The preliminary discussion of the applications for Special capacitor in new energy industry(1)

The preliminary discussion of the applications for Special capacitor in new energy industry（1）

Xushuang Sun ; Feng Zhou

(Tongling Tongfei Technology Co.,Ltd., Tongling , 244000) 

Abstract: With the energy crisis approaching, new energy has become one of the world's major energy in future. More and more enterprises will need use the high frequency and high pulse, high voltage, high current, high capacity , long-life special metalized film capacitors (hereinafter referred to as special capacitor), when design solar power, wind power, smart grid power management system, and battery module and the control system new energy vehicles.The article will make a preliminary study regarding the market prospect of special capacitors, the way to select special capacitors and so on.

 Keywords: new energy, wind power, smart grid, special capacitor, energy saving and environmental protection. 

0 Foreword
In modern electronic information industry, the capacitors are widely used in household appliances, computers, mobile communications, automotive electronics, wind power, smart grid, aerospace, rail transportation and other fields. "Decision of the State Council on accelerating the cultivation and development of strategic emerging industries" proposed that following seven industry: energy saving, new generation of information technology, biotechnology, high-end equipment manufacturing, new energy, new materials, and new energy automotive will be focused on cultivating. These emerging industries provide new opportunities and development space for capacitors, while also put forward higher requirements on capacitor manufacturing. All walks of life will focus on the new opportunities brought by new energy to their respective companies.

With the high-speed development of electronics, power industry and information technology, especially in recent years, the development of energy-saving and environmental protection, low-carbon emission reduction technologies, green energy (energy source, wind power, solar energy, ocean currents and tidal power generation etc.), and the smart grid development increase the demand for special metallized film capacitors. High-tech application and development put forward more and more strict requirements on capacitor variety, technical performance, reliability, structure, shape, physical dimension and the use of security. At the same time, the continuous improvement (dielectric material, processing technology, test technology) for special metalized film capacitors production technology and revolution in product design structure, greatly expand the application field of the special capacitor, promote the flourishing development of capacitor manufacturing industry.

1 Classification and market analysis of special capacitor

New energy and smart grid supporting special capacitor belongs to green environmental protection, prevent the pollution to the grid, anti electromagnetic interference and explosion-proof energy-saving type capacitor and has the advantages such as high voltage, small size, low loss, safety explosion-proof and earthquake-proof. With main function of absorbing the harmonic-filtering/improve the power factor-energy storage compensation,it is widely used in the field of wind power generation, power filter and compensation energy-saving, rail traffic electrification, all kinds of inverter and converter, power grid energy saving and power electric quality improvement, smart grid power transmission equipment etc,with broad market prospect.The series of products major include wind power filter compensation capacitor, electric locomotive capacitor, special filter capacitor, power grid and compensation high voltage capacitor. The literature [3] makes a preliminary analysis for four series of special capacitors market as follows:

1.1 Wind power filter compensation capacitor

As one kind of clean renewable energy, wind power is in the ascendant and get more and more attention around the world. It reserves huge. The world total amount is about 2.74 x 109 MW of wind energy resources, among which the available wind power is 2 x 107 MW. With the development of the world economy, developed rapidly in the wind energy market, global wind power takes 31% in 2009, a total of 37,500 MW of new capacity, and there is a new peak of global total installed capacity of 157,900 MW. Germany has reached 27,000 MW in Europe. Denmark, Spain and other countries wind power accounted for 30% of the national energy. The continued growth of wind energy, mainly from positive national energy policy of the world's major markets, as well as many national governments regard renewable energy as part of their economic recovery plan.

There are mainly 1.5MW and 0.75MW these two kinds of leading frequency converter in use for wind turbine generator at present. The latter will be eliminated in large wind power station.The 1.5MW inverter can be divided into two kinds: direct-drive and dual-feed expanding structure. Due to the advantage of direct drive inverter, in future the mainstream wind power generation inverter will be direct-drive structure (larger capacity than dual-feed structure), the power will be based on 1.5MW, 2MW, 3MW. Now the 1.5MW dual-feed wind power inverter has been mass use in domestic wind power station, the local 1.5MW, 2MW direct drive inverter will also gradually enter the market for mass use.

By the year 2013, with the stable production of wind turbine manufacturing domestic and joint venture, the market of domestic procurement for wind power compensation filter capacitor will present explosive growth.

1.2 Electric Locomotive Capacitor

The Literature [2] proposed, the power used as railway traction, was first appeared in the steam locomotive, then gradually replaced by the internal combustion engine and electric locomotive (electric railway, high-speed rail, urban rail transit operation, electric locomotive) . Due to the emergence of high power silicon rectifier technology, the DC - DC drive system of electric transmission diesel locomotive and electric locomotive is naturally replaced by more superior DC - AC transmission (AC generator or AC power supply → silicon rectifier→ DC motor). But with the development of power electronic devices in recent years which revolutionize converter technology, the high power thyristor especially the exit of high power GTO and development of the microcomputer control technology, has greatly promote the development of the locomotive traction technology, the advantages of ac drive is obviously played. And the emergence of AC - DC - AC drive since the 1970s (alternator→ AC power supply→ silicon rectifier→ inverter→AC motor), known as AC drive, naturally takes the replacement of the AC - DC transmission.

