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In modern power systems, transformers, as a key electrical equipment, play a vital role. Transformers are like the "eyes" of the power world, accurately measuring and transmitting relevant information about electric energy. Transformers are mainly divided into two categories: current transformers and voltage transformers. Current transformers convert large currents into small currents in proportion, allowing measurement and protection equipment to safely and accurately process current signals. It is like a fine "shunt officer", ensuring the accurate acquisition of current information, while ensuring that subsequent equipment is not damaged by excessive current.   Voltage transformers convert high voltages into low voltages, providing suitable voltage signals for measuring instruments and relay protection devices. Like a reliable "voltage reduction messenger", it converts high-voltage and dangerous electric energy into low-voltage signals that can be safely measured and monitored.   The working principle of the transformer is based on electromagnetic induction. Through ingenious winding design and the selection of core materials, accurate conversion of electric energy signals is achieved. In this process, factors such as the magnetic permeability of the core and the turns ratio of the winding have an important impact on the performance of the transformer.   In order to meet the growing demand for high precision and high reliability in power systems, transformer technology is also constantly developing and innovating. New transformer materials and manufacturing processes are constantly emerging, which improves the measurement accuracy and stability of transformers. At the same time, the emergence of digital transformer technology enables transformers to be better integrated with smart grids, achieving more efficient and intelligent power monitoring and control.   In practical applications, the correct selection and installation of transformers are crucial. Different power scenarios require the selection of appropriate transformer models and specifications based on factors such as voltage level, load characteristics, and measurement accuracy requirements. During installation, strict standards and specifications must also be followed to ensure that the transformer can work properly and provide accurate and reliable measurement data.   In short, transformer-related technologies play an indispensable role in the safe and stable operation of power systems. With the continuous advancement of science and technology, it is believed that transformer technology will continue to develop and improve, and contribute greater strength to building a more intelligent, efficient, and reliable power system.

Rogowski coil, also known as Rogwski coil in English, is hollow, that is, it has no solid core. It can be considered as applying the basic Faraday's law of electromagnetic induction to directly generate a voltage signal on the secondary side. The advantage of Rogowski coil relative to ordinary current transformers is that because it has no dead center, there is no dead center saturation phenomenon, and it can directly measure large currents. However, precisely because it has no dead center, the voltage signal induced by the Rogowski coil is very small compared to CT, and it is very easy to be affected by the stray magnetic field of the external environment, so the requirements for the winding process are very high. In addition, the voltage signal induced by the Rogowski coil cannot be used directly as a current signal. It must be differentiated to restore the current signal you want.   Application of Rogowski coil and current transformer: At present, Rogowski coil is only used in places with extremely large currents. Ordinary metering instruments use CT. Current transformer CT (current transformer) uses the principle of transformer. Generally, the large current on the primary side is converted into a small current on the secondary side, and then input to ADC for sampling after I/V conversion. The main differences between Rogowski coil and current transformer 1. Different properties 1. Rogowski coil: It is a toroidal coil evenly wound on non-ferromagnetic materials. 2. Current transformer: It is an instrument that converts a large current on the primary side into a small current on the secondary side for measurement based on the principle of electromagnetic induction. 2. Different structures 1. Rogowski coil: It does not contain ferromagnetic materials, has no hysteresis effect, and has almost zero phase error; there is no magnetic saturation phenomenon, so the measurement range can be from several amperes to hundreds of kiloamperes; the structure is simple, and there is no direct circuit connection with the measured current; the response bandwidth is 0.1Hz-1MHz. 2. Current transformer: The current transformer is composed of a closed solid and winding. Its primary side winding has very few turns and is connected in series in the circuit of the current to be measured.   Design principle of the amplification and integration circuit of the Rogowski coil: The theoretical basis for measuring current with the Rogowski coil is Faraday's law of electromagnetic induction and Ampere's loop law. When the measured current passes through the center of the Rogowski coil along the axis, a corresponding changing magnetic field is generated in the volume surrounded by the toroidal winding.   If you want to accurately restore the measured AC current, you must add an inverting integration circuit. Because the voltage induced by the Rogowski coil is very small, in order to amplify the induced voltage, you must add an amplifier circuit in front of the integrator. Integration is a very important link. The restored signal is very small. For the convenience of measurement, the signal is amplified and then integrated. This can increase the restored signal on the one hand, and on the other hand, the presence of the capacitor can filter out unnecessary interference.

