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What factors affect the results of the variable frequency series resonance test?
2025-09-16What factors affect the results of the variable frequency series resonance test? These uncertain factors include:1. The influence of test time: As the test process progresses for a long time, the equipment gradually heats up, the equivalent resistance increases, and the Q value also decreases. During the high heat period, this phenomenon is very important. Generally, the equipment needs about half an hour of rest before it can continue to be used.2. The influence of weather: Under high humidity conditions, the corona loss of wires increases significantly, the interference of surrounding electromagnetic fields increases, and the Q value decreases. When the temperature is high, the equivalent resistance of the circuit increases significantly, and the Q value decreases.3. The impact of not selecting a good resonance point for high-voltage testing frequency on Q value: It has been found in applications that when the voltage rises close to the test voltage, the voltage rises too quickly, ac
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Principle and operation method of series resonance test device
2025-09-16Basic principle of series resonance test deviceThe series resonance test device usually includes a frequency modulation power supply, a resonant reactor, an excitation transformer, and a voltage divider, among which the series resonance circuit is composed of a capacitor and a resonant reactor. The capacitor voltage divider is connected in parallel with the test object to measure its resonant voltage value, and is also used for overvoltage protection signal; The frequency and voltage regulation power is coupled to the series resonant circuit through an excitation transformer to provide excitation power for it.Operation method of series resonance test deviceBefore the experiment, the test voltage should be determined based on the test sample, and the capacitance of the test sample should be measured or consulted to determine its capacitance. Then select the appropriate parameters (inductance, rated current, rated voltage) and quantity of resonant reactors for testing and wiring. (1) Co
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How to conduct AC withstand voltage test for series resonant device?
2025-09-16The method of using a series resonant device for AC withstand voltage testing is to change the inductance and frequency of the test circuit to make it in a resonant state. This method can meet the testing requirements of high voltage and high current. When using a series resonant device for AC withstand voltage testing, the following points should be noted:1. Before conducting the experiment, it is necessary to know whether the non-destructive testing items of the tested equipment are qualified. If there are any defects or abnormalities, they should be eliminated before proceeding.2. The experimental site should be fenced and warning signs hung. And there is a dedicated person to supervise.3. Wipe the insulation surface of the tested equipment before testing, and ensure that the tested product casing and unmeasured winding are reliably grounded. For multi oil equipment, it should be left to stand for a certain period of time before testing.4. Adjust the gap between the protective balls
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What are the differences between series resonance and parallel resonance
2025-09-15The difference between series resonance (also known as variable frequency resonance) and parallel resonance:Difference 1: Different load resonance modes. The load resonance modes of series resonance and parallel resonance can be divided into two types: series inverters and parallel inverters. The difference between these two types lies in their technical characteristics and oscillation circuits. Series inverters use L, R, and C in series, while parallel inverters use L, R, and C in parallel. The impedance rates of these two types of load circuits to the power supply are also different. Series inverters have low impedance, while parallel inverters have high impedance; When the series inverter has low impedance, a voltage source is required for power supply, which leads to the need to connect a large filtering capacitor to the rectified and filtered DC power supply terminal. When the inverter fails, it will cause an increase in surge current, making protection difficult; When the parall
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Do you know the function of the variable frequency series resonant withstand voltage test circuit?
