Product List
Contact Us
Email：qiao@hvtest.cc
Mobile：+8615871365102
What's app：+8615871365102
-
What is the difference between AC and DC hipot test?
2025-06-24The DC hipot tester under Wuhan UHV can help many power workers conduct various power tests more conveniently.1.Applied Voltage:AC Test: Applies power-frequency (50/60Hz) sinusoidal AC voltage.DC Test: Applies constant or slowly rising DC voltage.2.Simulates Real Operation:AC Test: Most accurately simulates the AC voltage stress equipment experiences during actual operation. It's the gold standard for AC equipment insulation strength assessment.DC Test: Primarily simulates stress for DC equipment or serves as a supplementary test for AC equipment.3.Primary Applications:AC Test: Widely used for most AC power equipment (transformers, GIS, circuit breakers, instrument transformers, generator stators).DC Test: Particularly suited for long power cables and generator rotor windings; also used for leakage current measurement on some HV equipment (e.g., bushings, arresters).4.Defect Detection Focus:AC Test: Highly sensitive to overall insulation degradation, partial discharges (caused by v
MORE -
What is the difference between DC hipot and Megger?
2025-06-24The DC hipot test Kit under Wuhan UHV can help many power workers conduct various power tests more conveniently.1.DC Hipot TestPurpose: Verifies dielectric strength – the insulation’s ability to withstand high voltage without breaking down.Method: Applies a destructively high DC voltage (e.g., 2× to 10× operating voltage) to the insulation.Measurement: Monitors leakage current (µA/mA).Outcome: Pass/Fail (fails if current exceeds threshold or breakdown occurs).Risk: Potentially damages weak insulation. Critical safety step: Must discharge capacitive loads post-test.Use Cases:Safety certification (UL/IEC compliance).Production line quality checks.Detecting critical flaws (cracks, voids, thin spots).2.Megger TestPurpose: Measures insulation resistance – quantitative health of the insulation.Method: Applies a safe, low-to-medium DC voltage (e.g., 500V, 1000V, 2500V).Measurement: Reads resistance (MΩ/GΩ). Higher values = better insulation.Outcome: Numeric value (e.g., "200 MΩ"), used for tr
MORE -
AC voltage withstand test plan
2025-06-23AC voltage withstand test plan? Wuhan UHV specializes in producing AC withstand voltage testing equipment, with a wide range of product options. When looking for AC withstand voltage testing equipment, choose Wuhan UHV. In electrical engineering, equipment insulation testing is an important means to ensure the normal operation of electrical equipment in the device and to promptly detect potential insulation performance cracking faults caused by collisions, vibrations, and other factors during manufacturing and transportation. Through electrical testing, the insulation condition of electrical equipment can be understood, and problems can be promptly solved or replaced to ensure the normal operation of the electrical equipment in the device.test methodInsulation resistance, absorption ratio, and polarization index test(1) The significance and role of the experimentMeasuring the insulation resistance of electrical equipment can sensitively reflect the insulation condition, effectively de
MORE -
AC voltage withstand test equipment
2025-06-23AC voltage withstand test equipment? Wuhan UHV specializes in producing AC withstand voltage testing equipment, with a wide range of product options. When looking for AC withstand voltage testing equipment, choose Wuhan UHV. The AC withstand voltage test of various large power transformers, power cables, steam turbines, hydro generators, and other capacitive equipment must be strictly conducted regularly in accordance with 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. In order to ensure the safe and reliable operation of the cable, relevant international standards have made clear provisions for various tests of the cable. The main test items include measuring insulation resistance, DC withstand voltage, and leakage current. The measurement of insulation resistance is mainly used to check whether the cabl
MORE -
What is the voltage for VLF cable test?
2025-06-19The VLF cable tester under Wuhan UHV can help many power workers conduct various power tests more conveniently.Core Voltage Parameters1.Base Standard:VLF testing applies 0.1 Hz AC high voltage at 2 to 3 times the cable’s rated voltage (U₀).Examples:10 kV rated cable → Test voltage: 22–28 kV (typically 28 kV).35 kV rated cable → Test voltage: 70–105 kV (commonly 52–65 kV, subject to standards).2.Calculation Basis:Formula: Test voltage = (2.0 ~ 3.0) × Rated Voltage (U₀).International Standards:IEEE 400.2: Mandates 2U₀ for 15 minutes or 3U₀ for 30 minutes.IEC 60502-2: Requires 3U₀ for new cables; diagnostic tests on aged cables may use 2U₀.3.Safety Limits:Never exceed 3U₀: Higher voltages risk damaging healthy insulation.XLPE Cable Protection: 0.1 Hz polarity reversal prevents space charge buildup, ensuring test safety.Special Scenario AdjustmentsAged/Damaged Cables: Voltage may be reduced to 1.6U₀ (supported by tanδ diagnostics).Post-Repair Verification: 2U₀ for 15 minutes (per IEEE 400.