The development of split current transformers has been rapid, and the power industry is particularly important for the development of split current transformers. This is especially true for the accuracy of split current transformers. There are many types of split current transformers that we usually come into contact with. The split current transformers produced by Hemei Electronics include split current transformers, power extraction split current transformers, high-frequency split current transformers, zero-sequence split current transformers, and so on. However, in the power industry, the split current transformers used must be consistent with the use of the power system, and split current transformers with corresponding voltage levels and accuracy must be developed to meet the needs of power system measurement, maintenance and control. Therefore, with the development of science and technology and the application of new materials, the performance of split current transformers is getting better and better, and there are more and more types.   Split current transformers are adapted to the development needs of power construction with a variety of structures such as dry, oil-immersed and gas-insulated. However, with the continuous growth of power transmission capacity, the continuous improvement of grid voltage level and the continuous improvement of maintenance requirements, the general core-type split-type current transformer structure has gradually exposed its weaknesses that are not accustomed to it. Its inherent large size, magnetic saturation, ferromagnetic resonance, small dynamic range and many other shortcomings cannot meet the application requirements of the new generation of power system automation and power digital network, so it is necessary to continuously promote the development of the industry.   Split-type current transformer is an important equipment for power metering, current measurement and microcomputer protection in the power system. Generally, the primary winding of the split-type current transformer is connected in series in the power line during use, and the secondary winding is connected to the measuring instrument, microcomputer protection and automatic control device. Since the traditional split-type current transformer is connected in series in the equipment during the application of the substation, it is directly embedded in different circuits during the initial installation, and the electrical connection of the substation is a hard connection. Therefore, once the split-type current transformer needs to be repaired or replaced, it is necessary to dismantle it from the connection point, which is very inconvenient to maintain. However, the open-type split-type current transformer can be installed and disassembled under power, which is simple to install and maintain. Therefore, the open-type split-type current transformer will be a development direction of current measurement technology.

Application characteristics of split core current transformer:   Split current transformer is an important equipment for electric energy metering, current measurement and microcomputer protection in power system. Generally, the primary winding of split current transformer is connected in series in the power line during use, and the secondary winding is connected with measuring instrument, microcomputer protection and automatic control device. Since the traditional split current transformer is connected in series in the equipment in the application of substation, it is directly embedded in different circuits during initial installation, and the electrical connection of substation is hard connection, so once the split current transformer needs to be repaired and replaced, it needs to be disassembled from the connection point, which is very inconvenient to maintain. However, the open split current transformer can be installed and disassembled with power on, which is simple to install and maintain. Therefore, the open split current transformer will be a development direction of current measurement technology. Due to the special structure of the open split current transformer, it needs to be distinguished from the traditional electromagnetic split current transformer in terms of main materials, process, structure, etc. during design.   This series of split-type current transformers are designed for electrical installations that do not require disassembly or disconnection of existing main busbars or cables. The split core design does not require disconnection of the busbar, making it easy to open and close, easy to install, and beautiful in appearance.   1. Function: General measurement and protection in power systems with strong mobility or cramped space or uninterrupted power systems.   2. Application: Power instruments, electronic multi-function energy meters and field calibrators, instrument measurement and protection.   Electrical characteristics of split-type current transformers   1. Maximum voltage of the equipment: 720V   2. Power frequency withstand voltage: 4000V50Hz/1 min (1mA)   3. Primary rated current range: 0-6000A   4. Secondary rated current range: 1A/5A/mA   5. Frequency: 50/60Hz

