Breakthrough on Electrified Cleaning Technology in China

Rong xiaoping

    I.Causes of circuit failures

   Usually, because of air pollution (even deteriorated day by day) and different environments and management conditions where the equipment is located,, the contaminated substances such as dust,oil stain,acid and alkali(including their gases), salt, humidity,carbon stain ,metal dust , and various mechanical dirt etc. are inevitably absorbed on the circuit surface and other positions.Additionally,under the effect of static accumulation and electric field force ,the accumulation of contaminants is enforced, and various contaminants are firmly attached to the circuit surface, deeper layer and other parts . Dust, oil stain, acid and aldali (including gases), salt, moisture, carbon stain, metal dust, various mechanical dirt and accumulated static electricity etc. are called as harmful combination contaminants of electrical equipment.

The basic cause of electrical equipment failure is the existence of harmful combination contaminants.

For precise circuits , since salt, acid and alkali (including gases) are combined with humidity or water content to form electrolyte solution and plus the existence of carbon stain or passive metal serves as cathode and anode of primary battery reaction, which make circuital surface take place primary battery reaction and cause electrochemical corrosion, electric leakage, short circuit and electric immigration etc,; while dry dust can also cause poor contact at contacts and bring about a discharge, which will result in bad heat radiation and cause fire accidents. Acid and alkale (including gases) can corrode circuits through redox. Static accumulations of diferent extent can cause soft and hard breakdown upon components.

For high-voltage circuits, the primary cause of electrical pollution flashover accidents is the accumulation of fouling material on the surface of insulator. It reduces resistance of insulator surface, increase the leakage current, and finally cause the flashover.

As the successful rate for switching on after pollution flashover tripping is quite low, pollution flshover insulator is inclined to cause large-scale and prolonged malignant power failure. As a result, the hazard of pollution flashover accidents is severe, and the pecuniary loss caused by it takes a sizable proportion in the total circuital accidents.

Similarly, there is a depostion of fouling material on the surface of general row, terminal, switch, mutual inductor, knife switch, contactor, relay, comtacts of electrical equipment. That reduces the insurability, increases leakage current, and causes accidents such as short circuit, arc light and radiation failure. It severely influences regular work of equipment, shortens operation time and service life, increases running cost, poses the problem of personal safety, and greatly influences economic and social effectiveness.

   II.Necessity and purpose of circuit electrified cleaning and maintenance

The existence of harmful combination contaminants causes circuital electrochemical corrosion, creepage, short circuit, electro migration, arc light, and bad heat tadiation, and it also brings about a continuing rise in costs of commuication sercice provider and other service providers. Maintainers are weighed down with work because of the increase in the magnitude, frequency and time of replacing hardware (modules).Especially for those communication common carriers, the time of installation is quite long. It should be scheduled to the order of the day for communication service providers such as communication common carriers how to reinforce maintenance work and improve maintenance techniques.

On the other hand, since 1980s, with the rapid development of production and the more and more severe air pollution in our country, pollution flashovers of power network equipment have increased dramatically. Catastrophic large-scale pollution flashover of power network occurred frequently nationwide:In March 16, 1986 there was a  large-scale pollution flashover of 110~220KV power network in lanzhou:on February 17, 1987, there was a large-scale pollution flashover of 110~330kV power network in Guanzhong Area; on December 28, 1987, there was a large-scale pollution flashover of 200~500kV power network in Liaoxi in northeast China;on January 6 and December 5, 1989, there was a large-scale pollution flashover of 32 transmission lines and 4 transformer substations of Huadong 220~500kV power network ,which caused a power failure in main network;form February 10 to February 28,1990 there was a large-scale power failure at Jingjintang power network, Hebei power Network, Henan west and north power network. Form the end of 1996 to January of 1997 there were large-scale pollution flashover accidents in east China,central China,north China, northwest China and Shandong power Network. At the beginning of 1998, there were large-scale pollution flashovers in east China, north China and Shandong; From December of 2000 to February of 2001 there were large-scale pollution flashovers at Henan Yubei Power Network and Shenyang Power Network. They all caused severe lossees in our national economy.

Thus it can be seen that the technique of equipment maintenance in the fields such as communication and electric power needs improving.

