Foreign R&D institutions have launched cloud monitoring software and SensoNODE sensors to allow users to access machine status data through a Web browser, so as to achieve the purpose of identifying operations and improving performance. Industry 4.0 and the Internet of Things are bringing huge benefits to industry, and innovative solutions fill the gap between modern technology and traditional manufacturing.

R&D technology is a cloud-based continuous monitoring solution that reverses the chaos of traditional asset monitoring, enabling users to centrally access asset information, whether on site or miles away.

The remote continuous monitoring system allows factory employees to access asset data from any place connected to the Internet, monitor and solve machine health problems, analyze production or manufacturing potentially dangerous situations, and receive alarm notifications of problems through email, text and system messages. In addition, it also supports exporting data for analysis and reporting, and multiple users can monitor the data at the same time.

David Shannon, the R&D worker, said that continuous monitoring means that the system always pays attention to problems and reminds users when there are problems. He said this allows employees to "manage by exception" and focus on those assets and/or processes that require their attention, instead of spending unnecessary man-hours to manually check and collect data on assets/processes that are correctly operated. Check out the Reconnaissance Cloud Software product page for more details.

David Shannon said that continuous monitoring means that the system will constantly monitor equipment and alert users when there are problems, so that employees can manage exceptionally and focus on assets or processes that need their attention without spending unnecessary manual time. To manually check and collect asset or process data for correct operation.

With the continuous maturity of industrial wireless sensor network technology and the continuous improvement of market demand, the effect of industrial wireless sensor network products on the replacement of traditional industrial sensors has been continuously improved.
　　 In 2015, my country's industrial wireless sensor network products accounted for about 4.9% of the industrial sensor market, with a scale of 780 million yuan. By 2020, my country's industrial wireless sensor network products will account for 11.7% of the industrial sensor market, and the market size is expected to reach 3.6 billion yuan, with a compound annual growth rate of as high as 35.8%. The market prospect is broad.
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  working principle
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The component modules of the wireless sensor are encapsulated in a shell. When it is working, it will be powered by a battery or a vibration generator to form a wireless sensor network node. It consists of randomly distributed micro nodes integrated with sensors, data processing units and communication modules. The way of organization constitutes a network.
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　　 It can collect the digital signal of the device and transmit it to the wireless gateway of the monitoring center through the wireless sensor network, and send it directly to the computer for analysis and processing. If necessary, the wireless sensor can also transmit the entire time history signal collected in real time. The monitoring center can also wirelessly transmit information such as control and parameter settings to the nodes through the gateway. The data conditioning, acquisition and processing module amplifies and filters the weak signal output by the sensor, then sends it to the analog-to-digital converter, converts it into a digital signal, and sends it to the main processor for digital signal processing to calculate the effective value and displacement of the sensor. Value etc.
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　　 three advantages
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　　 With the development and maturity of wireless sensor network technology, wireless sensor network products have begun to gradually replace traditional wired sensor products with their own unique advantages, and have penetrated into all aspects of the industrial field, becoming an emerging hot spot in the market. Compared with traditional wired sensors, wireless sensors exist, and their advantages are mainly reflected in the following aspects:
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　　 Higher flexibility. It is suitable for situations with mobile requirements but inconvenient wiring, such as cranes, mobile bottling equipment, transportation industry, automatic guided vehicle systems and monorail conveyors.
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　　Higher reliability. The wireless sensor can avoid the damage caused by movement, such as the bending of the wire caused by the long drag chain, the twisting and breaking of the cable caused by the rotating movement, and so on. At the same time, the fault factor caused by the connector in the wired network is eliminated.
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　　Higher security. With the development of technology and the continuous emergence of new threats, the ability to upgrade security maintenance is essential. The new encryption strategy and covert data transmission indicate that wireless security levels will exceed wired systems. In addition, in some dangerous extreme environments, such as blasting occasions where wiring is inconvenient, wireless sensors can ensure the safety of personnel.
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　　Application area
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　　 The advantages of wireless sensor network make it have a wide range of market applications, almost involving all areas of social and economic activities.
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　　 One is the field of pipeline and trench monitoring, such as the monitoring of temperature, pressure, and flow parameters of pipelines such as water supply and drainage, heating, gas supply, and oil supply. The second is the field of warehouse monitoring, such as the monitoring of temperature and humidity, temperature, flammable and explosive gases, and toxic and harmful gases in grain warehouses, drug warehouses, food warehouses, and factory hazardous chemical warehouses. The third is the monitoring field of manhole covers and fire hydrants, such as the monitoring of the operation status of urban manhole covers and fire hydrants. The fourth is the field of liquid level and water level monitoring, such as the parameter monitoring of water level and liquid level in rivers, dams, reservoirs, and oil tanks. Fifth is the field of greenhouse monitoring, such as the monitoring of temperature, humidity, light, gas...parameters such as vegetables, flowers, breeding (chicken, duck, pig house, etc.). Sixth is the field of aquaculture monitoring, such as the monitoring of water quality and gas parameters such as fish ponds and cages. Seven is the field of atmospheric environmental monitoring, such as the monitoring of toxic and hazardous gases in public places such as parks, schools, and communities. In addition to the above 7 main application areas, there are other applications, such as military, scientific research and so on.
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　　 One of the key technologies in the Internet of Things is sensor technology. The wireless sensor network plays a pivotal role in the application process of the industrial Internet of Things. It is responsible for connecting independent sensor units through a wireless network, and collecting the data collected by each sensor, so as to realize the physical or environmental conditions in the scattered range of the space. Collaborative monitoring, and then perform corresponding analysis and processing based on this information. Nowadays, modern industrial production is developing in the direction of large-scale, rapid and low-consumption. The wireless sensor network will play a special role in the future intelligent production of enterprises by virtue of its advantages of flexibility, safety, reliability, convenience and low cost.

