IEEE C37.109-1988 pdf free.IEEE Guide for the Protection of ShuntReactors.
IEEE C37.109 shunt reactors generally are limited to voltages through 34.5 kV and are usually applied on the tertiary of atransformer which is connected to the transmission line being compensated.The reactors are of the air-core (coreless)type, open to the atmosphere, suitable for indoor or outdoor application.Natural convection of ambient air is generallyused for cooling the unit by arranging the windings so as to permit free circulation of air between layers and turns.
The layers and turns are supported mechanically by bracing members or supports made from materials such asceramics, glass polyester, and concrete.The reactors are constructed as single-phase units and are mounted on baseinsulators or insulating pedestals which provide the insulation to ground and the support for the reactor.
Because the dry-type shunt reactor has no housing or shielding, a high-intensity external magnetic field is producedwhen the reactor is energized.Care is thus required in specifying the clearances and arrangement of the reactor units,mounting pad, station structure, and any metal enclosure around the reactor or in the proximity of the reactor.A closedmetallic loop in the vicinity of the reactor produces losses, heating, and arcing at poor joints; therefore, it is importantto avoid these loops and to maintain sufficient separation distances. Shielding may be required when it is not possibleto arrange dry-type units in an equilateral-triangle configuration isolated from external magnetic influences. Thisshielding is required to limit the impedance deviation between phases. Deviation from impedance values for reactorswill result in a deviation from the actual MVAR rating.
For the same range of applications, the primary advantages of dry-type air-core reactors, compared to oil-immersedtypes， are lower initial and operating costs，lower weight, lower losses, and the absence of insulating oil and itsmaintenance. The main disadvantages of dry-type reactors are limitations on voltage and kVA ratings and the high-intensity external magnetic field mentioned above. Because these reactors do not have an iron core,there is nomagnetizing inrush current when the reactor is energized.
The two design configurations of oil-immersed shunt reactors are coreless type and gapped iron-core type. Bothdesigns are subject to low-frequency longtime constant currents during de-energizing, determined by the parallelcombination of the reactor’s inductance and line capacitance.However, the gapped iron-core design is subject to moresevere energizing inrush than the coreless type.Most coreless shunt reactor designs have a magnetic circuit (magnetic shield) which surrounds the coil to contain theflux within the reactor tank.The steel core-leg that normally provides a magnetic flux path through the coil of a powertransformer is replaced (when constructing coreless reactors) by insulating support structures. This type ofconstruction results in an inductor that is linear with respect to voltage.IEEE C37.109 pdf download.