The purposes of electrified cleaning maintenance for equipment cercuit:

(1)To eliminate hazardous material such dust, oil stain, humidity and carbon stain on equipment surface and deeper layer; to eliminate circuit board creepage and electrochemical corrosion, and to eliminate the source which causes the change, digeneration and invalidation of circuit performance;

(2)To eliminate static effectively, prevent the circuit from soft and hard breakdown, ensure the normal work of equipment, and prevent the occerrence of great hazardous accidents;

(3)To eliminate the source which causes pollution flashover and brume flashover;

(4)To reduce time, number. Manpower of replacing hardware or components,to decrease cost of maintenance;

(5)To prevent equipment from ageing, prolong service life raise the equipment utilization rate (prolong service time), increase business income, and promote economic effectivevess.

   III. Starting of electrified cleaning technique                

1.  Precursor of electrified cleaning technology

For many years, hand bellows have been used as traditional naintenance means for electrical equipment. Some engineers and technicians also use alcohol, gasoline and CCL4 to clean connection points and contacts of circuit, but the surface tension of alcohol, gasoline and CCL4 is higher and not easy to penetrate into clearances and to clean thoroughly. Furthermore, they are inflammable, exposive and dileterious. Afterward, they were replaced by special cleaning agents, such as gas and spraying mist (filled in drum), disigned for electrical equipment. There are some representative products, such as :American CRC Company’s cleaning agent for precision apparatus has a history of 40 years, and it’s used by China civil aviation for power-off cleaning, At the same time, there are also homemade cleaning agents for electrial equipment. That is the precursor of electrified cleaning technique---power-off cleaning.

For cleaning maintenance of high voltage and extra-high voltage circuits, electric power experts have tried electrified cleaning with water since 1960s and 1970s. It had a poor performance on both effectiveness and safety as accidents of personnel and equipments occurred froc time to time. So it was not popularized. But water power-off cleaning was used sometimes,which didn’t have a good performance and had a side effect of getting rusty.

In a word, for many years, methods of maintenance of electrial equipment circuit are power –off cleanings such as hand bellow, blower, dust collector, water cleaning, alcohol, gasoline, CCL4 and cleaning agent. There were no breakthrough innovations.

2.Starting of electrified cleaning technique

Until mid 1990s(1994), a company in Chengdu performed an electrified cleaning on SPC exchanges of Shenda Communication Company for the first time. This attempt started the research and cultivating market of electrified cleaning technique.

This company in Chengdu thought they came first in electrified cleaning for try just because the cleaning agent was featured with high insulating and extra-flash point. From 1994 to 1998, this company performed some small demonstrations and cleanings, which were all limited to small-scale, electrified or power- off cleanings.

At that time, market of electrified cleaning didn’t exist in most people’s eyes. Most of electrical engineers and technicians considered cleaning technique to be impossible, unsafe, and unacceptable. Actually, in 1999 Liaoning Telecom burned several CPU boards during cleaning.

In addition, after cleaning electrical control cabinet, buttons are glued and out use of due to the collosol effect of cleaning agent, and the electrical components burst and form ice crystal field effect, and communication signals are interrupted for unidentified causes.

   IV.Final breadthrough of electrified cleaning technology

1.      Surging electrified cleaning industry

When people were not sure about the perspective of electrified        

Cleaning and electrified cleaning technplpgy was just a coming thing, several companies in Shenzhen and Guangzhou were set up one after another in 1999.

In  2002, the most electrified cleaning companies were set up, which led to accelerate the disorderly competition.

2.      Serious problems existing in electrified cleaning technology and in this industry.

At the beginning, some enterprises’ founding members and

technicians though they could perform electrified cleaning just after knowing that the cleaning agent or some raw material is featured with high insulation and high flash point. Authority organizations’ reports also indicate that the products are highly insulating and nonflammable, and they have a good electrical and safety performance.

  But the practical situation is not so simple as imagination;                          

any mature technologies must be perfected by a procedure of “theory-practice” and needs to experience a lifting process of screw type.

After the electrified cleaning technology came to practice, different companies ran into a contest of propaganda and research to show that he is the best. How advanced is his technology actually? What is the principle of electrified cleaning? What about the insurance? How severe is the adventurism? All these factors have to be taken into consideration.

Firstly, some companies are not clear with the principle of electrified cleaniing.They just copied each other’s introdution material.

Secondly, after accidents of burning and interruption of communication signals happened due to the unidentified causes in Liaoning Longgang in Shenzhen, Hunan, and Sanmen Gorge on the Yellow River in Henan, companies concerned didn’t look for causes in technology to find a product with perfect performance to secure the electrified cleaning.

Thirdly, most products are not environmentally friendly, but the companies themselves declare that they are the environmental enterprises who can produce environmentally friendly product. They didn’t try to find out the way to break through in technology.

