News

Good news! Chairman of the board, Yun Qinghui was commended by the county committee

2025-02-25

  On February 20,at the meeting of the third-level cadres in 2025 in Yichuan County,the chairman of the company,Yun Qinghui,won the honorary title of"Outstanding individual in Yichuan County Private Enterprise".  It is reported that in order to commend the exemplary demonstration and leading role of outstanding business leaders,and encourage enterprises and individuals to continue to make new and greater achievements,a total of 20 business leaders at the meeting won the honorary title.  The award of this honor is not only a full affirmation of the personal leadership of President Yun Qinghui,but also a high recognition of Longjian Power's contribution to the economic and social development of Yichuan.In 2024,Chairman Yun Qinghui led all the staff in the traditional business field,the company's transformer,high and low voltage complete equipment not only gained a foothold in more than 20 provinces and cities in China,but also expanded the business territory to more than a dozen overseas markets in Africa,the Middle East,Eastern Europe,Southeast Asia and other markets;In the field of new energy,the company takes large-scale photovoltaic and wind power projects as the starting point,from project planning to grid-connected power generation,and contributes to the national"double carbon"strategy with a benchmark project;In the field of power construction and operation and maintenance,the company casts quality with professionalism,wins reputation with service,and establishes the golden brand of dragon Key in the fierce market competition.  Long Weihehe,bond strength is clear.Next,under the leadership of Chairman Yun Qinghui,the company will carry forward the corporate culture of"diligence,truth-seeking,innovation and great industry",uphold the fine tradition of"technological innovation,quality assurance,integrity and quality service",and make greater contributions to the development of the county economy with reliable quality,preferential prices and perfect after-sales service.

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Thank you for the warm winter | Longkey Group to visit the parents of old workers, build a warm home

2025-02-19

  Time flies,time flies,in the long river of development of Longjian Group,the old workers have always been the mainstay.They take root in their posts and write their persistence and dedication for a long time,which is the source force that pushes the group forward continuously.Behind their hard work,is a small family anonymous pay,it is these small and warm support,so that the old workers have no worries,to be able to devote themselves to work,they are also the group's development behind the hero.  The pace of the New Year is approaching,Longjian Group is permeated with joy and warmth.From January 23 to 24,in accordance with the group's carefully planned arrangement and deployment,a sympathy group composed of more than 20 members,full of enthusiasm,soldiers divided five ways,went to the home of the parents of old workers,and a warm sympathy activity was warmly opened.  Everywhere they went,they talked with the elderly,asked them about their health and life,and listened to their stories and voices.  The sympathizers expressed their deep gratitude to the old people for cultivating excellent talents for the company,and thanked them for their support and trust in the company all the time.At the same time,it also introduced the development status and future planning of the company to the old people,so that they can understand the work results of their children in the company and the good development trend of the company.  The old people's faces are filled with happy smiles,and they have expressed their gratitude for the company's concern,and the words are full of the value of this care.When it comes to their children,their eyes are shining with pride,unabasmuch as they say that their children can work in such a company full of humanistic care and extreme temperature,it is their great pride,this pride,has long been deeply rooted in the bottom of my heart,into the company full of recognition and praise.  Due to the sudden snowstorm,the sympathy team could not visit the parents of the old workers outside and outside the province one by one,but the warmth and greetings were not hindered by the snow.The sympathy team quickly opened the"warm heart emergency mode",through the video New Year,the most sincere feelings sent to each parent's heart.  At the end of the video,the members of the comfort team lined up in good spirits and with full sincerity,sent sincere New Year wishes to the parents of the old workers,and sincerely wished the elders good health and happiness in the New Year.  This condolence activity is not a simple visit,but the warm heart of the company to the old workers and their families to convey the deep friendship,so that the old workers feel the company's attention and care for them,but also let the old people feel the warmth of the company's big family.  In the future,the company will continue to uphold the people-oriented concept,pay attention to the needs of employees and their families,and pass the care to every corner.Let us look forward to a better tomorrow for the company,and wish all the parents of old workers health and longevity,happiness and happiness!