The high current temperature rise test is an important indicator to measure the performance of electrical equipment, especially in the factory inspection test of transformers and circuit breakers. Although there are many types of transformers and circuit breakers and their functions are very different, the process of temperature rise test is basically the same. The following explains the principle and application of the large current temperature rise test system using the simulated load method for the large current temperature rise test.

The temperature rise test of dry-type transformers with simulated load method needs to be carried out step by step. Carry out a no-load test, let the exciter core heat up, wait until the temperature is stable, and then perform a short-circuit test until its temperature is stable, and measure the temperature rise of the winding under the no-load test and the temperature rise of the winding under the short-circuit state respectively. According to the temperature rise in the two stages, the total temperature rise is calculated.

The no-load temperature rise test uses an open circuit on one side and a rated voltage on the other side. Place the thermometer at the point that needs to be measured, and then let the iron core generate heat due to no-load loss until the temperature is stable. Since the winding does not generate heat during the no-load test, the heat exchange process between the iron core and the winding cannot be effectively displayed. The measured value is only a reference value and cannot be evaluated as the actual temperature rise. When the temperature of the iron core stabilizes, the temperature rise of the winding is measured.

The measured temperature rise is obtained indirectly by measuring the change of the winding resistivity, and belongs to the average temperature rise. After cutting off the power, it will first measure a value, and then measure a value every 30 seconds, continuously measure ten times, and then measure once every 10 minutes. The measured value needs to use a semi-logarithmic coordinate to make a curve, and then measure its instantaneous thermal resistance value according to the extrapolation method. The short-circuit temperature rise test is carried out after the no-load temperature rise test. The connection method of the short-circuit temperature rise transformer is the same as the no-load temperature rise test. The low-voltage side is short-circuited and the high-voltage side is used for power supply. After the testing of the test circuit is completed, the rated current is applied to the high-voltage side, and the transformer generates heat due to the short-circuit of the winding. After the temperature rise is stable, the thermal resistance of the high- and low-voltage windings is tested.

The short-circuit temperature rise of the high and low voltage windings is calculated. The test method and calculation method are the same as the no-load temperature rise test. The actual temperature rise of the windings is calculated according to the temperature rise of the high and low voltage windings measured during no-load and short-circuit conditions.

The mutual load method uses an auxiliary transformer with the same test voltage ratio and connection group. One winding is used for rated excitation, and the other winding is connected in parallel through the auxiliary transformer and the end of the test product with the same name. By adjusting the input voltage of the load auxiliary transformer, Adjust the load current to reach the rated value. The power supply of the auxiliary transformer can be the same as or different from the rated excitation power supply, but no matter what kind of power supply, it should be ensured that the phase and frequency of the power supply are exactly the same, so as to ensure the smooth progress of the test.

Since in the actual test process, there are often many factors that affect the test results, it is necessary for the tester to take these factors into consideration. Under the existing conditions, effective measures should be taken to reduce the interference of external factors. Obtain more accurate data.