Precautions for using split core current transformers   1. In order to prevent the secondary winding from causing high voltage to enter the low voltage side, damage the instrument, and cause harm to people, a protective grounding point should be set. 2. Generally speaking, the connection of split-type current transformers is connected according to the polarity reduction, so the polarity connection must be correct. Once the connection is wrong, it will lead to inaccurate measurement or even short circuit. 3. For split core current transformers that use electric energy measurement, if the secondary circuit is used, then there is no need for automatic devices. The insulation of split-type current transformers is very thick, some insulation wraps are loose, there are wrinkles between the insulation layers, and the vacuum treatment is poor, the impregnation is incomplete, and the air-containing cavity is formed, which is easy to cause partial discharge defects. Among them, split core current transformers have a wide range of applications and can be divided into the following three categories 1. Iron core coil type low-power split-type current transformer. It is a development of the traditional split-type current transformer. The split current transformer is designed according to the high impedance resistor. Under very high primary current, the fullness characteristics are improved, the measurement range is expanded, and the power consumption is reduced. The split current transformer can measure the overcurrent and full offset short-circuit current up to the short-circuit current with high accuracy without fullness. The measurement and maintenance can share a core coil type low-power split current transformer, and its output is a voltage signal. 2. Optical current transformer refers to the use of optical equipment as the measured current sensor. The optical equipment is composed of optical glass, all-optical fiber, etc. 3. Hollow coil split current transformer. It can also be called Rogowski coil current transformer. Hollow coils are often made of enameled wires evenly wound on a ring frame. The frame is made of non-ferromagnetic materials such as plastics and ceramics. Its relative magnetic permeability is the same as the relative magnetic permeability of air. This is a significant feature of hollow coils that is different from current transformers with iron cores.

common faults of split core current transformers:   1. Overheating.   Overheating, smoking, and glue flow in split type current transformers may be caused by poor contact of the primary wiring, severe oxidation of the secondary wiring board surface, short circuit between turns in the split-type current transformer, or insulation breakdown of the primary and secondary sides.   2. The secondary side of the split-type current transformer is open. At this time, the ammeter suddenly has no indication, the sound of the split-type current transformer increases significantly, and ozone can be smelled and slight discharge sounds can be heard near the open circuit.   The damage of the secondary side open circuit is:   a. The split-type current transformer generates a very high voltage, which poses a threat to the safety of equipment and operating personnel.   b. The core loss of the split core current transformer increases, and severe heating may burn the equipment.   c. The core is magnetically saturated, which increases the error of the split-type current transformer.   3. There is a discharge sound or discharge phenomenon inside the split-type current transformer.   If there is a discharge phenomenon on the surface of the split-type current transformer, it may be that the surface of the transformer is too dirty, causing the insulation to decrease. The internal discharge sound is the internal insulation of the current transformer decreasing, causing the primary winding to discharge the secondary winding and the iron core.   4. The internal sound of the split-type current transformer is abnormal.   The reasons are: the fastening screws of the split-type current transformer are loose, the iron core is loose, the vibration of the silicon steel sheet increases, and an abnormal sound that does not change with the primary load is issued; some iron cores have a certain buzzing sound when there is no load or no load due to poor assembly process of silicon steel sheets; when the secondary side is open, due to magnetic saturation and non-sinusoidal magnetic flux, the silicon steel sheet vibrates and the vibration is uneven, emitting a large noise; the split-type current transformer is severely overloaded, which increases the vibration sound of the iron core.   5. The oil-filled split-type current transformer is seriously leaking oil.   If any of the above phenomena are found during the operation of the split-type current transformer, the load should be removed and the power should be cut off immediately.

The split-type current transformer uses a high-strength PVC shell and a fully cast busbar structure. The transformer is directly clamped on the cable, and three elastic rubber rings are pressed against the cable and integrated with the cable. The transformer core is made of high-quality silicon steel sheets, and the secondary wire is evenly wound on the core. The transformer is a split-type structure and can be installed without cutting the cable.   Functional features of split-type current transformer:   Primary current 100A~4000A, secondary current 5A or 1A, complete specifications, accuracy levels 1.0, 0.5   Suitable for fast loading and unloading without disconnection and removal, used for power collection and monitoring   The iron core used has undergone high vacuum heat treatment, with excellent performance and stable accuracy   The shell is made of high impact resistant ethylene PC material, with good safety performance and beautiful appearance   Easy to install, can be fixed by bending piece and pressing plate   Performance meets GB1208-2006 "Current Transformer" technical standard   Safety requirements of split-type current transformer:   Split-type current transformer is more of a later modification project, or a handheld measuring rod, so it involves the interactive operation between personnel and transformer, which puts forward the safety use requirements of split-type transformer. The national standard GB20840 of transformer has not yet defined split-type transformer. So there is no safety requirement. Therefore, we refer more to "GB4793.2 Safety requirements for electrical equipment for measurement, control and testing Part 2: Special requirements for hand-held and hand-operated current transformers for electrical measurement and testing", and the current version number of this standard is 2008. There are 3 categories in total. When using them, you must understand the characteristics of the three types of current transformers, otherwise accidents are likely to occur.