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Forge ahead | Dragon Key Group 2024 Annual Summary and Commendation Conference was held

2025-02-19

  Dragon treading waves don't old load,lead the snake to chase the dream of new Yuan.On January 21,2025,Dragon Key Group's"Reform and Forge Ahead"2024 annual summary and Commendation Conference was held,and group leaders and employees from all departments gathered together to review the struggle of the past year and look forward to the future development blueprint.  This conference is divided into three sections:work report,excellent commendation and lucky draw.Dragonkey mark2024,the road we traveled together  At the beginning of the conference,a well-crafted VCR was like a magical time tunnel,instantly bringing everyone back to the year 2024.This year,from the warm reception of customer visits to the day and night adherence to product delivery;From the meticulous care of the staff to the highlight of the moment of honor,every frame records the figure of the dragon key people forging ahead hand in hand.This is an affectionate look back on the past year,but also a lofty praise for the dragon key people's fighting spirit,so that every employee present has a surge of emotion.  Work report  Review the past,plan for the future  In 2024,the Group will forge ahead and achieve great results in a complex and changing market environment and fierce competition.The Board of Directors and the Group management team,together with all employees,have written a new chapter in the development of the Group with extraordinary courage and wisdom.  In the 2024 work report,Zhang Weifang,general manager of the Group,conducted a comprehensive and in-depth review of the work of the past year from multiple dimensions such as market expansion,product innovation,and team building,which not only affirmed the achievements,but also candidly analyzed the current market situation and the problems existing in the group.Looking ahead to 2025,she stressed that the group will unswervingly practice the concept of innovation-driven development,continue to increase investment in research and development,optimize product structure,actively open up a broader market,and strive to build a more competitive enterprise and move towards a higher goal.  Moment of recognition  The glory of witness,the power of example  In order to recognize the outstanding individuals and teams in the past year,the Group set up the"Best Dragon Key Person Award","Excellent Manager Award"and"Excellent Team Award".The struggle stories of the winners deeply touched everyone present,vividly explaining the concept of hard work in the Dragon Key Group can realize their own value.  In the warm applause,the winners climbed to the podium and accepted the honorary certificates and bonuses awarded to them by the group leaders.Under the backdrop of flowers,they were the brightest stars on the stage.These winners are representatives of many outstanding dragon key people in the company,who shine in their respective positions and make outstanding contributions to the development of the company.This honor is not only a high recognition of their work over the past year,but also an incentive for them to continue moving forward in the future.At the same time,they also become a role model for all employees to learn and lead everyone to progress together.  The most beautiful dragon key man  Excellent manager  Excellent team  Lucky draw  Surprises,joy to share  In order to add to the happy atmosphere of the conference,the scene also set up a lucky draw.The rich prize is exciting,there are three meals four seasons easy to cook multi-functional rice cooker,add convenience to life;The Huawei watch3 smart sports Watch that is always in tune with sports helps to live a healthy life;City shuttle super free Tailing electric vehicle,make travel more convenient;Huawei 2-in-1 tablet computer for efficient office work and study.  With the lucky code beating on the big screen,everyone's heart also rises and falls.When the name of the lucky person was revealed one by one,the scene suddenly sounded one after another cheers and applause.The employees who won the prize cheered,and the employees who did not win the prize also sent sincere wishes to their colleagues,and the scene was filled with a happy and peaceful atmosphere.This link not only made everyone harvest surprises,but also narrowed the distance between each other and enhanced the cohesion of the team.  In the New Year,all staff of Dragon Key Group will follow the example of award-winning excellent staff and team and work together;Under the leadership of the Group's board of directors and management team,pioneering and innovative,and strive to achieve the group's grand goals.  Let us look forward to 2025,Dragon Key Group will be able to innovate again brilliant,continue to write a more wonderful chapter!

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Gathering strength and seeking common development | Longkey Group held the 2024 annual business analysis meeting

2025-01-10

  On the morning of January 9,the 2024 annual Operation Analysis meeting of Longkey Group was successfully held in the conference room on the third floor of the administration.Zhang Weifang,the general manager of the group,presided over the meeting.A total of 15 people,including the group's management leadership,heads of departments and leaders of the group's branches,participated in the meeting.  The meeting reviewed the group's work in 2024,in-depth analysis of existing problems and shortcomings,and detailed deployment of work in 2025.  At the meeting,the core departments of the Group,such as the financial center,marketing center,production center and integrated management Department,reported in detail on the completion of the 2024 target tasks,existing problems and the 2025 work plan.The Group's respective leaders made accurate comments on the work carried out in 2024 in the respective business sectors,and gave clear guidance and deployment for the work in 2025.  In his speech,Zhang Weifang,general manager of the Group,affirmed the overall business performance of the Group in 2024,and also objectively pointed out the problems and risks existing in the current business development of the group.She emphasized that 2025 is of great symbolic significance for Longkey Group,which is not only a year of deep cultivation,hard training,and achieving quality and efficiency improvement,but also a key node of the Group's"14th Five-Year Plan"circle,but also carries the heavy responsibility of opening the"15th Five-Year Plan"new plan,and is an important watershed in the group's development process.All cadres and staff of the group should not only be responsible in their posts,but also be dedicated to their efforts,with a sense of urgency,a sense of crisis,and a sense of responsibility that they cannot afford to wait,slow or sit still,they should gather their hearts to promote various heavy work points,go all out to complete the annual goals and tasks,and promote the group to achieve high-quality leap forward and move towards a higher performance peak.

