What are the waveforms generated by the impulse voltage generator
The national standard"High Voltage Testing Technology Part 1 General Test Requirements"divides the waveform of lightning impulse voltage into standard lightning impulse(full wave)and standard lightning impulse cutoff special lightning impulse.
A full wave is a non periodic pulse voltage wave with a certain polarity,in which the voltage in the wavefront part rises rapidly,reaches its peak,and then slowly drops to zero.Chopped wave refers to the waveform of lightning impulse voltage that is truncated by the external gap after a certain time delay(a few microseconds).According to the length of the truncation time delay,chopping is divided into wavefront truncation and wavetail truncation.According to the national standard,the standard lightning impulse voltage full wave refers to a wavefront time T1 of 1.2μs.The apparent time at half peak T2 is 50μThe lightning shock full wave of s.
In actual impulse voltage generator waveforms,the starting part is usually not distinguishable,and the waveform near the peak is relatively smooth.In the standard,values such as 0.3,0.5,and 0.9 of the peak voltage Um are used to determine the actual impulse waveform.Standard lightning cutoff refers to the standard lightning shock wave passing through 2-6μThe waveform truncated by the external gap can be characterized by parameters such as the truncation time Te,truncation time Tj,truncation peak Ue,truncation voltage Uj,and voltage zero crossing coefficient U2/Ue.
Generally,it is determined by the amplitude of the loading voltage,the delay time of the generator circuit,the resistivity of the tested material,and even the humidity of the air.The simulated surge voltage wave is one or a series of high voltage short pulses,and the technical specifications generated by conventional instruments are:wavefront time 1.2μS±30%,half peak time after wave 50μS±20%.The higher the voltage value of its voltage wave,the steeper the dV/dt characteristic.Due to the release effect of high-voltage power semiconductor switches,the conduction time and cutoff time of semiconductor devices determine the slope of the front and back edges of the shock wave.The combined impedance formed by parasitic inductance and distributed capacitance,loop resistance and parasitic resistance in the circuit also participates in this process,especially in the generation of parasitic oscillations(various derived harmonics other than the frequency of the pulse itself),with the voltage energy of the 3rd and 5th harmonics being the highest.If you want to obtain as pure a pulse waveform as possible,your shock wave experiment should minimize the length of external wires and use cables with thicker wire diameters as much as possible.It is best to separate two wires and not use three core or two core cables to transmit signals.
A full wave is a non periodic pulse voltage wave with a certain polarity,in which the voltage in the wavefront part rises rapidly,reaches its peak,and then slowly drops to zero.Chopped wave refers to the waveform of lightning impulse voltage that is truncated by the external gap after a certain time delay(a few microseconds).According to the length of the truncation time delay,chopping is divided into wavefront truncation and wavetail truncation.According to the national standard,the standard lightning impulse voltage full wave refers to a wavefront time T1 of 1.2μs.The apparent time at half peak T2 is 50μThe lightning shock full wave of s.
In actual impulse voltage generator waveforms,the starting part is usually not distinguishable,and the waveform near the peak is relatively smooth.In the standard,values such as 0.3,0.5,and 0.9 of the peak voltage Um are used to determine the actual impulse waveform.Standard lightning cutoff refers to the standard lightning shock wave passing through 2-6μThe waveform truncated by the external gap can be characterized by parameters such as the truncation time Te,truncation time Tj,truncation peak Ue,truncation voltage Uj,and voltage zero crossing coefficient U2/Ue.
Generally,it is determined by the amplitude of the loading voltage,the delay time of the generator circuit,the resistivity of the tested material,and even the humidity of the air.The simulated surge voltage wave is one or a series of high voltage short pulses,and the technical specifications generated by conventional instruments are:wavefront time 1.2μS±30%,half peak time after wave 50μS±20%.The higher the voltage value of its voltage wave,the steeper the dV/dt characteristic.Due to the release effect of high-voltage power semiconductor switches,the conduction time and cutoff time of semiconductor devices determine the slope of the front and back edges of the shock wave.The combined impedance formed by parasitic inductance and distributed capacitance,loop resistance and parasitic resistance in the circuit also participates in this process,especially in the generation of parasitic oscillations(various derived harmonics other than the frequency of the pulse itself),with the voltage energy of the 3rd and 5th harmonics being the highest.If you want to obtain as pure a pulse waveform as possible,your shock wave experiment should minimize the length of external wires and use cables with thicker wire diameters as much as possible.It is best to separate two wires and not use three core or two core cables to transmit signals.