Measurement method   1. The primary wire should be placed in the center of the sensor inner hole, and should not be placed off-center as much as possible;   2. The primary wire should be placed as completely as possible in the sensor inner hole, without leaving any gaps;   3. The current to be measured should be close to the standard rated value IPN of the sensor, and should not differ too much. If conditions are limited, there is only one sensor with a very high rated value, and the current value to be measured is much lower than the rated value. In order to improve the measurement accuracy, the primary wire can be wound a few more times to make it close to the rated value. For example, when a sensor with a rated value of 100A is used to measure a current of 10A, in order to improve the accuracy, the primary wire can be wound around the center of the sensor inner hole ten times (generally, NP=1; one turn in the inner hole, NP=2; ...; nine turns, NP=10, then NP×10A=100A is equal to the rated value of the sensor, thereby improving the accuracy); [2]   4. When the current value to be measured is IPN/10, it can still have a high accuracy at 25℃.   Product Features Whether the Hall sensor is an open-loop or closed-loop principle, the basic performance is not much different. The basic advantages are: fast response time, low temperature drift, high accuracy, small size, wide bandwidth, strong anti-interference ability, and strong overload capacity.   Hemei's main products include common mode inductors, electromagnetic shielding shells, power carrier signal coupling transformers, permalloy cores, silicon steel cores, switch mode power supplies, split core current transformers and other products.     The power supply CT device is the latest product developed by our company, which can be used for 100V-220kv AC transmission lines and can be used as a continuous and stable power supply device. Hemei also provides customers with personalized services such as OEM, ODM and OPM. We welcome sample orders to test and check the quality.

For split core current transformers installed in outdoor overhead lines or cable trenches, the cut surface of the transformer is exposed to the air and will be exposed to rain or soaked in water in the cable trench, which will cause rust and affect product performance. Water accumulation in the secondary terminal will also cause short circuit, so measures need to be taken to prevent rain or water accumulation. There are currently two solutions that can be used, which are briefly introduced as follows:   The first solution is to bury the secondary wire directly into the resin casting body (the wire uses a three-proof silicone wire) to prevent short circuits in the secondary terminal, and add a waterproof silicone ring to the cut surface for sealing and waterproofing. This solution has good protection for the secondary end and the cut surface, and can be widely used in all rain and water immersion occasions. In addition, because the base cannot be fixed in the cable trench, the base installation method is not used. The inner hole with a rubber plug is fixed on the cable. This installation method is used.   The second solution is the "open current transformer + silicone rubber sleeve" solution, which is also used by customers for installation on low-voltage outdoor lines. However, this method can only prevent light rain and cannot prevent immersion in water, so it cannot be used for installation in places where water may accumulate, such as cable trenches. This solution is limited by the specifications of the silicone rubber sleeve, and the inner diameter of the transformer can only be 50mm.   1. Principle of zero-sequence current transformer   In a three-phase four-wire system, the vector sum of the three-phase current is equal to zero, that is, Ia+Ib+Ic=0. If a current transformer is connected to the three-phase four-wire, the induced current is zero. When an electric shock or leakage fault occurs, there is leakage current flowing through the circuit. At this time, the vector sum of the three-phase current passing through the current transformer is not equal to zero, and its vector sum is: Ia+Ib+Ic=I (leakage current). In this way, there is an induced voltage in the secondary coil of the transformer, and this voltage is applied to the electronic amplifier circuit of the detection part. The transformer connected to the protection is called a zero-sequence current transformer. The vector sum of the three-phase current is not equal to zero, and the current generated is the zero-sequence current.   2. Application of zero-sequence current transformer   The zero-sequence current transformer is a single-turn through-type current transformer, but its primary winding is the three-phase conductor of the protected system (the three-phase conductor passes through the transformer ring core together), and the secondary winding reflects the zero-sequence current of the primary system. Zero-sequence current transformers are generally used in conjunction with small current grounding line selection devices, microcomputer detuning devices, etc. When zero-sequence grounding current is generated in the power system, it is used in conjunction with relay protection devices or signals to activate the device components to achieve protection or monitoring.   In the 10kV power supply and distribution system, zero-sequence current transformers are generally divided into high-voltage zero-sequence and low-voltage zero-sequence:   1. High-voltage zero-sequence   When a ground fault occurs on the lower side of the 10kV circuit breaker, the zero-sequence CT can detect the grounding current and trip the circuit breaker. However, when the circuit breaker is equipped with comprehensive protection (the internal software has the function of calculating zero-sequence current), the zero-sequence current can be calculated from the current of the three-phase current transformer, causing the circuit breaker to trip.   2. Transformer low-voltage zero sequence   Install at a position where all N-line currents at the neutral point of the transformer can be detected. If the three-phase load of the three-phase transformer is balanced, the total current passing through the neutral point should be 0. When an asymmetric load occurs during operation, current will pass through the neutral point, which generally does not cause damage to the equipment, but in extreme cases or when the deviation is large, voltage drift will occur, that is, the voltage is unstable and even burns out the electrical equipment or the transformer itself. Therefore, the equipment can be effectively protected by monitoring the neutral point current.   3. Selection of zero-sequence current transformer   1. Installation method   From the aspects of maintenance and installation, try to use an open-and-close zero-sequence current transformer.   2. Product structure   Select according to the actual use. Generally, most of them use cable type, and busbar type is used in very few occasions, such as zero-sequence protection of generator outlet.   3. Selection of zero-sequence current transformer ratio   For 10kV system, high-voltage zero-sequence can be selected according to the calculated protection setting. For example, when the protection setting is 80A, the protection action can be selected as 100/1 or 100/5.   Generally, transformers with a capacity of more than 500kVA are equipped with transformer low-voltage zero-sequence. The calculated current is obtained according to the installed capacity of a single transformer/0.4/1.732.   4. Selection of the inner diameter of the zero-sequence current transformer   When selecting the inner diameter of the zero-sequence current transformer, the inner diameter of the transformer is required to be 20-30mm larger than the outer diameter of the cable to facilitate installation and maintenance.