2025-09-15The frequency conversion series resonance withstand voltage test is an indispensable testing method for the daily debugging of electrical equipment.(1) AC voltage withstand test for power cables. The traditional DC withstand voltage method has many problems in the testing of cross-linked cables. Due to the fact that cross-linked cables are high-capacity test samples, the frequency conversion series resonance withstand voltage test method is simple and convenient. It can also obtain good AC voltage frequency and waveform, making it the most ideal testing method for AC withstand voltage testing of cross-linked cables at present.2) AC withstand voltage test for power transformers, reactors, and transformers. The AC withstand voltage test for power transformers, reactors, and transformers has been clearly defined internationally. Both the power frequency voltage test method and the induced voltage test method can be used, and the test voltage waveform should be as close to sine as possible
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Basic principle of series resonant withstand voltage test device inverter
2025-09-15The series resonant withstand voltage test device is usually accompanied by an inverter, and this combination is called the series resonant withstand voltage test device inverter. Below is an introduction to the basic principle of the series resonant withstand voltage test device inverter:Inverter structure of series resonant withstand voltage test deviceFrom the figure, we can see some basic principles of the series resonant withstand voltage test device inverter. Firstly, it includes a DC voltage source, an inverter bridge consisting of switches S1 to S4, and a series resonant withstand voltage test device load consisting of R, L, and C; Among them, switches S1 to S4 can be selected from IGBT, SIT, MOSFET, SITH, and other power semiconductor devices with self turn off function, and the inverter is a single-phase full bridge circuit; The control method is that the driving signals of the two switching devices on the same bridge arm are complementary, and the two diagonally opposite swi
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The advantages of series resonance in power systems
2025-09-12The advantage of a series resonant (also known as an AC withstand voltage test device) circuit is that it allows for the use of smaller capacitor values, and if the capacitors are matched with appropriate inductance and resistance values. A smaller capacitor value can be used to generate series resonance effect, and the smaller the capacitor, the more accurate the circuit. For example, one-fifth of the common value of a capacitor requires a tolerance of about 10% for the capacitor and inductor components, and one tenth of the normal value of a capacitor requires a tolerance of ± 5%, and so on. It is difficult to achieve high-frequency inductors with such strict tolerances. If you think the layout inductance is fixed and plan a smaller capacitance value to place the series resonance point in the correct position. You will face the same difficulty: you cannot easily control the precise values of capacitors and inductors.Resonance must continue and repeat without interruption or space. If
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The role of Q value in variable frequency series resonance withstand voltage test device
2025-09-12In electrical systems, many customers inquire about the correlation between Q values, especially when purchasing variable frequency series resonant devices, as Q values are influenced by external factors such as voltage levels, process structures, and material properties. In theory, the larger the Q value, the smaller the allowable frequency deviation within the unit current variation range, and the higher the frequency selectivity. Q value is a measure of electricity, and the main parameters of inductance are calculated as follows: Q=energy carried by energy storage devices such as inductance and capacitance ÷ power loss due to resistance.The magnitude of Q value is influenced by a combination of factors such as manufacturing process, raw materials, and material properties. For example, if other parameters of the same inductor remain unchanged and only the thickness of the winding inductance wire is changed, the Q value of the inductance of thick conductors is higher than that of thin
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Attention to AC voltage withstand test of variable frequency series resonant voltage withstand device
2025-09-12The method of measuring AC withstand voltage with a frequency conversion series resonant withstand voltage device is to change the inductance and frequency in the test circuit, and the circuit is in a resonant state. This method can meet the testing requirements of high voltage and high current. When conducting AC withstand voltage tests on devices with series resonant frequency voltage, the following points should be noted:1. Before the experiment, it is necessary to understand whether the non-destructive testing technology project management of the tested equipment is qualified. If there are any defects or abnormalities, testing should be conducted after they have been eliminated. 2. At the site of the experiment, a fence should be set up, a warning enterprise sign should be hung, and a dedicated person should supervise. 3. The insulation surface of the equipment to be tested should be cleaned before the test, and the test equipment, test object casing, and non test winding should
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What factors affect the Q value in series resonance
