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The reason for the large series resonant current
2025-08-22Wuhan UHV specializes in producing series resonance (also known as series resonance withstand voltage equipment). Next, we will share with you the reasons for the large series resonance current.Principles of series resonance and parallel resonanceIn a series circuit of resistors, inductors, and capacitors, the phenomenon where the terminal voltage of some circuits is in phase with the total current of the circuit is called knowledge series resonance. A series resonant circuit is purely resistive, with terminal voltage and total current in phase. At this point, the impedance is low, the current is high, and high voltages many times greater than the power supply voltage may be generated on the inductance and capacitance. So series resonance is also called voltage resonance. In a circuit where the coil of an inductive sensor is connected in parallel with a capacitor, the phenomenon where the terminal voltage of a parallel control circuit is in phase with the total current of the circuit
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Purpose of AC withstand voltage test equipment testing
2025-08-22Wuhan UHV specializes in producing series resonance (also known as AC withstand voltage test equipment). Next, we will share with you the purpose of testing AC withstand voltage test equipment.Purpose of series resonant AC withstand voltage testSeries resonant AC pressure testing is the most effective and direct method for identifying the insulation strength of power equipment. However, non-destructive tests such as insulation resistance and absorption ratio tests, dielectric loss TG δ tests, and direct current leakage current tests can detect some insulation technical defects. However, due to the low voltage level of these tests, some local control defects may not be reflected clearly, and these local defects pose information security risks during operation. In order to effectively identify local control defects in certain enterprises, it is necessary to conduct information exchange withstand voltage tests on the test samples. The AC withstand voltage test will make the existing insu
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Introduction to series resonant voltage withstand device
2025-08-22Wuhan UHV specializes in producing series resonance (also known as cable withstand voltage test equipment). Next, we will share with you an introduction to the series resonance withstand voltage device.Composition of series resonant deviceSeries resonance is mainly composed of a frequency conversion series resonance test console, excitation transformer, high-voltage reactor, high-voltage voltage divider, etc. Principle of series resonant deviceSeries resonance is the application of the principle of variable frequency resonance, which uses an excitation transformer to excite a series resonant circuit, adjusts the output frequency of the variable frequency controller, and causes the circuit inductance L and the test sample C to resonate in series. The resonant voltage is the voltage applied to the test sample. Analysis of the principle of series resonance deviceIn an AC circuit with resistance R, inductance L, and capacitance C, the voltage at both ends of the circuit is generally diff
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Operation process of power frequency withstand voltage test equipment
2025-08-21Wuhan UHV specializes in producing series resonance (also known as power frequency withstand voltage test equipment). Next, we will share with you the operation process of power frequency withstand voltage test equipment.1. Check the connecting wires and confirm that they are correct;2. Power on: The voltage regulator console of the inductive series resonance test device starts the "power switch" after power on, the "power indicator" light is on, and the LCD lights up to display3. Increase the output voltage of the voltage regulator: generally increase it by 20V to 40V.4. Adjusting the gap of the reactor: (i.e. finding the resonance point) In general, the adjustable reactor core should be in the zero gap position after the last test and before the start of this series resonance test. Start pressing the "Increase Gap" button and pay attention to the value of the "Test Voltage". During the process of adjusting the gap, the test voltage increases with the increase of the iron core gap (be
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Operation steps of AC withstand voltage test device
2025-08-21Wuhan UHV specializes in producing series resonance (also known as AC withstand voltage test device). Next, we will share with you the operation steps of the AC withstand voltage test device.With the development of the power system, the capacity of operating equipment is increasing. For example, thermal power generation units have a single unit capacity of over 1000MW, and hydroelectric power generation units have a maximum single unit capacity of 800MW. Traditional testing equipment requires a large capacity for testing, and test transformers and voltage regulators are very bulky. Large capacity test power sources are also difficult to solve on site, making on-site testing extremely inconvenient. The series resonant AC withstand voltage test device has great advantages in terms of test power capacity, equipment weight, test waveform, and investment1. The overcurrent protection setting is set at 1.2 times the rated current on the high-voltage side of the test transformer.2. Overvoltage
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Selection of reactance rate of series resonant reactor
