1.2.1 Development status of domestic and foreign electric porcelain industry

Electric porcelain was a product of the 19th century industrial revolution. After humans mastered power generation technology, the transmission of electricity to the electric field was inseparable from insulating media, and the earliest applied insulating medium was electric porcelain. With the increase of power generation capacity and the extension of transmission distance, the voltage level continues to improve, and the requirements for the mechanical and electrical properties of electric ceramics are also increasing. In the mid to late 20th century, with the rapid development of industrial technology, the demand for electricity increased sharply, driving the development of ultra-high voltage and even ultra-high voltage transmission and transformation technology. At present, the 500kV AC/DC power grid has become the backbone transmission network in China (330kV in the northwest region), and the 800kV DC and 1000kV AC ultra-high voltage transmission and transformation systems are under construction. The rated mechanical strength of domestic disc suspension insulators has reached 530kN, and the bending strength of unglazed ceramic material samples has increased from 50-60MPa to over 180MPa, with glazed strength reaching over 200MPa.

Japan's electric porcelain manufacturing technology is in a leading position internationally. NGK Corporation (NGK) is a leading enterprise in the Japanese porcelain manufacturing industry and a global multinational company. It has first-class porcelain manufacturing technology and equipment, and can produce porcelain insulators for various line and power station electrical appliances with voltage levels up to 1100kV. The company's production of disc suspension insulators adopts 3 σ Quality control, with reports on the production and use of 700kN and 840kN products; The height of the components of the integrally formed pillar and hollow insulator reaches about 2.5m, and the bending strength reaches over 160kNm. The majority of the ceramic materials used are C130 porcelain according to IEC 60672-3.

In September 2001, the European Ceram Group and the American Electric Porcelain Products Group successfully merged to form the PPC Electric Porcelain Group. PPC Group currently has six factories in Germany, Austria, Sweden, Slovakia, Thailand, and China, with an annual production of approximately 30000 tons of qualified porcelain components. The main products include rod post insulators, hollow insulators, and long rod insulators. Its most representative product is the long rod insulator, which is made of tungsten antimony alloy adhesive and has a non breakdown structure, avoiding zero value breakdown of disc suspension insulators. Its performance is excellent, but its manufacturing difficulty and control requirements are high. Among various products, dry molding accounts for approximately 36%.

There are also internationally renowned electric porcelain manufacturers such as Lap Company.

There are over 400 domestic manufacturers of insulators and lightning arresters. In 2006, 152 enterprises with statistical data had a total industrial output value of 9.145 billion yuan, an increase of 31.85% compared to 2005; The sales revenue was 8.875 billion yuan, an increase of 32.65% compared to 2005; The industrial added value is 2.879 billion yuan, an increase of 35.77% compared to 2005; The export delivery value is 904 million yuan, an increase of 42.23% compared to 2005; The total profit was 779 million yuan, an increase of 40.27% compared to 2005. The total labor productivity (added value) is 80300 yuan/person, an increase of 34.60% compared to 2005. The top 5 enterprises in terms of total industrial output value in 2006 were Zigong Sadeville Tempered Glass Insulator Co., Ltd., Nanjing Electric (Group) Co., Ltd., Xi'an Xidian High Voltage Electric Porcelain Co., Ltd., Dalian Electric Porcelain Co., Ltd., and NGK Tangshan Electric Porcelain Co., Ltd. Among the top five, Zigong Sediville Tempered Glass Insulator Co., Ltd. produces single disc suspension glass insulators; Nanjing Electric (Group) Co., Ltd. mainly produces disc suspension glass insulators and bushings, and electric porcelain products also account for a certain proportion; Xi'an Xidian High Voltage Porcelain Co., Ltd. mainly produces pillar and hollow insulators, with a certain proportion of sleeve products; Dalian Electric Porcelain Co., Ltd. and NGK Tangshan Electric Porcelain Co., Ltd. mainly produce disc suspension porcelain insulators, and are the largest supplier of disc suspension porcelain insulators in China. Tangshan High Voltage Electric Porcelain Co., Ltd. has the largest production capacity of pillar porcelain insulators, with a production capacity of approximately 140000 porcelain insulator units in 2007. It should be noted that the number of enterprises with statistical data is less than half of the actual number of enterprises. The main ones without statistical data are composite insulator production enterprises and private enterprises that have developed in recent years. According to empirical data on the newly installed capacity of electricity and the production of insulators over the years, the sales revenue of the insulator industry in 2007 exceeded 10 billion yuan, with exports of approximately 200 million US dollars.