2025-09-11When purchasing a variable frequency series resonant device (also known as a series resonant device), we are often asked what the Q value is. So what is the Q value here? What kind of influence does it have on the Q value of the variable frequency series resonant device? Is it better to be taller?What is Q value? The Q value is influenced by external factors such as voltage level, process structure, material characteristics, etc. In theory, the larger the Q value, the smaller the allowable deviation current per unit frequency, and the higher the frequency selectivity. The Q value is the main parameter used to measure inductance, and its calculation formula is: Q=energy storage devices such as inductance and capacitance ÷ power loss resistance. Variable frequency series resonant deviceWhat factors affect the Q value of the variable frequency series resonant device by students? The magnitude of the Q value is influenced by various factors, such as our manufacturing technology, raw mat
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Do you know the control method of series resonant inverter
2025-09-11Wuhan UHV specializes in producing series resonant devices (also known as series resonant). Next, we will share with you the control method of series resonant inverters. Do you knowWith the development of self turn off power electronic devices, series resonant inverter circuits have gained more and more applications, and various control methods suitable for series resonant inverter circuits continue to emerge. This article discusses and compares commonly used control methods such as amplitude modulation, pulse frequency modulation, pulse density modulation, and resonant pulse width modulation, and provides a detailed analysis of the control method of pulse width plus frequency modulation.Basic structure of inverterThe basic schematic diagram of an inverter includes a DC voltage source, an inverter bridge composed of switches S1-S4, and a series resonant load composed of R, L, and C. Switches S1-S4 can use power semiconductor devices with self turn off capabilities such as IGBT, SIT, MO
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Common troubleshooting methods for AC withstand voltage test devices
2025-09-11Common faults and solutions of series resonance (also known as AC withstand voltage test device):1、 The host cannot find the resonance point. Reason: The resonance point of the system is outside the output frequency range of the host; System wiring error; The system is not reliably grounded; High voltage sampling feedback signal open circuit or unreliable connection; The test sample has a malfunction. Exclusion method:1. Check the reliability of the grounding device and whether there are any disconnection points in the grounding connection wire; 2. Check the continuity of the high and low voltage coils of the excitation transformer; 3. Check the continuity of each reactor; 4. Check the continuity of the signal line of the voltage divider; 5. Check the continuity of the high and low voltage capacitor arms of the voltage divider;6. If there is no resonance point when the device is boosted, it is necessary to check the on/off of the compensation capacitor;2、 Host reset. Reason: Flu
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What is the principle of variable frequency series resonant device
2025-09-10Wuhan UHV specializes in producing series resonant devices (also known as variable frequency series resonant devices). Next, we will share with you the principle of variable frequency series resonant devices.Working principle of series resonance test device:A device that uses tuned inductors and load capacitors to generate power frequency series resonance and obtain power frequency test voltage. Composed of a variable frequency power supply, excitation transformer, reactor, and capacitive voltage divider. The capacitor and reactor of the test sample form a series resonant connection; The voltage divider is connected in parallel to the test sample to measure the resonant voltage on the test sample and provide an overvoltage protection signal; The frequency modulation power output is coupled to the series resonant circuit through an excitation transformer, providing excitation power for series resonance. The series resonance test device is a generation of equipment specifically designe
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What are the advantages of variable frequency series resonant voltage withstand device
2025-09-10Wuhan UHV specializes in producing series resonance (also known as variable frequency series resonance withstand voltage device). Next, we will share with you the advantages of variable frequency series resonance withstand voltage device.1. The required power capacity is greatly reduced. Series resonant power supply generates high voltage and high current through resonance between resonant reactor and the tested capacitor. In the entire system, the power supply only needs to provide the active consumption part of the system. Therefore, the required power supply for the experiment is only 1/Q of the test capacity.2. The weight and volume of the equipment have been greatly reduced. In a series resonant power supply, not only is the bulky high-power voltage regulating device and ordinary high-power power frequency test transformer eliminated, but the resonant excitation power supply only requires 1/Q of the test capacity, greatly reducing the system weight and volume, usually 1/10-1/30 of
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The principles of series resonance and parallel resonance, as well as the reasons for the large parallel resonance current
2025-09-10Wuhan UHV specializes in producing series resonance (also known as series resonance withstand voltage equipment). Next, we will share with you the principles of series resonance and parallel resonance, as well as the reasons for the large parallel resonance currentPrinciples of series resonance and parallel resonanceIn a series circuit of resistors, inductors, and capacitors, the phenomenon where the terminal voltage of the circuit is in phase with the total current of the circuit is called series resonance. A series resonant circuit is purely resistive, with terminal voltage and total current in phase. At this time, the impedance is small and the current is large, which may generate high voltages on the inductance and capacitance that are many times greater than the power supply voltage. Therefore, series resonance is also known as voltage resonance. In a circuit where an inductor is connected in parallel with a capacitor, the phenomenon of parallel resonance occurs where the termina