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Henan Longjian Power Equipment Co., LTD. : The glorious journey and bright chapter of Ruoqiang photovoltaic project

2025-01-08

  On December 18,the circuit breaker of China Green Power Ruoqiang 400 million kW photovoltaic project was successfully closed,marking the successful grid-connection of the"Shage famine"photovoltaic project with the largest single installed capacity in China.At this point,after more than 400 days and nights of hard work,the Sino-Green Power Ruoqiang 300MW photovoltaic and 220KV No.3 booster station project undertaken by Henan Longjian Power Equipment Co.,LTD.,a subsidiary of Longjian Group,has achieved major stage results and won the initial battle.  Since the start of the project,the Longkey construction team has adhered to the spirit of ingenuity,overcome difficulties all the way,accurately respond to complex sites,cleverly protect against bad weather,delve into overcoming technical difficulties,and always complete the excellent delivery of the project with quality and quantity,which has added a strong mark to the construction performance of Longkey Group.  Professional industry cast reputation,open a new chapter in new energy construction  Henan Longjian Electric Power Equipment Co.,Ltd.has the power engineering construction general contracting level II and the installation(repair,trial)of power facilities level IV qualification.Over the years,we have always adhered to the spirit of professionalism and focus,relying on the advanced and efficient management concept and experienced professional team,undertaken more than 130 power construction projects and completed high-quality delivery.Accumulated rich and solid practical experience in engineering construction,established an excellent reputation in the industry,and won widespread praise and high favor in the market.  In September 2023,when the successful bid for the civil construction and installation of 300MW photovoltaic and 220KV No.3 booster station of China Green Power Ruoqiang project,Longjian Group ushered in a new opportunity for development.This is not only a strong witness to the group's years of careful preparation,the unremitting efforts of the professional team and the precipitation of good reputation,but also a key breakthrough in the field of new energy construction,laying a rock-solid foundation for the follow-up in-depth cultivation of this promising fertile soil.  Believe in the power of belief,vowed to make the project into a work of art  Ruoqiang 4 million kilowatt photovoltaic project is located in the south of Ruoqiang County,the north of Altun Mountain,as a large-scale photovoltaic project under construction in the country at present,it is also the largest Shage desert base project in the country,where the terrain is complex,the weather conditions are harsh,the construction scale is huge,and the technical requirements are complex.For the first time to undertake the construction of Shage desert power project team,It's definitely a new challenge.  At the beginning of the project,Dragon Key Group made a bold vow:"Vowed to build the project into a work of art."This is not an empty slogan,it carries the dragon key's brave challenge to its own limits,but also contains the deep awe and respect for the market.  The photovoltaic site is in the alluvial inclined plain area,which is crisscrossed by trenches.At the project construction site,the dragon key people dance with the wind and sand,and every grain of sand bears in mind their adherence.Up to now,the project team has laid 2,500 tons of supports,383,000 pieces of photovoltaic modules,4,000 kilometers of cables,and completed 130,000 square meters of concrete pouring,laying a solid foundation for the entire project.  Longjian people with superb skills and tenacious perseverance,the photovoltaic panel column center line is uniform,arranged a pleasing visual beauty,which is not only an intuitive reflection of the quality of the project,but also their persistent pursuit of high standards and strict requirements.They use practical actions to make a solemn commitment to high-quality delivery,highlighting the determination of Dragon Key Group to create high-quality projects.  220KV booster station,as the key hub of the entire photovoltaic power station's electric energy collection and booster transmission,has highly dense electrical equipment and complicated operation.The geological condition of the project site is bad and the foundation construction period is long.The windy weather is raging,and the high-altitude operation and equipment installation are dangerous.The remote geographical location increases the risk of loss of materials transportation;These factors put forward extremely high requirements for the technology,management and adaptability of the construction team.  Believe in the power of believing.In the face of various complex situations,the Dragon Key project team is undaunted,and has worked tirelessly day and night for more than a year,handing over a brilliant answer sheet:Completed the infrastructure construction of 250 tons of steel bars and 5000 square meters of commercial mix,laid 3,000 secondary lines with a length of 180 kilometers,16 kilometers of bus and equipotential network,6.5 kilometers of ground network,30 kilometers of distribution network,65 kilometers of optical fiber,and connected 30,000 terminal terminals.Completed the installation and debugging of 30 SVG control cabinets,32 main transformer control cabinets,50 unmanned devices,66 35KV cabin switchgear and 158 secondary screen cabinets.Behind these figures,is the dragon key construction team adhere to the original heart,brave to shoulder the mission of blood and sincerity,is to uphold the ingenuity,the persistent pursuit of excellence,is to use sweat and professional industry watering quality engineering vivid practice.  In November 2024,in the rigorous inspection work within the State Grid system,the"China Green Power Ruoqiang 4 million kW photovoltaic Project 220KV No.3 booster Station"undertaken by Longjian Group stood out and won the first comprehensive score in the comprehensive evaluation of the overall quality,image and joint adjustment test results of the project.This honor is both the project for Dragon Key Group exclusive  Watching and learning promote promotion,experience sharing cast brilliant  The good news came,all the staff of the group company were surging and deeply proud.From November 12 to 14,Mr.Yun Qinghui,chairman of the Group,personally led the team and led the backbone of the group's four subsidiaries and three core business departments to the project site to observe and learn.They go deep into the construction site,carefully learn from the successful experience of the project,and strive to integrate these valuable assets into the daily operation of the group,further improve the overall business level,lay a solid foundation for the high-quality promotion of subsequent projects,and continue to promote the Dragon Key Group in the field of power engineering to climb the peak and create more legends.  On December 23,while the iron is hot,the Group company organized the personnel who went to the project site to visit and study,the leading cadres and staff representatives above the heads of branches and functional departments to gather together and held a special sharing meeting full of dry goods.At the meeting,everyone spoke freely and deeply analyzed the advanced concept,superb technology and high efficiency management mode contained in the Longkey team 300MW photovoltaic and 220KV No.3 booster station project,promoted the wisdom collision and experience exchange between various departments,and further sublimated the team cohesion and combat effectiveness of Longkey Group.  Gather energy and start again,leading the green electric future  Now,standing at a new starting point,Longkey Group has been ready to move forward towards a more brilliant future,with the valuable experience accumulated in the Ruoqiang photovoltaic project,the excellent team and the industry reputation,Longkey Group has begun to lay out a broader market blueprint.

