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Protective measures for grounding arrangement of power frequency withstand voltage test equipment
2025-08-08Wuhan UHV specializes in producing series resonance (also known as power frequency withstand voltage test equipment). Next, we will share with you the protective measures for the grounding arrangement of power frequency withstand voltage test equipment.Variable frequency series resonance is mainly composed of variable frequency controller, excitation transformer, high-voltage reactor, high-voltage voltage divider, etc. During the frequency conversion series resonance test, the capacity of the excitation transformer should be greater than the active power P, and the transformation ratio of the excitation transformer should be reduced as much as possible on the premise that the minimum output voltage of the excitation transformer meets the test requirements, so as to correspondingly reduce the input current on the primary side of the excitation transformer. Due to the large capacitance of the tested cable, if the test sample breaks down or high-voltage leads discharge to ground during th
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Introduction to the characteristics of the variable frequency series resonance test device
2025-08-08Wuhan UHV specializes in producing series resonance (also known as variable frequency series resonance test device). Next, we will share with you the characteristics of the variable frequency series resonance test device.Series resonance testFirst of all, let's talk about the series resonance test, which is also commonly known as the AC withstand voltage test. It is the most effective and direct way to identify the insulation strength of power operating equipment before commissioning, and can play a decisive role in the pre commissioning process. Series resonance is a principle technology of electronic circuits, and it is a method or preventive test for insulation testing. Due to its large test capacity and high voltage, series resonance is widely used in power generation, power supply and other departments. The significance of series resonance testDuring the operation of power equipment, insulation will gradually deteriorate under the long-term effects of electric field, temperat
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Composition of variable frequency series resonance test device
2025-08-07Wuhan UHV specializes in producing series resonance (also known as variable frequency series resonance test device). Next, we will share with you the composition of the variable frequency series resonance test device.When we come into contact with the frequency conversion series resonance withstand voltage device, we will know that the power system and power engineering cannot do without the series resonance test device, because the series resonance withstand voltage test device is the most basic testing equipment for power safety. In the power industry, basic tools such as cables, transformers, and switches need to be tested for their voltage resistance performance using series resonance tests, in order to provide safety control for power equipment.So what are the components of the variable frequency series resonant withstand voltage device?The variable frequency series resonant withstand voltage device mainly consists of a variable frequency power supply, an excitation transformer, a
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Comprehensive answer on how to select series resonance
2025-08-07Wuhan UHV specializes in producing series resonance (also known as series resonance test device). Next, we will share with you a comprehensive answer on how to select series resonance.Introduction to series resonant deviceSeries resonance is a necessary test equipment for insulation inspection of large capacity and high voltage power equipment in power preventive testing projects. It achieves the functional requirements of resonant boosting by adjusting inductance and frequency in combination. Variable frequency series resonance is composed of a control power supply, excitation transformer, high voltage reactor, compensation capacitor, and capacitor divider.Selection requirements for series resonanceBefore purchasing a series resonance device, we need to understand the basic situation on site. Taking the voltage withstand test of power cables with many unknown parameters as an example, how to choose the capacity and maximum voltage of the series resonance test device based on the volta
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Analysis and Application of Series Resonant AC Voltage Test Device
2025-08-07Wuhan UHV specializes in producing series resonance (also known as AC/DC withstand voltage test device). Next, we will share with you the analysis and application of series resonance AC withstand voltage test device.In the debugging of power supply and distribution systems, it is necessary to inspect cross-linked polyethylene power cables (XLPE), high-voltage switchgear GIS、 High voltage and large capacity power equipment such as high-voltage motors, large generator sets, large power transformers, and transformers are subjected to insulation withstand voltage tests.The insulation withstand voltage test is divided into two types: DC withstand voltage test and AC withstand voltage test. In the past, DC voltage withstand test was used for cable voltage withstand test. Around 1980, foreign power departments discovered that DC withstand voltage testing was ineffective and harmful to rubber insulation. China began researching and practicing voltage withstand testing technology in the 1990s.
