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Longbian (Shanghai) Electric Manufacturing Co., LTD

Contact person: Fu Yong

Tel: 021-61462346

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QQ: 1537738997 2210282015

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askPressure regulator classification？: answerVoltage regulator is divided into: autotransformer, isolation voltage regulator, oil immersed type induction voltage regulator, column type electric pressure regulator thyristor voltage regulator five. Method and voltage regulation device manual voltage and electric voltage. Pressure regulator noun explanation: pressure regulator English name The thyristor voltage regulator is also called "thyristor power regulator" "thyristor power regulator" or "power regulator" . "Thyristor" also known as "silicon controlled" (SCR) is a kind of four layer three terminal semiconductor device, it is connected to intermediate load in power supply and distribution, phase Trigger control circuit board should be, you can adjust the voltage applied to the load, the current and power. "Thyristor regulator" is mainly used for various electric heating device (such as an electric industrial furnace, electric heating drying machine, electrothermal oil stove, all kinds of reaction tank, a reaction kettle electric heating device) heating power adjustment, can be "manual" adjustment, but also can and electric control, intelligent instrument Regulating instrument, PLC and computer control system coordination, to achieve constant value or a procedure to control the heating temperature.
askWhat does a reactor do?: answerThe common reactors used in power system are series reactors and shunt reactors. Series-connected reactors are mainly used to limit short-circuit current, and also in series or parallel with capacitors in filters to limit higher harmonics in the power grid. The reactors in the 220kV, 110kV, 35kV and 10kV power grids are used to absorb the charge capacitive reactive power of the cable lines. The operating voltage can be adjusted by adjusting the number of shunt reactors. The UHV parallel reactor has a variety of functions to improve the reactive power operation of the power system, including:1, light no-load or light load line capacitance effect, to reduce the power frequency transient overvoltage;2. Improve voltage distribution on long transmission lines;3, make the reactive power in light load line balance as far as possible, prevent the irrational flow of reactive power and reduce the power loss on the line;4, when the large unit is juxtaposed with the system, the steady-state voltage of the power frequency on the high voltage bus is reduced, which is convenient for the generator to be juxtaposed at the same time;5, prevent the generator with a long line may appear self-excitation resonance phenomenon;6. When the neutral point of the reactor is used through the small reactance earthing device, the small reactor can also be used to compensate the line phase-to-phase and phase-to-ground capacitance to accelerate the automatic extinction of the latent power supply current, which is easy to use.The wiring of reactor is divided into series and parallel two ways. Series reactors usually act as current limiting, and shunt reactors are often used for reactive power compensation.1, half core dry shunt reactor: in the ultra-high voltage long-distance transmission system, connected to the transformer on the tertiary coil. It is used to compensate the capacitive charging current of the line, limit the system voltage rise and operating overvoltage, and ensure the reliable operation of the line.2, half core dry series reactor: installed in the capacitor circuit, in the capacitor circuit input from.Current limiting and filtering function of reactor:With the expansion of power network capacity, the rating of system short-circuit capacity increases rapidly. For example, in the low-voltage 35kV side of the 500kV substation, the maximum three-phase symmetric short-circuit current effective value has been close to 50kA. In order to limit the short circuit current of the transmission line and protect the power equipment, the reactor must be installed. The reactor can reduce the short circuit current and keep the voltage of the system constant at the moment of short circuit.A damped reactor (i.e. series reactor) is installed in the capacitor loop to inhibit inrush current when the capacitor loop is put in. At the same time, the harmonic circuit is formed together with the capacitor bank to filter each harmonic. For example, in the capacitor circuit of 35kV reactive power compensation device in 500kV substation, in order to limit the inrush current when the capacitor is put in and restrain the higher harmonics of the power system, the damping reactor must be installed in the 35kV capacitor circuit. When the third harmonic is suppressed, the rated voltage is 35kV and the rated inductance is 26.2mH. Rated current 350A dry hollow single-phase outdoor type damping reactor, it and 2.52Mvar capacitor to the third harmonic resonance loop, that is, the third harmonic filtering loop.Similarly, in order to suppress the fifth or more higher harmonics, a single-phase outdoor resistive reactor with rated voltage of 35kV, rated inductance of 9.2mH and rated current of 382A is used. It forms a resonant loop with a 2.52Mvar capacitor to the fifth or more higher harmonics. Has played a role in the suppression of high harmonics, it needs to be explained that in the national standard "reactor" GB10229-88 and IEC289-88 international standards for the use of the damping reactor and technical conditions have made provisions. But at present some domestic departments will be damped reactor called series reactor, strictly speaking is not appropriate, because there is no series reactor this name in the above standards.
