Industry News_News Center_Chenglai Electric Technology Co., Ltd.

10-15 

Three Gorges New Energy signed a cooperation framework agreement with Zhenlai County, Jilin Province

On September 17, Three Gorges New Energy signed the "Cooperation Framework Agreement" with the Zhenlai County People's Government in Jilin. According to the agreement, the two parties will carry out in-depth cooperation on new energy development and industrial chain layout. 　　Wu Jingkai, Secretary of the Party Committee and Chairman of Three Gorges New Energy, Zhao Guoqing, Deputy Secretary and General Manager of the Party Committee, Zhao Nan, Deputy Secretary of the Zhenlai County Party Committee and County Mayor, and Wang Xiquan, Chairman of Chenglai Electric Technology Co., Ltd. attended the signing ceremony. 　　Through strategic investment, Three Gorges New Energy reached a cooperation with Chenglai Electric Technology Co., Ltd. (hereinafter referred to as Chenglai Electric), a leading enterprise in the new energy equipment manufacturing industry in Zhenlai County, to make equity investment in Chenglai Electric, forming a strategic synergy for Chenglai Electric The rapid growth of the main business of Technology Co., Ltd. has jointly promoted the IPO process of Chenglai Electric, and provided guarantee for local economic development. 　　Wu Jingkai, Secretary of the Party Committee and Chairman of Three Gorges New Energy, and Zhao Guoqing, Deputy Secretary and General Manager of the Party Committee, visited Chenglai Electric Technology Co., Ltd. for inspection.

10-14 

Commonly used mine explosion-proof electrical appliances series

1. Commonly used mine electrical equipment 　　Commonly used mining electrical equipment includes vacuum switches, transformers, lighting signals and electric drill comprehensive protection devices. 　　Explosion-proof electrical equipment for mine

09-16 

How many types of explosion-proof electrical equipment for mines include

Mine electrical equipment is divided into two categories, general electrical equipment and mine explosion-proof electrical equipment. 　　General mine electrical equipment is a non-explosion-proof electrical equipment used in coal mines. It can only be used in underground mines where there is no danger of gas and coal dust explosion. The basic requirements are: the shell is strong and closed, which can prevent direct contact and live parts from the outside; it is drip-proof, splash-proof and moisture-proof; it has a cable entry device and can prevent the cable from twisting, unplugging and damage; switching handles and doors There are interlocking devices between the covers. 　　There is a clear permanent embossed mark "KY" on the obvious places of the casing of general mine electrical equipment. 　　According to different explosion-proof requirements, mine explosion-proof electrical equipment is mainly divided into mine explosion-proof type, mine-increased safety type, mine-used intrinsic safety type, mine-used positive pressure type, mine-used sand-filled type, mine-used encapsulation type and Airtight type for mines, etc. 　　Mine explosion-proof electrical appliances series 　　1. Explosion-proof electrical equipment for mine 　　The so-called explosion-proof means that the live parts of electrical equipment are placed in a special shell, which has the function of isolating the sparks and arcs generated by the electrical parts in the shell from the explosive mixture outside the shell, and can withstand the explosive mixture entering the shell The explosion pressure generated when the electrical equipment in the shell is detonated by sparks and arcs, while the shell is not destroyed, and at the same time, it can prevent the explosion products in the shell from spreading to the explosive mixture outside the shell. This special enclosure is called a flameproof enclosure. Electrical equipment with flameproof enclosures is called flameproof electrical equipment. 　　2. Increased safety electrical equipment for mines 　　The explosion-proof principle of increased-safety electrical equipment is: for those mine electrical equipment that do not produce arcs, sparks and dangerous temperatures under normal operating conditions, in order to improve their safety, the structure, manufacturing process and technical conditions of the equipment A series of measures have been taken to avoid sparks, arcs and dangerous temperatures under operating and overload conditions, and to achieve electrical explosion protection. Increased safety electrical equipment is based on the original technical conditions of electrical equipment, and certain measures have been taken to improve its safety, but it does not mean that this electrical equipment has better explosion-proof performance than other types of explosion-proof electrical equipment. The degree of safety performance of increased-safety electrical equipment depends not only on the structure of the equipment itself, but also on the maintenance of the equipment's operating environment. The electrical equipment that can be made into increased-safety electrical equipment is only those electrical equipment that does not produce arcs, sparks and overheating during normal operation, such as transformers, motors, and lighting fixtures. 　　3. Intrinsically safe electrical equipment for mines 　　The principle of explosion protection of intrinsically safe electrical equipment is to limit the spark discharge energy and heat energy of the circuit by restricting various parameters of the electrical equipment circuit, or taking protective measures, so that the electric spark and the electric spark generated under normal operation and specified fault conditions No thermal effect can ignite the explosive mixture in the surrounding environment, thus realizing electrical explosion-proof. The circuit of this kind of electrical equipment has explosion-proof performance, that is, it is "essentially" safe, so it is called intrinsically safe type (hereinafter referred to as intrinsically safe type). Electrical equipment using intrinsically safe circuits is called intrinsically safe electrical equipment. 　　4. Positive pressure electrical equipment 　　The explosion-proof principle of positive pressure electrical equipment is: put the electrical equipment in the shell, there is no flammable gas release source in the shell; fill the shell with protective gas, and make the pressure of the protective gas in the shell higher than the surrounding explosive environment In order to prevent the external explosive mixture from entering the shell and realize the explosion-proof of electrical equipment. 　　The sign of positive pressure type electrical equipment is "p", and the full name of the sign is "Expl". 　　5. Sand-filled electrical equipment for mines 　　The explosion-proof principle of sand-filled electrical equipment is: filling the shell of the electrical equipment with quartz sand, burying the conductive part