MORE -
What is the difference between IR test and VLF test?
2025-06-19The VLF hipot tester under Wuhan UHV can help many power workers conduct various power tests more conveniently.1. Fundamental PrinciplesIR Testing: Applies low-voltage DC (typically 500V–10kV) to measure leakage current and calculate insulation resistance (in MΩ or GΩ). It is a static resistance measurement, analogous to using a multimeter.VLF Testing: Applies 0.1 Hz very low-frequency AC high voltage (2–3 times rated cable voltage, e.g., 28kV for a 10kV cable) to simulate power-frequency voltage stress, performing a dynamic withstand test + diagnostics.2. Core ObjectivesIR Testing:Detects bulk insulation degradation (e.g., moisture ingress, contamination, major damage).Provides the Polarization Index (PI) to assess moisture absorption trends.VLF Testing:Identifies latent defects (water trees, voids, interfacial aging).Verifies cable withstand strength (whether breakdown occurs under high voltage).Combines tan delta (tanδ) and partial discharge (PD) measurements to locate defects.3.Saf
MORE -
Purpose of AC withstand voltage test
2025-06-18What is the purpose of the communication withstand voltage test? Wuhan UHV specializes in producing AC withstand voltage testerswith a wide range of product options. When looking for an AC withstand voltage tester, choose Wuhan UHV.1、 Purpose of communication withstand voltage testThe AC withstand voltage test of a transformer is a test in which a sine frequency AC test voltage exceeding a certain multiple of the rated voltage is applied to the winding and bushing of the tested transformer for a duration of 1 minute. The purpose is to use a test voltage that is a certain multiple higher than the rated voltage instead of atmospheric overvoltage and internal overvoltage to assess the insulation performance of transformers. It is the most effective way to evaluate the insulation strength of transformers and an important experimental project to ensure the safe operation of transformers and avoid insulation accidents. Conducting AC withstand voltage tests can discover moisture and concentra
MORE -
What is the difference between impulse voltage test and surge test?
2025-06-18The Impulse Voltage Test System under Wuhan UHV can help many power workers conduct various power tests more conveniently.1.Purpose & Core Focus:Impulse Voltage Test: This is a core part of high-voltage insulation testing. Its primary purpose is to verify that the main insulation system of high-voltage electrical equipment will not break down or flash over when subjected to extreme transient overvoltages (e.g., lightning strikes or switching operations). It directly assesses the dielectric strength of insulating materials and the withstand capability of the insulation structure. The goal is to ensure safe operation and personnel safety under extreme overvoltages.Surge Immunity Test: This is part of Electromagnetic Compatibility (EMC) testing. Its primary purpose is to evaluate the immunity of electronic/electrical equipment or systems to transient overvoltage disturbances conducted via power lines or signal lines. It focuses on whether the device functions correctly, suffers performanc
MORE -
AC withstand voltage test system
2025-06-17AC voltage tester? Wuhan UHV specializes in producing AC withstand voltage testers with a wide range of product options. When looking for an AC voltage withstand tester, choose Wuhan UHV. Today, taking the Wuhan UHV cable AC withstand voltage series resonant device as an example, we will briefly introduce the AC withstand voltage tester, a portable variable frequency resonant boost device for cables. It uses the method of adjusting the frequency of the power supply to achieve resonance between the reactor and the tested capacitor, obtaining high voltage and high current on the tested object. This is a new method and trend in current high-voltage testing, which has been widely used both domestically and internationally. The frequency conversion resonant boost device adopts a dedicated SPWM digital waveform generation chip with a frequency resolution of 16 bits, and the frequency fineness can reach 0.1Hz between 20-300Hz. It adopts an orthogonal asynchronous fixed carrier
MORE -
AC withstand voltage test method for transformers
2025-06-17What is the AC withstand voltage test method for transformers? Wuhan UHV specializes in producing AC voltage withstand testers with a wide range of product options. When looking for an AC voltage withstand tester, choose Wuhan UHV. AC withstand voltage test is an external AC test voltage applied to the insulation of electrical equipment. The test voltage is higher than the rated working voltage of the equipment and lasts for a certain period of time (usually 1 minute). AC withstand voltage test is a test that best meets the actual operating conditions of electrical equipment and is an important means to avoid insulation accidents. Therefore, the AC withstand voltage test is a decisive test among various insulation tests.Wiring principle for AC withstand voltage testThe wiring for the AC withstand voltage test should be determined according to the requirements of the test object (voltage, capacity) and the existing test equipment conditions. Usually, high-voltage complete sets o
MORE -