askBooster transformer design booster transformer classification has what: answer1 IntroductionStep-up transformer and on-load voltage regulation are transformer tap switch voltage regulation mode, the difference is that the non-exciting voltage regulation switch does not have the ability to shift gears with load, because this tap switch in the process of shift gears, there is a short-time disconnect process, disconnect the load current will cause the arc between contacts burn the tap switch or short circuit, so the transformer must be cut off when shifting. Therefore, it is generally used for transformers that are not very strict in voltage requirements and do not need to shift frequently. And the on-load tap switch can be load switching gear, because the on-load tap switch in the shift process, there is no short-time disconnection process, through a transition resistance transition, from one gear to another gear, so there is no load current disconnection arc pulling process. It is generally used for transformers with strict voltage requirements and frequent shifting.2 DefinitionDefinition: A transformer is a common electrical device used to convert a value of alternating voltage into another value of alternating voltage at the same frequency. A booster transformer is a transformer used to convert a low value alternating voltage into another high value alternating voltage of the same frequency. It is widely used in the field of high frequency, such as inverter power supply.3 Classification of high frequency expressionsThe high frequency booster transformer adopts the high frequency doubling voltage rectifier circuit, the application of the latest PWM pulse width modulation technology and power IGBT devices, and according to the electromagnetic compatibility theory, the use of special technology, so that the DC generator to achieve high quality, portable. It is composed of two parts: control box and voltage doubling device. It is equipped with protection resistance, which has the functions of voltage zero gate protection, overcurrent protection and overvoltage protection. Small size, light weight, easy to carry, convenient, safe and reliable, suitable for power department field DC high voltage test, arrester DC characteristics test and other occasions requiring DC high voltage.Straight flowDc booster transformer has the characteristics of small volume, light weight, compact structure, complete functions, strong versatility and easy to use. Especially suitable for power system, industrial and mining enterprises, scientific research departments and other high voltage electrical equipment, electrical components, insulation materials under the manifold frequency or DC high voltage insulation strength test. It is an essential and important equipment in high pressure test.Energy saving and low noise: using high quality cold rolled silicon steel sheet stacked; Full oblique joint; Special processing technology is adopted to effectively reduce the vibration and noise during operation. As well as computer optimization design and other new materials, new process, new technology introduction, make the transformer more energy saving, more quiet.High reliability: To improve product quality and reliability, will be our unremitting pursuit. In the quality assurance system and reliability engineering of a large number of basic research, active reliability certification, further improve the reliability and service life of the transformer.Environmental protection properties: heat resistance, moisture resistance, stability, chemical compatibility, low temperature, radiation resistance and non-toxicity.Alternating flowAc booster transformer is a device that transforms AC voltage, current and impedance. When there is AC current in the primary coil, AC flux is generated in the iron core (or magnetic core), so that the voltage (or current) is induced in the secondary coil. A transformer consists of an iron core (or magnetic core) and a coil. The coil has two or more windings. The winding connected to the power supply is called the primary coil, and the rest is called the secondary coil. Ac booster transformer has the characteristics of small volume, light weight, compact structure, complete functions, strong versatility and easy to use. Especially suitable for power system, industrial and mining enterprises, scientific research departments and other high voltage electrical equipment, electrical components, insulation materials to carry out manifold frequency or AC high voltage insulation strength test. It is an essential and important equipment in high pressure test.Dry type is relative to oil type transformer, dry type booster transformer because there is no oil, there is no fire, explosion, pollution and other problems, so electrical codes and regulations do not require dry type transformer placed in a separate room. Especially with the new series, loss and noise are reduced to new levels, and the transformer and low voltage panel are placed in the same distribution room to create conditions. The safe operation and service life of dry booster transformer largely depend on the safety and reliability of transformer winding insulation. The insulation damage caused by the winding temperature exceeding the insulation resistance temperature is one of the main reasons for the transformer not working normally. Therefore, it is very important to monitor the running temperature of the transformer and its alarm control. According to the environmental characteristics and protection requirements, the dry booster transformer can choose different shells. IP23 protective shell is usually used to prevent the entry of solid foreign bodies with diameter larger than 12mm and small animals such as rats, snakes, cats and finches, which may cause malignant faults such as short circuit and power failure, and provide a safety barrier for live parts. If the transformer must be installed outdoors, you can choose IP23 protection shell, in addition to the above IP20 protection function, but also can prevent water drop and vertical line Angle within 60°. But the IP23 shell will reduce the cooling capacity of the transformer, and attention should be paid to the reduction of its operating capacity when selecting.Low frequency typeThe low frequency transformer core flux is related to the applied voltage. The excitation current in the current does not increase with the load. Although the load increase core will not be saturated, will make the coil resistance loss increase, more than the rated capacity due to the heat generated by the coil can not be timely out, coil will be damaged, if you use the coil is composed of superconducting materials, current increases will not cause heat, but the transformer and the impedance caused by magnetic leakage, but the current increases, the output voltage will drop, the greater the current, The lower the output voltage, so the transformer output power cannot be unlimited. If you say that the transformer has no impedance, then when the transformer flows through the current will produce a particularly large electric power, it is easy to damage the transformer coil, although you have a power unlimited transformer but can not use. It can only be said that with the development of superconducting materials and iron core materials, the output power of transformers of the same volume or weight will increase, but not infinitely large! [1]4 Physical Properties Physical propertiesTransformer ---- A stationary electromagnetic device that converts alternating current energy of one voltage into alternating current