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Knowledge of series resonance withstand voltage test device
2025-08-06Wuhan UHV specializes in producing series resonance (also known as cable withstand voltage test equipment). Next, we will share with you the knowledge of series resonance withstand voltage test device.Knowledge of series resonance withstand voltage test deviceWhat is series resonance used for? The series resonance withstand voltage test device applies the principle of series resonance. By adjusting the output frequency of the variable frequency controller, the reactor inductance L and the sample capacitance C in the circuit undergo series resonance, and the resonance voltage is the voltage applied to the sample. The frequency conversion series resonance test device is widely used in industries such as power, metallurgy, petroleum, and chemical engineering. It is suitable for large capacity, high-voltage capacitive test samples, such as generators, power transformers, GIS and high cross-linking power cables, transformers, bushings, and other handover and preventive tests. The frequency
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A comprehensive introduction to the series resonance test device
2025-08-05The structure of variable frequency series resonance mainly consists of a variable frequency control power supply, excitation transformer, capacitor, and capacitor voltage divider. The application range of variable frequency series resonance: Suitable for various large power transformers, power cables, steam turbines, hydro generators, and other capacitive equipment. The AC withstand voltage test must be strictly conducted regularly according to the test regulations. Under power frequency conditions, due to the large capacitance of the test object or high requirements for the test voltage, there are also high requirements for the power capacity of the test device. Traditional power frequency withstand voltage devices often have large individual volumes, heavy weights, are not easy to transport on site, and are not easy to combine arbitrarily, resulting in poor flexibility.The principle of frequency conversion series resonance: When the circuit frequency f=1/2 π√ LC, the circuit resona
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What are the characteristics of the variable frequency series resonance withstand voltage test device?
2025-08-05The frequency conversion series resonance withstand voltage test device applies the principle of series parallel resonance. By adjusting the output frequency of the frequency conversion controller, the inductance L of the reactor in the circuit and the capacitance C of the test sample resonate, and the resonant voltage is the voltage applied to the test sample. Variable frequency series resonance provides power supply through a frequency modulation controller. The test voltage is initially boosted by an excitation transformer, and high voltage is applied to the reactor L and the test sample CX. By changing the output frequency of the frequency modulation controller, the circuit is in series resonance state; The resonant frequency of the circuit depends on the capacitance CX of the test sample and the inductance L of the reactor. Adjust the output voltage of the variable frequency controller to achieve the required voltage value on the high voltage of the variable frequency series reson
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What are the conditions for series resonance to occur? What are the factors involved?
2025-08-04What are the conditions for series resonance to occur? What are the factors involved? Series resonance is the combination of high current and high voltage, which has a significant impact on daily use and is also related to electrical safety. The occurrence of a series resonant circuit has certain conditions.In a series circuit composed of resistors, inductors, and capacitors, when the capacitive reactance XC is equal to the inductive reactance XL, i.e. XC=XL, the voltage U and current I in the circuit are in phase, and the circuit behaves as a pure resistor. This phenomenon is called series resonance. When the circuit has series resonance, the circuit impedance Z=√ R ^ 2+(XC-XL) ^ 2=R, the total impedance in the circuit is the smallest, and the current reaches the maximum value. Impedance condition, after resonance, the imaginary parts are equal and the signs are opposite. The series impedance is equal to 0, and the parallel impedance is equal to infinity. When resonating, the resonant
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The testing principle of series resonant withstand voltage tester
2025-08-04Fully utilizing the advantages of Wuhan UHV in electronic measurement technology and electromagnetic compatibility, we independently develop, design, and produce all components of this equipment, including high-voltage withstand voltage testing, variable frequency power supply, excitation transformer, cast high-voltage reactor, and high-precision capacitive voltage divider. Due to the widespread application of the method of generating high voltage through series resonance, problems may also be encountered when using this high-voltage method for withstand voltage testing on site. This article mainly analyzes the testing principle of the series resonant withstand voltage tester.The working principle of series resonance withstand voltage test is that the series resonance withstand voltage test device, also known as series resonance, is divided into frequency modulation type and inductance modulation type. It generally consists of a variable frequency power supply, excitation transformer,
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Application and precautions of frequency conversion series resonance withstand voltage test device
2025-08-01Years of practical experience in power testing and inspection have taught us that only variable frequency series resonant withstand voltage testing devices can meet the preventive testing of insulation performance for large capacity power equipment. Due to the high voltage level of large capacity power equipment and the need for large capacitors, general power frequency withstand voltage test devices are no longer able to meet the withstand voltage test requirements of large capacity power equipment. Due to the greatly reduced capacitance of the variable frequency series resonance, the required power supply for testing is only 1/Q of the testing capacity (q is the quality factor). Therefore, by using a variable frequency series resonance testing device, it is easier to increase the voltage to the required power level. It is safer and more reliable to use a variable frequency series resonant withstand voltage test device for the withstand voltage test of large capacity power equipment.