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Analysis of Common Faults in Mining Transformers

2021-04-29

During the use of transformers, there are various types of faults that occur due to differences in the duration of use, the degree of damage caused by overvoltage and overcurrent, and the different situations of use and maintenance. Therefore, in order to detect faults in a timely manner, analyze and eliminate them, and improve the ability and accuracy of fault detection and diagnosis, it is necessary to fully utilize various diagnostic techniques and integrate various historical data of equipment operation. Here are some opinions on the common fault diagnosis of transformers.1、 Inspection of Transformer Faults1. Look. Carefully inspect every part of the transformer from the outside to the inside by detecting any abnormal phenomena such as color when a fault occurs Leakage of oil. During the operation of transformers, oil leakage is a common phenomenon that can be easily identified by humans on the outer body of the equipment. Small transformers are installed in some shells, and attention should be paid to the bottom plate on or below the shell during inspection. Oil leakage varies greatly, mainly due to poor sealing between the oil tank and components, defects in welding or casting parts, equipment overload, or impact vibration. In addition, internal faults in transformers during use can also cause an increase in transformer oil temperature, volume expansion, and oil leakage Due to temperature, humidity, ultraviolet radiation, or the presence of acids, salts, etc. in the surrounding air, the surface paint film of the box may crack, bubble, or peel off. Overvoltage can cause surface cracks and discharge marks on porcelain parts, porcelain sleeves, and porcelain bottles. Loose screws in the fastening part of the porcelain bottle terminal wiring can cause surface contact surface peroxidation and discoloration.The discoloration of the moisture absorbent inside the dehumidifier is caused by excessive moisture absorption, damaged gaskets, and excessive water volume in the turbid room. Typically, the material of the moisture absorbent is alumina, silicone, etc., and it appears blue. If it turns pink, it needs to be regenerated.2. Listen. During normal operation, the transformer emits a uniform buzzing sound. If uneven or other noises are produced, it is considered an abnormal phenomenon.① The sound is louder and sharper than usual, partly due to overvoltage in the power grid, and partly due to transformer overload.② If a "chirping" sound is made and the high-voltage fuse is blown, it is because the tap changer is not closed properly. If a slight "squeaking" sound is produced, it is a discharge sound and a poor contact of the tap changer.③ If the transformer emits a "whooshing" sound and a "creaking" sound, and the sound is loud and chaotic, it may be a problem with the transformer's iron core.④ There is a hissing sound of discharge in the sound, and corona or blue sparks can be seen at night, which may be due to partial discharge of the transformer's wiring porcelain bottle.⑤ If you hear a "crackling" sound while standing in front of the transformer, it may indicate poor grounding or static discharge from ungrounded metal parts. At this time, the operation of the transformer should be stopped for maintenance.⑥ During operation, there is a loud and uneven cracking sound, which may be due to insulation breakdown of the transformer. If the dull "crackling" sound is the discharge of the conductor through the transformer oil to the shell.⑦ When there is a "gurgling" sound of water boiling in the transformer, it may be due to interlayer or turn to turn short circuit in the winding of the transformer. At this time, the operation of the transformer must be stopped for maintenance.3. Testing. The diagnosis of transformer faults based on sound, color, and other phenomena can only be used as a preliminary analysis and judgment on site, because the condition of any equipment cannot be directly reflected by a single aspect. There are many factors that can sometimes create false impressions. Therefore, it is necessary to measure and conduct comprehensive analysis in order to accurately identify the cause of the fault and the nature of the accident, and propose a more complete and economically reasonable solution.① Measurement of insulation. Mainly used to determine the insulation condition of windings, this is a relatively simple and effective method. Insulation resistance measurement usually uses an insulation resistance meter, and high-voltage transformers above 3KV generally use a 2500V insulation resistance meter. Measurement item: Measure the insulation resistance of the winding. Three items should be measured: high voltage winding to ground, low voltage winding to ground, and high voltage winding to low voltage winding. Here, "ground" refers to the metal shell of the transformer.