08-03 

Mine explosion-proof electrical appliances series

Explosion-proof electrical equipment refers to electrical equipment with a flame-proof enclosure. definition: Electrical equipment with flameproof enclosure. The explosion-proof enclosure can not only withstand the explosion pressure generated by the detonation of the internal mixed gas, but also prevent the internal explosive flame and high-temperature gas from escaping from the explosion-proof gap and ignite the explosive mixture around the enclosure. The standard label of explosion-proof electrical equipment is GB3836.2-2000 (GB3836.2-2010 after revision in 2010), and the label is "d"

07-24 

Process and Analysis of Amorphous Alloy Core Step-up Transformer for Photovoltaic Inverter

　　introduction 　　Solar energy is one of the most valuable renewable energy sources, and photovoltaic power generation has gradually become the main body of the world's energy supply. Solar energy is affected by factors such as weather conditions, seasonal changes, day and night alternation, and the uncertainty of sunshine intensity and duration, which makes the output power of photovoltaic power generation system discontinuous and unstable, and long-term low-load operation has become the norm. Reference [1] Point out that low-loss power transformers should be used. Amorphous alloy iron core transformer (abbreviated as amorphous) has extremely low no-load loss characteristics, suitable for long-term low-load operation environment, applied to photovoltaic power generation is conducive to reducing energy consumption and improving the conversion rate of solar energy to electricity. 　　1. Photovoltaic power generation unit module 　　At present, the inverters with mature technology, stable operation and large-scale applications on the market have a single capacity of 500 to 630kW. Restricted by the capacity of the inverter, photovoltaic power plants generally connect the photovoltaic module and the inverter to form a minimum power generation unit, and use a double-split step-up transformer to form a power generation unit module, that is, a step-up transformer is connected in parallel with two sets of inverters. The smallest power generation unit of the transformer, as shown in Figure 1, effectively reduces the number of transformers and limits the circulating current on the AC output side of the two inverters connected in parallel. 　　Figure 1 Schematic diagram of photovoltaic power generation unit module 　　Therefore, the capacity of the step-up transformer is 1000 ~ 1300kVA, and the output voltage of the inverter mainly has three specifications of 270, 315, and 400V. It is boosted to 10kV or 35kV on-site by a photovoltaic step-up transformer, and finally sent to the power transmission and distribution system to complete the integration. Net work. Photovoltaic step-up transformers are generally supplied as complete sets of combined transformers (Meibian) or pre-installed substations (European transformers). This article only analyzes the transformer itself. 　　2. Step-up transformer for photovoltaic 　　2.1 Analysis of winding split form 　　The double split transformer is composed of 1 high-voltage winding and 2 low-voltage windings, and its electromagnetic working principle is similar to that of a three-winding transformer. The split form of the transformer can be split in the amplitude direction and split in the axial direction, and there are certain differences in the manufacturing process, as shown in Figure 2. 　　Figure 2 Schematic diagram of transformer split form 　　Figure 2a) shows the amplitude split 1: Two low-voltage windings are located on both sides of the high-voltage winding and have two main channels. The manufacturing cost is high, the hidden danger of insulation accidents increases, and it is difficult to ensure the half-passing of the two split windings. The impedance is the same. 　　Figure 2b) shows the second amplitude split: the two low-voltage windings are located inside the high-voltage winding. This split method, in order to ensure that the impedance of the two sets of low-voltage windings are the same, the interleaved winding method can be used; in fact, the two sets of low-voltage windings are made into a double-layer foil winding form, but insulation must be provided between the copper foil and the copper foil. So as to become two independent windings. As shown in Figure 3. 　　Figure 3 Schematic diagram of staggered winding 　　If it is a wire-wound winding, it can be made into a multi-layer cylinder, but the turns need to be divided into two independent leads to lead out to make it into two sets of low voltage windings. The disadvantage is that the split impedance is small, the magnetic coupling of the two low-voltage windings is strong, and the mutual influence is greater during operation. 　　Figure 2c) shows the axial split: the high and low voltage windings are split axially, as if they are symmetrical up and down. This ensures that the parameters are basically the same from the structure and manufacturing, the split impedance is relatively large, and the half-through impedance is almost equal. Therefore, the photovoltaic step-up transformer is recommended to adopt the axial split form shown in Figure 2c). The impedance calculation can refer to the reference [2]. 　　2.2 Connection group label 　　The third harmonic can circulate in the D-connection winding, which can effectively reduce the impact of harmonics on the power grid. For the 10kV photovoltaic step-up transformer, the Dy11y11 form can be used, which is in line with the habit of ordinary distribution transformers. For 35kV photovoltaic step-up transformer, Yd11d11 form is more recommended. The high voltage is