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Precautions for safe wiring of frequency conversion resonance withstand voltage test device
2025-08-01The frequency conversion resonance withstand voltage test device adopts a dedicated broadband voltage regulation power supply, with a voltage regulation range of ac0-400V, a frequency modulation range of 30-300Hz, and a frequency fineness of up to 0.1Hz. The output waveform in the entire frequency range is good, ensuring the stability and safety of the instrument at the minimum weight and volume. The device consists of a frequency and voltage regulating power supply, an excitation transformer, a reactor, and a capacitor voltage divider. The frequency conversion resonance withstand voltage test belongs to the high-voltage withstand voltage test. There are many things to pay attention to during the testing process. The circuit connection and precautions of the frequency conversion resonance withstand voltage test device are as follows:Through on-site testing of the full load wiring method of different specifications of frequency conversion resonance withstand voltage test devices, share
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How to choose series resonant equipment?
2025-07-311、 Power testing instruments, apparatus, and testing equipment for testing accuracyThe precision of an instrument is called accuracy, also known as precision. Accuracy and error can be said to be twin brothers, because there are errors, precise concepts. The accuracy of an instrument is only the precision with which the measured value is close to the true value, usually expressed as relative percentage error (also known as relative folding error). The formula for relative percentage error is as follows: δ - the relative percentage error during the detection process; (Proportional upper limit - Proportional lower limit) - Instrument measurement range; Δ x - Absolute error, the difference between the measured parameter value x1 and the measured parameter standard value x0. The so-called standard value is the value measured by a standard instrument, which is 3 to 5 times higher than the instrument being tested. The accuracy of the instrument is not only related to absolute error, but als
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Characteristics of series resonant reactor
2025-07-311、 Definition of ReactorThe main components of an electrical circuit are resistors, capacitors, and inductors. Inductance has the function of suppressing current changes and shifting the phase of alternating current. A wound type static induction device with inductive function is called a reactor. 2、 Characteristics of reactors1. Iron core reactorHigh noise, poor linearity of reactors, can cause magnetic leakage, local overheating, easy magnetic saturation, and coil burnout. The effects of system overvoltage, overcurrent, and harmonics cause a sharp decrease in the iron core's supersaturated reactance value, a decrease in the ability to suppress harmonics, and a low ability to withstand short-circuit currents. In addition to the above drawbacks, dry-type iron core reactors cannot operate outdoors. 2. Dry type air core reactorGood linearity, no noise, strong overcurrent ability, strong heat dissipation ability, simple and sturdy mechanical structure, suitable for indoor and outdoo
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The principle and application of frequency conversion series resonance
2025-07-30The structure of variable frequency series resonance mainly consists of a variable frequency control power supply, excitation transformer, capacitor, and capacitor voltage divider. The application range of variable frequency series resonance: Suitable for various large power transformers, power cables, steam turbines, hydro generators, and other capacitive equipment. The AC withstand voltage test must be strictly conducted regularly according to the test regulations. Under power frequency conditions, due to the large capacitance of the test object or high requirements for the test voltage, there are also high requirements for the power capacity of the test device. Traditional power frequency withstand voltage devices often have large individual volumes, heavy weights, are not easy to transport on site, and are not easy to combine arbitrarily, resulting in poor flexibility. The principle of frequency conversion series resonance: When the circuit frequency f=1/2 π√ LC, the circuit reso
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Correct use of frequency conversion series resonance withstand voltage test device and power supply
