IEEE 1313-1993 pdf free.IEEE Standard for Power Systems-Insulation Coordination.
IEEE 1313 Switching and lightning impulse tests may be either withstand tests，with a suitable number of voltageimpulses at the specified BIL or BSL applied to the insulation, or critical flashover tests in which the abilityof the insulation to withstand impulses at the rated BIL and BSL are inferred from the measurement of thecritical flashover voltage.The critical flashover tests are only applicable to selfrestoring insulation.
Short-duration lowfrequency tests are withstand tests and values are not presently specified in this standard.Preferred BILs and BSLs are included in this standard.Guidance for long-duration low-frequency tests ispresented in 4.4.
Selection of dielectric tests for the medium- and high-voltage classes The performance under lightning overvoltages shall be established by lightning impulse tests. The perfor-mance under system frequency operating voltages shall be established by short-duration low-frequencytests. The low-frequency tests also provide a measure of performance for temporary overvoltages. Powertransformers，however，require special consideration since higher frequency temporary overvoltages mayexcite natural frequencies of oscillation within the windings to produce greater than turns ratio voltagebetween parts. Also, the short-duration low-frequency tests generally provide a measure of performance forswitching overvoltages.
Selection of dielectric tests for the extra-high and ultra-high voltage class
The performance under lightning overvoltages shall be established by lightning impulse tests.
The performance under switching overvoltages shall be established by switching impulse tests.
The performance under system frequency operating voltages shall be established by short-duration and/orlong-duration low-frequency tests. The low-frequency tests also provide a measure of performance for tem-porary overvoltages.Power transformers，however,require special consideration since higher frequencytemporary overvoltages may excite natural frequencies of oscillation within the windings to provide greaterthan turns ratio voltage between parts.
NOTE–In the past, the values of the traditional short-duration low-frequency withstand test voltages in this range havebeen of sufficient magnitude to account for some effects of switching overvoltages and temporary overvoltages.With theintroduction of switching impulse tests for equipment for systems with maximum system voltages in the extra-high andultra-high voltage class and the availability of tests specific to corona or partial discharges, the values of the low-fre-quency test voltages may be reduced and defined to be more representative of normal operating voltages and temporaryovervoltages only.The low-frequency tests presently prescribed by the standard developers will apply.IEEE 1313 pdf download.