In many applications controlled by single-chip microcomputers, split core current transformers are used to convert signals that cannot be directly measured by single-chip microcomputers into electrical analog signals that can be processed by single-chip microcomputers, such as AC transmitters, pressure transmitters, and temperature transmitters. Transmitters, fluid quality transmitters, etc. Most early transmitters are voltage output types, which convert the measurement signal into a 0-5V voltage output. This is the direct output of the operational amplifier. The signal power is <0.05W. The digital signal is converted by the analog/digital conversion circuit for the single-chip microcomputer to read and control.   The split current transformer sends the lower water and upper steam condensate in the liquid level sensor to both sides of the transmitter bellows through the meter tube. The pressure difference on both sides of the bellows drives the mechanical amplification and installation. The pointer indicates the water level. Of course, there is also a transmitter that can convert electrical analog quality into digital quantity. The above is just a conceptual clarification of the difference between sensors and transmitters. Two-wire current output AC transmitters are widely used because of their extremely high anti-interference ability.   Precautions for using split-type current transformers:   1. Pay attention to the auxiliary power supply information on the product label. The auxiliary power supply level and polarity of the transmitter cannot be connected incorrectly, otherwise the transmitter will be damaged;   2. The transmitter is an integrated structure and cannot be disassembled. It should be prevented from collision and falling;   3. When the transmitter is used in a strong magnetic interference environment, please pay attention to the shielding of the input line and the output signal should be as short as possible. When the equipment is concentrated, the equipment distance should not be less than 10mm;   4. There is no lightning protection circuit inside this series of transmitters. When the input and output feeders of the transmitter are exposed to harsh outdoor environments, lightning protection measures should be taken;   5. This product is packaged in a flame-retardant ABS plastic shell. The temperature resistance of the shell is +85℃, and it will deform when baked at high temperature, affecting the product performance. Do not use or store the product near a heat source, and do not bake the product in a high-temperature box;   6. Do not damage or modify the product label or logo, and do not disassemble or modify the transmitter, otherwise the company will no longer provide the "three guarantees" (replacement, return, repair) service of the product.   Hemei Electronics has been developing in the power industry for more than ten years, focusing on the research of electromagnetic materials, electromagnetic equipment, electromagnetic shielding and other projects, producing silicon steel, Permalloy materials, magnetic cores, current transformers, power harvesting current transformers, magnetic shielding shells, common mode inductors, coupling transformers and other electromagnetic products, which are deeply trusted and supported by domestic and foreign customers. If you have any needs in this regard, please feel free to contact us, we will customize products that satisfy you.