The domestic electric porcelain industry has advantages in production scale and technology among enterprises such as Xi'an XD High Voltage Electric Porcelain Co., Ltd., Nanjing Electric (Group) Co., Ltd., Dalian Electric Porcelain Co., Ltd., Fushun Legend Bushing Co., Ltd., Suzhou Electric Porcelain Factory Co., Ltd., and Tangshan High Voltage Electric Porcelain Co., Ltd. Xi'an Xidian High Voltage Electric Porcelain Co., Ltd. is the first in China to produce 500kV porcelain sleeves using isostatic pressure dry method, with technology leading the domestic level. Dalian Electric Porcelain Co., Ltd.'s suspension type porcelain insulators below 530 (550) kN level represent the advanced level in China.

Through technological transformation and the introduction of key foreign technologies and equipment, the overall level of domestic ceramic manufacturing technology is continuously narrowing compared to foreign countries. The isostatic pressure dry forming technology has been increasingly adopted by more and more electric porcelain production enterprises, gradually becoming the mainstream method for producing large-sized electric porcelain products of 500kV and above. The technical level of the key equipment in the electric porcelain industry, the kiln, has also reached or approached the international advanced level. By adopting a lightweight kiln structure, isothermal high-speed burners, and a relatively complete automatic control system, natural gas is used as the roasting fuel, which improves the firing quality of electric porcelain products and significantly reduces energy consumption.

Table 1 shows the comparison of domestic and international technical levels of typical insulator products.

Table 1 Summary and Comparison of Typical Product Classifications at Home and Abroad

Serial Number Product Category Main Technical Indicators Domestic and Foreign

1 Porcelain disc suspension rated failure load kN 530 840

Annual deterioration rate ＜% 0.02 0.01

Voltage level used kV 750 1200

2 porcelain long rod rated breaking load kN 160 300

Used voltage level kV-500

3 Glass disc suspension rated failure load kN 400 530

Voltage level used kV 500 1150

4 Composite rod suspension rated failure load kN 530 300

Used voltage level kV 750 1000

Material marking level ＞ kV 4.5 3.5

5 Composite line column rated failure load kNm 10 10

Used voltage level kV 110 110

Material marking level ＞ kV 4.5 3.5

6 Oil paper capacitive bushing dielectric loss tg δ＜％ 0.7 0.5

Voltage level used kV 750 1200

7 adhesive impregnated paper capacitive sleeve dielectric loss tg δ＜％ 0.5 0.5

Used voltage level kV 500 500

Rated breaking load of 8 porcelain pillars kNm 140 160

Used voltage level kV 750 1150

9 Composite pillar rated failure load kNm 100 100

Used voltage level kV 500 500

10 porcelain hollow rated breaking load kNm 120 130

Overall unit height m 2.5 2.8

Used voltage level kV 750 1150

11 Composite hollow rated failure load kNm 100 100

Overall unit height m 8 8

Used voltage level kV 500 500

 

1.2.2 Development Trends of the Electric Porcelain Industry

Electricity is the basic guarantee for social and economic development. China's power industry is in a period of rapid development, with annual installed capacity of over 100 million kilowatts added in recent years. The long-distance and high-capacity power transmission characterized by the mutual supply of electricity from the west to the east and from the north to the south is an important part of China's power grid construction. Therefore, the development of ultra-high voltage transmission and transformation projects is an inevitable trend in the development of China's power industry.