2025-07-30The power input of the variable frequency series resonant withstand voltage test device is divided into two parts. From the production design requirements of the variable frequency series resonant withstand voltage test device, the "working power supply", as the name suggests, is mainly used to provide power for the normal operation of the instrument. It can also be referred to as variable frequency series resonant withstand voltage. The frequency modulation power box of the testing device provides neural control for the working power supply, and the "power supply" provides a guarantee for the resonant output high voltage of the upper and lower stages. The quality of power supply is directly related to the output voltage and power when testing cables or tested products.1. The working power supply of the instrument generally needs to be connected to 220V; the recommended power supply for the equipment is 380V;2. The live wire of the instrument's working power supply should be discon
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Condition analysis before series resonance withstand voltage test
2025-07-29In electrical testing, parallel resonance and series resonance are both structural branches of the series resonance testing device, with a slight difference in their names. Below is a basic introduction to series resonance. What is series resonance? Due to the fact that most power preventive tests are conducted on large capacity and high voltage electrical equipment, it is recommended to use power frequency withstand voltage for insulation performance testing, which eliminates the requirement for using DC high-voltage generators for insulation performance testing of electrical equipment. Although both belong to destructive tests, after long-term research, the use of power frequency withstand voltage has better stability and safety compared to DC withstand voltage. Due to the large capacity and high voltage of electrical equipment, power frequency withstand voltage equipment such as oil immersed test transformers often cannot meet the testing requirements. In China, in order to achiev
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A comprehensive introduction to the components of series resonance
2025-07-29Series resonance is a circuit property and also a testing device for series resonance. Series resonance is a very practical and important voltage withstand test device in power systems. Its components are: variable frequency power supply, excitation transformer, high-voltage reactor, and capacitive voltage divider. So what are the functions of these components? 1、 Variable frequency power supplyThe function of a variable frequency power supply is to convert a 220V/380V, 50Hz power supply into a frequency adjustable and voltage continuously adjustable power supply. The variable frequency power supply also has functions such as operation, protection, control, and monitoring of the power system.2、 Excitation transformerThe function of the excitation transformer is to boost the voltage output by the variable frequency power supply, and the excitation transformer isolates both high and low voltage. 3、 High voltage reactorThe function of a high-voltage reactor is to cause series resonance
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What are the main methods for voltage withstand testing of power cables?
2025-07-28Cable withstand voltage test is a detection method for discovering cable faults. During the testing process, it is susceptible to various factors that may cause malfunctions, short circuits, and other issues. The following introduces the main methods of cable withstand voltage testing.1、 Ultra low frequency withstand voltage testThe ultra-low frequency (0.1Hz) withstand voltage test method first appeared in 1980, mainly used as a non-destructive testing method to observe whether there are insulation defects in cables during operation. This method has been validated through extensive laboratory and field experiments, and the low-frequency withstand voltage test has shown good application results in the withstand voltage test of low-voltage power cables. This method utilizes the principle of converting 50Hz AC power into DC voltage through rectification and filtering, then converting the DC voltage into 1kHz AC voltage through an inverter circuit, and finally completing the amplitude mod
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What is series resonance? What are the hazards of series resonance in circuit systems?
2025-07-28Series resonant devices are widely used in power systems. What is series resonance? What are the hazards of series resonance in circuit systems?What is series resonance?In a series circuit composed of resistors, inductors, and capacitors, when the capacitive reactance XC is equal to the inductive reactance XL, i.e. XC=XL, the phase of the voltage U and current I in the circuit are the same, and the circuit is purely resistive. This phenomenon is called series resonance. When a circuit has series resonance, the impedance of the circuit is Z=√ R2+(XC-XL)/2=R. The total impedance in the circuit is minimized, and the current will reach its maximum value. When resonance occurs, inductance equals capacitance, so the effective value of the voltage across the inductance and capacitance is equal, i.e. UL=UC. And due to their opposite phases, these two voltages cancel each other out.What are the hazards of series resonance in circuit systems?In the formula, ω 0LU/R is referred to as the quality
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