② Measurement of DC resistance. When a transformer is subjected to short-circuit impact, it often causes winding distortion and deformation. In addition, insulation damage to the transformer winding can lead to turn to turn short circuits, and even phase to phase short circuits. When the winding fails, the distance between turns changes due to overall or local stretching and compression, and the resistance between turns also changes. When measuring, the DC resistance values of the high and low voltage windings of the transformer should be measured separately. According to the relevant regulations on the manufacturing of power transformers, the DC resistance difference between the windings of each phase of transformers above 630KVA should not exceed 2% of the average value of the three phases. For transformers below 630KVA, the phase difference should not exceed 4% of the average value of the three phases, and the line difference should not exceed 2% of the average value of the three phases.③ Measurement of absorption ratio. The insulation condition and moisture content of transformer windings can be determined by measuring the absorption ratio. When measuring, use a stopwatch to measure the time. When the insulation resistance meter reaches the rated speed of 120 revolutions per minute, connect the insulation resistance meter and start timing. Read one value at 15 seconds and another at 60 seconds. The ratio of the two values is the absorption ratio, which should be greater than 1.3. Otherwise, it indicates that the transformer has been affected by moisture or has insulation defects, and a detailed inspection is required.2、 Common faults and causes of high temperature rise in transformersDuring the operation of transformers, their losses mainly include hysteresis and eddy current losses of the iron core, as well as resistance losses of the windings. These losses generate a large amount of heat, which is normally transmitted to the outside through the heat dissipation device, while also causing the temperature of the transformer to rise to a certain extent. After a certain period of time, the transformer should reach a stable temperature rise. If the temperature rise is too high or too fast, or if the temperature rise is significantly higher compared to transformers of the same type and load, it should be considered as a fault. The common causes of high temperature rise in transformers are as follows:1. Local short circuit in the iron core.2. Poor grounding of the iron core.3. Iron yoke screw grounding.4. The power supply voltage is too high.5. Caused by poor contact, looseness, burning out, etc. of the lead part.6. The tap changer has malfunctioned.7. Caused by poor quality in coil manufacturing and maintenance.8. The large burrs and uneven gaps around the core laminations are caused.9. The transformer load is too high.10. Caused by unqualified primary and secondary wiring or poor contact of transformers.3、 Common faults and causes of abnormal output voltage in transformers. Under normal circumstances, the output voltage of transformers should be maintained within a certain range. Low or high voltage is considered a fault phenomenon and should be promptly eliminated. Firstly, the power supply voltage should be checked to see if it is caused by abnormal power supply voltage. If the power supply voltage is high, it can be measured through a transformer. In addition to power supply reasons, there are several common causes of malfunctions, including:1. Caused by short circuit between turns of the winding. This type of fault is often caused by transformer overload or insulation reduction. When a turn to turn short circuit occurs, the transformer will exhibit abnormal output voltage, sometimes accompanied by overheating and abnormal sound.2. It is caused by incorrect gear position of the tap changer. Tap changers are used to regulate voltage. If the gear is incorrect and cannot match the actual power supply voltage, it can cause the output voltage to be too high or too low.3. Caused by unbalanced three-phase load. If the secondary three-phase of the transformer is unbalanced, it will cause changes in the three-phase voltage of the transformer and abnormal output voltage. In severe cases, the phase voltage increases by 1.732 times.4. There is a phase loss on the high-voltage side. Phase loss on the high voltage side can cause serious imbalance in the output voltage on the low voltage side, and even damage to low voltage equipment. There are many reasons for high voltage phase loss, but generally it is caused by inadequate maintenance and other reasons that result in burnt wiring or faults in the old higher-level circuit.In addition, there are also many cases of abnormal secondary voltage output caused by defects in the iron core and winding.