Currently the electrified railway use single-phase power supply to provide electricity for the trains, inevitably resulted in the unbalanced three-phase power system. Besides, most of China's current operating locomotive with AC - DC single phase half controlled thyristor rectifier system, such as SS4, SS8 and typical type SS9 locomotive, which is a harmonic source itself. Moreover, the termination of the electric locomotive is large impact load for grid, which has great influence on the electrified rail power grid quality and reactive power balance. Due to the technical indexes and economic performance of traction substation power supply are related to reactive power, harmonic and negative sequence, establishing the compensation device of comprehensive compensation function is very important. The comprehensive compensation should be mainly reflects in:

a) reactive power compensation, improve power factor; b) reduce negative sequence; c) reduce bus voltage losses and improve the level of network voltage;

d) reducing traction transformer power loss and net loss (loss reduction), increased capacity utilization (expanded) of traction transformer, and thereby improve the ability of transportation power supply, etc.

In China, the majority of reactive power compensation device of electric railway traction substation adopts the parallel capacitor compensation mode. Due to the use of classification compensation device, traction load changes, will cause light load reactive power compensation and heavy reactive power compensation, thus can not reach the national standard of the average power factor 0.90, resulting in a fine some even up to millions of cost, increase operating costs. Moreover, such compensation device generally adopt mechanical switch for capacitor, with slow response, which cannot satisfy the need of dynamic reactive power compensation of traction load. In order to solve above problem, SVG dynamic reactive power compensation device can better solve of the system reactive power fluctuations over compensation and compensation problem, improve the power quality; From an economic point of view, to avoid the huge fines of traction substation of per month, SVG itself has the function of filtering harmonics at the same time, it will save the harmonic control device of land use, and reduce the occupation of land area of traction substation. At present Tianjin power supply system, Shitai high speed railway power supply system, ten thousand tons of Baolan railway reconstruction project is adopted the method of dynamic reactive power compensation. SVG has superior performance, it is the environmental protection energy-saving products of the new century, it represents the development direction of dynamic reactive power compensation device, especially in the electrified railway, urban rail traffic, metallurgy, mining and other need rapid dynamic reactive power compensation area has incomparable advantage, SVG dynamic reactive power compensation device rquires important power electronic components - SVG compensation, filter capacitor, will meet rapid growth with the rapid development of SVG reactive compensation devices.

1.3 Special filter capacitor

Special filter capacitor is mainly used for medium frequency furnace, the magnetization and demagnetization machine; For all kinds of transmission equipment such as dry process cement rotary kilns, large medical equipment, ship propulsion equipment, Large lifting machine of mine, Large oil pump in oil field, military equipment and other kinds of motor, fan, water pump, compressor, and all kinds of welding inverter in the leading in welding machine industry in equipment manufacturin, assorted frequency converter secondary field.

An welder inverter power supply by using anyone of the MFD filter capacitor 4 uF, 5uF, 6 uF, one 20 uF of MFD filter capacitor, one 50 uF of MFD filter capacitor. Used in Frequency Converter Motor, blower, pump, compressor, the market of special filter capacitor for inverter power supply, gain sustainable development and expand rapidly due to the energy conservation and the state policy of emissions reduction.

1.4 Grid filter, compensation power capacitor

Compensation filter power capacitor, mainly used in electric industry power grid and the smart grid filter and concentration of reactive power compensation, while electric power industry is our country focus industry, the smart grid is the inevitable trend in the development of China's power grid, it will write a new chapter of power grid construction.

The Literature [4] put forward: By 2020, the whole society power consumption at about 7.5 trillion KWH, electricity installed capacity of more than 1.5 billion kw, implement installed 1000 watts, 5000 kilowatt-hours per capita goal. With the rapid growth of installed capacity, power grid in China will also have a big development in the next five years, and the matching of a huge urban and rural power grid renovation project has started. Grid end users are almost motor, fan, compressor these perceptual load, with big reactive power loss, and all kinds of electric circuits and brake pipe will bring a large number of harmonic, which must match capacitive compensation, to offset reactive power loss and absorb harmonic. At the same time Energy conservation and emissions reduction policy, as well as the more and more profound understanding of the importance on the aspects of filtering and compensating capacitor in power system of reactive power compensation to improve the power factor, saving energy and reducing consumption, absorb harmonic and improve the voltage quality and power line transmission capacity. All of this factor has provided a broad reactive compensation special capacitor equipment market for the electric power capacitor industry in our country.