IEEE C37.90.2-1995 pdf download IEEE Standard for Withstand Capability of Relay Systems to Radiated Electromagnetic Interference from Transceivers
5. Test conditions
5.1 Selection and preparation of samples
5.1.1 Relay systems Static protective or control relays, when supplied as an integrated relay system with an enclosure, shall be tested in the enclosure. All components should be mounted and interconnected. Where system components are unavailable at the time of the test, dummy modules may be used, and these modules shall, insofar as pos- sible, duplicate the shielding to be realized from the actual components.
5.1.2 Individual relays Individual relays shall be tested separately without regard to their ultimate relationship to other circuit com- ponents after the relays are Þnally installed in a system. The responsibility for testing a complete system that is assembled by the user shall rest with the user.
5.1.3 Selection of test sample
This test is a design test and shall, therefore, be applied to a randomly selected relay or relay system of eachtype. The test shall be repeated for each modification to the physical arrangement or selection of componentscontained in the relay or svstem, unless documentation is available to indicate tests are not needed
5.2 External wiring
The equipment shall be tested in as close to installed conditions as possible. Wiring shall be consistent withthe manufacturer’s recommended procedures. lf the use of shielded cable is not specified by the manufacturer for normal installation, unshielded wiring shall be used for the test. At least I m of the external wiringshall be run vertically to simulate rack wiring. All external connection terminals of the relay shall be con-nected to external wiring. To reduce the amount of wiring required, more than one terminal may be connected to a wire provided that such grouping does not interfere with the normal operation of the relay.
5.3 Grounding
All equipment used in the tests, such as relays, relay panels, relay enclosures, and cable shields, shall beproperly grounded. Cable trays, conduit, or external cables shall also be grounded.
6.Test methods
6.1 General
The purpose of this clause is to establish a method of determining the susceptibility of static protective andcontrol relays to single-frequency sources of radio frequency interference. A method of developing electromagnetic fields in the vicinity of a protective relay is described. To generate fields that are useful for simulation of field conditions may require significant antenna drive power to achieve high field-strength levels.
6.2 In-Service conditions It is the intent of this test to duplicate as nearly as possible in-service conditions with the relay in its normal non-transitional state. Where appropriate, the relay shall be energized with rated voltage and current equal to 75% of the nominal current transformer (CT) rating. The relay settings should be chosen such that the relay is as close as possible to its transitional state, but not closer than the recommended margins for its applica- tion. Input voltage to the power supply circuit should be within the speciÞed limits. The relay shall be tested in its case with the cover(s) and access doors, if any, in the closed position.
IEEE C37.90.2-1995 pdf download
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