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Methods for locating cable faults
2025-01-15The cable fault tester under UHV power can help many power workers conduct various power tests more conveniently.Methods for locating cable faultsShort circuit fault locationUse a multimeter to check the continuity of each pair (core core, core armor) by keeping both ends of the cable open. A pair with continuity will be identified as a faultThe cable length and fault distance are determined using the TDR method with a pre locatorThe audio generator is connected to the fault pair of the tested cable (CUT), and a suitable receiver is used to track the cable path until the last signal peak (fault point), after which the signal completely disappears.After excavation, with the help of a cable identification system, identify the faulty cable from the cable bundle (if applicable).Identify faulty cables and repair the faulty parts.Low/high resistance/flicker fault locationAfter identifying the faulty wire pair and fault resistance, the total length of the cable is determined using the TDR met
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Charging of insulation resistance tester
2025-01-14The insulation resistance tester under UHV power can help many power workers conduct various power tests more conveniently.After power failure, insert the DC plug of the charger into the instrument charging socket and connect the dedicated charging cable AC220V to the panel charging socket. After connecting the power, the instrument enters the charging management interface. After charging, it shows that the battery is sufficient. It is recommended to charge for at least 8 hours each time.Do not fully discharge the battery. Frequent charging will maximize battery life.1) Charging should be carried out in a dry environment.2) When charging indoors, keep the environment well ventilated.3) Charging must be carried out at a temperature of 0 ℃ -40 ℃.4) If the battery is constantly in a charging state, it will only benefit the battery and will not cause damage to it.5) The instrument should be charged every six months and 24 hours if it is idle for a long time. If the storage temperature is h
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Introduction to Measurement of Q Value in RLC Series Resonant Circuit
2025-01-14The series resonance under UHV power can help many power workers conduct various power tests more conveniently.RLC series resonance characteristicsThe study of the series resonance characteristics of RLC, especially the measurement of the quality factor Q, is an important experiment in electromagnetics. Although there are various methods for measuring Q value, its measurement accuracy is greatly affected by the measurement method and measuring instruments. The relationship between the AC voltage and the AC current value I (effective value) of the RLC series resonant circuit is shown in Figure 1. Two methods were used to measure the RLC series resonant circuit, and the results were approximately close to the theoretical values, indicating that both methods are correct. But both methods have their own advantages and disadvantages, as follows:(1) The results of the broadband method are in good agreement with the resonant constant voltage method, and compared with the theoretical values, t
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What is an insulated megohmmeter?
2025-01-13The megohmmeter under UHV power can help many power workers conduct various power tests more conveniently.In order to insulate and prevent current flow between conductors, the resistance can be intentionally very high. Learn how to use a megohmmeter to measure insulation.Resistors typically exist in one of two categories. The first type is the "small" resistance range used in devices that regulate the amount of current allowed to pass through control and load devices.The second type is resistance, which is intentionally very high to insulate and prevent current flow between conductors. It may be difficult to measure insulation using a traditional multimeter, but instead, a megohmmeter or "megohmmeter" is used to determine appropriate insulation characteristics.It is difficult to argue endlessly about the definitions of "high" and "low" values, as different fields may use completely different proportions of components in electrical aspects. However, we can consider two general resistanc
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Common problems and solutions for series resonant voltage withstand devices on site
2025-01-10The series resonance under UHV power can help many power workers conduct various power tests more conveniently.1、 PrefaceWith the rapid development of the economy, the demand for green energy such as electricity is also expanding rapidly. Land resources are becoming increasingly scarce and the demand for electricity is increasing. Power cables are becoming more and more long, transformer voltage levels are increasing, and capacities are growing. GIS equipment is also widely used, and on-site AC withstand voltage is becoming more and more popular in power equipment. Series resonant equipment, with its characteristics of small size, high voltage, and lightweight installation, is becoming increasingly widely used. This article analyzes several problems encountered in the testing of series resonance equipment and proposes solutions.2、 On site series resonant withstand voltage equipment test wiring diagramWiring diagram for frequency conversion resonance testIn the figure: FC variable frequ
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Precautions for on-site detection of underground cable fault detector