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The Necessity of Informationization Construction in the Transformer Industry

2021-04-29

Due to the fact that the main users of transformer manufacturing enterprises are the power sector, many leaders of transformer enterprises believe that as long as they establish good relationships with them, the enterprise can develop and there is no need for information technology construction. This viewpoint of weak information awareness seriously affects the informationization construction of the transformer manufacturing industry, resulting in low level of enterprise information infrastructure management, insufficient investment in informationization construction, and few applications of e-commerce. In fact, the vast majority of transformer manufacturing enterprises have the following problems:(1) The market response is slow, customers often complain, and there are loopholes in marketing. In the information age, the speed of response to rapidly changing markets has become the key to determining a company's competitive advantage. Transformer manufacturing enterprises have a wide variety and specifications. Without establishing a sales information system, it is difficult to handle a large amount of product and customer information to ensure customer satisfaction with pre-sales, in sales, and after-sales services. It is also difficult to manage sales personnel and customers in a timely and effective manner, in order to improve the enthusiasm of sales personnel and reduce loopholes for business personnel to embezzle public funds and individual customers with low reputation to owe or default on accounts.(2) The phenomenon of delayed delivery is common, and the contract fulfillment rate is not high. In recent years, due to the power shortage, the demand for transformers has increased, and the order quantity of transformer manufacturing enterprises has generally increased. But a problem that comes with it is the prominent phenomenon of many companies not delivering goods on time, and the low rate of contract on-time performance. There are reasons for insufficient production capacity, insufficient working capital, and the tight supply of silicon steel sheets in the past two years. In general, delayed delivery is most affected by production capacity. In fact, in many cases, it is not a true lack of production capacity, but rather a lack of balance in production capacity.(3) The level of digital design and manufacturing is relatively low. In design, computer-aided drawing and the use of Excel to calculate electromagnetic schemes are more commonly used, while the use of computer programs for computer-aided design (CAD) is rare. Using 3D CAD design is even less common. Only true CAD can effectively reduce design costs, improve design efficiency, and ensure design quality.(4) Quality problems are common, and the first pass rate of products is low. Due to the imperfect quality system, the IS09001 quality assurance system has not been truly implemented. Except for a few enterprises such as Siemens in Jinan, the vast majority of enterprises have not implemented the Six Sigma quality management method. Therefore, the first pass rate of transformer finished product testing is low, mostly below the Three Sigma quality level, resulting in frequent rework and high quality costs. The defect rate required for the Three Sigma quality level is 0.27%, which means a pass rate of 99.73%. Not to mention the Six Sigma quality level, which requires a defect rate of 3.4 parts per million, almost zero defects.(5) Accounts receivable and inventory occupy a large proportion of funds, and working capital is tight. Due to the impact of rising raw material prices, transformer prices have increased in the past two years, coupled with an increase in order volume, many enterprises have tight working capital. From an internal perspective, many reasons for the tight working capital of enterprises are the high proportion of accounts receivable and inventory occupying funds, resulting in insufficient cash flow.(6) The level of supply management is low, and many transformer manufacturing enterprises have not established good supply relationships, lack win-win thinking, and even basic business procedures are not sound, such as the lack of contracts, resulting in many loopholes in supply work and easily causing losses to the company. Almost none adopt supply chain management. With the help of enterprise informatization, it is possible to fully utilize the resource information of the enterprise, carry out business process restructuring, change the organizational and management mode of the enterprise, introduce modern management concepts, achieve rational and scientific decision-making, and effectively solve the above problems.

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Inspection of oil immersed transformers