energy of another voltage of the same frequency. The main components of a transformer are an iron core and two windings over the core. The principle of transformer is that the coil connected to the power supply receives AC electric energy, which is called the primary winding, and the coil connected to the load sends AC electric energy, which is called the secondary winding, the primary winding, the secondary winding, voltage phasor U1 voltage phasor U2, current phasor I1 current phasor I2, electromotive force phasor E1 electromotive force phasor E2, the number of turns N1 turns N2, and the alternating chain once, The phasor of the magnetic flux of the secondary winding is φm, which is called the primary magnetic flux.Physical formulaU1/U2=N1/N2 =I2/I1 (U1 and U2 are voltage, N1 and N2 are coil turns, I1I2 is current).There are many and complex reasons for transformer internal faults and accidents caused by transformer outlet short circuit. It is related to structural design, quality of raw materials, technological level, operating conditions and other factors, but the selection of electromagnetic line is the key. In recent years, the electromagnetic wires selected by transformer based on the static theory design are different from the stress acting on the electromagnetic wires in actual operation.1. The winding is loose, the transposition is not handled properly, and the electromagnetic wire is too thin, resulting in hanging. From the point of view of accident damage, the deformation is more common in the transposition, especially the transposition of the transposition wire.2. At present, the calculation program of various manufacturers is based on the idealized model of uniform distribution of leakage magnetic field, the same turns diameter, equal phase force, etc., but in fact, the leakage magnetic field of transformer is not uniform distribution, relatively concentrated in the yoke part, the electromagnetic line in this area is subjected to a large mechanical force; The climbing of the transposition wire will change the direction of force transmission at the transposition point and generate torque. Due to the factor of the elastic modulus of the pad, the unequal distribution of the axial pad will cause delayed resonance of the alternating force generated by the alternating leakage magnetic field. This is also the fundamental reason why the wire cake at the yoke part of the core, the transposition part and the corresponding part with the pressure regulation tap deform first.3. Improper control of the winding preload causes the wires of the ordinary transposition wires to be misaligned with each other.4. The influence of temperature on the bending and tensile strength of electromagnetic wire is not considered in the calculation of short-circuit resistance. The anti-short-circuit capability designed at normal temperature can not reflect the actual operation condition. According to the test results, the temperature of the electromagnetic wire has no effect on its yield limit. 0.2 has a great influence. With the increase of the temperature of the electromagnetic wire, its bending strength, tensile strength and elongation all decrease. The bending tensile strength at 250℃ is lower than that at 50℃, and the elongation is reduced by more than 40%. In the actual operation of the transformer, under the rated load, the average winding temperature can reach 105℃, and the most hot spot temperature can reach 118℃. General transformers have reclosing process during operation, so if the short circuit point cannot disappear for a while, it will bear the second short circuit impact in a very short time (0.8s), but because of the impact of the first short circuit current, the winding temperature increases sharply, according to the provisions of GBl094, the maximum allowed 250℃, At this time, the anti-short-circuit ability of the winding has been greatly reduced, which is why the short-circuit accidents of Satons transformer occur most after reclosing.5, the use of flexible wire, is also one of the main reasons for the transformer short-circuit resistance is poor. Due to the lack of early understanding of this, or winding equipment and process difficulties, manufacturers are reluctant to use semi-hard wire or design without this requirement, from the fault transformer point of view are soft wires.6. External short-circuit accidents are frequent. The accumulated effect of electric power after multiple short-circuit current impacts causes electromagnetic line softening or internal relative displacement, and eventually leads to insulation breakdown.7. The winding turns or wires are not cured, and the resistance to short circuit is poor. There is no damage to the windings treated with lacquer in the early stage. [2]6 Daily Maintenance1. In order to protect the insulation performance of the insulating oil installed in the high voltage generator and the head, it is generally not appropriate to open the observation window and loosen the fixing screws around, so as to prevent the oil from absorbing moisture or falling dust and reducing the insulation performance.2. Check whether the lighting, heat dissipation and dust removal equipment around the transformer are in good condition, and wipe the dust on the transformer body and porcelain bottle with a clean cloth.3, check the transformer high voltage side load switch, to ensure flexible operation, good contact, transmission part for lubrication.4. Open the high-voltage grounding knife, check that the grounding is in the off position, close the high-voltage load switch, let the transformer test run, and take down the high-voltage side sign plate, pay attention to disconnect or close the transformer high-voltage load switch, there must be more than two people on site.5, when the need to replace the new oil, should obtain the assistance of the local power department, check the performance of the new oil, the insulation strength is required to be not less than 25,000 volts /2.5 mm; The oil insulation strength in the combined head should be above 30,000 volts /2.5 mm.6, use 2500V dial to measure the transformer high and low voltage coil insulation resistance value (to the ground and phase), confirm that meet the requirements (at room temperature 30℃, 1OKV transformer high voltage side is greater than 20MΩ, low voltage side is greater than 13MΩ. Before the test, the ground wire should be connected, and after the test, the discharge should be carried out.7, the high voltage generator or combination head must have a good grounding wire, should often use the ohmmeter to measure the shell, console shell, external ground three are on, and tighten the grounding bolt.

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