2025-01-10The cable fault tester under UHV power can help many power workers conduct various power tests more conveniently.a) If the "output" overload signal or the tested cable has a short circuit phenomenon, the "overload" indicator light of the routing instrument will light up, and the signal source will have no output; At this time, the source output adjustment should be reduced or the short circuit of the tested cable should be eliminated(It is best to use "good phase"), then press the "start" button to make the signal source work normallyb) Before testing, operators should carefully read the operation manual and proficiently operate the instrument; During the detection process, the "adjustment knob" should be kept stable, so that the sound of the headset can be stable and reliable. All of these can ensure that the detected results are accurate. Therefore, the proficiency and accumulated operational experience of operators are one of the necessary prerequisites for successfully detecting ca
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Introduction to Insulation Resistance Measurement
2025-01-09The insulation resistance tester under UHV power can help many power workers conduct various power tests more conveniently.What is a megohmmeter test?A megohmmeter, also known as an insulation resistance meter, is a device used to test the insulation resistance of cables. The test conducted to understand the insulation resistance value is called a megohmmeter test.What is the purpose of insulation resistance?The motor winding wound inside the motor must provide a certain insulation resistance. This insulation is provided to resist high currents in the event of a short circuit. If a conductor has high insulation, its resistance to current will be higher. Similarly, if the provided insulation resistance is weak, it is more likely to cause damage to the equipment due to high current flow. Therefore, in order for any device to function properly, it should have high insulation resistance. Therefore, a megohmmeter insulation resistance test was conducted for this purpose.Procedure for testin
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Tracking and positioning principles of cable fault tester
2025-01-08The cable fault tester under UHV power can help many power workers conduct various power tests more conveniently.The cable fault tester consists of a transmitter, a receiver, a magnetic induction detection rod, a positioning detection frame, and other equipment. This instrument is a specialized instrument for optical cable and optical cable fault location testing. Suitable for various optical cables and cables with metal conductors (wire pairs, sheaths, shielding layers). The main functions of the street lamp cable fault tester are to locate and test the poor insulation points on the ground, detect the cable path, and test the cable burial depth.1、 Tracer principle (signal method)When an alternating current flows through a conductor, an alternating magnetic field is generated around the conductor, and the magnetic field lines of the field are coaxial with the conductor. At this point, if an electromagnetic coil is placed in a magnetic field, induced voltage will be generated at both en
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Karl Fischer titration measurement principle for water content
2025-01-08The trace moisture analyzer under UHV power can help many power workers conduct various power tests more conveniently.measuring principle In Karl Fischer moisture content measurement, water reacts with iodine and sulfur dioxide in the presence of alkali and alcohol.[H. sub. 2] O+S [O.sub. 2]+C [H. sub. 3] OH+3 RN+[I.sub. 2] [Right arrow] [RHN] S [O.sub. 4] C [H. sub. 3]+2 [RNH] I (1)In volumetric titration, iodine is added as a titrant.In the Coulomb method, iodine is electrolyzed in an anode solution containing iodine ions.2I - [Right Arrow] [I.sub.2]+2e - (2)As long as there is water in the titration cell, the generated iodine will react according to reaction (1). Once all the water reacts, excess iodine will appear in the anolyte. Iodine was detected by a platinum electrode, and the production of iodine stopped. According to Faraday's law, the amount of iodine produced is proportional to the current produced. In equation (1), [I.sub. 2] and [H. sub. 2] O react with each other in
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Resonant capacitors and inductors
2025-01-07The series resonance under UHV power can help many power workers conduct various power tests more conveniently.Inductance and capacitance are still two separate components during resonance, otherwise energy exchange cannot occur; But from the perspective of equivalent impedance, it has become a component: a resistor with a value of zero or infinity. 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 exhibits pure resistive behavior. This phenomenon is called series resonance (also known as voltage resonance). When a series resonance occurs in the circuit, the impedance of the circuit Z=√ R2+XC-XL2=R, the total impedance in the circuit is minimized, and the current will reach its maximum value.For ideal L and C components, when series resonance occurs, the voltage on the L and C components is equal i
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The importance of cable fault locator
2025-01-07The cable fault tester under UHV power can help many power workers conduct various power tests more conveniently.Fault locator is used to identify faults that occur in communication/control cables for quick repair. In order to reduce downtime and facilitate maintenance, cable fault locators are essential. They use the principle of pulse reflection technology to quickly locate the point of fault occurrence, making them very flexible and time-saving. Considering the growth of the telecommunications industry and cable TV operators in the urban, subway, and entertainment industries, the demand for this product is bound to increase.Cable failure is damage to the cable, which can affect the resistance in the cable. If allowed to persist, this may lead to voltage breakdown. Equipment users must use the fastest and most effective method to accurately locate underground cable faults, and the training required for using cable fault locator equipment is minimal. Manufacturers must design equipmen
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How is series resonance generated?