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Comprehensive knowledge explanation of series resonance
2025-09-09Wuhan UHV specializes in producing series resonance (also known as power frequency withstand voltage test equipment). Next, we will share comprehensive knowledge of series resonance with you.Application of series resonant deviceSeries resonance device is an important electrical indicator for insulation inspection of electrical equipment before operation, which is achieved through the principle of series circuit and constant voltage and current. For small capacity electrical equipment, we can use oil immersed test transformers for measurement. For large capacity electrical equipment, series resonance must be used, such as common power cables, transformers, and GIS combiners. Characteristics of series resonance device testDue to the fact that series resonance fully simulates the actual operating conditions of the power system, it is easier to directly and intuitively reflect the insulation situation of the equipment. Compared with using a DC high-voltage generator to check insulation, t
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13 characteristics of resonant devices
2025-09-09Wuhan UHV specializes in producing series resonators (also known as resonant devices). Next, we will share with you the 13 characteristics of resonant devices.Variable frequency series resonant devices typically have the following 13 characteristics:1. Voltage, current, time, status information and other data are displayed on a 4.7-inch large LCD screen, with clear and intuitive readings;2. Full Chinese interface, simple and clear operation, suitable for various application scenarios;3. The variable frequency series resonant device is operated by touch sensitive panel buttons, and all functions can be set through the buttons, improving the safety and reliability of the product; 4. The fully digital calibration method abandons the outdated potentiometer adjustment, making it extremely convenient for on-site use and easy to control accuracy (with password protection function);5. The button directly sets the voltage conversion ratio (with password protection function), and when connectin
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How to identify cable breakdown using cable withstand voltage testing equipment
2025-09-09Wuhan UHV specializes in producing series resonance (also known as cable withstand voltage test equipment). Next, we will share with you how cable withstand voltage test equipment can identify cable breakdown.Partial discharge and high-voltage testing of cables often lead to the phenomenon of cable breakdown; The reasons for the phenomenon of cable "breakdown" are not only the real breakdown caused by the quality management problems of cable enterprises themselves, but also some other important reasons for the false breakdown phenomenon of cables. So how can we judge the authenticity of cable breakdown? A manufacturer of variable frequency series resonant devices, shares with you some methods for identifying cable breakdown:1. Due to the fact that the partial discharge and high voltage environment tests of network cables are conducted one by one in the shielded room, when breakdown occurs, the enterprise can fully consider replacing the insulated wire core for retesting. If the wire co
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A comprehensive explanation of the AC withstand voltage test device for testing
2025-09-08Wuhan UHV specializes in producing series resonance (also known as AC withstand voltage test device). Next, we will share a comprehensive explanation of the AC withstand voltage test device for testing.Preparation work before GIS AC withstand voltage testGIS equipment should be debugged and qualified. After passing the insulation characteristic test, SF6 gas should be inspected at rated pressure. The TA secondary in the test circuit should be short circuited and grounded. The lightning arrester and protective spark gap in the test circuit should be disconnected from the tested GIS. Before the experiment, check whether the high-voltage cables and overhead lines, voltage transformers, lightning arresters, and high-voltage outgoing lines of power transformers are disconnected from the GIS before conducting the series resonant AC withstand voltage test. Series resonance test deviceConnect and check. During the experiment, if an isolation switch or tee is used to connect the detection slee
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What equipment is required for voltage withstand test
2025-09-08The function of voltage withstand testVoltage withstand test, also known as high voltage dielectric strength test, is one of the main methods for testing the ability of electrical appliances, electrical equipment, electrical devices, electrical circuits, and electrical safety equipment to withstand overvoltage. Voltage endurance is divided into two types: AC voltage endurance test and DC voltage endurance test. AC withstand voltage testAC withstand voltage refers to the highest voltage value that equipment can withstand when the voltage is positive or negative peak. The test voltage is more than one to several times the rated voltage of the tested equipment, and the AC voltage test equipment's withstand voltage is closer to the actual situation, without the need to gradually increase the voltage. From the perspective of thermal breakdown caused by dielectric loss, it can effectively discover local free defects and weak points of insulation aging. However, AC withstand voltage is m
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