2025-08-21Wuhan UHV specializes in producing series resonance (also known as series resonance test equipment). Next, we will share with you the selection of reactance rate for series resonance reactors.As a common low-voltage reactive power compensation device, power capacitors are commonly used to improve the power factor of power systems, ensure the safety and stable operation of the power grid. Usually, a series reactor is also connected in the capacitor circuit, with two main purposes: limiting inrush current and suppressing harmonics. Because capacitors will amplify the harmonics injected into the system after being put into the power grid, exacerbating the harm of harmonics. How to choose the reactance rate of a series reactor based on the different purposes of capacitors? Selection of reactance rateThe reactance rate is an important parameter of a reactor, and its magnitude will directly affect its function and the safety of the system. In order to select the appropriate reactance rate,
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Three common AC test devices
2025-08-20Wuhan UHV specializes in producing series resonance (also known as series resonance withstand voltage test device). Below are three common AC test devices introduced to you.At present, there are three common types of communication testing devices:1. Power frequency AC withstand voltage device2. Inductive series resonant withstand voltage device3. Frequency modulation series resonant withstand voltage test deviceDue to its large and bulky size, the power frequency AC withstand voltage device is rarely used on site and is only used during the withstand voltage test of electrical equipment at a voltage level of 10kV. The inductive type is abandoned due to its use of adjustable iron core air gap reactors, which have the disadvantages of high noise, complex structure, and bulky equipment. IEC517 and GB7674 consider the test frequency to be basically equivalent to the power frequency voltage test in the range of 10-300Hz. Therefore, most domestic and foreign countries currently use frequenc
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Time and voltage standards for 20~300Hz AC withstand voltage test device
2025-08-20Wuhan UHV specializes in the production of series resonance (also known as AC withstand voltage test device). Next, we will share with you the time and voltage standards for the 20-300Hz AC withstand voltage test device.Series resonance, also known as series resonance test device, is a test device used to test the power frequency withstand voltage of high-voltage electrical equipment such as power cables, high-voltage switchgear, power transformers, and combiners. The series resonance device consists of a 20~300Hz variable frequency power supply, reactors, excitation transformers, compensation capacitors, and capacitor dividers. With the popularity of series resonance devices, today we will talk about the series resonance withstand voltage time and series resonance voltage standards. Series resonance withstand voltage timeThe series resonance withstand voltage time refers to the time that the test sample can withstand after being raised to the test voltage through the series resonance
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Precautions for various withstand voltage tests of variable frequency series resonance
2025-08-20Wuhan UHV specializes in producing series resonance (also known as cable withstand voltage test equipment). Next, we will share with you the precautions for various withstand voltage tests of variable frequency series resonanceAttention to Series Resonance (GIS) Test:1. During the experiment, the high-voltage source should be connected to the test, and the high-voltage lead should use a dedicated non corona lead. Non test connections should be grounded to the GIS casing;2. The test must ensure that the SF6 gas in each chamber is at the rated pressure, and the gas content is within the qualified range after 4 hours of inflation. The GIS must be in an operational state and confirmed to be correct before the test can be conducted;3. Before the test pressurization, ensure that the voltage transformers inside the GIS are removed (if approved by the GIS manufacturer, the voltage transformers can be pressurized together, but the test resonance frequency must be greater than 100Hz), the CT is
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Requirements for configuration of AC withstand voltage test equipment
2025-08-19Wuhan UHV specializes in producing series resonance (also known as AC withstand voltage test equipment). Next, we will share with you the configuration requirements for AC withstand voltage test equipment.Introduction to Cable AC Voltage Withstand Test DeviceThe cable frequency conversion series resonant voltage withstand device, also known as the cable AC voltage withstand test device, generates high voltage and high current on the test object by creating resonance conditions between the reactor and the tested capacitor at a frequency of 20~300Hz. The cable AC voltage withstand test device is designed based on the cross-sectional area and length of the cable, combined with different configuration methods of the reactor to achieve cable AC voltage withstand test. Therefore, when choosing a cable AC voltage withstand test device, we do not consider the model of the cable AC voltage withstand test device. The model is only a code, and we cannot provide a plan or quotation for the cable A
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Application characteristics of power frequency withstand voltage test equipment