Fourthly, in the construction technology (application method), many companies, which are popularizing electrified cleaning technologies, don’t know the structure of equipment, They just spray cleaning agents on the naked components, especially exertiing no effectiveness to the emission cabinets of mobile base stations. Though there are big spaces between naked components, contaminants from the upside can’t be removed effectively at last.

Fifthly, when cleaning, many companies make the equipment and materials cause chap, hydrogen brittleness, collosol and ice crystal effect.

Sixthly, the same mixing formulation is adopted for many different products with different names, but actually it is only a single product.

Lastly, it is lack of industrial specifications and there exists keen competition. Because of no industrial specifications and lack of unified technical standards, many customers can’t distinguish those good electrified cleaning companies from bad ones, so it’s difficult to secure their safety and effcetiveness. On the other hand, it is lack of scientificalness in making price offer, the companies with poor technology all competite with price war. Some companies even use concoctive inspection report, ISO authentication, user’s opinions, insurance, and so on.

3.      final breakthrough in electrified cleaning technology

Rongzun Company stands on the development of electrified cleaning products with an environmental protection formulation, so Rongzun’s products have been environmentally friendly since the founding of the company. Rongzun Company has deeply studied the principle of electrified cleaning and causes of failure of electrical equipment, anslyzed and proved the feasibility of electrified cleaning technology from different angles, including theory, test and application etc., made scientific specifications and prices offer of cleaning equipment in different industries, and made a scientific summarization on social effectiveness and significance etc. brought by the electrified cleaning. Further more, it has made a scientific assortment and definition for the electrified cleaning which had been unclear in this field:i.e. electrostatic balance electrified cleaning maintenance technology for precision circuit and anti-pollution-flashover electrified cleaning maintenance technology for high voltage circuit.

With electrostatic balance electrified cleaning maintenance technoloy of precision circuit, specialized technicians will use special service regulations, hish insulating, nonflammable, volatile and environmental cleaning agents and special tools to remove thoroughly and rapidly various dust, oil stain, humidity, salt, carbon stain, acid and alkali gases, and other combination contaminants, which are staying on the circuit surface or corroding deeply into the precision circuits, while the equipment is in running condition (or in electrified condition). It can eliminate static effectively and prevent circuit arc light, creepage, electric breakdown, electro-migration, electrochemical corrosion, radiation failure and so on. It can prevent replacement, degeneration, and invalidation of equipment, secure equipment to be in normal working state, prolong service life, and prevent major accidents. It is the most effective means of electrified maintenance of circuit at present.

Real time data monitoring is used during the whole cleaning process. And real time temperature, insulation resistance and static electricity value of cleaning parts are collected together. Cleaning control parameters and technology are adjusted according to practical situation to ensure the cleaning process to be safe and effective and realize an excellent project.

Anti-pollution-flashover electrified cleaning on high voltage circuits can be performed on 550kV electrical equipment while they are in running condition. It can eliminate various contaminants on surface or deeper parts of insulator. Bus bar, terminal box. Transformer, high and low voltage switch cabinet and preventive device of microcomputer. It can also eliminate the sources which cause short circuit, arc light, poor heat radiation and severe pollution flashover, secure that electrical equipment working in a normal state, increase the economic benefits of power supply and power consuming enterprises, and guarantee an normal order of social production and social life.

After cleaning, a layer of semi-permanent protection film with the functions of waterproof, mildew proof, enhancement of insulation and anti-oxidation etc. will be formed, realizing the functions of 2 combined in 1.

Because of the unqualified products, the accidents of destroying the boards that happened in Liaonin, Longgang of the city of Shenzhen, Hunan and Sanmenxia of Hennan province are inevitable, and those cases with undestroyed boards fortunately are occasional. To secure electrified cleaning technique, there are special strict requirements on performance of cleaning agents. They have to have high flash point, static high insulation,dynamic high insulation, low surface tension, reasonable volatilization rate (no ice crystal effect when being cleaned), no corrosion, no chap, hydrogen brittleness, collosol and other side effects on equipment after cleaning. Electrified cleaning technique is an organic system. The scientificalness of construction technological process and the maturity of operational experience are both essential. Only after accumulating abundant experience at construction and long-term technical trainings, can we know in detail equipment structures of different fields, and take it as a piece of cake when cleaning. And we can realize deep and thorough cleaning in the real sense.

Additionally, the breakthrough of technique of ecletrified cleaning with high voltage or extra high voltage is a positive contribution to the industry of electrified cleaning.