As a key supporting product for power transmission and transformation projects, electric porcelain should first meet the needs of China's ultra-high voltage and ultra-high voltage power transmission and transformation projects. Vigorously developing various electric porcelain products for 500kV and above lines and power stations is an important part of the development of the electric porcelain industry. At the same time, energy conservation and consumption reduction in the industry, accelerating technological progress, improving production efficiency, and stabilizing product quality are also important prerequisites for ensuring the healthy and stable development of the electric porcelain industry.

In the past decade, China's electric porcelain industry has shown the following development trends:

(1) State owned enterprise restructuring, relocation and technological transformation

During the "Tenth Five Year Plan" period, the main backbone enterprises, including Fushun Electric Porcelain Manufacturing Company, Dalian Electric Porcelain Co., Ltd., Suzhou Electric Porcelain Factory Co., Ltd., Tangshan High Voltage Electric Porcelain Co., Ltd., and Nanjing Electric (Group) Co., Ltd., have successively completed enterprise restructuring and transformed from state-owned enterprises to joint-stock enterprises. The restructuring of enterprises and the establishment of modern enterprise systems have brought new vitality to the development of the electric porcelain industry. Driven by strong market demand, most of the restructured enterprises have stable production, prosperous production and sales, and significantly improved economic benefits.

With the restructuring of enterprises, their financing channels have been expanded, and their financing capabilities have been further strengthened, which has led to the relocation and technological transformation of Dalian Electric Porcelain Factory and Suzhou Electric Porcelain Factory. After the relocation, the process and technology routes of the enterprises have become more scientific and reasonable, with advanced equipment, increased production capacity, and significantly enhanced development potential.

(2) The rapid development of private enterprises and the strong intervention of foreign enterprises

In the past decade, driven by strong market demand, the speed of private capital entering the electric porcelain industry has accelerated. According to incomplete statistics, there are more than 50 private enterprises above designated size that have been newly built or converted, mainly concentrated in rod shaped pillar porcelain insulators, hollow porcelain insulators, suspension porcelain insulators, and gradually becoming a new force in the market.

At the same time, foreign-funded enterprises have utilized their strong technological and financial advantages to strongly intervene in China's insulator industry, such as NGK Tangshan Electric Porcelain Co., Ltd., NKG (Suzhou) Electric Porcelain Co., Ltd., PPC Wuxi Insulator Co., Ltd., Tianjin Diefu Insulator Co., Ltd., and Zigong Saidiweier Tempered Glass Insulator Co., Ltd.

(3) Enhanced independent research and development capabilities, and industrialization of some high-tech products

In the past decade, China's electric porcelain industry has strengthened research and development of ultra-high voltage and ultra-high voltage electric porcelain products, especially high-tech and difficult products that rely on imports, through technological transformation, such as 400kN DC suspension porcelain insulators, 400kN, 530kN disc suspension porcelain insulators and glass insulators, 160kN long rod suspension porcelain insulators, 80kNm DC rod support insulators, 750kV rod support porcelain insulators, etc. The use of isostatic pressure technology to dry form rod shaped pillar porcelain insulators and hollow insulators, as well as the production of rod shaped suspension composite insulators using integral injection molding technology, have achieved large-scale production, enabling the basic localization of various insulators required for the construction of China's 500kV main power grid. The 750kV AC, 800kV DC, and 1000kV AC ultra-high voltage test lines also use independently developed electric porcelain products, It has effectively met the needs of the rapid development of China's power industry.

Despite the overall good development momentum of China's electric porcelain industry, there are still the following shortcomings:

(1) Some enterprises have poor economic performance. The reasons for this are not only the product structure, technical level, and management level of each enterprise, but also the long-term market disorder competition, low price competition, and difficulties in fund recovery that have plagued the insulator industry.

(2) Some high-end products have lagged behind in research and development, resulting in insufficient production capacity. The import of porcelain sleeves for circuit breakers of 330kV and above still accounts for over one-third of the total usage.

