Lightning Impulse Generator

Lightning impulse generator is is a test equipment to simulate the high voltage of pulse. In real life, pulse high voltage is often encountered. For example, in nature, lightning strikes, the lightning will appear very high pulse current and voltage, the surrounding will also sense a very high pulse voltage, and in the power system, the switching equipment in the joint operation will also lead to transient pulse voltage. These transient pulse voltage amplitudes are often in the tens of thousands of kV or more, which will cause equipment damage and endanger personal safety, so it is necessary to conduct test studies on shock voltage. On the other hand, it is very meaningful to simulate the natural lightning phenomenon to carry out the study of discharge mechanism.

400kV/20kJ Lightning Impulse Generator as one example:

1.Output vol: 400KV

2. Voltage class rating: 100KV

3. Energy: 20KJ

4. Total Impulse capacitance: 0.25µF

5. Single stage pulse capacitor: 1µF/100KV (2*2.67μF/50KV each, 4 pieces)

6. Number of stage: 4 (5KJ each stage)

7. Power Supply: 220V±10% , or 380V±10% 50/60Hz

8. Impulse voltage waveform: it can give 4 lightning impulse waveform when load capacitance is below 300 ~ 2000pF:

1) Standard lightning impulse voltage full wave: 1.2/50 μ S;

2) Standard operating voltage impulse waveform: 250ms/2500ms;

3)test special operating shock wave: 20/200us;

4) test special shock wave oscillation: peak deviation ± 3%; Single peak value of oscillation and overshoot is less than the impulse waveform peak value of 5%. Lightning impulse voltage waveform parameters and its deviation shall comply with the relevant international IEC 61083-1-2001 and IEC60076-4-2002 standards.

9.Voltage utilization coefficient: when load capacity is below 1000pF, standard lightning wave utilization voltage coefficient ≥85%; when load capacitance is below 2000PF, standard lightning wave utilization voltage coefficient ≥ 80%.

10. Synchronous scope: voltage level is in the rated range of 20% ~ 99%, positive and negative polarity synchronous range is not less than 25%;

11. Synchronous discharge uncontrol ratio: <5%

12. Minimum output voltage: ≥ ± 20% rated voltage

13. Charging voltage instability: < ± 1%

14.Duration: over 2/3 rated voltage: it can continue working every 120 seconds charge/discharge;

below 2/3 rated voltage: it continues working every 60 seconds charge/discharge.

Application of Lightning Impulse Generator in High Voltage Test

1. overvoltage withstａnd performance test of edge material

Through artificial simulation of lightning current waveform and peak value to test the ability of electrical equipment insulation to withstａnd lightning impulse voltage. According to the actual measurement results of lightning discharge, the wave waveform is considered to be a unipolar double exponential curve with a wave head length of several microseconds and a wave tail length of tens of microseconds. Most thunders are of negative polarity. National standards around the world have calibrated the standard shock wave as: apparent wave head time T1=1.2μs, also known as wave head time; apparent half-wave peak time T2=50μs, also known as wave tail time.

The allowable deviation between the voltage peak value and waveform generated by the actual test device and the standard wave is: peak value, ±3%; wave head time, ±30%; half-wave peak time, ±20%; usually the standard lightning waveform is expressed as 1.2 /50μs.

The test voltage is generated by an Lightning Impulse Generator. The multiple capacitors of the instrument are switched from parallel to series through many ignition ball gaps, that is, when the ignition ball gap is controlled to discharge, multiple capacitors are connected in series. The speed of the voltage rise on the device under test and the speed of the voltage drop after the peak value can be adjusted by the resistance value in the capacitor circuit. The resistance that affects the wave head is called the wave head resistance, and the resistance that affects the wave tail is called the wave tail resistance. During the test, by changing the resistance values of the wave head resistance and wave tail resistance, the predetermined wave head time and half-wave peak time of the standard impulse voltage wave are obtained. By changing the polarity and amplitude of the output voltage of the rectifier power supply, the required polarity and peak value of the impulse voltage wave can be obtained. Thus, impulse voltage generators ranging from hundreds of thousands of volts to millions of volts, or even ten million volts, can be realized. The maximum voltage of the impulse voltage generator designed and installed in China is 6000kV. The lightning impulse voltage test includes 4 items.

①Shock withstａnd voltage test: It is usually used for non-self-recovery insulation, such as insulation of transformers and reactors. The purpose is to test whether these equipment can withstａnd the voltage specified by the insulation class.

②50% impact flashover test: usually self-healing insulation such as insulators, air gaps, etc. are used as the object, and the purpose is to determine the voltage value U with a flashover probability of 50%. With the standard deviation between this voltage value and the flashover value, other flashover probabilities can also be determined, such as a 5% flashover voltage value, and U is generally regarded as the withstａnd voltage.

③ Breakdown test: The purpose is to determine the actual strength of the insulation. Mainly carried out in electrical equipment manufacturing plants.

④ Voltage-time curve test (Volt-second curve test): The voltage-time curve represents the relationship between the application of voltage to insulation failure (or porcelain insulation flashover) and time. The volt-second curve (V-t curve) can provide a basis for considering the insulation coordination between protected equipment such as transformers and protective equipment such as lightning arresters.

1.First-use responsibility system

After the product is delivered, the technician can guide the operation at site if the client requires, and be responsible for the first use of each part

2.One year warranty

All products warranty is 1year, life-time maintenance .

During the warranty period, if any defects or damaged because of product’s quality, maintenance or replacement can be provided with free charge in order to let our client’s satisfied !

3.Troubleshooting

If the troubleshooting is not difficult, and client can handle with it by themselves, we can offer the call-on line guide within 1 hour!

If the troubleshooting is difficult to handle with for client, we can promise that the best solution can be provided within 24 hours!

Wuhan Goldhome Hipot Electrical Co.,ltd(short for Goldhome Hipot) was established in 2008, its predecessor was state-owned third industry enterprises, developed into manufacture of high voltage test equipment after system-reform and recombination .

Goldhome Hipot has 20 year’s rich experience in R&D and manufacture . At beginning , only produce single product , now product line covers AC/DC hipot tester, transformer testing device, CT/PT analyzer , Circuit breaker tester, insulation resistance tester set , earth continuity tester, protection relay tester as well as transformer oil testing equipment . And Goldome hipot now developed into high-tech enterprise, integrating manufacturing, R&D, marketing, Consultation, installation and commissioning

Goldome Hipot make production strictly in accordance with international and national standards as well as power industry regulations . Products have passed test from National and provincial authoritative institution.

As high-tech enterprise, supported by natural advantages from various research universities in Wuhan city, Goldhome Hipot work closely with professors from State Grid Power Science Research Institute, Electrical Engineering Colleges of Wuhan University (formerly Wuhan University of Water Resources and Electric Power) and other scientific research institutions, constantly improve technology and update products . Now Goldome Hipot has more than 20 patented technologies, and many software Copyrights!

Goldhome Hipot always stick to conception of "credit is the basis, quality is the first" , provide high quality products and perfect after-sales service for customers at home and abroad.