2025-01-06The series resonance under UHV power can help many power workers conduct various power tests more conveniently.In an AC circuit with resistor R, inductor L, and capacitor C, series resonance generally results in different phases of voltage and current at both ends of the 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. In a series circuit composed of resistors, inductors, and capacitors, when the capacitive reactance XC is equal to t
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The Karl Fischer titration method that you should know
2025-01-03The trace moisture analyzer under UHV power can help many power workers conduct various power tests more conveniently.In 1935, a German scientist named Karl Fischer made a discovery that provided a new perspective for scientific computing at the time. He found that the sulfur dioxide added to the reaction would determine the water content in the titration. This discovery is today known as the Karl Fischer titration method.What is Karl Fischer titration?Karl Fischer titration is a scientific method used to determine the moisture content in various samples. This concept refers to the titration method involving sulfur dioxide, iodine, and aqueous solutions in the endogenous reaction.In its calculation, Karl Fischer titration involves three main components, namely an analytical balance with a minimum resolution of 0.1 mg, a long syringe with a small needle, and Karl Fischer reagent for determining water content.All components in the instrument must always be placed in an area with constant
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What factors can affect the test results of the grounding resistance tester
2025-01-03The grounding resistance tester under UHV power can help many power workers conduct various power tests more conveniently.The grounding resistance tester is used to measure the grounding resistance values of various equipment such as power, communication, lightning protection, iron towers, electromechanical, broadcasting and television, buildings, troops, laboratories, workshops, water affairs, large factories, railways, and industries. And departments such as mining enterprises.1) The soil composition around the grounding system (ground grid) is inconsistent, the geology is different, the tightness and dryness are different, and it is dispersed. There are stray currents on the surface, especially overhead ground wires, underground water pipes, cable sheaths, etc. The impact of testing is particularly significant. The solution is to measure at different points and take the average.2) The direction of the test line is incorrect and the distance is not long enough. The solution i
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Advantages of Karl Fischer method based on measurement
2025-01-02The trace moisture analyzer under UHV power can help many power workers conduct various power tests more conveniently.The moisture analyzer based on Karl Fischer (KF) coulometric titration method utilizes the following advantages to accurately measure trace moisture content (microgram level):The KF reaction exhibits high selectivity towards water; If no side reactions occur, this allows for high-precision measurement of only water.Coulombic titration is an absolute measurement technique that determines the mass of a given substance by measuring the amount of electricity required to electrolyze the substance. It doesn't necessarily require a standard solution.A 1-mA electrolysis current (easily measurable current and duration) flowing for 1 second generates a charge of 1 mC, which is equivalent to only 93.4 ng of water. Therefore, this technology allows for high-sensitivity measurements.Due to these reasons, the KF coulometric titration method is widely used for quality control anal
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Gas Chromatography Analysis in Transformer Fault Analysis
2025-01-02The oil chromatography analyzer under UHV power can help many power workers conduct various power tests more conveniently.Once a transformer malfunctions, it will have a serious impact on production, causing major power outages and long cycles. Timely understanding of the internal operation of oil immersed transformers and identifying fault symptoms is of great significance for ensuring the safe, reliable, and high-quality operation of transformers. For oil immersed transformers, both the coil and core are immersed in transformer oil. It is impossible to determine the hidden dangers of transformers with naked eyes and direct measurement. A certain technical method must be adopted to understand the operating status of the transformer.Gas chromatography, also known as chromatography, is a physical separation technique. The separation principle is to distribute the components in the mixture between two phases, one is the stationary phase, called the stationary phase, and the other is the