(3) High energy consumption per unit. At present, the energy consumption level of China's electric porcelain industry is: 1.09 tons of standard coal/ton of qualified porcelain for line porcelain insulators; Porcelain insulators for power station electrical appliances: 1.59 tons of standard coal/ton of qualified porcelain, which is 20% to 30% higher than the world's advanced level, and there is still significant energy-saving space.

Although the electric porcelain industry has made significant progress in the past 10 years, there is still a certain gap in product grade and preparation technology compared to the advanced level abroad. In order to enhance the competitiveness of China's electric porcelain products in the international market and promote the healthy and stable development of the industry, the future research and development focuses mainly on:

(1) Energy conservation, consumption reduction, and clean production technologies in the production process of electric porcelain, namely the use of new processes and technologies to further reduce the production energy consumption of electric porcelain and improve the product qualification rate.

(2) Purification and micro refinement processing technology of raw materials for electric porcelain, as well as serialization and standardization technology of raw and auxiliary materials.

(3) Research on special forming, sintering, and precision machining technologies for high-tech large-sized insulator products, such as injection molding, isostatic pressing forming, high-speed isothermal sintering, laser processing technology, etc., applied in the electric porcelain industry.

(4) Basic technical research on electric porcelain, including product design, simulation, sintering mechanism, detection and analysis technology, etc.

1.3 Prediction of Domestic Insulator Market Demand

Insulators are an important component of power transmission and transformation equipment, and their main users are the power industry. The annual installed capacity of new power generation is an important basis for predicting the demand for insulators. At present, the international demand for insulators has maintained a stable growth trend, basically increasing in proportion to the global economic growth rate. Relatively speaking, the demand growth in developed countries is slow, while the demand growth in developing countries is relatively fast. As the world's largest developing country, China's national economy is growing rapidly, with an expected average growth rate of 7.2% from 2000 to 2020. It is planned that by 2010, China's installed power generation capacity will increase from around 300 million kilowatts at the beginning of this century to 680 to 700 million kilowatts, with an average annual increase of over 40 million kilowatts. In fact, in the past three years, the installed capacity of new electricity generation has been around 100 million kilowatts. By the end of 2007, the planned target for 2010 had been basically achieved.

If calculated based on the annual additional installed capacity of 80 million kilowatts, the demand for high-voltage insulators in the market will also increase from around 100000 tons per year at the beginning of this century to 55-60000 tons per year. It is expected that after 2010, the demand for insulators in China will shift from the current high-speed growth to a stable growth rate that is in line with the national economic growth rate, with an average annual growth rate of about 6%, and reach around 900000 tons by 2020.

Table 2 shows the predicted data of China's insulator and lightning arrester industry for the total demand of the insulator market in 2010 and 2020. From Table 2, it can be inferred that the domestic demand for porcelain insulators was estimated to be approximately 2.225 million tons in 2010 and 3.6-4 million tons in 2020, accounting for 40-45% of the total demand for insulators.

Table 2 Forecast of Total Demand for Insulator Market

Number Name Unit 2010

Demand in 2020

Requirement remarks

1. 10000 tons of line insulators 33.2~40.6 66, of which composite insulators account for about 45%, glass insulators account for 35%, and porcelain insulators account for 20%



Among them: 10000 tons of suspension insulators, ranging from 23.4 to 29.8 47

2. 10000 tons of electrical insulators for power plants 14.4-17.026, of which composite insulators account for about 10%

2.1 10000 sets of 110kV and above hollow insulators, 30.0-36.6 60, of which 50% are SF6 hollow insulators

2.2 Ten thousand rod insulators of 110 kV and above, 50.4~57.696

2.3 Ten thousand capacitive bushings of 110 kV and above, 3.8-5.0, 7.5

3. A total of 10000 tons of high-voltage insulators, ranging from 47.8 to 57.688, of which composite insulators account for about 30%