IEEE - The Institute of Electrical and Electronics Engineers@ Inc.
适用范围
The following general methods of test are either discussed or referred to in this publication: (1) Low-frequency@ low- and high-voltage loss characteristic measurements. The measurement at power frequencies of power factor@ dissipation factor or watts loss and capacitance or charging current; or equivalent quantities which define the electric circuit constants of the test specimen in the voltage range of approximately 80 volts to 50 kilovolts or higher. (2) Alternating-voltage corona measurements. The determination of the presence of corona discharge in the test specimen@ usually related to the magnitude of the applied power-frequency voltage. The presence and the severity of corona are usually determined by indirect means; for example@ by the resultant increase in dielectric loss or by the measurement of high-frequency components in the current. (3) Alternating-voltage distribution measurements. The measurement of the potential of the terminal electrodes and of one or more defined points between the high- and low-voltage electrodes of the test specimen@ usually with applied voltage of power frequency. (4) Direct low- and high-voltage insulation resistance measurements. The measurement of the current-voltage relationship of the test specimen with the application@ for a specified time@ of direct voltage in the range of approximately 500 volts to 75 kilovolts or higher. (5) Direct low- and high-voltage absorption or resistance-time measurements. The measurement of the insulation resistance@ or total current@ as a function of time of application of a fixed voltage. Alternatively a measurement of absorption current as a function of time on discharge may be made. (6) 60-cps breakdown tests (liquid samples only). The determination of the dielectric strength of samples of insulating fluid from or for use in power apparatus. (7) Surge-comparison tests. The evaluation of the insulation between turns of coil structures by a comparative impulse test. (8) 60-cps withstand tests. The demonstration of the ability of the insulation to withstand a specified 60-cps voltage for a specified time. (9) Direct-voltage withstand tests. The demonstration of the ability of the insulation to withstand a specified direct voltage for a specified time All electric power apparatus in all voltage and power ratings is considered in this Guide@ as for example: rotating machinery; transformers@ regulators and reactors; cables; circuit breakers; lightning arresters; capacitors; insulators; hot-line tools; insulating liquids. PURPOSE The primary purpose of this Guide is to present and discuss the applicability and limitations of the various measurement methods now in use@ or available@ for testing the electrical insulation of power apparatus in the field. Although factory tests assure the initial quality and condition@ electric apparatus is subject@ during shipment and installation and in operation@ to influences which may affect the insulation and shorten its useful life. As a result the practice has grown of testing the