2025-08-19Wuhan UHV specializes in producing series resonance (also known as power frequency withstand voltage test equipment). Next, we will share with you the application characteristics of power frequency withstand voltage test equipment.Application of power frequency withstand voltage test equipmentThe principle of series resonance is widely used in power preventive testing projects, targeting insulation inspection of large capacity and high-voltage power equipment. Different combinations of adjustable reactors are used to adjust the size of the reactance and generate resonance conditions with the test object. The series resonance test device is mainly composed of a variable frequency power supply, excitation transformer, reactor, compensation capacitor, and capacitive voltage divider. Compared with oil immersed test transformers, its function is broader, but its disadvantage is that it loses the advantages of portability in terms of volume and weight. However, this also conforms to the engi
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Introduction to the composition and selection of cable withstand voltage testing equipment
2025-08-19Wuhan UHV specializes in producing series resonance (also known as cable withstand voltage test equipment). Next, we will share with you the composition and selection of cable withstand voltage test equipment.Overview and Basic Components of Series ResonanceFirstly, let's talk about the purpose of series resonance. Series resonance is an indicator requirement for insulation inspection of large capacity and high voltage power equipment in power preventive testing projects. It is achieved by adjusting inductance and frequency in combination to achieve the function of resonant boosting. Variable frequency series resonance is composed of a control power supply, excitation transformer, high voltage reactor, compensation capacitor, and capacitive voltage divider. Before purchasing, we need to understand the basic situation on site. For example, for power cables, we need to know the length and cross-sectional area of the cable in advance, calculate the maximum capacitance of the test subj
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Introduction to Safety and Operation Issues of Series Resonant Voltage Endurance Equipment
2025-08-18Wuhan UHV specializes in producing series resonance (also known as series resonance withstand voltage equipment). Next, we will share with you an introduction to the safety and operation issues of series resonance withstand voltage equipment.Safety of series resonant deviceOperational Requirements1. It is not allowed to suddenly cut off the system power during testing. The testing state must be exited before cutting off the power during each test.2. After the host malfunctions, non professional maintenance personnel should not disassemble the chassis for repair, otherwise the consequences will be borne by themselves.3. Do not store or use instruments in high temperature, high humidity, flammable, explosive, and strong magnetic field environments. What is the problem of 'unable to find resonance point'Once the frequency converter series resonance is found and the resonance point cannot be found, please do not rush to determine if it is a malfunction of the equipment. Check if t
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What is the difference between parallel resonance and series resonance
2025-08-18Wuhan UHV specializes in producing series resonance (also known as series resonance withstand voltage equipment). Next, we will share with you the difference between parallel resonance and series resonance.Characteristics of parallel resonance and series resonanceParallel resonance refers to the phenomenon in which the resistance, capacitance, and inductance in a parallel resonance circuit have the same phase as the circuit terminal voltage and total current. We call it a parallel resonance circuit. In the parallel resonance test, when the voltage remains constant and the current is added, the corresponding parallel resonance is series resonance. The characteristic of series resonance is to form a series connection between the capacitance of the test object and the reactor to generate resonance. The electrical characteristic of voltage addition and current remains constant is called series resonance, which can also be called a series circuit. Composition of parallel resonance and seri
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What are the hazards of non sinusoidal waves on AC withstand voltage testing
2025-08-18Wuhan UHV specializes in producing series resonance (also known as AC/DC voltage withstand test device). Next, we will share with you the hazards of non sinusoidal waves on AC voltage withstand tests.1. When conducting AC withstand voltage tests, some voltage measuring instruments measure the effective value of the voltage. Power frequency discharge or breakdown generally determines the amplitude of the voltage. When the test voltage waveform is non sinusoidal, the ratio of the amplitude of the voltage to the effective value (i.e. the crest factor) is not √ 2. When the waveform is severely distorted, a large third harmonic component is mainly superimposed on the sinusoidal fundamental component, resulting in a crest factor of 1.45-1.55. At this time, if the amplitude is calculated by multiplying the effective value by √ 2, it will cause significant test errors. 2. The waveform of the power frequency test voltage also has a certain impact on the insulation test results of certain elect