High voltage and extra-high voltage, electrified cleaning needs the breakdown voltage of cleaning agent to be for above working voltage, needs the cleaning guns’ withstand voltage to be far above their working voltage, and the material of cleaning guns needs to have a high intensity, good mechanical property and portable.Pressure of cleaning guns must be steplessly adjustable, stable and easy to use.Table 1 shows the test voltage of the cleaning guns.

  Table 1: The testing voltage of high voltage cleaning guns

      V. Resrlts after cleaning the equipment

1.      Results of electrifiec cleaning for precision equipment circuits(see table 2)

Table 2 Results of electrified cleaning precision equipment circuits

2.Results of electrified cleaning for electrical equipment(Table 3)

  Table 3 Results of electrified cleaning for electrical equipment

3.Important performance index of electrified cleaning agent:

Boiling point (℃):40-80

Volatile rate (25℃,101.3kpa):0.14mg/s.㎝2

Residual quantity (wt):0.25%

Density (25℃):1.00-1.60g/㎝3

PH:6.8-7.2(neutrality)

Flash point None

Inflammation point:None

Flammable range of vapor(℃):None

Freezing point (℃): -130

Viscosity (℃):0.6mPa.s

Surface tension (25℃):16.4mN/m

ODP value (depleting index of ozone):0

Insurability (insulation resistance 欧母)：6×10 13

Breakdown voltage:10KV/2mm

Corrodibility: No corrosion, color change and swelling happen  

to following materials:

1)      Plastic: PVC, LDPE, HDPE, PP, Phenolic, Nylon, PET, PTFE, Epoxy, PPS, etc;    

2)      Metal:Copper, zinc, aluminum, iron, magnesium, stainless steel, steel, tin, silver, nickel silver, brass, etc;

3)      Other: PET, rubber, glass, ceramic, etc.

VI. Discrimination of some tichnical terms and concepts

    1.  “Electrified cleaning” is not “online cleaning”

Some people or companies call “e-lectrified cleaning”as“on-

line cleaning”, and even some of them think it is more proper to call

it“on-line cleaning”. The opinion of the arthor is in the opposite: It is

“e-lectrified cleaning”, not “on-line cleaning”.The word “on-line” had been used before appearance of our industry, such as:”on-line”  in internet, the saying “on-line” before product line. And our characteristic is that we perform the cleaning maintenance on circuits without power off, which is quite different from former ones and can’t be mixed up.

2. “condensation water”, not “condensation humidity” or “condensation dew”

During the cleaning process, as the electrified cleaning agent has a strong volatility, it absords heat of components being cleaned, and causes water vapor in the air to form sweat. So, it is quite improper for people to call it “coagulating damp” or “coagulating dew”. It’s quite simple:there is tri-state for materials. Sweat formed when water vapor meets cold is called condensation water. So it should be called “coagulating water”. This is a simple physical change in chemistry. There can be icing in severe cases, when “ice crystal effect” arises. Damp doesn’t mean arise of sweat. For example, no sweat can be seen at the humidity of 30%, 50% and 70%. Dew is the common saying of sweat caused by natural factors. Furthermore, people in the field mistake the other of “coagulating water” and “ice crystal effect”.

3.confusion of chemical concepts and properties such as alkyl, hydrocarbon

Organic compound can be divided into: hydrocarbon, ether, alcohol, ketone, carboxylic acid, ester, etc; hydrocarbon can be divided into:alkane, olefin, aromatic, etc; alkane includes alky1 halide such as CFC-113,AK225, etc. These concepts and chemical property of these materials should be distinguished.

VII. conclusion

There has been important material breakthrough in electrified

Cleaning technology field. However, there is no end in the technology studying. Reviewing the hard course of breakthrough in the development of electrified cleaning technology, we have to realize that it is through thick and thin that we could reach the top of success.

                   Author

Rong xiaoping: Male with age of 40, graduated from university, in study of MBA, senior engineer

81~89 Technical Deputy Director of Factor, Jiangxi Yunshan Enterprise Group Resin Plant

90~92Technical Chief and Enterprise Management Chief of Jiangxi Wuning Metalurgical and Chemical Plant

93~97 Dirctor of Personnel Department, Director of Branch Plant and the Directory of General Works of Nanchang Rare Metal Material Genera Works

98 Administration Work at Dongguan, Guangdong Provice

99~upto now: Established Shenzhen Rongzun Scientific & Technical Development Co.Ltd. and Shanghai Rongzun Environmental Protection Scientific and Technical Co.Ltd., Chairman of Board