The detachable low-voltage current transformer is also called the split core current transformer. It is mainly used in the transformation projects of the power distribution system of 0.66kV and below. It is easy to install, without removing the primary busbar, and can be operated with power on, which does not affect the normal power consumption of customers. It saves manpower, material resources, and financial resources for the transformation projects of users and improves efficiency. This series of current transformers can be used in conjunction with relay protection, measurement, and metering installation.   In the actual application process, there are always customers asking why the split-type current transformer makes noise during operation?   1. When the split-type current transformer is in operation, if the secondary output lines S1 and S2 are not connected reliably (that is, the secondary circuit is open), a noise will be generated. If it is operated for a long time, a large open-circuit voltage will be generated due to the saturation of the magnetic core, causing the iron core to heat up until the transformer burns out. For this reason, when the split-type current transformer makes noise during operation, first check whether the secondary output lines S1 and S2 of the transformer are connected firmly and reliably.   2. When installing the split-type current transformer, it is necessary to ensure that P1 of the upper shell corresponds to P1 of the lower shell on the same side, and P2 corresponds to P2 on the same side. The core of the split-type current transformer must be used in pairs. After the unpaired core is installed, there will be a gap on the contact surface, and the transformer will make a sound when it is used; therefore, when the split-type current transformer makes a sound during operation, check whether P1 and P2 on the same side of the upper and lower shells correspond.   3. When there are foreign objects on the upper and lower contact surfaces of the split-type current transformer core, a sound will be generated. Therefore, when installing, pay attention to the contact surface of the core to ensure that it is clean and free of foreign objects.   Hemei Electronics is located in Hefei, Anhui Province, China. Our products cover more than 30 provinces, cities and districts in China and are exported to more than 20 countries. The company mainly produces magnetic materials/current sensors/current transformers/transformer cores/magnetic shielding shells/common mode inductors/coupling coils and other products, which are mainly used in power, communications, environmental protection, water affairs, automobiles, high-speed rail, military industry, new energy, rail transit, smart cities, smart fire protection, intelligent low-voltage test units, industrial Internet of Things, industrial control automation, power station area transformation and other industries. Our quality is obvious to all and is deeply trusted by consumers. If you have any needs in this regard, please feel free to contact us.

The split core current transformer is suitable for indoor equipment with a rated voltage of 10kV and below. It is used for circuit control, maintenance and other functions. There are many names for split current transformers, such as card current transformer, combined transformer, split transformer, split power transformer, etc. There are so many names, which fully illustrates the versatility of the instrument, and this versatility shows its applicability.   The split current transformer is suitable for AC power systems below 10KV, 35KV power supply equipment, and microcomputer maintenance and current measurement. If you want to fully evaluate the characteristics of split current transformers, it can be said that split current transformers have the characteristics of light weight, small size, openable, and easy installation.   There are multiple series of split current transformers, such as ZK series, LMWK series and other outdoor series, AKH-0.66-K series, etc., which are mainly used in distribution system transformation projects. Of course, there are also national standard models for indoor open transformers, such as LMZK. There are still some open transformers on the market, such as LDZK, LZK, etc. Users may have a headache when seeing so many series, but in fact, there is no difference between these series. In fact, we can all regard them as the same product.   How to install the split current transformer product? Open the transformer installation screws and nuts, remove the lower body of the transformer, install the upper body of the transformer into the primary busbar of the power distribution system, close the lower body of the transformer, pass the installation screws of the transformer through the transformer, screw on the nuts on the upper and lower body fixing holes of the transformer, fix the upper and lower bodies of the transformer together, and then fix the transformer on the busbar through the installation fixing holes on both sides of the transformer to complete the installation of the transformer. Then connect the secondary side of the transformer to the measuring device.   Hemei Electronics is an innovative and developing enterprise. The company has excellent equipment, advanced technology and a complete quality assurance system. It is also one of China's self-operated import and export enterprises.     The company has strong technical force, exquisite production technology, advanced inspection equipment and excellent equipment, including fully automatic transformer inspection bench, intelligent transformer calibrator, interference discrimination partial discharge tester, three-frequency generator, high current withstand voltage tester, balance characteristic tester, and high current load tester, which provide reliable guarantee for the quality of transformer production and win the praise of users. The products are sold well in various places and exported to more than 20 regions including Europe, America, Africa, the Middle East and Southeast Asia.