2021-04-29

1. Monitoring instrumentsThe instruments of the transformer control panel, such as ammeters, voltmeters, power meters, etc., should be read every 1-2 hours and the daily load curve should be drawn. When operating under overload, the meter should be read every 0.5 hours. When the meter is not in the control room, it should be recorded at least twice per shift.2. Monitor the voltage of the transformer power supplyThe variation range of power supply voltage should be within ± 5% of the rated voltage. If the voltage is too high or too low for a long time, the tap changer of the transformer should be adjusted to make the secondary voltage tend to be normal.3. Measure whether the three-phase current is balancedFor transformers with Y and Yn0 connections, the line current should not exceed 25% of the rated current on the low voltage side. If it exceeds this limit, the load on each phase should be adjusted to balance the loads as much as possible.4. Allowable temperature and temperature rise of transformers(1) Allowable temperatureDuring the operation of transformers, copper and iron losses occur, causing the coils and iron cores to heat up. The allowable temperature of a transformer is determined by the heat resistance strength of the insulation material used in the transformer. The insulation of oil immersed power transformers belongs to Class A, and the insulation is made of impregnated organic materials such as paper, wood, and cotton yarn, with an allowable temperature of 105 ℃. The component with the highest temperature in a transformer is the coil, followed by the iron core, and the transformer oil temperature is the lowest. The insulation between coil turns is made of cable paper, and the average temperature of the coil can be measured. Therefore, the temperature of the coil during operation should be ≤ 95 ℃.The operating temperature of power transformers directly affects their output capacity and service life. If the temperature exceeds the allowable value for a long time, the insulation of the transformer is easily damaged and the service life is reduced. The reduction of the service life of transformers can generally be calculated according to the "eight degree rule", that is, when the temperature rises by 8 ℃, the service life is reduced by half. The experiment shows that if the temperature of the hottest point of the transformer winding is maintained at 95 ℃, the transformer can operate continuously for 20 years. If the winding temperature rises to 105 ℃, the service life decreases to 7.5 years. If the winding temperature rises to 120 ℃, the service life decreases to 2.3 years. It can be seen that the service life of a transformer is mainly determined by the operating temperature of the winding.The temperature of transformer winding is related to the load size and ambient temperature. The difference between the temperature of the transformer and the ambient temperature is called the temperature rise of the transformer. For transformers with Class A insulation, when the ambient temperature is 40 ℃ (the highest ambient temperature), the national standard stipulates that the temperature rise of the winding is 65 ℃, and the allowable temperature rise of the upper layer oil temperature is 45 ℃. As long as the upper layer oil temperature and temperature rise do not exceed the specified value, the safe operation of the transformer within the specified service life can be guaranteed.Allowable temperature=Allowable temperature rise+40 ℃When the ambient temperature is above 40 ℃ and heat dissipation is difficult, the transformer is not allowed to operate at full load. When the ambient temperature is less than 40 ℃, although it is beneficial for heat dissipation, the heat dissipation capacity of the coil is limited by structural parameters and cannot be improved, so overloading operation is not allowed. When the ambient temperature is below zero degrees, the transformer is overloaded and the upper oil temperature is maintained below 90 ℃, not exceeding the allowable value of 95 ℃. However, due to the inability to improve the heat dissipation capacity of the coil, the coil temperature rises and heats up, exceeding the allowable value.For example, in an oil immersed self cooling transformer, when the ambient temperature is 32 ℃, the upper oil temperature is 60 ℃, which does not exceed 95 ℃. The temperature rise of the upper oil is 60 ℃ -32 ℃=28 ℃, which is less than the allowable temperature rise of 45 ℃. The transformer can operate normally. If the ambient temperature is 44 ℃ and the upper oil temperature is 99 ℃, although the temperature rise of the upper oil is 99 ℃ -44 ℃=55 ℃, which does not exceed the temperature rise limit, the upper oil temperature exceeds the allowable value, so operation is not allowed. If the ambient temperature is -20 ℃ and the upper oil temperature is 45 ℃, although it is less than 95 ℃, the temperature rise of the upper oil is 45 ℃ - (-20) ℃=65 ℃, which has exceeded the temperature rise limit and is not allowed to operate.Therefore, only when the upper oil temperature and temperature rise value do not exceed the allowable values, can the safe operation of the transformer be guaranteed.5. Operation of Transformer OilCheck the height of the oil level inside the oil pillow and oil filling sleeve, and whether there is any oil leakage at the sealing point. The oil level indicator should generally be at 1/4 to 3/4. Excessive oil level is generally caused by abnormal operation of the cooling device or internal faults in the transformer, resulting in high oil temperature. If the oil level is too low, check whether there is serious oil leakage at each sealing point of the transformer and whether the oil drain valve is tightly closed. The oil color inside the oil gauge tube should be transparent with a slight yellow tint. If it appears reddish brown, it may be caused by dirt on the oil level gauge or by the transformer oil running for too long and the oil temperature being high, resulting in deterioration of the oil quality.