05-10 

Combined wind power generation series: conventional power transformer test items and standards

　　The power test is divided into handover test and preventive test, so let’s talk about the handover test items and standards of conventional transformers today. 　　Combined wind power generation series 　　1 Measure the DC resistance of the winding and bushing 　　2 Check the voltage ratio of all taps 　　3 Check the three-phase wiring group of the transformer and the lead wire of the single-phase transformer 　　4Measure the insulation resistance of the iron core and clamps 　　6Measure the insulation resistance, absorption ratio or polarization index of the winding and bushing 　　7 AC withstand voltage test of winding and bushing 　　8 Long-term induction withstand voltage test of winding and bushing with partial discharge measurement 　　9 Insulating oil test or SF gas test 　　10Check the phase 　　The test items of oil-immersed power transformers with a capacity of 2500kVA and below are: insulating oil test or SF gas test, measuring the DC resistance of the winding and bushing, checking the voltage ratio of all taps, and checking the three-phase wiring group and single-phase of the transformer Lead out the transformer, measure the insulation resistance of the iron core and clamps, AC withstand voltage test of the winding and bushing, check the phase 　　Dry-type transformer test items: Measure the DC resistance of the winding and bushing, check the voltage ratio of all taps, check the three-phase wiring group of the transformer and the lead wire of the single-phase transformer, measure the insulation resistance of the core and clamps, and measure the windings Together with the insulation resistance, absorption ratio or polarization index of the bushing, the AC withstand voltage test of the winding and the bushing, and the long-term induction withstand voltage test of the winding and the bushing. With partial discharge measurement, check the phase 　　Check the three-phase wiring group of the transformer and the polarity standard of the lead wire of the single-phase transformer 　　The three-phase wiring group of the transformer and the polarity of the lead wire of the single-phase transformer should match the mark on the nameplate and the symbol on the shell. 　　Standards for measuring the insulation resistance of cores and clamps: 　　The insulation resistance of the core to the ground, the insulation resistance of the clamp to the ground, and the insulation resistance of the core to the clamp should be measured. 　　For transformers undergoing body inspection, the insulation resistance of accessible through bolts, iron clamps and strapping steel belts to the iron yoke, iron core, fuel tank and winding pressure ring shall be measured. 　　After the completion of all installation work of the transformer, the insulation resistance of the iron core to the ground, the clamp with external grounding wire to the ground and the iron core to the clamp should be measured. 　　Measured with a 2500V megohmmeter, the duration should be 1min, and there should be no flashover and breakdown

04-12 

The Strucell series of structural foam materials have successfully entered the fields of wind power generation, rail transit, etc.