Relay protection technology is very important for the safe and stable operation of HVDC transmission lines. As the current commonly used technical means have certain deficiencies, we should increase research efforts and develop a relay protection scheme that is more suitable for my country's DC transmission requirements , Thereby promoting the long-term development of the power system. Here are four common relay protection technologies. Traveling wave protection In the process of HVDC transmission, the main protection measure is traveling wave protection. The protection principle is as follows: When the line fails, the fault point will propagate the anti-traveling wave to both ends of the line, and the traveling wave protection can pass the reading Identify and judge the situation of the fault-related area. At this stage, when using traveling waves to protect HVDC transmission lines, two more schemes are adopted. One is the ABB scheme. The fault detection of this scheme is carried out by pole waves, and at the same time, the fault pole is determined by ground model waves; the other is Siemens In the scheme, the starting criterion of the scheme is voltage differentiation, but the fault determination method is to observe the sudden change of the reverse traveling wave within 10MS. The above description shows that the two schemes adopt different detection methods, and there are certain differences in effect. Because the differential link exists in the Siemens scheme, the detection speed is relatively slower than the ABB scheme, but it is precisely because of this link. Makes the Siemens solution has better anti-interference ability. However, these two schemes have certain shortcomings, such as insufficient resistance to excessive resistance, high sampling requirements, and lack of good anti-interference ability. Since many problems exist in the traveling wave protection technology, a traveling wave directional protection scheme based on wavelet changes is proposed; another example is to optimize the sensitivity and study the principle of polarity comparison equation.

Differential undervoltage protection In DC transmission lines, differential undervoltage protection belongs to the main protection. At the same time, when using traveling wave protection, it also acts as a backup protection. The main way to realize protection is to detect the voltage differential value and voltage amplitude level. From the protection principle, the differential undervoltage protection is the same as the ABB scheme and the Siemens scheme. Both are the determination of the polar voltage differential and amplitude, and the voltage differential setting is consistent with the traveling wave protection. The difference is that the original 6ms is extended. It becomes 20ms. As a result, when the traveling wave protection exits or there is no sufficient rising edge width, the differential undervoltage protection can fully exert its backup protection function. Compared with traveling wave protection, differential undervoltage protection has a slower operating speed, and its accuracy is significantly improved. However, it is still not ideal in terms of resistance to excessive resistance and is very limited.

Low-voltage protection For the first two protection technologies, low-voltage protection is a backup protection method, and the relay protection function of the fault pole is determined by voltage amplitude detection. According to its design, after a high-impedance fault occurs, when the traveling wave protection and differential under-voltage protection fail to act, the low-voltage protection will cut it off. However, from the actual application situation, the low-voltage protection mirror is equipped in the extreme In a small number of HVDC transmission lines, there are two types of low-voltage protection, one is line low-voltage protection, and the other is pole-controlled low-voltage protection. Compared with the latter, the former has a higher protection rating, and the former acts After that, the line restart procedure will start, and after the latter action, the fault will be blocked. Although the low-voltage protection has a relatively simple principle, it also has many problems, such as poor selectivity and inaccurate discrimination of high resistance faults. Pilot current differential protection In HVDC transmission lines, pilot current differential protection is a backup protection scheme. The principle is to promote insulation selectivity through double-ended electrical quantities. According to the design, high-resistance faults can be cut off. Judging from the existing longitudinal current differential protection, because the capacitive current problem has not been fully considered, the differential criterion only uses the sum of the two ends of the power, which leads to a relatively long waiting time and relatively slow action speed. For example, the Siemens scheme of longitudinal current differential protection has large current fluctuations at the beginning of the fault, and the differential protection will have a delay of 600ms. At the same time, the delay of the differential criterion itself is 500ms, that is, the differential The action will not appear until at least 1100ms after the fault occurs, and during this period, accidents where the fault is directly blocked may occur many times, causing the equipment to fail to start, and the backup actions of the longitudinal current differential protection can not be fully performed. . In order to enhance the effect of this protection technology, improvements can be made from multiple aspects, including compensation capacitor currents to promote the sensitivity of differential protection; upgrading high-frequency channels to fiber channels to speed up the protection action.

structure

The iron core of this series of products is a single-phase core type, which is made of high-quality cold-rolled oriented silicon steel sheets, and the fastening method uses steel as a clamp. The high-voltage coil is a cylindrical multi-layer tower type, wound by high-quality polyester enameled wire and high-voltage insulation material. The low voltage coil is outside, and the instrument coil is an independent winding, generally 100V. The shell is octagonal, and test transformers above 10KVA are equipped with movable iron wheels. It has light weight, small size, convenient movement and superior performance.