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Overview and Performance Parameters Price of Mining Explosion proof Mobile Substation

2021-04-29

The mining explosion-proof mobile substation (referred to as the mobile substation) consists of mining explosion-proof high-voltage vacuum switches (referred to as high-voltage vacuum switches) for mobile substations, mining explosion-proof dry-type transformers (referred to as dry-type transformers) for mobile substations, and mining explosion-proof low-voltage protection boxes (referred to as low-voltage protection boxes) for mobile substations.The distribution method of KBSGZY mining explosion-proof mobile substation adopts the power supply load of the mobile substation. In case of faults such as short circuit, overload, undervoltage and leakage, the signal feedback is obtained through the low-voltage protection box and sent to the high-voltage vacuum switch to drive the high-voltage side circuit breaker to open. If the dry-type transformer itself fails, it can also be protected by the high-voltage vacuum switch without cutting off the upper level distribution equipment. The high-voltage side of the mobile substation has current, voltage and fault display; Due to the interruption of high voltage, the current is smaller than that of low voltage, overcoming the weakness of the original mobile substation load side fault that can only be protected by the low voltage feeder switch, and the high voltage switch is only an isolation switch. Dry type transformers are required to be explosion-proof for mining, with small volume, low loss, low impedance, and strong ability to withstand short-circuit mechanical forces.The main performance parameters of this product are reasonably selected, which is beneficial for both power supply and product reliability. It is superior to similar foreign products and leads the domestic market, filling the domestic gap and replacing imports.

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How to calculate the capacity of power transformers

2021-04-29

The power of a transformer is determined by the load, i.e. P2=U2II2I+U2III2II++ U2nI2In(VA)  P1=P2/η(VA)In the formula: Calculation value of secondary power of P2 transformer. Low level power calculation value of P1 transformer.U2I and U2II The voltage (V) of each secondary winding of the transformer is determined by the load.I2I and I2II The current (A) of each secondary winding of the transformer is determined by the load.For transformers with a capacity of less than 1KVA, where the capacity is small and the efficiency is low, η can generally be taken as 0.8 to 0.9. For transformers with a capacity of less than 100VA, the smaller value of η should be selected; Choose the larger value for transformer capacity between 100VA and 1000VA For poor quality silicon steel sheets, an optional value of 0.7 can be chosen.I1=P1/U1 (1.1 to 1.2) (A), where U1 is the low-level voltage (V)1.1 to 1.2 are empirical coefficients considering the no-load excitation current.The capacity of a power transformer is the apparent power S=1.732 × U × I, where s is the apparent power, U is the line voltage, and I is the line current. Due to the presence of inductive and capacitive loads, the power factor of the line cannot be 1, so P=S × 0.8, where p is the active power and 0.8 is the assumed power factor. 4500 ÷ 0.8=5625, so a transformer of 5625KW is needed. However, the manufacturing of transformers is divided by capacity, and it is impossible to manufacture them separately based on your calculation results. Therefore, only the capacity level of 6300KVA can be selected. KVA is the unit of apparent power, and KW is the unit of active power.Here is also an example for everyone:The efficiency of transformer capacity is generally around 0.8. When the load power factor of 500 × 0.8=400 (KW) is 0.8, a 500KVA transformer can normally load 400KW power. As the power factor increases, the load power of the transformer also increases accordingly. The power factor has been increased from 0.7 to 0.95, and for every KW of power, a compensation capacitance of 0.691 kilovolts is required. Therefore, 500 × 0.691 ≈ 346 kilovolts (Kvar)

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Longjian Electricity 35KV-3150KVA Chinese substation project equipment delivered smoothly

2024-11-01

On November 1, the charging station 35KV-3150KVA Hu-style substation project equipment of Hebi Fenghe Power Generation Co., Ltd. was successfully delivered by Longjian Group, and the project is currently under construction.Intelligent empowerment, excellent qualityThe 35KV-3150KVA Chinese-style substation of the project was independently designed, installed and constructed by Longjian Group. The equipment has beautiful appearance, neat and beautiful appearance, reasonable structure and excellent numerical value, which fully meets the requirements of the current national grid for new energy efficiency equipment.Double efficiency for productionAs the equipment and facilities favored by energy projects in recent years, Longjian technical team attaches great importance to Hua-type transformers and supporting facilities, and on the basis of the original design, for the actual demand of customers, the depth of optimization and improvement, whether it is the design concept or the equipment's energy saving, consumption reduction and risk resistance ability have reached the optimal standard, providing a strong guarantee for the stable operation of the power system.Hebi Fenghe Power Generation Co., LTD. 35KV-3150KVA Chinese type substation project is funded by Hebi Wanhong New Energy Technology Co., LTD. Henan Longjian Power Equipment Co., Ltd. and Henan Xuguang Yulong Construction Engineering Co., LTD., subsidiaries of Longjian Group, respectively undertake equipment production and supporting engineering construction. The complete set of substation equipment has passed the experiment, delivered to the site and completed the installation, the engineering construction is being carried out simultaneously, and the conditions can be powered on recently.

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