1 Scope
This Standard specifies some technical details of the test connection, test equipment, test method and cautions etc. involved in AC voltage withstanding test on high-voltage electrical equipment.
This Standard is applicable to the AC voltage withstanding test on high-voltage electrical equipment in the condition of power plant, substation field, repair workshop and laboratory etc.
2 Normative References
The following standards contain provisions which, through reference in this text, constitute provisions of this standard. For dated reference, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, the parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards. For undated references, the latest edition of the normative document referred to applies.
GB 1094.3—2003 Power transformer Part 3: Insulation level, Insulation Test and External Insulation Air Gap (mod IEC 60076-3:2000)
GB/T 1692.7.2—1997 High Voltage Test Techniques Part 2: Measurement System
DL/T 596—1996 Preventive Test Code for Electric Power Equipment
DL/T 1015 Guide for Application of Voltage Measuring System in DC and AC High Voltage Tests on Site
3 Terms
3.1 Peak value
It refers to the maximum value of AC voltage with no view of the minute high frequency oscillation arising from nondestructive discharge.
3.2 Root-mean-square value (rms)
It refers to the square root of the mean value of the squared voltage in a complete cycle.
3.3 Test voltage
It refers to the value of its peak value divided by
4 The Requirements to AC Test Voltage
4.1 Voltage Frequency and Waveform
Test voltage usually shall be AC voltage of 45 to 65Hz and is generally called power-frequency test voltage. According to the requirements of relevant equipment standards, some special tests may require the frequency far below or above that scope. For example, AC withstand voltage of 0.1 Hz or AC withstand voltage between 10 Hz and 300 Hz can be applied in cross-linked PE cable and AC withstand voltage between 10 Hz and 300 Hz can be applied in GIS.
The result of high voltage test will be considered free from the effects of the waveform distortion if the waveform of test voltage is approximately sine wave of two half identical waves and the ratio of the peak value to the root-mean-square shall be within
Bigger distortion is permitted for some test circuits. We should pay attention that the tested object, especially the one with the characteristic of nonlinear impedance, may trigger apparent distortion to the waveform.
DL/T 474.4-2006 The following standards are cited：