The working principle of TWSB high voltage test transformer

1. AC, AC and DC test transformers:

Input the power frequency power into the operation box (or console), adjust the voltage through the auto-voltage regulator and input it to the primary winding of the test transformer. According to the principle of electromagnetic induction, power frequency high voltage can be obtained in the secondary (high voltage) winding. After the power frequency high voltage is rectified by the high-voltage silicon stack and capacitor filtering, the DC high voltage can be obtained, and its amplitude is 1.4 times the effective value of the power frequency high voltage. It's just that the short-circuit bar should be drawn out when using DC, and the short-circuit bar should be inserted when using AC.

2. Transformer with tapped test:

In order to satisfy the contradiction between a transformer with a higher voltage and a lower voltage and a lower current and a higher current, the high-voltage winding is divided into two windings, one is the winding with the larger current, the other is the winding with the smaller current, and then Two windings are connected in series and lead out separately, schematic diagram

3. Cascade test transformer:

In order to obtain a higher voltage test transformer, a cascade method can also be used to obtain a higher voltage. Figure 2 shows the principle wiring diagram of a three-stage cascade test transformer. The relationship between the capacity and voltage of the three transformers satisfies: P1=2P2=3P3, U(total)=1U+2U+3U.

characteristics

◆ Data such as voltage, current, time, status information and prompt information are displayed on a 4.7-foot large-screen LCD with clear and intuitive readings;

◆ All Chinese interface, simple and clear operation, can adapt to a variety of applications;

◆ Light touch button operation, all functions can be set by buttons, which improves the safety and reliability of the product;

◆ All-digital calibration method, abandoning the old potentiometer adjustment, extremely convenient on-site use, and easy to control accuracy (this function is protected by a password);

◆ Press the button to directly set the transformation ratio of the test transformer (this function is protected by a password). When connecting testers of different voltage levels, the application is flexible and free, and it is true that one control box can be matched with multiple transformers;

◆ Status reminder function, full Chinese-guided operation, even if there is no manual, it can be manipulated skillfully;

◆ During the test, there are flashing high voltage symbols on the screen to remind the operator to pay attention to safety;

◆ Test result display function, which can automatically judge the test result (test passed or failed), and can reliably record the overcurrent, flash or breakdown voltage of the sample;

◆ Test result sound alarm function, when the test passes or fails, the equipment will emit different alarm sounds, and the test personnel can directly identify the test results by the alarm sound;

◆ Pause function, under automatic control, this function can realize the pause of boosting or depressing at any point, and the time of the pause can be flexibly controlled by the tester to facilitate the observation of the state of the test product;

◆ Automatic timing function. In automatic control, when the voltage automatically rises to the set value, the device automatically starts timing. When the timing expires, the test result is displayed and the device automatically returns to zero;

◆ Manual timing function. When manually controlled, the timer can be started manually. When the withstand voltage time is up, the device will automatically return to the zero position (only desktop devices have this function);

◆ Manual control mode, this mode is similar to the traditional electric boost/decrease method, the up/down is controlled by the button, the device automatically judges the upper/lower limit, there is overvoltage protection;

◆ The boost speed is intelligently controlled. When the voltage reaches 80% of the target voltage, the boost speed will automatically slow down. When it reaches 90% of the target voltage, the boost speed will further slow down;

◆Optional remote communication, door interlocking warning light alarm bell, external voltage divider verification interface, etc.;

◆ Using the combination of hardware and software anti-interference technology, stable performance and strong anti-interference.

Transformer drying method

induction heating method

This method is to put the body in the oil tank, and pass the power frequency current to the outer winding coil, and use the heat of the eddy current loss in the oil tank wall to dry. At this time, the temperature of the box wall should not exceed 115~120℃, and the temperature of the body should not exceed 90~95℃. For the convenience of winding the coil, try to make the number of turns of the coil as small as possible or the current is smaller. Generally, the current is 150A, and the wire can be 35~50mm2. Multiple asbestos strips can be placed on the wall of the fuel tank, and the wires are wound on the asbestos strips.

　　 hot air drying method

　　This method is to put the body in a drying room with hot air for drying. The inlet hot air temperature should gradually rise, and the temperature should not exceed 95℃. A filter should be installed at the hot air inlet to prevent sparks and dust from entering. Do not blow the hot air directly to the body, as far as possible from the bottom of the body to blow evenly in all directions, so that the moisture is released from the vent of the box cover.