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Principle of AC/DC voltage withstand test device
2025-08-15Wuhan UHV specializes in producing series resonance (also known as AC/DC withstand voltage test device). Next, we will share with you the principle of AC/DC withstand voltage test device.Principle of AC/DC voltage withstand test deviceScope of application: AC withstand voltage test for various power equipment. The basic principle of the frequency conversion series resonance test device is to use an adjustable (30-300Hz) series resonance test equipment to resonate with the tested capacitor to generate an AC test voltage. The working power supply is single-phase 380/220V ± 10%, 50Hz.Series resonance, series resonance test device, frequency conversion series resonance test device, functions and characteristics1. Frequency modulation tuning method. The fixed inductance reactor is used to achieve resonance in the test circuit by adjusting the frequency of the excitation power supply. Its characteristics are small size, light weight, high quality factor, and easy to use. It has gradually rep
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Solution to series resonance without voltage boost
2025-08-15Wuhan UHV specializes in producing series resonance (also known as variable frequency series resonance test device). Next, we will share with you the solution of series resonance without voltage boost.In order to facilitate the maintenance of the power grid and improve the safety of electricity consumption, high-voltage transmission and transformation equipment is required to undergo AC withstand voltage testing. However, the frequency conversion series resonance test device is a measuring device that achieves high voltage and large capacity, and can be used for power cables, busbars, switches, etc GIS、 Transformers are subjected to power frequency withstand voltage tests, consisting of reactors, excitation transformers, compensation capacitors, and main control devices. As the voltage, waveform, and frequency are consistent with the actual operating conditions and the electric field state inside the insulation of the test object, and the test voltage is higher than the actual operatin
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Why is the series resonance transformer test necessary
2025-08-15Wuhan UHV specializes in producing series resonance (also known as power frequency withstand voltage test device). Next, we will share with you why series resonance transformer test is necessary.Series resonant transformers are essential for insulation integrity testing of all high-voltage equipment. The standard communication testing system is already able to provide a solution for certain applications, but for certain devices with higher voltage and current requirements, linear AC testing systems may not be sufficient.In order to limit the input power requirements of the resonance test system, a capacitor test object and a variable core (variable reactor) are needed. The design method of the resonance test system is to adjust the inductance in high voltage circuits, thereby adjusting the capacitance compensation resonance system. The main advantage of a series resonant transformer is its very low (actual) input power and high output (reactive power) requirements. Series resonant tra
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How to prevent overvoltage in power frequency withstand voltage testing equipment
2025-08-14The series resonance (also known as power frequency withstand voltage test equipment) produced by Wuhan UHV professional will now share with you how to prevent overvoltage in power frequency withstand voltage test equipment.The complete set of frequency conversion series resonance test equipment is used to evaluate the insulation strength of electrical equipment. It has a decisive significance in determining whether the electrical equipment can be put into operation and ensuring the insulation level of the equipment. An important means to avoid insulation accidents. Because the frequency conversion series resonance test device can fully reflect the actual operation of electrical equipment under AC voltage, it can truly and effectively detect insulation defects.The complete set of frequency conversion series resonance test equipment adopts the resonance principle. It generates resonance between the voltage at a certain frequency in the system circuit and the capacitor and reactance in t
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The principle of series resonance and series resonance circuit
2025-08-14Wuhan UHV specializes in producing series resonance (also known as power frequency withstand voltage test equipment). Next, we will share with you the principles of series resonance and series resonance circuits.In an AC circuit with resistor R, inductor L, and capacitor C, the voltage at both ends of the circuit is generally different from the current phase in the resonant circuit. If we adjust the parameters or power frequency of circuit components (L or C), we can make their phases the same, and the entire circuit appears purely resistive. When a circuit reaches this state, it is called resonance. In the resonant state, the total impedance of the circuit reaches or approximates its maximum value. The purpose of studying resonance is to understand this objective phenomenon and fully utilize its characteristics in science and applied technology, while also preventing the harm it may cause. There are two types of circuit connections: series resonance and parallel resonance.When in seri
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