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Karl Fischer reagent and its reaction
2024-12-31The trace moisture analyzer under UHV power can help many power workers conduct various power tests more conveniently.How would you determine the amount of water in a sample containing trace amounts of water? The method used is Karl Fischer (KF) moisture analysis. The Karl Fischer method uses Karl Fischer reagent to determine the moisture content of a sample, which is a popular method because it allows you to determine the moisture content of a drug in a very fast, accurate, and specific way, and requires a very small sample size for analysis.What is Karl Fischer reagent?The reagent consists of a solvent alcohol (ROH), a known concentration of iodine (I2), a base (RN), and sulfur dioxide (SO2).Reaction principleThe intrinsic reaction of iodine and sulfur dioxide in water systems is based on the Karl Fischer reagent reaction.12+SO2+2H20=>2HI+H2SOThe above reaction was adjusted by Fischer and used to determine the moisture content of substances in non-aqueous systems.When you titrate KF
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Five points to note in microcomputer relay AC test
2024-12-30The relay protection tester under UHV power can help many power workers conduct various power tests more conveniently.The issues that power workers need to pay attention to when using microprocessor relay protection testers for AC testing are summarized as follows:1. One of the general testing steps for relay protectors is to set the "switch positioning confirmation time". We need to pay attention to setting it larger here, such as around 20ms. If there is a significant error in the test return value, it may be due to the large shaking of the relay contacts. In this case, the test can continue in "manual" mode. To ensure reliable operation of relay protection, it is necessary to ensure that the output of the tester is greater than the starting value of the protection when detecting the relay action time.2. The conventional method for detecting multi-stage overcurrent protection is to test separately in a section and gradually increase the current until the protection is activated. Howe
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Comprehensive introduction of three types of test frequency ranges in series resonance
2024-12-30The series resonance under UHV power can help many power workers conduct various power tests more conveniently.It is important to select an appropriate testing frequency range based on relevant technical data from both domestic and international sources. There are some different perspectives and formulations in this regard. Based on current domestic and international terminology, we can summarize it into three categories: the first category covers a wide frequency range of 30-300Hz, 20-300Hz, and 1-300Hz; The second category is the power frequency range, 45-65Hz, 45-55Hz; The third category is close to the power frequency, 35-75Hz.1. Wide frequency rangeThe "Test Guidelines" released by the 21st and 9th working groups of the International Conference on Power Grids recommend a frequency range of 30-300Hz. But in reality, even lower frequencies have better equivalence. The draft standards IEC60840 and IEC62067 (2001 and 2000) stipulate that 20-300Hz can be used.Some foreign manufacturers
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Types of grounding devices and grounding reference resistance values
2024-12-27The grounding resistance tester under UHV power can help many power workers conduct various power tests more conveniently.Types of grounding devices and grounding reference resistance valuesThe electrical installation technical standards specify the following types of grounding installations and grounding resistance values * 1:Grounding installation grounding resistance valueClass A (formerly Class 1) 10 Ω or lessClass B (formerly Class 2) calculated value * 2Class C (old level 3) 10 Ω or lower * 3D-level (old level 3) 100 Ω or lower * 3*1 lists the values of a certain standard.Please note that these values vary by country/region.*2 The ohm value is equal to the ground fault current (ampere) of a wire in the high voltage side or extra high voltage side circuit of a transformer divided by 150 (or, if the voltage of the low voltage circuit exceeds 150 V due to the combination of the low voltage side circuit of the transformer and the high voltage side circuit of the [a] transformer or th
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