crux of dealing with crises of energy security. China needs a state-class energy administration body and should make massive research on energy economics.     

A robust model-free controller for a three-phase grid-connected photovoltaic system based on ultra-local model

In this paper, a robust model-free controller for a grid-connected photovoltaic (PV) system is designed. The system consists of a PV generator connected to a three-phase grid by a DC/AC converter. The control objectives of the overall system are to extract maximum power from the PV source, to control reactive power exchange and to improve the quality of the current injected into the grid. The model-free control technique is based on the use of an ultra-local model instead of the dynamic model of the overall system. The local model is continuously updated based on a numerical differentiator using only the input–output behavior of the controlled system. The model-free controller consists of a classical feedback controller and a compensator for the effects of internal parameter changes and external disturbances. Simulation results illustrate the efficiency of the controller for grid-connected PV systems.     

Pricing Mechanism in Power Market Construction

The reform on electricity pricing mechanism is a critical problem in power market construction in China, and is in mutual supplementation and promotion with the latter. In particular, the pricing mechanism for electricity fed into network and that for electricity transmission and distribution as well as the relationship between coal and electricity prices, etc. have to be studied in depth. This paper presents several solutions and suggestions to these problems.     

Speed up the Retrofit of Thermal Power Generating Units, Raise the Effectiveness of Power Plant Comprehensively

In the second step of the reform of State Power Corporation(SP), the organizational separation of power plant from powernetwork will be implemented positively, it will bring newpressure upon the power plant to bid for accessing to powernetwork and to implement the new operation mechanism offair, open and just dispatching, that is, the electric powerprovided by power sources will be competitive in low price andhigh quality. That also urges power plants into making technicalimprovements and cre…     

Opinions on Deepening Power Institutional Reform in the 11th Five-Year Period

Power industry is an important infrastructure for national economic and social development. In the 10th Five-Year Plan period, power institutional reform in China has gained important progress, the basic realization of separation between government and enterprises, as well as between power plants and power grids, the formation of competitive situation in power generation field and power enterprises＇ vitality have been strengthened; along with power tariff reform incessantly deepening, regional power market initiating and power legal construction further strengthening, the construction of power regulatory system achieving progression.     

Review on China Power Economy in 2004 and Near-Term Prospects

This paper introduces overall policy and economic environment for power industry in China. The policy environment tends to be favorable, while the economic environment seems worrisome. The latter is mainly due to energy transportation blocking and price escalating. The paper also introduces the performance and development of listed power companies, and points out that the power stock market is still promising and power industry is still valuable for investment.     

Management Innovations in Power Generation Groups

Since the institutional reform of power industry in 2002, power sectors, in particular electricity generation enterprises in China have been greatly changed, not only in institution and industrial pattern but also in operational environment. The year 2006 is a turning point of tense power supply lasting for three years and a half. The change of power supply situation in the 11th Five-Year Plan period and in-depth reform of power institutional system have placed serious challenges in front of power generation groups. In this new historical era, power generation groups can keep undefeated only by carrying out actively management innovations.     

“Powering Up” for the 21^st Century： The Power Supply Industry in Major Transition

The power supply industry is changing more today than ever before. From business composition to architectures, design methods, sourcing, geographic composition and infrastructure, every element of the power supply industry is changing. The challenges are dramatic, with solutions having long term impact. An overview is presented of the power supply industry today based on the author‘s industry association work, experience as a supplier, and discussions with industry leaders. Since power supplies is such a broad subject, the paper‘s focus is on some key aspects of the industry that may have wide interest to readers and participants. The major trends, market drivers, and issues are examined with some basic conclusions and challenges cited. The objective is to provide the reader with 1) a better overall impression of the state of the power supply industry is today 2) some insight into what the transitional driving elements are and 3) some ideas for assisting in the transitioning movements. The comments are mainly regarding North America and Europe, however these trends are affecting the Asian and Japanese regions.     

Simulation with Ideal Switch Models Combined with Measured Loss Data Provides a Good Estimate of Power Loss

Ideally,converter losses should be determined without using an excessive amount of simulation time.State-of-the-art power semiconductor models provide good accuracy,unfortunately they often require a very long simulation time.This paper describes how to estimate power losses from simulation using ideal switches combined with measured power loss data.The semiconductor behavior is put into a look-up table,which replaces the advanced semiconductor models and shortens the simulation time.To extract switching and conduction losses,a converter is simulated and the semiconductor power losses are estimated.Measurement results on a laboratory converter are compared with the estimated losses and a good agreement is shown.Using the ideal switch simulation and the post processing power estimation program,a ten to twenty fold increase in simulation speed is obtained,compared to simulations using advanced models of semiconductors.     

Goal and Progress of Power Tariff Reform——An interview with Liu Zhenqiu,Vice Director ofDepartment of Price,NDRC

● Power tariffreform has made many important and substantialprogresses in respect ofmarketization● The benchmark tariff is a revolutionary progress made in China's power tariff reform● Coal-electricity price linkage is a transitional approach which needs further improvement● The principle of T&D pricing is "cost plus profit," but it can also be based on pro rata control● China's electricity market should choose the mode of bilateral contracting combined withcentralized market● The direction of the power tar...     

Internal electrical fault detection techniques in DFIG-based wind turbines: a review

The keys factor in making wind power one of the main power sources to meet the world’s growing energy demands is the reliability improvement of wind turbines (WTs). However, the eventuality of fault occurrence on WT com ponents cannot be avoided, especially for doubly-fed induction generator (DFIG) based WTs, which are operating in severe environments. The maintenance need increases due to unexpected faults, which in turn leads to higher operating cost and poor reliability. Extensive investigation into DFIG internal fault detection techniques has been carried out in the last decade. This paper presents a detailed review of these techniques. It discusses the methods that can be used to detect internal electrical faults in a DFIG stator, rotor, or both. A novel sorting technique is presented which takes into consideration different parameters such as fault location, detection technique, and DFIG modelling. The main mathematical representation used to detect these faults is presented to allow an easier and faster under standing of each method. In addition, a comparison is carried out in every section to illustrate the main differences, advantages, and disadvantages of every method and/or model. Some real monitoring systems available in the market are presented. Finally, recommendations for the challenges, future work, and main gaps in the field of internal faults in a DFIG are presented. This review is organized in a tutorial manner, to be an effective guide for future research for enhancing the reliability of DFIG-based WTs.     

Trend of China’s Electric Power Industry During Economic Transformation

The year 2011 marks the commencement of China's "12th Five-Year Plan." Yet the most alarming keyword throughout the year in China's electric power industry is "power shortage." After a rapid development since the economic reform and opening up,China's electric power industry extricated itself from the long lasting nationwide power shortage,and kept the overall balance between demand and supply across the country over the 11th FiveYear Plan period.However,power shortage seemed to arrive unexpectedly all of sudden as it stepped into 2011.It is an unavoidable question:What are the trends of the power industry in 2012 and the years ahead?     

Reforms in the Chinese Electric Power Sector

This paper summarizes the reforms happened in the Chinese electric power sector in recent years.Although some major measures for the electricity reforms have made progress in a phase sense,including direct trading between major electricity producers and consumers,energy-saving power dispatch and the increase of electricity prices,the deployment of these reforms into practice is facing more difficulties than expected.The author also gives an outlook for the electric power reform in the 12th Five-Year Plan period,and deems that the government may not take substantial steps to reform the electricity system.Reforms on the electricity system will continue in a more moderate manner and focus on electricity prices.