　　According to Securities Times e company news, Wu Haizhou, chairman of Tiansheng New Materials, was a guest in a micro interview with Securities Times e company, and said that the company’s self-developed high-tech products-structural foam material Strucell series products, have the characteristics of light weight and high strength, and have won the national 863 Projects, major scientific and technological achievements transformation projects in Jiangsu Province, key R&D projects in Jiangsu Province, and other projects. The products have won the Jiangsu Science and Technology Progress Award and the Changzhou Science and Technology Progress Award, and have successfully entered wind power generation, rail transit, RV camping vehicles, and ship manufacturing. , Energy-saving buildings and other fields, filling the gaps in the country. Combined wind power generation series

02-03 

Combined wind power generation series my country launches new power northeast transformers, substations can also be built in the building

　　Economic Daily News reporter Yu Jian reported: As the available construction land resources in big cities become increasingly saturated, the research on "indoor, miniaturization, and oil-free" substations is of great significance for realizing the coordinated development of substation construction and the economic, social, and ecological environment. A few days ago, Shenzhen Aodian High Voltage Electric Co., Ltd. released an innovative product-220kV evaporative cooling power transformer. This new type of power transformer is the key to promoting the implementation of the "embedded substation" project and will realize the construction of substations in the central area of high-density cities. 　　Combined wind power generation series 　　According to reports, the 220kV evaporative cooling power northeast transformer uses a new type of fluorocarbon material as the insulating cooling medium, which has no flash point, non-combustible, non-explosive, and realizes the integration of fire protection, environmental protection and heat dissipation. "Compared with previous products, this product has a higher voltage level, setting a new high in non-combustible power transformer capacity, and is more energy-efficient, more environmentally friendly, and more efficient." said Xiao Xia, chairman of Shenzhen Aodian High Voltage Electric Co., Ltd., said the product The research and development lasted for 5 years, breaking through a series of key technical problems. Among them, the good environment that Shenzhen provides for innovative technologies has greatly contributed to it. 　　Li Hanming, former deputy chief engineer of Shenzhen Power Supply Bureau Co., Ltd., believes that 220kV evaporative cooling power transformer is a breakthrough product with milestone significance in the history of power transformer technology development. On the one hand, it can prevent fire and explosion accidents of power transformers and protect people's lives and property; on the other hand, evaporative cooling power transformers can be "embedded" into office areas, production areas, and living areas, greatly saving urban land space. 　　Combined wind power generation series 　　The Guangdong-Hong Kong-Macao Greater Bay Area is contiguous, densely populated, and has a huge demand for electricity. Take Shenzhen as an example. In 2019, Shenzhen's power load reached 19.1 million kilowatts, ranking first in the country. There are about 270 existing substations in Shenzhen, and more than 100 will be added in the future, covering a huge area for conventional construction. It is estimated that if it is replaced by embedded substations, the Guangming District of Shenzhen alone can reduce more than ten substations. 　　Combined wind power generation series 　　Jia Xingdong, director of the Shenzhen Municipal Bureau of Industry and Information Technology, said that in many large cities, due to the increasingly saturated land resources for construction, promoting the construction of embedded attached substations is of great significance for improving the comprehensive land development benefits and the coordinated development of the economic, social and ecological environment. 　　Combined wind power generation series