AC withstand voltage testing
2025-06-16AC withstand voltage test? Wuhan UHV specializes in producing AC voltage withstand testers with a wide range of product options. When looking for an AC voltage withstand tester, choose Wuhan UHV.The AC withstand voltage plays a decisive role in assessing the main insulation strength of transformers and checking for local defects in the main insulation. It is an important means of checking and verifying the quality of transformer design, manufacturing, and installation.Scope of AC withstand voltage test1. For transformers with a capacity of 8000KV or less and a rated winding voltage of 110KV or less, an AC withstand voltage test should be conducted for the terminal test.2. Transformers with a capacity of 8000KV. A or above and a rated winding voltage of 110KV or below can undergo terminal AC withstand voltage testing when equipped with testing equipment.3. For transformers with a rated winding voltage of 110KV or above, the neutral point should undergo an AC withstand voltage test, and
MORE -
AC voltage withstand test device
2025-06-13Communication voltage withstand test device? Wuhan UHV specializes in producing AC voltage withstand testers with a wide range of product options. When looking for an AC voltage withstand tester, choose Wuhan UHV. During the operation of power equipment, insulation will gradually deteriorate due to the long-term effects of electric fields, temperature, and mechanical vibrations, including overall deterioration and partial deterioration, forming defects. AC withstand voltage test is the most effective and direct method for evaluating the insulation strength of power equipment, and is an important part of preventive testing. In addition, due to the fact that the AC withstand voltage test voltage is generally higher than the operating voltage, the equipment has a large safety margin after passing the test. Therefore, AC withstand voltage test is an important means to ensure the safe operation of power equipment.The Wuhan UHV series variable frequency automatic resonance test devic
MORE -
Preventive measures for using insulation oil dielectric loss tester
2025-06-12Wuhan UHV professional production insulation oil dielectric loss tester 1. The instrument must be grounded, otherwise it will alarm. Do not enter the main menu. 2. Remove the oil cup from the instrument and ensure that the power is turned off. 3. After installing the oil cup, check the empty cup first. The capacitance value should be 60 ± 2pF, and the dielectric loss should be less than 0.005%; If the capacitance value is greater than 62, it should be reinstalled, the dielectric loss is invalid, and the oil cup should be cleaned again. 4. The new oil cup may have dust or cloth dust, so after installing the new oil cup, clean it three times with sample oil (add oil, rotate around the inner ring up and down, and then drain the water). The cleaning and heating effect is better. 5. When installing porcelain, pay attention to moderate force and do not apply too much force to avoid damaging the porcelain or causing the capacitance value to be unqualified after installation. 6. The temperatur
MORE -
RLC series resonant circuit experiment
2025-06-11Series resonance? Wuhan UHV specializes in producing series resonance. When looking for series resonance, choose Wuhan UHV. Starting from the equation analysis of the RLC series resonant circuit, the Wuhan UHV circuit experiment derived the resonant frequency, quality factor, and input impedance of the circuit in the resonant state. Based on Multisim simulation software, the RLC series resonant circuit was created, and its theoretical basis was verified using virtual instruments and simulation analysis methods, respectively. The results indicate the consistency between simulation and theoretical analysis, providing a feasible research method for the application of simulation analysis in electronic circuit design. The resonance phenomenon is a specific working state of a sinusoidal steady-state circuit. Usually, resonant circuits are composed of capacitors, inductors, and resistors, and can be divided into series resonant circuits, parallel resonant circuits, and coupled resonant circ
MORE -
Power cable fault tester
2025-06-10Power cable fault tester? Wuhan UHV specializes in producing power cable fault testers with a wide range of product options. When looking for a power cable fault tester, choose Wuhan UHV. At present, there are various types of power cable fault testers on the market, with prices ranging from several thousand yuan to several hundred thousand yuan, making it difficult for users to choose when purchasing such instruments. The materials, structures, uses, laying methods, voltage levels, and wiring methods of cables used in various industries are not the same. The common fault characteristics and solutions should also be different. At present, there are uneven manufacturers in the market, and few products can effectively solve various cable faults. The power cable fault tester developed by Wuhan UHV precisely solves various cable fault problems. Let's introduce them in detail below. Working principle of power cable fault testerThe working principle of the power cable fault tester is t
MORE -
How to estimate the series resonant frequency?
