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定价： 222元 / 折扣价： 189 元

The scope of this guide is to describe field test methods that assure current transformers (CTs) are connected properly, are of marked ratio and polarity, and are in a condition to perform as designed both initially and after being in service for a period of time. Annex A describes wiring integrity checks, the use of test jacks, current-shorting switches, and relay test equipment. Annex B illustrates excitation voltage measurement differences between rms responding voltmeters(commonly used… read more under field conditions) and average responding voltmeters (commonly used in laboratory tests) and also discusses the effect of the source impedance. Annex C describes the characteristics, and other pertinent information, of optical current sensor systems used with protective relaying. It provides an overview of the components used in an optical sensor system, discusses the differences from conventional CTs, and provides testing information. Annex D is the bibliography for this guide. read less

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This specification covers material, design, fabrication, and testing requirements for vertical, cylindrical,  aboveground, closed-top, welded steel storage tanks in various standard sizes and capacities for internal pressures of approximately atmospheric, not to exceed those listed in Column 2 of Table 1a or Table 1b.

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This document is a guide for field testing and commissioning of static var compensators (SVCs). As such, the document establishes general guidelines and criteria for field testing to verify the specified performance of SVC systems. Many clauses will be useful for compensator systems using gate turn-off (GTO) thyristor technology (static compensator [STATCOM]) or other semiconductor devices such as insulated gate commutated transistor (IGCT). This guide does not a) Cover factory and simulator… read more tests of SVC system components (but it assumes that such tests have been performed beforehand). b) Discuss the division of responsibility between user and supplier, since this division is usually defined in the contract between buyer and supplier. Most often, however, the practice is for the equipment, subsystem, and commissioning tests to be performed by the supplier, and the acceptance tests to be performed by the buyer or user. read less

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The following general methods of test are either discussed or referred to in this publication:Low-frequency, low- and high-voltage losscharacteristic 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.… read more 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. read less

定价： 65元 / 折扣价： 56 元