10-08 

Power equipment: One Belt One Road's Indian Power Grid

　　The construction of India's power grid is still in the growth stage. The "Made in China" plant in India will go deep into India's transmission, distribution, and energy storage links. China's manufacturing is expected to expand its market share in India. 　　 India is short of energy and electricity, so the power grid is still in the growth stage, providing an incremental market for Chinese manufacturing. ① India is at the peak of power construction: India’s two major blackouts in 2012 reflect the reality of power shortages. The current per capita power consumption is only 1/4 of China, and 240 million people have no access to power. 　　 In order to improve the current power shortage, India plans to add 147GW of installed capacity during the 13th Five-Year Plan (2017.4-2022.3), with an average annual grid investment exceeding 100 billion yuan. ②India's power equipment relies on imports, and Chinese companies take the lead: The Indian power equipment market exceeds 20 billion U.S. dollars, and 37% is dependent on imports. Chinese companies are the main suppliers of power generation equipment in India, occupying 40% of the share of traditional power generation equipment; power transmission and transformation companies have been deeply involved in the Indian market in the form of product sales and EPC. In recent years, they have actively established factories in India to increase their gross profit margins; energy storage companies have also Successfully entered the Indian market. 　　 India’s power transmission, distribution, and energy storage exchange technology for the market, and Chinese companies set up factories in India to open up the market. ① Power generation: India's 100GW photovoltaic installation plan brings huge opportunities. Chinese companies' exports to India have shifted from traditional power generation equipment to photovoltaic equipment. In 2016, India imported solar energy (12.55 +0.56%, buy) 84% of cells and modules from China. ②Power transmission and transformation: Chinese companies have been deeply involved in the Indian market in the form of product sales and EPC for many years. As India has put forward territorial requirements for power equipment manufacturers and set 21% import tariffs, relevant companies have chosen to build plants in India in recent years to increase Gross profit margin. ③Distribution network link: India's distribution network equipment is backward and electricity theft is serious. In 2014, it has successively released urban and rural distribution network upgrade plans, focusing on investment in smart meters, distribution network automation and other fields, bringing opportunities for Chinese distribution network companies. ④ Energy storage link: The substantial increase in photovoltaic wind power installed capacity opens up supporting space for energy storage. India's wind and solar energy storage project entered the bidding and construction phase in the second half of 2016. Chinese energy storage companies are actively deploying in India to seize the opportunity.

01-06 

The purpose of the impact test before the power transformer series is put into operation

　　In addition to some necessary tests, protection and secondary tests in accordance with the handover test standards for the newly put into operation of the power transformer series, the no-load full-voltage closing impulse test is usually done before it is officially put into operation. 　　Why do impact tests? 　　1. Check whether there are weaknesses or defects in the insulation of the power transformer series and its circuits 　　When the no-load transformer is opened, operating overvoltage may occur. When the neutral point of the power system is not grounded or the arc suppression coil is grounded, the overvoltage amplitude can reach 4 to 4.5 times the phase voltage; when the neutral point is directly grounded, the overvoltage amplitude can reach 3 times the phase voltage. In order to check whether the insulation strength of the transformer can withstand the effects of full voltage or operating overvoltage, it is necessary to do a no-load full voltage impulse test before the transformer is put into operation. If the transformer and its circuit have insulation weaknesses, they will be exposed by operating overvoltage breakdown. 　　2. Check whether the transformer differential protection is malfunctioning 　　When the no-load transformer is powered on, an excitation inrush current will be generated, which can reach 6 to 8 times the rated current. The magnetizing inrush current begins to decay relatively quickly, generally it can be reduced to 0.25-0.5 times the rated current after 0.5 to 1s, but it takes a long time to complete the attenuation, which is about a few seconds for small and medium transformers, and 10 to 20 seconds for large transformers, so the magnetizing inrush current decays In the initial stage, the differential protection is often malfunctioning, causing the transformer to fail to be put into operation. Therefore, during the no-load impact closing, under the action of the magnetizing inrush current, the wiring, characteristics and fixed value of the differential protection can be actually checked, and the evaluation and conclusion of whether the protection can be put into use can be made. 　　3. Assess the mechanical strength of the power transformer series 　　Since the magnetizing inrush current produces a large amount of electromotive force, in order to assess the mechanical strength of the transformer, a no-load impact test is required. 　　Generally five times? 　　The number of full-voltage no-load impulse tests. Generally, five consecutive no-load impulses should be carried out before the new product is put into operation. Because the closing angle is different at each closing time, the corresponding excitation inrush current is also different, sometimes large and sometimes small. Generally, five times of no-load closing are required to comprehensively detect the transformer's insulation, mechanical strength and the action of the differential protection. 　　What is the magnetizing inrush current? 　　Characteristics of magnetizing inrush current: 　　1. Contains aperiodic components with a large component, which tends to make the inrush flow to one side of the time axis. Generally, one phase is opposite to the other two phases. 　　2. Contains a large number of high-order harmonics, and the second harmonic component is the largest 　　3. There is a discontinuous angle between the inrush current waveforms 　　4. In the initial stage, the inrush current has a large value, which can reach 6-8 times the rated current, and then gradually decays.

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