Transmission and distribution of electrical energy involves the application of high-voltage appar... more Transmission and distribution of electrical energy involves the application of high-voltage apparatus like power transformers, switchgear, overvoltage arrestors, insulators, power cables, transformers, etc., which are exposed to high transient voltages and currents due to internal and external overvoltages. Before commissioning , they are therefore tested for reliability with standard impulse voltages or impulse currents. Depending on the apparatus and the type of their proposed application, one differentiates between various types of waveforms of test voltages and test currents. These waveforms are defined by several parameters with tolerances during generation and uncertainties during measurement. For data evaluation of these waveforms, measured, as a rule, with digital recorders, partially standardised evaluation procedures are applied. Thereby, experimental data obtained from extensive investigations with respect to the evaluation of peak oscillations, which are superimposed on a lightning impulse voltage, are taken into account as a function of the oscillation frequency. In the second part of this chapter, various circuits for the generation of high impulse voltages and impulse currents will be discussed in principle. 2.1 Parameters of High-Voltage Impulses For testing high-voltage apparatus, several waveshapes of the high-voltage test impulses are standardised. In addition to switching and lightning impulse voltages with aperiodic waveform, oscillating switching and lightning impulse voltages, which are generated by transportable generators for on-site tests, are also stand-ardised. Lightning impulse voltages are again subdivided into full and chopped lightning impulse voltages, with the chopping occurring at widely variable times. Impulse voltages with an approximately linear rise are designated wedge-shaped and those with a very steep front as steep-front impulse voltages. An analytic representation of impulse voltages is given in Sect. 3.1 and calculation of the spectrum in Sect. 3.2. K. Schon, High Impulse Voltage and Current Measurement Techniques,
Transmission and distribution of electrical energy involves the application of high-voltage appar... more Transmission and distribution of electrical energy involves the application of high-voltage apparatus like power transformers, switchgear, overvoltage arrestors, insulators, power cables, transformers, etc., which are exposed to high transient voltages and currents due to internal and external overvoltages. Before commissioning , they are therefore tested for reliability with standard impulse voltages or impulse currents. Depending on the apparatus and the type of their proposed application, one differentiates between various types of waveforms of test voltages and test currents. These waveforms are defined by several parameters with tolerances during generation and uncertainties during measurement. For data evaluation of these waveforms, measured, as a rule, with digital recorders, partially standardised evaluation procedures are applied. Thereby, experimental data obtained from extensive investigations with respect to the evaluation of peak oscillations, which are superimposed on a lightning impulse voltage, are taken into account as a function of the oscillation frequency. In the second part of this chapter, various circuits for the generation of high impulse voltages and impulse currents will be discussed in principle. 2.1 Parameters of High-Voltage Impulses For testing high-voltage apparatus, several waveshapes of the high-voltage test impulses are standardised. In addition to switching and lightning impulse voltages with aperiodic waveform, oscillating switching and lightning impulse voltages, which are generated by transportable generators for on-site tests, are also stand-ardised. Lightning impulse voltages are again subdivided into full and chopped lightning impulse voltages, with the chopping occurring at widely variable times. Impulse voltages with an approximately linear rise are designated wedge-shaped and those with a very steep front as steep-front impulse voltages. An analytic representation of impulse voltages is given in Sect. 3.1 and calculation of the spectrum in Sect. 3.2. K. Schon, High Impulse Voltage and Current Measurement Techniques,
Uploads