2025-06-06A series resonant capacitor is simply the result of surface mount devices and pin leads. For a typical plug-in capacitor, its average equivalent series inductance is 2.5nH/2.54mm. The average equivalent series inductance of surface mounted capacitors is 1nH. Based on the above, it is important to consider the equivalent series inductance of capacitors when using decoupling capacitors. Surface mounted capacitors have better performance than plug-in capacitors at high frequencies because their equivalent series inductance is very low. Blocking network 2 is used to block f1=747KHZ, taking C2=1250pF, then:What is resonant frequencyA power of 1mW is applied on a 600 Ω load, and the voltage value on the load is at zero level. At this time, the AC voltage on the load is 0.775V.Definition of resonant frequencyThe impedance of an ideal capacitor decreases with increasing frequency, while the impedance of an actual capacitor exhibits capacitive characteristics at lower frequencies, where the im
MORE -
The function of AC series resonant reactor
2025-06-04As the name suggests, a reactor refers to a series connected inductor in a circuit. In the field of reactive power compensation and harmonic control, series reactors mainly refer to reactors connected in series with capacitors. The series connected reactor and capacitor form a resonant circuit. To eliminate or filter harmonics. Reduce the surge current multiplier and surge frequency of the capacitor bank, protect the capacitors, and facilitate the selection of supporting equipment. Form a complete resonant circuit together with the capacitor bank to filter out specific subharmonics. After the inductance of the series filter reactor and the capacitance of the capacitor are fully adjusted, an AC filter with characteristic subharmonics is formed to filter out the characteristic subharmonics, thereby reducing the voltage distortion of the harmonic on the bus and reducing the line. Harmonic current improves the power quality of the network and bus power supply. A bias that forms a resona
MORE -
The use and precautions of non partial discharge withstand voltage test device
2025-05-30In order to work in different usage environments and conditions, while adapting to different voltage levels and capacity requirements. Our company has designed a series of power frequency non partial discharge test transformers and their corresponding complete sets of equipment, including four models and over sixty specifications. Power frequency non partial discharge test transformers are divided into four types according to their structural types: single-phase iron shell type, single-phase iron shell cascade type, single-phase insulation cylinder shell type, and single-phase insulation cylinder external cascade type. Single phase iron shell is suitable for gas applications with low voltage capacity, easy portability, or high voltage capacity but low partial discharge requirements; Suitable for situations where the voltage is not too high and the use is relatively fixed. Users can choose single-phase insulated cylinder cascade products according to different needs. They are suitable
MORE -
What is the difference between the partial discharge high-voltage test system and the partial discharge test device?
2025-05-29What is the difference between high-voltage non partial discharge withstand voltage test kit and partial discharge withstand voltage test kit? This equipment is capable of conducting power frequency withstand voltage tests and partial discharge tests on power transformers, high-voltage circuit breakers, power cables, transformers, and insulation materials of 35kV and below, and belongs to the non partial discharge withstand voltage test equipment group. 1. Characteristics of the product. This device is fully functional, compact in size, lightweight, aesthetically pleasing, and easy to move. 2. All operations can be completed through the keyboard, all measurement and control data are digitized, and the entire workflow is intelligent.3. There are four display windows at the same time, which can display high and low voltage, current, and withstand voltage time. There are also multiple status indicator lights that make the workflow and status clear at a glance. 4. Enter automatic or ma
MORE -
The influence of operating parameters on the error of electric energy meters
2025-05-28The electric energy meters calibrated from the calibration room are all measured under normal conditions specified in the regulations. In fact, it is impossible for all electric energy meters to operate under the rated conditions specified in the regulations. Operating parameters such as voltage, load, waveform, etc. are subject to variation, which can cause additional errors in the energy meter. The reasons for the formation of additional errors in electric energy meters and their compensation measures will be discussed below. 1. The impact of voltage changes on errorsDue to the voltage variation of the power grid usually between 90% and 105% Ue, there is a voltage drop in each line, which causes the voltage U applied to the energy meter to be different from the rated voltage Ue. This will cause the voltage working flux to not change proportionally with the voltage, and destroy the original proportional relationship between the voltage suppression torque, compensation torque, and dri
MORE
